Re: [PATCH v2 2/2] media:imx274 V4l2 driver for Sony imx274 CMOS sensor

From: Sakari Ailus
Date: Tue Aug 29 2017 - 05:35:13 EST

Hi SÃren,

Thanks for the patch. Some comments below.

On Mon, Aug 28, 2017 at 06:40:26PM -0700, Soren Brinkmann wrote:
> From: Leon Luo <leonl@xxxxxxxxxxxxxxxxxx>
>
> The imx274 is a Sony CMOS image sensor that has 1/2.5 image size.
> It supports up to 3840x2160 (4K) 60fps, 1080p 120fps. The interface
> is 4-lane MIPI running at 1.44Gbps each.

"MIPI CSI-2" I believe.

>
> This driver has been tested on Xilinx ZCU102 platform with a Leopard
> LI-IMX274MIPI-FMC camera board.
>
> Support for the following features:
> -Resolutions: 3840x2160, 1920x1080, 1280x720
> -Frame rate: 3840x2160 : 5 â 60fps
> 1920x1080 : 5 â 120fps
> 1280x720 : 5 â 120fps
> -Exposure time: 16 â (frame interval) micro-seconds
> -Gain: 1x - 180x
> -VFLIP: enable/disable
> -Test pattern: 12 test patterns
>
> Signed-off-by: Leon Luo <leonl@xxxxxxxxxxxxxxxxxx>
> Tested-by: SÃren Brinkmann <soren.brinkmann@xxxxxxxxxx>
> ---
> v2:
> - Fix Kconfig to not remove existing options
> ---
> drivers/media/i2c/Kconfig | 7 +
> drivers/media/i2c/Makefile | 1 +
> drivers/media/i2c/imx274.c | 1842 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1850 insertions(+)
> create mode 100644 drivers/media/i2c/imx274.c
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 94153895fcd4..ad2e70a02363 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -547,6 +547,13 @@ config VIDEO_APTINA_PLL
> config VIDEO_SMIAPP_PLL
> tristate
>
> +config VIDEO_IMX274
> + tristate "Sony IMX274 sensor support"
> + depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> + ---help---
> + This is a V4L2 sensor-level driver for the Sony IMX274
> + CMOS image sensor.
> +
> config VIDEO_OV2640
> tristate "OmniVision OV2640 sensor support"
> depends on VIDEO_V4L2 && I2C
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index c843c181dfb9..f8d57e453936 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -92,5 +92,6 @@ obj-$(CONFIG_VIDEO_IR_I2C) += ir-kbd-i2c.o
> obj-$(CONFIG_VIDEO_ML86V7667) += ml86v7667.o
> obj-$(CONFIG_VIDEO_OV2659) += ov2659.o
> obj-$(CONFIG_VIDEO_TC358743) += tc358743.o
> +obj-$(CONFIG_VIDEO_IMX274) += imx274.o
>
> obj-$(CONFIG_SDR_MAX2175) += max2175.o
> diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
> new file mode 100644
> index 000000000000..fcbb5ad2763c
> --- /dev/null
> +++ b/drivers/media/i2c/imx274.c
> @@ -0,0 +1,1842 @@
> +/*
> + * imx274.c - IMX274 CMOS Image Sensor driver
> + *
> + * Copyright (C) 2017, Leopard Imaging, Inc.
> + *
> + * Leon Luo <leonl@xxxxxxxxxxxxxxxxxx>
> + * Edwin Zou <edwinz@xxxxxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/media.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
> +#include <linux/ratelimit.h>
> +#include <linux/regmap.h>
> +#include <linux/seq_file.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/uaccess.h>
> +#include <linux/videodev2.h>
> +#include <media/media-entity.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-image-sizes.h>
> +#include <media/v4l2-mediabus.h>
> +#include <media/v4l2-subdev.h>

You include a lot of headers directly. Do you need them all? Such as
linux/debugfs.h or linux/uaccess.h.

> +
> +static int debug;
> +module_param(debug, int, 0644);
> +MODULE_PARM_DESC(debug, "Debug level (0-2)");

Please rely on dynamic debug instead, see
Documentation/admin-guide/dynamic-debug-howto.rst .

> +
> +/*
> + * See "SHR, SVR Setting" in datasheet
> + */
> +#define IMX274_DEFAULT_FRAME_LENGTH (4550)
> +#define IMX274_MAX_FRAME_LENGTH (0x000fffff)
> +
> +/*
> + * See "Frame Rate Adjustment" in datasheet
> + */
> +#define IMX274_PIXCLK_CONST1 (72000000)
> +#define IMX274_PIXCLK_CONST2 (1000000)
> +
> +/*
> + * The input gain is shifted by IMX274_GAIN_SHIFT to get
> + * decimal number. The real gain is
> + * (float)input_gain_value / (1 << IMX274_GAIN_SHIFT)
> + */
> +#define IMX274_GAIN_SHIFT (8)
> +#define IMX274_GAIN_SHIFT_MASK ((1 << IMX274_GAIN_SHIFT) - 1)
> +
> +/*
> + * See "Analog Gain" and "Digital Gain" in datasheet
> + * min gain is 1X
> + * max gain is calculated based on IMX274_GAIN_REG_MAX
> + */
> +#define IMX274_GAIN_REG_MAX (1957)
> +#define IMX274_MIN_GAIN (0x01 << IMX274_GAIN_SHIFT)
> +#define IMX274_MAX_ANALOG_GAIN ((2048 << IMX274_GAIN_SHIFT)\
> + / (2048 - IMX274_GAIN_REG_MAX))
> +#define IMX274_MAX_DIGITAL_GAIN (8)
> +#define IMX274_DEF_GAIN (20 << IMX274_GAIN_SHIFT)
> +#define IMX274_GAIN_CONST (2048) /* for gain formula */
> +
> +/*
> + * 1 line time in us = (HMAX / 72), minimal is 4 lines
> + */
> +#define IMX274_MIN_EXPOSURE_TIME (4 * 260 / 72)
> +
> +#define IMX274_DEFAULT_MODE IMX274_MODE_3840X2160
> +#define IMX274_MAX_WIDTH (3840)
> +#define IMX274_MAX_HEIGHT (2160)
> +#define IMX274_MAX_FRAME_RATE (120)
> +#define IMX274_MIN_FRAME_RATE (5)
> +#define IMX274_DEF_FRAME_RATE (60)
> +
> +/*
> + * register SHR is limited to (SVR value + 1) x VMAX value - 4
> + */
> +#define IMX274_SHR_LIMIT_CONST (4)
> +
> +/*
> + * Constants for sensor reset delay
> + */
> +#define IMX274_RESET_DELAY1 (2000)
> +#define IMX274_RESET_DELAY2 (2200)
> +
> +/*
> + * shift and mask constants
> + */
> +#define IMX274_SHIFT_8_BITS (8)
> +#define IMX274_SHIFT_16_BITS (16)
> +#define IMX274_MASK_LSB_2_BITS (0x03)
> +#define IMX274_MASK_LSB_3_BITS (0x07)
> +#define IMX274_MASK_LSB_4_BITS (0x0f)
> +#define IMX274_MASK_LSB_8_BITS (0x00ff)
> +
> +#define DRIVER_NAME "IMX274"
> +
> +/*
> + * IMX274 register definitions
> + */
> +#define IMX274_FRAME_LENGTH_ADDR_1 0x30FA /* VMAX, MSB */
> +#define IMX274_FRAME_LENGTH_ADDR_2 0x30F9 /* VMAX */
> +#define IMX274_FRAME_LENGTH_ADDR_3 0x30F8 /* VMAX, LSB */
> +#define IMX274_SVR_REG_MSB 0x300F /* SVR */
> +#define IMX274_SVR_REG_LSB 0x300E /* SVR */
> +#define IMX274_HMAX_REG_MSB 0x30F7 /* HMAX */
> +#define IMX274_HMAX_REG_LSB 0x30F6 /* HMAX */
> +#define IMX274_COARSE_TIME_ADDR_MSB 0x300D /* SHR */
> +#define IMX274_COARSE_TIME_ADDR_LSB 0x300C /* SHR */
> +#define IMX274_ANALOG_GAIN_ADDR_LSB 0x300A /* ANALOG GAIN LSB */
> +#define IMX274_ANALOG_GAIN_ADDR_MSB 0x300B /* ANALOG GAIN MSB */
> +#define IMX274_DIGITAL_GAIN_REG 0x3012 /* Digital Gain */
> +#define IMX274_VFLIP_REG 0x301A /* VERTICAL FLIP */
> +#define IMX274_STANDBY_REG 0x3000 /* STANDBY */
> +
> +#define IMX274_TABLE_WAIT_MS 0
> +#define IMX274_TABLE_END 1
> +
> +/*
> + * imx274 I2C operation related structure
> + */
> +struct reg_8 {
> + u16 addr;
> + u8 val;
> +};
> +
> +#define imx274_reg struct reg_8

Please don't. Use the struct definition instead.

