Re: [PATCH/RFC v3 3/5] leds: Add support for max77693 mfd flash cell

[Sakari Ailus]

Hi Jacek,

Thanks for the answers to my comments! :-)

On Thu, Apr 17, 2014 at 11:23:06AM +0200, Jacek Anaszewski wrote:
> On 04/16/2014 07:26 PM, Sakari Ailus wrote:
> >Hi Jacek,
> >
> >Thanks for the patch! Comments below.
> >
> >On Fri, Apr 11, 2014 at 04:56:54PM +0200, Jacek Anaszewski wrote:
> >>This patch adds led-flash support to Maxim max77693 chipset.
> >>A device can be exposed to user space through LED subsystem
> >>sysfs interface or through V4L2 subdevice when the support
> >>for V4L2 Flash sub-devices is enabled. Device supports up to
> >>two leds which can work in flash and torch mode. Leds can
> >>be triggered externally or by software.
> >>
> >>Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> >>Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
> >>Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> >>Cc: Bryan Wu <cooloney@xxxxxxxxx>
> >>Cc: Richard Purdie <rpurdie@xxxxxxxxx>
> >>Cc: SangYoung Son <hello.son@xxxxxxxxxxx>
> >>Cc: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
> >>Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> >>---
> >>  drivers/leds/Kconfig         |   10 +
> >>  drivers/leds/Makefile        |    1 +
> >>  drivers/leds/leds-max77693.c |  794 ++++++++++++++++++++++++++++++++++++++++++
> >>  drivers/mfd/max77693.c       |    2 +-
> >>  include/linux/mfd/max77693.h |   38 ++
> >>  5 files changed, 844 insertions(+), 1 deletion(-)
> >>  create mode 100644 drivers/leds/leds-max77693.c
> >>
> >>diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> >>index 1e1c81f..b2152a6 100644
> >>--- a/drivers/leds/Kconfig
> >>+++ b/drivers/leds/Kconfig
> >>@@ -462,6 +462,16 @@ config LEDS_TCA6507
> >>  	  LED driver chips accessed via the I2C bus.
> >>  	  Driver support brightness control and hardware-assisted blinking.
> >>
> >>+config LEDS_MAX77693
> >>+	tristate "LED support for MAX77693 Flash"
> >>+	depends on LEDS_CLASS_FLASH
> >>+	depends on MFD_MAX77693
> >>+	depends on OF
> >>+	help
> >>+	  This option enables support for the flash part of the MAX77693
> >>+	  multifunction device. It has build in control for two leds in flash
> >>+	  and torch mode.
> >>+
> >>  config LEDS_MAX8997
> >>  	tristate "LED support for MAX8997 PMIC"
> >>  	depends on LEDS_CLASS && MFD_MAX8997
> >>diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> >>index 8861b86..64f6234 100644
> >>--- a/drivers/leds/Makefile
> >>+++ b/drivers/leds/Makefile
> >>@@ -52,6 +52,7 @@ obj-$(CONFIG_LEDS_MC13783)		+= leds-mc13783.o
> >>  obj-$(CONFIG_LEDS_NS2)			+= leds-ns2.o
> >>  obj-$(CONFIG_LEDS_NETXBIG)		+= leds-netxbig.o
> >>  obj-$(CONFIG_LEDS_ASIC3)		+= leds-asic3.o
> >>+obj-$(CONFIG_LEDS_MAX77693)		+= leds-max77693.o
> >>  obj-$(CONFIG_LEDS_MAX8997)		+= leds-max8997.o
> >>  obj-$(CONFIG_LEDS_LM355x)		+= leds-lm355x.o
> >>  obj-$(CONFIG_LEDS_BLINKM)		+= leds-blinkm.o
> >>diff --git a/drivers/leds/leds-max77693.c b/drivers/leds/leds-max77693.c
> >>new file mode 100644
> >>index 0000000..979736c
> >>--- /dev/null
> >>+++ b/drivers/leds/leds-max77693.c
> >>@@ -0,0 +1,794 @@
> >>+/*
> >>+ *	Copyright (C) 2014, Samsung Electronics Co., Ltd.
> >>+ *
> >>+ *	Authors: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> >>+ *		 Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
> >>+ *
> >>+ * This program is free software; you can redistribute it and/or
> >>+ * modify it under the terms of the GNU General Public License
> >>+ * version 2 as published by the Free Software Foundation.
> >>+ */
> >>+
> >>+#include <asm/div64.h>
> >>+#include <linux/leds_flash.h>
> >>+#include <linux/module.h>
> >>+#include <linux/mutex.h>
> >>+#include <linux/platform_device.h>
> >>+#include <linux/slab.h>
> >>+#include <media/v4l2-flash.h>
> >
> >I guess this should be last in the list.
> >
> >>+#include <linux/workqueue.h>
> >>+#include <linux/mfd/max77693.h>