> +
> +static struct regmap_config imx274_regmap_config = {

const?

> + .reg_bits = 16,
> + .val_bits = 8,
> + .cache_type = REGCACHE_RBTREE,
> +};
> +
> +/*
> + * imx274 format related structure
> + */
> +struct imx274_frmfmt {
> + u32 mbus_code;
> + enum v4l2_colorspace colorspace;
> + struct v4l2_frmsize_discrete size;
> + int mode;

Please use e.g. unsigned int consistently. Elsewhere you have e.g. int /
u32.

> +};
> +
> +/*
> + * imx274 test pattern related structure
> + */
> +enum {
> + TEST_PATTERN_DISABLED = 0,
> + TEST_PATTERN_ALL_000H,
> + TEST_PATTERN_ALL_FFFH,
> + TEST_PATTERN_ALL_555H,
> + TEST_PATTERN_ALL_AAAH,
> + TEST_PATTERN_VSP_5AH, /* VERTICAL STRIPE PATTERN 555H/AAAH */
> + TEST_PATTERN_VSP_A5H, /* VERTICAL STRIPE PATTERN AAAH/555H */
> + TEST_PATTERN_VSP_05H, /* VERTICAL STRIPE PATTERN 000H/555H */
> + TEST_PATTERN_VSP_50H, /* VERTICAL STRIPE PATTERN 555H/000H */
> + TEST_PATTERN_VSP_0FH, /* VERTICAL STRIPE PATTERN 000H/FFFH */
> + TEST_PATTERN_VSP_F0H, /* VERTICAL STRIPE PATTERN FFFH/000H */
> + TEST_PATTERN_H_COLOR_BARS,
> + TEST_PATTERN_V_COLOR_BARS,
> +};
> +
> +static const char * const tp_qmenu[] = {
> + "Disabled",
> + "All 000h Pattern",
> + "All FFFh Pattern",
> + "All 555h Pattern",
> + "All AAAh Pattern",
> + "Vertical Stripe (555h / AAAh)",
> + "Vertical Stripe (AAAh / 555h)",
> + "Vertical Stripe (000h / 555h)",
> + "Vertical Stripe (555h / 000h)",
> + "Vertical Stripe (000h / FFFh)",
> + "Vertical Stripe (FFFh / 000h)",
> + "Horizontal Color Bars",
> + "Vertical Color Bars",
> +};
> +
> +/*
> + * All-pixel scan mode (10-bit)
> + * imx274 mode1(refer to datasheet) register configuration with
> + * 3840x2160 resolution, raw10 data and mipi four lane output
> + */
> +static const imx274_reg imx274_mode1_3840x2160_raw10[] = {
> + {0x3004, 0x01},
> + {0x3005, 0x01},
> + {0x3006, 0x00},
> + {0x3007, 0x02},
> +
> + {0x3018, 0xA2}, /* output XVS, HVS */
> +
> + {0x306B, 0x05},
> + {0x30E2, 0x01},
> + {0x30F6, 0x07}, /* HMAX, 263 */
> + {0x30F7, 0x01}, /* HMAX */
> +
> + {0x30dd, 0x01}, /* crop to 2160 */
> + {0x30de, 0x06},
> + {0x30df, 0x00},
> + {0x30e0, 0x12},
> + {0x30e1, 0x00},
> + {0x3037, 0x01}, /* to crop to 3840 */
> + {0x3038, 0x0c},
> + {0x3039, 0x00},
> + {0x303a, 0x0c},
> + {0x303b, 0x0f},
> +
> + {0x30EE, 0x01},
> + {0x3130, 0x86},
> + {0x3131, 0x08},
> + {0x3132, 0x7E},
> + {0x3133, 0x08},
> + {0x3342, 0x0A},
> + {0x3343, 0x00},
> + {0x3344, 0x16},
> + {0x3345, 0x00},
> + {0x33A6, 0x01},
> + {0x3528, 0x0E},
> + {0x3554, 0x1F},
> + {0x3555, 0x01},
> + {0x3556, 0x01},
> + {0x3557, 0x01},
> + {0x3558, 0x01},
> + {0x3559, 0x00},
> + {0x355A, 0x00},
> + {0x35BA, 0x0E},
> + {0x366A, 0x1B},
> + {0x366B, 0x1A},
> + {0x366C, 0x19},
> + {0x366D, 0x17},
> + {0x3A41, 0x08},
> +
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * Horizontal/vertical 2/2-line binning
> + * (Horizontal and vertical weightedbinning, 10-bit)
> + * imx274 mode3(refer to datasheet) register configuration with
> + * 1920x1080 resolution, raw10 data and mipi four lane output
> + */
> +static const imx274_reg imx274_mode3_1920x1080_raw10[] = {
> + {0x3004, 0x02},
> + {0x3005, 0x21},
> + {0x3006, 0x00},
> + {0x3007, 0x11},
> +
> + {0x3018, 0xA2}, /* output XVS, HVS */
> +
> + {0x306B, 0x05},
> + {0x30E2, 0x02},
> +
> + {0x30F6, 0x04}, /* HMAX, 260 */
> + {0x30F7, 0x01}, /* HMAX */
> +
> + {0x30dd, 0x01}, /* to crop to 1920x1080 */
> + {0x30de, 0x05},
> + {0x30df, 0x00},
> + {0x30e0, 0x04},
> + {0x30e1, 0x00},
> + {0x3037, 0x01},
> + {0x3038, 0x0c},
> + {0x3039, 0x00},
> + {0x303a, 0x0c},
> + {0x303b, 0x0f},
> +
> + {0x30EE, 0x01},
> + {0x3130, 0x4E},
> + {0x3131, 0x04},
> + {0x3132, 0x46},
> + {0x3133, 0x04},
> + {0x3342, 0x0A},
> + {0x3343, 0x00},
> + {0x3344, 0x1A},
> + {0x3345, 0x00},
> + {0x33A6, 0x01},
> + {0x3528, 0x0E},
> + {0x3554, 0x00},
> + {0x3555, 0x01},
> + {0x3556, 0x01},
> + {0x3557, 0x01},
> + {0x3558, 0x01},
> + {0x3559, 0x00},
> + {0x355A, 0x00},
> + {0x35BA, 0x0E},
> + {0x366A, 0x1B},
> + {0x366B, 0x1A},
> + {0x366C, 0x19},
> + {0x366D, 0x17},
> + {0x3A41, 0x08},
> +
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * Vertical 2/3 subsampling binning horizontal 3 binning
> + * imx274 mode5(refer to datasheet) register configuration with
> + * 1280x720 resolution, raw10 data and mipi four lane output
> + */
> +static const imx274_reg imx274_mode5_1280x720_raw10[] = {
> + {0x3004, 0x03},
> + {0x3005, 0x31},
> + {0x3006, 0x00},
> + {0x3007, 0x09},
> +
> + {0x3018, 0xA2}, /* output XVS, HVS */
> +
> + {0x306B, 0x05},
> + {0x30E2, 0x03},
> +
> + {0x30F6, 0x04}, /* HMAX, 260 */
> + {0x30F7, 0x01}, /* HMAX */
> +
> + {0x30DD, 0x01},
> + {0x30DE, 0x07},
> + {0x30DF, 0x00},
> + {0x40E0, 0x04},
> + {0x30E1, 0x00},
> + {0x3030, 0xD4},
> + {0x3031, 0x02},
> + {0x3032, 0xD0},
> + {0x3033, 0x02},
> +
> + {0x30EE, 0x01},
> + {0x3130, 0xE2},
> + {0x3131, 0x02},
> + {0x3132, 0xDE},
> + {0x3133, 0x02},
> + {0x3342, 0x0A},
> + {0x3343, 0x00},
> + {0x3344, 0x1B},
> + {0x3345, 0x00},
> + {0x33A6, 0x01},
> + {0x3528, 0x0E},
> + {0x3554, 0x00},
> + {0x3555, 0x01},
> + {0x3556, 0x01},
> + {0x3557, 0x01},
> + {0x3558, 0x01},
> + {0x3559, 0x00},
> + {0x355A, 0x00},
> + {0x35BA, 0x0E},
> + {0x366A, 0x1B},
> + {0x366B, 0x19},
> + {0x366C, 0x17},
> + {0x366D, 0x17},
> + {0x3A41, 0x04},
> +
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 first step register configuration for
> + * starting stream
> + */
> +static const imx274_reg imx274_start_1[] = {
> + {IMX274_STANDBY_REG, 0x12},
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 second step register configuration for
> + * starting stream
> + */
> +static const imx274_reg imx274_start_2[] = {
> + {0x3120, 0xF0}, /* clock settings */
> + {0x3121, 0x00}, /* clock settings */
> + {0x3122, 0x02}, /* clock settings */
> + {0x3129, 0x9C}, /* clock settings */
> + {0x312A, 0x02}, /* clock settings */
> + {0x312D, 0x02}, /* clock settings */
> +
> + {0x310B, 0x00},
> +
> + /* PLSTMG */
> + {0x304C, 0x00}, /* PLSTMG01 */
> + {0x304D, 0x03},
> + {0x331C, 0x1A},
> + {0x331D, 0x00},
> + {0x3502, 0x02},
> + {0x3529, 0x0E},
> + {0x352A, 0x0E},
> + {0x352B, 0x0E},
> + {0x3538, 0x0E},
> + {0x3539, 0x0E},
> + {0x3553, 0x00},
> + {0x357D, 0x05},
> + {0x357F, 0x05},
> + {0x3581, 0x04},
> + {0x3583, 0x76},
> + {0x3587, 0x01},
> + {0x35BB, 0x0E},
> + {0x35BC, 0x0E},
> + {0x35BD, 0x0E},
> + {0x35BE, 0x0E},
> + {0x35BF, 0x0E},
> + {0x366E, 0x00},
> + {0x366F, 0x00},
> + {0x3670, 0x00},
> + {0x3671, 0x00},
> +
> + /* PSMIPI */
> + {0x3304, 0x32}, /* PSMIPI1 */
> + {0x3305, 0x00},
> + {0x3306, 0x32},
> + {0x3307, 0x00},
> + {0x3590, 0x32},
> + {0x3591, 0x00},
> + {0x3686, 0x32},
> + {0x3687, 0x00},
> +
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 third step register configuration for
> + * starting stream
> + */
> +static const imx274_reg imx274_start_3[] = {
> + {IMX274_STANDBY_REG, 0x00},
> + {0x303E, 0x02}, /* SYS_MODE = 2 */
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 forth step register configuration for
> + * starting stream
> + */
> +static const imx274_reg imx274_start_4[] = {
> + {0x30F4, 0x00},
> + {0x3018, 0xA2}, /* XHS VHS OUTUPT */
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 register configuration for stoping stream
> + */
> +static const imx274_reg imx274_stop[] = {
> + {IMX274_STANDBY_REG, 0x01},
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 disable test pattern register configuration
> + */
> +static const imx274_reg imx274_tp_disabled[] = {
> + {0x303C, 0x00},
> + {0x377F, 0x00},
> + {0x3781, 0x00},
> + {0x370B, 0x00},
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 test pattern register configuration
> + * reg 0x303D defines the test pattern modes
> + */
> +static imx274_reg imx274_tp_regs[] = {

const? Same for other static variables, except the i2c_driver struct.

> + {0x303D, 0x00},
> + {0x303C, 0x11},
> + {0x370E, 0x01},
> + {0x377F, 0x01},
> + {0x3781, 0x01},
> + {0x370B, 0x11},
> + {IMX274_TABLE_END, 0x00}
> +};
> +
> +/*
> + * imx274 mode related structure
> + */
> +enum {
> + IMX274_MODE_3840X2160,
> + IMX274_MODE_1920X1080,
> + IMX274_MODE_1280X720,
> +
> + IMX274_MODE_START_STREAM_1,
> + IMX274_MODE_START_STREAM_2,
> + IMX274_MODE_START_STREAM_3,
> + IMX274_MODE_START_STREAM_4,
> + IMX274_MODE_STOP_STREAM
> +};
> +
> +static const imx274_reg *mode_table[] = {
> + [IMX274_MODE_3840X2160] = imx274_mode1_3840x2160_raw10,
> + [IMX274_MODE_1920X1080] = imx274_mode3_1920x1080_raw10,
> + [IMX274_MODE_1280X720] = imx274_mode5_1280x720_raw10,
> +
> + [IMX274_MODE_START_STREAM_1] = imx274_start_1,
> + [IMX274_MODE_START_STREAM_2] = imx274_start_2,
> + [IMX274_MODE_START_STREAM_3] = imx274_start_3,
> + [IMX274_MODE_START_STREAM_4] = imx274_start_4,
> + [IMX274_MODE_STOP_STREAM] = imx274_stop,
> +};
> +
> +/*
> + * imx274 format related structure
> + */
> +static const struct imx274_frmfmt imx274_formats[] = {
> + {MEDIA_BUS_FMT_SRGGB10_1X10, V4L2_COLORSPACE_SRGB, {3840, 2160},
> + IMX274_MODE_3840X2160},
> + {MEDIA_BUS_FMT_SRGGB10_1X10, V4L2_COLORSPACE_SRGB, {1920, 1080},
> + IMX274_MODE_1920X1080},
> + {MEDIA_BUS_FMT_SRGGB10_1X10, V4L2_COLORSPACE_SRGB, {1280, 720},
> + IMX274_MODE_1280X720},
> +};
> +
> +/*
> + * minimal frame length for each mode
> + * refer to datasheet section "Frame Rate Adjustment (CSI-2)"
> + */
> +static int min_frame_len[] = {
> + 4550, /* mode 1, 4K */
> + 2310, /* mode 3, 1080p */
> + 2310 /* mode 5, 720p */
> +};
> +
> +/*
> + * minimal numbers of SHR register
> + * refer to datasheet table "Shutter Setting (CSI-2)"
> + */
> +static int min_SHR[] = {
> + 12, /* mode 1, 4K */
> + 8, /* mode 3, 1080p */
> + 8 /* mode 5, 720p */
> +};
> +
> +static int max_frame_rate[] = {
> + 60, /* mode 1 , 4K */
> + 120, /* mode 3, 1080p */
> + 120 /* mode 5, 720p */
> +};
> +
> +/*
> + * Number of clocks per internal offset period
> + * a constant based on mode
> + * refer to section "Integration Time in Each Readout Drive Mode (CSI-2)"
> + * in the datasheet
> + * for the implemented 3 modes, it happens to be the same number
> + */
> +static const int nocpiop[] = {
> + 112, /* mode 1 , 4K */
> + 112, /* mode 3, 1080p */
> + 112 /* mode 5, 720p */
> +};
> +
> +/*
> + * struct imx274_ctrls - imx274 ctrl structure
> + * @handler: V4L2 ctrl handler structure
> + * @exposure: Pointer to expsure ctrl structure
> + * @gain: Pointer to gain ctrl structure
> + * @vflip: Pointer to vflip ctrl structure
> + * @test_pattern: Pointer to test pattern ctrl structure
> + */
> +struct imx274_ctrls {
> + struct v4l2_ctrl_handler handler;
> + struct v4l2_ctrl *exposure;
> + struct v4l2_ctrl *gain;
> + struct v4l2_ctrl *vflip;
> + struct v4l2_ctrl *test_pattern;
> +};
> +
> +/*
> + * struct stim274 - imx274 device structure
> + * @sd: V4L2 subdevice structure
> + * @pd: Media pad structure
> + * @client: Pointer to I2C client
> + * @ctrls: imx274 control structure
> + * @format: V4L2 media bus frame format structure
> + * @frame_rate: V4L2 frame rate structure
> + * @regmap: Pointer to regmap structure
> + * @reset_gpio: Pointer to reset gpio
> + * @lock: Mutex structure
> + * @mode_index: Resolution mode index
> + */
> +struct stimx274 {
> + struct v4l2_subdev sd;
> + struct media_pad pad;
> + struct i2c_client *client;
> + struct imx274_ctrls ctrls;
> + struct v4l2_mbus_framefmt format;
> + struct v4l2_fract frame_interval;
> + struct regmap *regmap;
> + struct gpio_desc *reset_gpio;
> + struct mutex lock; /* mutex lock for operations */
> + u32 mode_index;
> +};
> +
> +/*
> + * Function declaration
> + */
> +static int imx274_set_gain(struct stimx274 *priv, s64 val);
> +static int imx274_set_exposure(struct stimx274 *priv, s64 val);
> +static int imx274_set_vflip(struct stimx274 *priv, int val);
> +static int imx274_set_test_pattern(struct stimx274 *priv, int val);
> +static int imx274_set_frame_interval(struct stimx274 *priv,
> + struct v4l2_fract frame_interval);
> +
> +static inline void msleep_range(unsigned int delay_base)
> +{
> + usleep_range(delay_base * 1000, delay_base * 1000 + 500);
> +}
> +
> +/*
> + * v4l2_ctrl and v4l2_subdev related operations
> + */
> +static inline struct v4l2_subdev *ctrl_to_sd(struct v4l2_ctrl *ctrl)
> +{
> + return &container_of(ctrl->handler,
> + struct stimx274, ctrls.handler)->sd;
> +}
> +
> +static inline struct stimx274 *to_imx274(struct v4l2_subdev *sd)
> +{
> + return container_of(sd, struct stimx274, sd);
> +}
> +
> +/*
> + * imx274_regmap_util_write_table_8 - Function for writing register table
> + * @regmap: Pointer to device reg map structure
> + * @table: Table containing register values
> + * @wait_ms_addr: Flag for performing delay
> + * @end_addr: Flag for incating end of table
> + *
> + * This is used to write register table into sensor's reg map.
> + *
> + * Return: 0 on success, errors otherwise
> + */
> +static int imx274_regmap_util_write_table_8(struct regmap *regmap,
> + const struct reg_8 table[],
> + u16 wait_ms_addr, u16 end_addr)
> +{
> + int err;
> + const struct reg_8 *next;
> + u8 val;
> +
> + int range_start = -1;
> + int range_count = 0;
> + u8 range_vals[16];
> + int max_range_vals = ARRAY_SIZE(range_vals);
> +
> + for (next = table;; next++) {
> + if ((next->addr != range_start + range_count) ||
> + (next->addr == end_addr) ||
> + (next->addr == wait_ms_addr) ||
> + (range_count == max_range_vals)) {
> + if (range_count == 1)
> + err = regmap_write(regmap,
> + range_start, range_vals[0]);
> + else if (range_count > 1)
> + err = regmap_bulk_write(regmap, range_start,
> + &range_vals[0],
> + range_count);
> +
> + if (err)
> + return err;
> +
> + range_start = -1;
> + range_count = 0;
> +
> + /* Handle special address values */
> + if (next->addr == end_addr)
> + break;
> +
> + if (next->addr == wait_ms_addr) {
> + msleep_range(next->val);
> + continue;
> + }
> + }
> +
> + val = next->val;
> +
> + if (range_start == -1)
> + range_start = next->addr;
> +
> + range_vals[range_count++] = val;
> + }
> + return 0;
> +}
> +
> +static inline int imx274_read_reg(struct stimx274 *priv, u16 addr, u8 *val)
> +{
> + int err;
> +
> + err = regmap_read(priv->regmap, addr, (unsigned int *)val);
> + if (err)
> + v4l2_err(&priv->sd,
> + "%s : i2c read failed, addr = %x\n", __func__, addr);
> + else
> + v4l2_dbg(2, debug, &priv->sd,
> + "%s : addr 0x%x, val=0x%x\n", __func__,
> + addr, *val);
> + return err;
> +}
> +
> +static inline int imx274_write_reg(struct stimx274 *priv, u16 addr, u8 val)
> +{
> + int err;
> +
> + err = regmap_write(priv->regmap, addr, val);
> + if (err)
> + v4l2_err(&priv->sd,
> + "%s : i2c write failed, %x = %x\n", __func__,
> + addr, val);
> + else
> + v4l2_dbg(2, debug, &priv->sd,
> + "%s : addr 0x%x, val=0x%x\n", __func__,
> + addr, val);
> + return err;
> +}
> +
> +static int imx274_write_table(struct stimx274 *priv, const imx274_reg table[])
> +{
> + return imx274_regmap_util_write_table_8(priv->regmap,
> + table, IMX274_TABLE_WAIT_MS, IMX274_TABLE_END);
> +}
> +
> +/*
> + * imx274_start_stream - Function for starting stream per mode index
> + * @priv: Pointer to device structure
> + * @mode: Mode index value
> + *
> + * This is used to start steam per mode index.
> + * mode = 0, start stream for sensor Mode 1: 4K/raw10
> + * mode = 1, start stream for sensor Mode 3: 1080p/raw10
> + * mode = 2, start stream for sensor Mode 5: 720p/raw10
> + *
> + * Return: 0 on success, errors otherwise
> + */
> +static int imx274_start_stream(struct stimx274 *priv, int mode)
> +{
> + int err = 0;
> +
> + err = imx274_write_table(priv, mode_table[IMX274_MODE_START_STREAM_1]);
> + if (err)
> + return err;
> +
> + err = imx274_write_table(priv, mode_table[IMX274_MODE_START_STREAM_2]);
> + if (err)
> + return err;
> +
> + err = imx274_write_table(priv, mode_table[mode]);
> + if (err)
> + return err;
> +
> + /*
> + * Refer to "Standby Cancel Sequence when using CSI-2" in
> + * imx274 datasheet, it should wait 10ms or more here.
> + * give it 1 extra ms for margin
> + */
> + msleep_range(11);
> + err = imx274_write_table(priv, mode_table[IMX274_MODE_START_STREAM_3]);
> + if (err)
> + return err;
> +
> + /*
> + * Refer to "Standby Cancel Sequence when using CSI-2" in
> + * imx274 datasheet, it should wait 7ms or more here.
> + * give it 1 extra ms for margin
> + */
> + msleep_range(8);
> + err = imx274_write_table(priv, mode_table[IMX274_MODE_START_STREAM_4]);
> + if (err)
> + return err;
> +
> + v4l2_dbg(1, debug, &priv->sd, "%s : finished\n", __func__);

These look like something that was quite possibly useful during development
time, but I'd remove them now.

> + return 0;
> +}
> +
> +/*
> + * imx274_reset - Function called to reset the sensor
> + * @priv: Pointer to device structure
> + * @rst: Input value for determining the sensor's end state after reset
> + *
> + * Set the senor in reset and then
> + * if rst = 0, keep it in reset;
> + * if rst = 1, bring it out of reset.
> + *
> + */
> +static void imx274_reset(struct stimx274 *priv, int rst)
> +{
> + gpiod_set_value_cansleep(priv->reset_gpio, 0);
> + usleep_range(IMX274_RESET_DELAY1, IMX274_RESET_DELAY2);
> + gpiod_set_value_cansleep(priv->reset_gpio, !!rst);
> + usleep_range(IMX274_RESET_DELAY1, IMX274_RESET_DELAY2);
> +}
> +
> +/**
> + * imx274_s_ctrl - This is used to set the imx274 V4L2 controls
> + * @ctrl: V4L2 control to be set
> + *
> + * This function is used to set the V4L2 controls for the imx274 sensor.
> + *
> + * Return: 0 on success, errors otherwise
> + */
> +static int imx274_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> + struct v4l2_subdev *sd = ctrl_to_sd(ctrl);
> + struct stimx274 *imx274 = to_imx274(sd);
> + int ret = -EINVAL;
> +
> + v4l2_dbg(1, debug, &imx274->sd,
> + "%s : s_ctrl: %s, value: %d\n", __func__,
> + ctrl->name, ctrl->val);
> +
> + mutex_lock(&imx274->lock);

You could assigne the same lock to the control handler and omit explicit locking
here. See e.g. the smiapp-core.c for an example.

> +
> + switch (ctrl->id) {
> + case V4L2_CID_EXPOSURE:
> + v4l2_dbg(1, debug, &imx274->sd,
> + "%s : set V4L2_CID_EXPOSURE\n", __func__);
> + ret = imx274_set_exposure(imx274, ctrl->val);
> + break;
> +
> + case V4L2_CID_GAIN:
> + v4l2_dbg(1, debug, &imx274->sd,
> + "%s : set V4L2_CID_GAIN\n", __func__);
> + ret = imx274_set_gain(imx274, ctrl->val);
> + break;
> +
> + case V4L2_CID_VFLIP:
> + v4l2_dbg(1, debug, &imx274->sd,
> + "%s : set V4L2_CID_VFLIP\n", __func__);
> + ret = imx274_set_vflip(imx274, ctrl->val);
> + break;
> +
> + case V4L2_CID_TEST_PATTERN:
> + v4l2_dbg(1, debug, &imx274->sd,
> + "%s : set V4L2_CID_TEST_PATTERN\n", __func__);
> + ret = imx274_set_test_pattern(imx274, ctrl->val);
> + break;
> + }
> +
> + mutex_unlock(&imx274->lock);
> + return ret;
> +}
> +
> +/**
> + * imx274_get_fmt - Get the pad format
> + * @sd: Pointer to V4L2 Sub device structure
> + * @cfg: Pointer to sub device pad information structure
> + * @fmt: Pointer to pad level media bus format
> + *
> + * This function is used to get the pad format information.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_get_fmt(struct v4l2_subdev *sd,
> + struct v4l2_subdev_pad_config *cfg,
> + struct v4l2_subdev_format *fmt)
> +{
> + struct stimx274 *imx274 = to_imx274(sd);
> +
> + if (fmt->pad)
> + return -EINVAL;
> +
> + fmt->format = imx274->format;

You should acquire the mutex here.

> +
> + return 0;
> +}
> +
> +/**
> + * imx274_set_fmt - This is used to set the pad format
> + * @sd: Pointer to V4L2 Sub device structure
> + * @cfg: Pointer to sub device pad information structure
> + * @format: Pointer to pad level media bus format
> + *
> + * This function is used to set the pad format.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_fmt(struct v4l2_subdev *sd,
> + struct v4l2_subdev_pad_config *cfg,
> + struct v4l2_subdev_format *format)
> +{
> + struct v4l2_mbus_framefmt *fmt = &format->format;
> + struct stimx274 *imx274 = to_imx274(sd);
> + struct i2c_client *client = imx274->client;
> + int index;
> +
> + v4l2_dbg(1, debug, client,
> + "%s: width = %d height = %d code = %d mbus_code = %d\n",
> + __func__, fmt->width, fmt->height, fmt->code,
> + imx274_formats[imx274->mode_index].mbus_code);
> +
> + if (format->pad)
> + return -EINVAL;

If you expose just a single pad, pad will be always zero.

> +
> + mutex_lock(&imx274->lock);
> +
> + for (index = 0; index < ARRAY_SIZE(imx274_formats); index++) {
> + if (imx274_formats[index].size.width == fmt->width &&
> + imx274_formats[index].size.height == fmt->height)
> + break;
> + }
> +
> + if (index >= ARRAY_SIZE(imx274_formats)) {
> + /* default to first format */
> + index = 0;
> + }
> +
> + imx274->mode_index = index;
> +
> + if (fmt->width > IMX274_MAX_WIDTH)
> + fmt->width = IMX274_MAX_WIDTH;
> + if (fmt->height > IMX274_MAX_HEIGHT)
> + fmt->height = IMX274_MAX_HEIGHT;
> + fmt->width = fmt->width & (~IMX274_MASK_LSB_2_BITS);
> + fmt->height = fmt->height & (~IMX274_MASK_LSB_2_BITS);
> + fmt->field = V4L2_FIELD_NONE;
> +
> + if (format->which == V4L2_SUBDEV_FORMAT_TRY)
> + cfg->try_fmt = *fmt;
> + else
> + imx274->format = *fmt;
> +
> + mutex_unlock(&imx274->lock);
> + return 0;
> +}
> +
> +/**
> + * imx274_g_frame_interval - Get the frame interval
> + * @sd: Pointer to V4L2 Sub device structure
> + * @fi: Pointer to V4l2 Sub device frame interval structure
> + *
> + * This function is used to get the frame interval.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_g_frame_interval(struct v4l2_subdev *sd,
> + struct v4l2_subdev_frame_interval *fi)
> +{
> + struct stimx274 *imx274 = to_imx274(sd);
> +
> + fi->interval = imx274->frame_interval;
> + v4l2_dbg(1, debug, &imx274->sd, "%s frame rate = %d / %d\n",
> + __func__, imx274->frame_interval.numerator,
> + imx274->frame_interval.denominator);
> +
> + return 0;
> +}
> +
> +/**
> + * imx274_s_frame_interval - Set the frame interval
> + * @sd: Pointer to V4L2 Sub device structure
> + * @fi: Pointer to V4l2 Sub device frame interval structure
> + *
> + * This function is used to set the frame intervavl.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_s_frame_interval(struct v4l2_subdev *sd,
> + struct v4l2_subdev_frame_interval *fi)
> +{
> + struct stimx274 *imx274 = to_imx274(sd);
> + struct v4l2_ctrl *ctrl = imx274->ctrls.exposure;
> + int min, max, def;
> + int ret;
> +
> + mutex_lock(&imx274->lock);
> + ret = imx274_set_frame_interval(imx274, fi->interval);
> + mutex_unlock(&imx274->lock);
> +
> + if (!ret) {
> + /*
> + * exposure time range is decided by frame interval
> + * need to update it after frame interal changes
> + */
> + min = IMX274_MIN_EXPOSURE_TIME;
> + max = fi->interval.numerator * 1000000
> + / fi->interval.denominator;
> + def = max;
> + if (v4l2_ctrl_modify_range(ctrl, min, max, 1, def))

I'd keep the mutex locked. You can use __v4l2_ctrl_modify_range() here.

> + v4l2_err(sd, "Exposure ctrl range update failed\n");
> +
> + /* update exposure time accordingly */
> + mutex_lock(&imx274->lock);
> + imx274_set_exposure(imx274, imx274->ctrls.exposure->val);
> + mutex_unlock(&imx274->lock);
> +
> + v4l2_dbg(1, debug, &imx274->sd, "set frame interval to %uus\n",
> + fi->interval.numerator * 1000000
> + / fi->interval.denominator);
> + }
> +
> + return ret;
> +}
> +
> +/**
> + * imx274_load_default - load default control values
> + * @priv: Pointer to device structure
> + *
> + * Return: 0 on success, errors otherwise
> + */
> +static int imx274_load_default(struct stimx274 *priv)
> +{
> + struct v4l2_control control;
> + int ret;
> +
> + /* load default control values */
> + priv->frame_interval.numerator = 1;
> + priv->frame_interval.denominator = IMX274_DEF_FRAME_RATE;
> + priv->ctrls.exposure->val = 1000000 / IMX274_DEF_FRAME_RATE;
> + priv->ctrls.gain->val = IMX274_DEF_GAIN;
> + priv->ctrls.vflip->val = 0;
> + priv->ctrls.test_pattern->val = TEST_PATTERN_DISABLED;
> +
> + /* update frame rate */
> + ret = imx274_set_frame_interval(priv,
> + priv->frame_interval);
> + if (ret)
> + return ret;
> +
> + /* update exposure time */
> + control.id = V4L2_CID_EXPOSURE;
> + control.value = priv->ctrls.exposure->val;
> + ret = v4l2_s_ctrl(NULL, &priv->ctrls.handler, &control);

v4l2_ctrl_s_ctrl(), please.

> + if (ret)
> + return ret;
> +
> + /* update gain */
> + control.id = V4L2_CID_GAIN;
> + control.value = priv->ctrls.gain->val;
> + ret = v4l2_s_ctrl(NULL, &priv->ctrls.handler, &control);
> + if (ret)
> + return ret;
> +
> + /* update vflip */
> + control.id = V4L2_CID_VFLIP;
> + control.value = priv->ctrls.vflip->val;
> + ret = v4l2_s_ctrl(NULL, &priv->ctrls.handler, &control);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +/**
> + * imx274_s_stream - It is used to start/stop the streaming.
> + * @sd: V4L2 Sub device
> + * @on: Flag (True / False)
> + *
> + * This function controls the start or stop of streaming for the
> + * imx274 sensor.
> + *
> + * Return: 0 on success, errors otherwise
> + */
> +static int imx274_s_stream(struct v4l2_subdev *sd, int on)
> +{
> + struct stimx274 *imx274 = to_imx274(sd);
> + struct v4l2_control control;
> + int ret = 0;
> +
> + v4l2_dbg(1, debug, &imx274->sd, "%s : %s, mode index = %d\n", __func__,
> + on ? "Stream Start" : "Stream Stop", imx274->mode_index);
> +
> + mutex_lock(&imx274->lock);
> +
> + if (on) {
> + /* start stream */
> + ret = imx274_start_stream(imx274, imx274->mode_index);
> + if (ret)
> + goto fail;
> +
> + /*
> + * update frame rate & expsoure. if the last mode is different,
> + * HMAX could be changed. As the result, frame rate & exposure
> + * are changed.
> + * gain is not affected.
> + */

Shouldn't you do these before starting streaming?

I don't know your hardware but usually this is what you want to do.

> + ret = imx274_set_frame_interval(imx274,
> + imx274->frame_interval);
> + if (ret)
> + goto fail;
> +
> + mutex_unlock(&imx274->lock);
> +
> + control.id = V4L2_CID_EXPOSURE;
> + control.value = imx274->ctrls.exposure->val;
> + ret = v4l2_s_ctrl(NULL, &imx274->ctrls.handler, &control);
> + if (ret)
> + goto fail;
> +
> + mutex_lock(&imx274->lock);
> +
> + } else {
> + /* stop stream */
> + ret = imx274_write_table(imx274,
> + mode_table[IMX274_MODE_STOP_STREAM]);
> + if (ret)
> + goto fail;
> + }
> +
> + mutex_unlock(&imx274->lock);
> + v4l2_dbg(1, debug, &imx274->sd,
> + "%s : Done: mode = %d\n", __func__, imx274->mode_index);
> + return 0;
> +
> +fail:
> + mutex_unlock(&imx274->lock);
> + v4l2_err(&imx274->sd, "s_stream failed\n");
> + return ret;
> +}
> +
> +static inline void imx274_calculate_frame_length_regs(imx274_reg *regs,

You use this once. Please either move the code where it's used or
explicitly denote there will be three entries. Same below.

> + u32 frame_length)
> +{
> + regs->addr = IMX274_FRAME_LENGTH_ADDR_1;
> + regs->val = (frame_length >> IMX274_SHIFT_16_BITS)
> + & IMX274_MASK_LSB_4_BITS;
> + (regs + 1)->addr = IMX274_FRAME_LENGTH_ADDR_2;
> + (regs + 1)->val = (frame_length >> IMX274_SHIFT_8_BITS)
> + & IMX274_MASK_LSB_8_BITS;
> + (regs + 2)->addr = IMX274_FRAME_LENGTH_ADDR_3;
> + (regs + 2)->val = (frame_length) & IMX274_MASK_LSB_8_BITS;
> +}
> +
> +static inline void imx274_calculate_coarse_time_regs(imx274_reg *regs,
> + u32 coarse_time)
> +{
> + regs->addr = IMX274_COARSE_TIME_ADDR_MSB;
> + regs->val = (coarse_time >> IMX274_SHIFT_8_BITS) & IMX274_MASK_LSB_8_BITS;
> + (regs + 1)->addr = IMX274_COARSE_TIME_ADDR_LSB;
> + (regs + 1)->val = (coarse_time) & IMX274_MASK_LSB_8_BITS;
> +}
> +
> +static inline void imx274_calculate_gain_regs(imx274_reg *regs, u16 gain)
> +{
> + regs->addr = IMX274_ANALOG_GAIN_ADDR_MSB;
> + regs->val = (gain >> IMX274_SHIFT_8_BITS) & IMX274_MASK_LSB_3_BITS;
> +
> + (regs + 1)->addr = IMX274_ANALOG_GAIN_ADDR_LSB;
> + (regs + 1)->val = (gain) & IMX274_MASK_LSB_8_BITS;
> +}
> +
> +/*
> + * imx274_get_frame_length - Function for obtaining current frame length
> + * @priv: Pointer to device structure
> + * @val: Pointer to obainted value
> + *
> + * frame_length = vmax x (svr + 1), in unit of hmax.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_get_frame_length(struct stimx274 *priv, s64 *val)
> +{
> + int err;
> + u16 svr;
> + u32 vmax;
> + u8 reg_val[3];
> +
> + /* svr */
> + err = imx274_read_reg(priv, IMX274_SVR_REG_LSB, &reg_val[0]);
> + err |= imx274_read_reg(priv, IMX274_SVR_REG_MSB, &reg_val[1]);
> + if (err)
> + goto fail;
> + svr = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
> +
> + /* vmax */
> + err = imx274_read_reg(priv, IMX274_FRAME_LENGTH_ADDR_3, &reg_val[0]);
> + err |= imx274_read_reg(priv, IMX274_FRAME_LENGTH_ADDR_2, &reg_val[1]);
> + err |= imx274_read_reg(priv, IMX274_FRAME_LENGTH_ADDR_1, &reg_val[2]);

Please don't use bit-wise or on integer error codes.

> + if (err)
> + goto fail;
> + vmax = ((reg_val[2] & IMX274_MASK_LSB_3_BITS) << IMX274_SHIFT_16_BITS)
> + + (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
> +
> + *val = vmax * (svr + 1);
> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +static int imx274_clamp_coarse_time(struct stimx274 *priv, s64 *val,
> + s64 *frame_length)
> +{
> + int err;
> +
> + err = imx274_get_frame_length(priv, frame_length);
> + if (err)
> + return err;
> +
> + if (*frame_length < min_frame_len[priv->mode_index])
> + *frame_length = min_frame_len[priv->mode_index];
> +
> + *val = *frame_length - *val; /* convert to raw shr */
> + if (*val > *frame_length - IMX274_SHR_LIMIT_CONST)
> + *val = *frame_length - IMX274_SHR_LIMIT_CONST;
> + else if (*val < min_SHR[priv->mode_index])
> + *val = min_SHR[priv->mode_index];
> +
> + return 0;
> +}
> +
> +/*
> + * imx274_set_digital gain - Function called when setting digital gain
> + * @priv: Pointer to device structure
> + * @dgain: Value of digital gain.
> + *
> + * Digital gain has only 4 steps: 1x, 2x, 4x, and 8x
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_digital_gain(struct stimx274 *priv, u32 dgain)
> +{
> + int ret;
> + u8 reg_val;
> +
> + switch (dgain) {
> + case 1:
> + reg_val = 0;
> + break;
> + case 2:
> + reg_val = 1;
> + break;
> + case 4:
> + reg_val = 2;
> + break;
> + case 8:
> + reg_val = 3;
> + break;
> + default:
> + return -EINVAL;

Please set the closest value instead of returning an error. That's more
user friendly. You could use fls().

> + }
> +
> + ret = imx274_write_reg(priv, IMX274_DIGITAL_GAIN_REG,
> + reg_val & IMX274_MASK_LSB_4_BITS);
> + return ret;
> +}
> +
> +/*
> + * imx274_set_gain - Function called when setting gain
> + * @priv: Pointer to device structure
> + * @val: Value of gain. the real value = val << IMX274_GAIN_SHIFT;
> + *
> + * Set the gain based on input value.
> + * The caller should hold the mutex lock imx274->lock if necessary
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_gain(struct stimx274 *priv, s64 val)
> +{
> + imx274_reg reg_list[2];
> + int err;
> + u32 gain, analog_gain, digital_gain, gain_reg;
> + int i;
> +
> + gain = (u32)(val);
> +
> + v4l2_dbg(1, debug, &priv->sd,
> + "%s : input gain = %d.%d\n", __func__,
> + gain >> IMX274_GAIN_SHIFT,
> + ((gain & IMX274_GAIN_SHIFT_MASK) * 100) >> IMX274_GAIN_SHIFT);
> +
> + if (gain > IMX274_MAX_DIGITAL_GAIN * IMX274_MAX_ANALOG_GAIN)
> + gain = IMX274_MAX_DIGITAL_GAIN * IMX274_MAX_ANALOG_GAIN;
> + else if (gain < IMX274_MIN_GAIN)
> + gain = IMX274_MIN_GAIN;
> +
> + if (gain <= IMX274_MAX_ANALOG_GAIN)
> + digital_gain = 1;
> + else if (gain <= IMX274_MAX_ANALOG_GAIN * 2)
> + digital_gain = 2;
> + else if (gain <= IMX274_MAX_ANALOG_GAIN * 4)
> + digital_gain = 4;
> + else
> + digital_gain = IMX274_MAX_DIGITAL_GAIN;
> +
> + analog_gain = gain / digital_gain;
> +
> + v4l2_dbg(2, debug, &priv->sd,
> + "%s : digital gain = %d, analog gain = %d.%d\n",
> + __func__, digital_gain, analog_gain >> IMX274_GAIN_SHIFT,
> + ((analog_gain & IMX274_GAIN_SHIFT_MASK) * 100)
> + >> IMX274_GAIN_SHIFT);
> +
> + err = imx274_set_digital_gain(priv, digital_gain);
> + if (err)
> + goto fail;
> +
> + /* convert to register value, refer to imx274 datasheet */
> + gain_reg = (u32)IMX274_GAIN_CONST -
> + (IMX274_GAIN_CONST << IMX274_GAIN_SHIFT) / analog_gain;
> + if (gain_reg > IMX274_GAIN_REG_MAX)
> + gain_reg = IMX274_GAIN_REG_MAX;
> +
> + imx274_calculate_gain_regs(reg_list, (u16)gain_reg);
> +
> + for (i = 0; i < ARRAY_SIZE(reg_list); i++) {
> + err = imx274_write_reg(priv, reg_list[i].addr,
> + reg_list[i].val);
> + if (err)
> + goto fail;
> + }
> +
> + /* convert register value back to gain value */
> + priv->ctrls.gain->val = (IMX274_GAIN_CONST << IMX274_GAIN_SHIFT)
> + / (IMX274_GAIN_CONST - gain_reg)
> + * digital_gain;

Please pass the struct v4l2_ctrl pointer and use that instead. It'd be much
cleaner.

> +
> + v4l2_dbg(1, debug, &priv->sd,
> + "%s : GAIN control success, gain_reg = %d, new gain = %d\n",
> + __func__, gain_reg, priv->ctrls.gain->val);
> +
> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +/*
> + * imx274_set_coarse_time - Function called when setting SHR value
> + * @priv: Pointer to device structure
> + * @val: Value for exposure time in number of line_length, or [HMAX]
> + *
> + * Set SHR value based on input value.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_coarse_time(struct stimx274 *priv, s64 *val)
> +{
> + imx274_reg reg_list[2];
> + int err;
> + s64 coarse_time, frame_length;
> + int i;
> +
> + coarse_time = *val;
> +
> + /* convert exposure_time to appropriate SHR value */
> + err = imx274_clamp_coarse_time(priv, &coarse_time, &frame_length);
> + if (err)
> + goto fail;
> +
> + /* prepare SHR registers */
> + imx274_calculate_coarse_time_regs(reg_list, coarse_time);
> +
> + /* write to SHR registers */
> + for (i = 0; i < ARRAY_SIZE(reg_list); i++) {
> + err = imx274_write_reg(priv, reg_list[i].addr,
> + reg_list[i].val);
> + if (err)
> + goto fail;
> + }
> +
> + *val = frame_length - coarse_time;
> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +/*
> + * imx274_set_exposure - Function called when setting exposure time
> + * @priv: Pointer to device structure
> + * @val: Variable for exposure time, in the unit of micro-second
> + *
> + * Set exposure time based on input value.
> + * The caller should hold the mutex lock imx274->lock if necessary
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_exposure(struct stimx274 *priv, s64 val)
> +{
> + int err;
> + u16 hmax;
> + u8 reg_val[2];
> + s64 coarse_time; /* exposure time in unit of line (HMAX)*/
> +
> + /* step 1: convert input exposure_time (val) into number of 1[HMAX] */
> +
> + /* obtain HMAX value */
> + err = imx274_read_reg(priv, IMX274_HMAX_REG_LSB, &reg_val[0]);
> + if (err)
> + goto fail;
> + err = imx274_read_reg(priv, IMX274_HMAX_REG_MSB, &reg_val[1]);
> + if (err)
> + goto fail;
> + hmax = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
> + if (hmax == 0) {
> + err = -EINVAL;
> + goto fail;
> + }
> +
> + coarse_time = (IMX274_PIXCLK_CONST1 * val / IMX274_PIXCLK_CONST2
> + - nocpiop[priv->mode_index]) / hmax;
> +
> + if (coarse_time < 0)
> + coarse_time = 0;
> +
> + /* step 2: convert exposure_time into SHR value */
> +
> + /* set SHR */
> + err = imx274_set_coarse_time(priv, &coarse_time);
> + if (err)
> + goto fail;
> +
> + priv->ctrls.exposure->val =
> + (coarse_time * hmax + nocpiop[priv->mode_index])
> + * IMX274_PIXCLK_CONST2 / IMX274_PIXCLK_CONST1;
> +
> + v4l2_dbg(1, debug, &priv->sd,
> + "%s : EXPOSURE control success\n", __func__);
> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +/*
> + * imx274_set_vflip - Function called when setting vertical flip
> + * @priv: Pointer to device structure
> + * @val: Value for vflip setting
> + *
> + * Set vertical flip based on input value.
> + * val = 0: normal, no vertical flip
> + * val = 1: vertical flip enabled
> + * The caller should hold the mutex lock imx274->lock if necessary
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_vflip(struct stimx274 *priv, int val)
> +{
> + int err;
> +
> + err = imx274_write_reg(priv, IMX274_VFLIP_REG, val);
> + if (err) {
> + v4l2_err(&priv->sd, "VFILP control error\n");
> + return err;
> + }
> +
> + v4l2_dbg(1, debug, &priv->sd,
> + "%s : VFLIP control success\n", __func__);
> + priv->ctrls.vflip->val = val;

Why?

> + return 0;
> +}
> +
> +/*
> + * imx274_set_test_pattern - Function called when setting test pattern
> + * @priv: Pointer to device structure
> + * @val: Variable for test pattern
> + *
> + * Set to different test patterns based on input value.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_test_pattern(struct stimx274 *priv, int val)
> +{
> + int err = 0;
> +
> + if (val == TEST_PATTERN_DISABLED) {
> + err = imx274_write_table(priv, imx274_tp_disabled);
> + } else if (val <= TEST_PATTERN_V_COLOR_BARS) {
> + imx274_tp_regs[0].val = val - 1;
> + err = imx274_write_table(priv, imx274_tp_regs);
> + } else {
> + v4l2_err(&priv->sd, "TEST PATTERN control our of range\n");

Wouldn't this be a driver bug?

> + return -EINVAL;
> + }
> +
> + if (err)
> + goto fail;
> +
> + v4l2_dbg(1, debug, &priv->sd,
> + "%s : TEST PATTERN control success\n", __func__);
> +
> + priv->ctrls.test_pattern->val = val;

Ditto.

> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +/*
> + * imx274_set_frame_length - Function called when setting frame length
> + * @priv: Pointer to device structure
> + * @val: Variable for frame length (= VMAX, i.e. vertical drive period length)
> + *
> + * Set frame length based on input value.
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_frame_length(struct stimx274 *priv, u32 val)
> +{
> + imx274_reg reg_list[3];
> + int err;
> + u32 frame_length;
> + int i;
> +
> + v4l2_dbg(1, debug, &priv->sd, "%s : input length = %d\n",
> + __func__, val);
> +
> + frame_length = (u32)val;
> +
> + imx274_calculate_frame_length_regs(reg_list, frame_length);
> + for (i = 0; i < ARRAY_SIZE(reg_list); i++) {
> + err = imx274_write_reg(priv, reg_list[i].addr,
> + reg_list[i].val);
> + if (err)
> + goto fail;
> + }
> +
> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +/*
> + * imx274_set_frame_interval - Function called when setting frame interval
> + * @priv: Pointer to device structure
> + * @frame_interval: Variable for frame interval
> + *
> + * Change frame interval by updating VMAX value
> + * The caller should hold the mutex lock imx274->lock if necessary
> + *
> + * Return: 0 on success
> + */
> +static int imx274_set_frame_interval(struct stimx274 *priv,
> + struct v4l2_fract frame_interval)
> +{
> + int err;
> + s64 frame_length, req_frame_rate;
> + u16 svr;
> + u16 hmax;
> + u8 reg_val[2];
> +
> + v4l2_dbg(1, debug, &priv->sd, "%s: input frame interval = %d / %d",
> + __func__, frame_interval.numerator,
> + frame_interval.denominator);
> +
> + if (frame_interval.denominator == 0) {
> + err = -EINVAL;
> + goto fail;
> + }
> +
> + req_frame_rate = (u64)(frame_interval.denominator
> + / frame_interval.numerator);
> +
> + /* boundary check */
> + if (req_frame_rate > max_frame_rate[priv->mode_index]) {
> + frame_interval.numerator = 1;
> + frame_interval.denominator =
> + max_frame_rate[priv->mode_index];
> + } else if (req_frame_rate < IMX274_MIN_FRAME_RATE) {
> + frame_interval.numerator = 1;
> + frame_interval.denominator = IMX274_MIN_FRAME_RATE;
> + }
> +
> + /*
> + * VMAX = 1/frame_rate x 72M / (SVR+1) / HMAX
> + * frame_length (i.e. VMAX) = (frame_interval) x 72M /(SVR+1) / HMAX
> + */
> +
> + /* SVR */
> + err = imx274_read_reg(priv, IMX274_SVR_REG_LSB, &reg_val[0]);
> + err |= imx274_read_reg(priv, IMX274_SVR_REG_MSB, &reg_val[1]);
> + if (err)
> + goto fail;
> + svr = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
> + v4l2_dbg(2, debug, &priv->sd,
> + "%s : register SVR = %d\n", __func__, svr);
> +
> + /* HMAX */
> + err = imx274_read_reg(priv, IMX274_HMAX_REG_LSB, &reg_val[0]);
> + err |= imx274_read_reg(priv, IMX274_HMAX_REG_MSB, &reg_val[1]);
> + if (err)
> + goto fail;
> + hmax = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
> + v4l2_dbg(2, debug, &priv->sd,
> + "%s : register HMAX = %d\n", __func__, hmax);
> +
> + frame_length = IMX274_PIXCLK_CONST1 / (svr + 1) / hmax
> + * frame_interval.numerator
> + / frame_interval.denominator;
> +
> + err = imx274_set_frame_length(priv, frame_length);
> + if (err)
> + goto fail;
> +
> + priv->frame_interval = frame_interval;
> + return 0;
> +
> +fail:
> + v4l2_err(&priv->sd, "%s error = %d\n", __func__, err);
> + return err;
> +}
> +
> +/*
> + * imx274_open - Called on v4l2_open()
> + * @sd: Pointer to V4L2 sub device structure
> + * @fh: Pointer to V4L2 File handle
> + *
> + * This function is called on v4l2_open().
> + *
> + * Return: 0 on success
> + */
> +static int imx274_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> + return 0;
> +}
> +
> +static int imx274_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> + return 0;
> +}

No need for empty open/close callbacks.

> +
> +static const struct v4l2_subdev_pad_ops imx274_pad_ops = {
> + .get_fmt = imx274_get_fmt,
> + .set_fmt = imx274_set_fmt,
> +};
> +
> +static const struct v4l2_subdev_video_ops imx274_video_ops = {
> + .g_frame_interval = imx274_g_frame_interval,
> + .s_frame_interval = imx274_s_frame_interval,
> + .s_stream = imx274_s_stream,
> +};
> +
> +static const struct v4l2_subdev_internal_ops imx274_subdev_internal_ops = {
> + .open = imx274_open,
> + .close = imx274_close
> +};
> +
> +static const struct v4l2_subdev_core_ops imx274_core_ops = {
> +};
> +

No need for empty core ops.

> +static const struct v4l2_subdev_ops imx274_subdev_ops = {
> + .core = &imx274_core_ops,
> + .pad = &imx274_pad_ops,
> + .video = &imx274_video_ops,
> +};
> +
> +static const struct v4l2_ctrl_ops imx274_ctrl_ops = {
> + .s_ctrl = imx274_s_ctrl,
> +};
> +
> +static const struct of_device_id imx274_of_id_table[] = {
> + { .compatible = "sony,imx274" },
> + { }
> +};
> +
> +MODULE_DEVICE_TABLE(of, imx274_of_id_table);
> +static const struct i2c_device_id imx274_id[] = {
> + { "IMX274", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, imx274_id);
> +
> +static int imx274_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct v4l2_subdev *sd;
> + struct stimx274 *imx274;
> + int ret;
> +
> + /* initialize imx274 */
> + imx274 = devm_kzalloc(&client->dev, sizeof(*imx274), GFP_KERNEL);
> + if (!imx274)
> + return -ENOMEM;
> +
> + mutex_init(&imx274->lock);
> +
> + /* initialize regmap */
> + imx274->regmap = devm_regmap_init_i2c(client, &imx274_regmap_config);
> + if (IS_ERR(imx274->regmap)) {
> + dev_err(&client->dev,
> + "regmap init failed: %ld\n", PTR_ERR(imx274->regmap));

mutex_destroy(). You might want to add more labeles for error handling.

> + return -ENODEV;
> + }
> +
> + /* initialize subdevice */
> + imx274->client = client;
> + sd = &imx274->sd;
> + v4l2_i2c_subdev_init(sd, client, &imx274_subdev_ops);
> + strlcpy(sd->name, DRIVER_NAME, sizeof(sd->name));
> + sd->internal_ops = &imx274_subdev_internal_ops;
> + sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
> +
> + /* initialize subdev media pad */
> + imx274->pad.flags = MEDIA_PAD_FL_SOURCE;
> + sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
> + ret = media_entity_pads_init(&sd->entity, 1, &imx274->pad);
> + if (ret < 0) {
> + dev_err(&client->dev,
> + "%s : media entity init Failed %d\n", __func__, ret);
> + return ret;
> + }
> +
> + /* initialize sensor reset gpio */
> + imx274->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(imx274->reset_gpio)) {
> + if (PTR_ERR(imx274->reset_gpio) != -EPROBE_DEFER)
> + dev_err(&client->dev, "Reset GPIO not setup in DT");
> + return PTR_ERR(imx274->reset_gpio);
> + }
> +
> + /* pull sensor out of reset */
> + imx274_reset(imx274, 1);
> +
> + /* initialize controls */
> + ret = v4l2_ctrl_handler_init(&imx274->ctrls.handler, 2);
> + if (ret < 0) {
> + dev_err(&client->dev,
> + "%s : ctrl handler init Failed\n", __func__);
> + goto err_me;
> + }
> +
> + /* add new controls */
> + imx274->ctrls.test_pattern = v4l2_ctrl_new_std_menu_items(
> + &imx274->ctrls.handler, &imx274_ctrl_ops,
> + V4L2_CID_TEST_PATTERN,
> + ARRAY_SIZE(tp_qmenu) - 1, 0, 0, tp_qmenu);
> +
> + imx274->ctrls.gain = v4l2_ctrl_new_std(&imx274->ctrls.handler,
> + &imx274_ctrl_ops,
> + V4L2_CID_GAIN, IMX274_MIN_GAIN,
> + IMX274_MAX_DIGITAL_GAIN * IMX274_MAX_ANALOG_GAIN, 1,
> + IMX274_DEF_GAIN);
> +
> + imx274->ctrls.exposure = v4l2_ctrl_new_std(&imx274->ctrls.handler,
> + &imx274_ctrl_ops,
> + V4L2_CID_EXPOSURE, IMX274_MIN_EXPOSURE_TIME,
> + 1000000 / IMX274_DEF_FRAME_RATE, 1,
> + 1000000 / IMX274_DEF_FRAME_RATE);
> +
> + imx274->ctrls.vflip = v4l2_ctrl_new_std(&imx274->ctrls.handler,
> + &imx274_ctrl_ops,
> + V4L2_CID_VFLIP, 0, 1, 1, 0);
> +
> + imx274->sd.ctrl_handler = &imx274->ctrls.handler;
> + if (imx274->ctrls.handler.error) {
> + ret = imx274->ctrls.handler.error;
> + goto err_ctrls;
> + }
> +
> + /* setup default controls */
> + ret = v4l2_ctrl_handler_setup(&imx274->ctrls.handler);
> + if (ret) {
> + dev_err(&client->dev,
> + "Error %d setup default controls\n", ret);
> + goto err_ctrls;
> + }
> +
> + /* initialize format */
> + imx274->mode_index = IMX274_MODE_3840X2160;
> + imx274->format.width = imx274_formats[0].size.width;
> + imx274->format.height = imx274_formats[0].size.height;
> + imx274->format.field = V4L2_FIELD_NONE;
> + imx274->format.code = MEDIA_BUS_FMT_SRGGB10_1X10;
> + imx274->format.colorspace = V4L2_COLORSPACE_SRGB;
> + imx274->frame_interval.numerator = 1;
> + imx274->frame_interval.denominator = IMX274_DEF_FRAME_RATE;
> +
> + /* register subdevice */
> + ret = v4l2_async_register_subdev(sd);
> + if (ret < 0) {
> + dev_err(&client->dev,
> + "%s : v4l2_async_register_subdev failed %d\n",
> + __func__, ret);
> + goto err_ctrls;
> + }
> +
> + /* load default control values */
> + ret = imx274_load_default(imx274);
> + if (ret)

v4l2_async_unregister_subdev();

> + goto err_ctrls;
> +
> + v4l2_info(sd, "imx274 : imx274 probe success !\n");
> + return 0;
> +
> +err_ctrls:
> + v4l2_ctrl_handler_free(sd->ctrl_handler);
> +err_me:
> + media_entity_cleanup(&sd->entity);
> + mutex_destroy(&imx274->lock);
> + return ret;
> +}
> +
> +static int imx274_remove(struct i2c_client *client)
> +{
> + int ret;
> + struct v4l2_subdev *sd = i2c_get_clientdata(client);
> + struct stimx274 *imx274 = to_imx274(sd);
> +
> + /* stop stream */
> + ret = imx274_write_table(imx274,
> + mode_table[IMX274_MODE_STOP_STREAM]);
> + if (ret)
> + return ret;
> +
> + v4l2_device_unregister_subdev(sd);

Instead: v4l2_async_unregister_subdev().

> + v4l2_ctrl_handler_free(sd->ctrl_handler);
> + media_entity_cleanup(&sd->entity);
> + mutex_destroy(&imx274->lock);
> + return 0;
> +}
> +
> +static struct i2c_driver imx274_i2c_driver = {
> + .driver = {
> + .name = DRIVER_NAME,
> + .of_match_table = imx274_of_id_table,
> + },
> + .probe = imx274_probe,
> + .remove = imx274_remove,
> + .id_table = imx274_id,
> +};
> +
> +module_i2c_driver(imx274_i2c_driver);
> +
> +MODULE_AUTHOR("Leon Luo <leonl@xxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("IMX274 CMOS Image Sensor driver");
> +MODULE_LICENSE("GPL v2");

--
Regards,

Sakari Ailus
e-mail: sakari.ailus@xxxxxx