> >>+#include <linux/mfd/max77693-private.h>
> >>+
> >>+#define MAX77693_LED_NAME		"max77693-flash"
> >>+
> >>+#define MAX77693_TORCH_IOUT_BITS	4
> >>+
> >>+#define MAX77693_TORCH_NO_TIMER		0x40
> >>+#define MAX77693_FLASH_TIMER_LEVEL	0x80
> >>+
> >>+#define MAX77693_FLASH_EN_OFF		0
> >>+#define MAX77693_FLASH_EN_FLASH		1
> >>+#define MAX77693_FLASH_EN_TORCH		2
> >>+#define MAX77693_FLASH_EN_ON		3
> >>+
> >>+#define MAX77693_FLASH_EN1_SHIFT	6
> >>+#define MAX77693_FLASH_EN2_SHIFT	4
> >>+#define MAX77693_TORCH_EN1_SHIFT	2
> >>+#define MAX77693_TORCH_EN2_SHIFT	0
> >>+
> >>+#define MAX77693_FLASH_LOW_BATTERY_EN	0x80
> >>+
> >>+#define MAX77693_FLASH_BOOST_FIXED	0x04
> >>+#define MAX77693_FLASH_BOOST_LEDNUM_2	0x80
> >>+
> >>+#define MAX77693_FLASH_TIMEOUT_MIN	62500
> >>+#define MAX77693_FLASH_TIMEOUT_MAX	1000000
> >>+#define MAX77693_FLASH_TIMEOUT_STEP	62500
> >>+
> >>+#define MAX77693_TORCH_TIMEOUT_MIN	262000
> >>+#define MAX77693_TORCH_TIMEOUT_MAX	15728000
> >>+
> >>+#define MAX77693_FLASH_IOUT_MIN		15625
> >>+#define MAX77693_FLASH_IOUT_MAX_1LED	1000000
> >>+#define MAX77693_FLASH_IOUT_MAX_2LEDS	625000
> >>+#define MAX77693_FLASH_IOUT_STEP	15625
> >>+
> >>+#define MAX77693_TORCH_IOUT_MIN		15625
> >>+#define MAX77693_TORCH_IOUT_MAX		250000
> >>+#define MAX77693_TORCH_IOUT_STEP	15625
> >>+
> >>+#define MAX77693_FLASH_VSYS_MIN		2400
> >>+#define MAX77693_FLASH_VSYS_MAX		3400
> >>+#define MAX77693_FLASH_VSYS_STEP	33
> >>+
> >>+#define MAX77693_FLASH_VOUT_MIN		3300
> >>+#define MAX77693_FLASH_VOUT_MAX		5500
> >>+#define MAX77693_FLASH_VOUT_STEP	25
> >>+#define MAX77693_FLASH_VOUT_RMIN	0x0c
> >>+
> >>+#define MAX77693_LED_STATUS_FLASH_ON	(1 << 3)
> >>+#define MAX77693_LED_STATUS_TORCH_ON	(1 << 2)
> >>+
> >>+#define MAX77693_LED_FLASH_INT_FLED2_OPEN	(1 << 0)
> >>+#define MAX77693_LED_FLASH_INT_FLED2_SHORT	(1 << 1)
> >>+#define MAX77693_LED_FLASH_INT_FLED1_OPEN	(1 << 2)
> >>+#define MAX77693_LED_FLASH_INT_FLED1_SHORT	(1 << 3)
> >>+#define MAX77693_LED_FLASH_INT_OVER_CURRENT	(1 << 4)
> >>+
> >>+#define MAX77693_MODE_OFF			0
> >>+#define MAX77693_MODE_FLASH			(1 << 0)
> >>+#define MAX77693_MODE_TORCH			(1 << 1)
> >>+#define MAX77693_MODE_FLASH_EXTERNAL		(1 << 2)
> >>+
> >>+enum {
> >>+	FLASH1,
> >>+	FLASH2,
> >>+	TORCH1,
> >>+	TORCH2
> >>+};
> >>+
> >>+enum {
> >>+	FLASH,
> >>+	TORCH
> >>+};
> >>+
> >>+struct max77693_led {
> >>+	struct regmap *regmap;
> >>+	struct platform_device *pdev;
> >>+	struct max77693_led_platform_data *pdata;
> >>+	struct mutex lock;
> >>+
> >>+	struct led_classdev ldev;
> >>+
> >>+	unsigned int torch_brightness;
> >>+	struct work_struct work_brightness_set;
> >>+	unsigned int mode_flags;
> >>+};
> >>+
> >>+static u8 max77693_led_iout_to_reg(u32 ua)
> >>+{
> >>+	if (ua < MAX77693_FLASH_IOUT_MIN)
> >>+		ua = MAX77693_FLASH_IOUT_MIN;
> >>+	return (ua - MAX77693_FLASH_IOUT_MIN) / MAX77693_FLASH_IOUT_STEP;
> >>+}
> >>+
> >>+static u8 max77693_flash_timeout_to_reg(u32 us)
> >>+{
> >>+	return (us - MAX77693_FLASH_TIMEOUT_MIN) / MAX77693_FLASH_TIMEOUT_STEP;
> >>+}
> >>+
> >>+static const u32 max77693_torch_timeouts[] = {
> >>+	262000, 524000, 786000, 1048000,
> >>+	1572000, 2096000, 2620000, 3144000,
> >>+	4193000, 5242000, 6291000, 7340000,
> >>+	9437000, 11534000, 13631000, 1572800
> >>+};
> >>+
> >>+static u8 max77693_torch_timeout_to_reg(u32 us)
> >>+{
> >>+	int i, b = 0, e = ARRAY_SIZE(max77693_torch_timeouts);
> >
> >I haven't run this, but it looks like it'll access max77693_torch_timeouts[]
> >array after the last element if you pass it a value greater than 1572800.
> >Shouldn't e be initialised to ARRAY_SIZE() - 1 instead?
> >
> >>+
> >>+	while (e - b > 1) {
> >>+		i = b + (e - b) / 2;
> >>+		if (us < max77693_torch_timeouts[i])
> >>+			e = i;
> >>+		else
> >>+			b = i;
> >>+	}
> >>+	return b;
> >>+}
> 
> Let's track this case:
> 
> us = 1600000
> e = 16 (ARRAY_SIZE(max77693_torch_timeouts))
> 
> 1st iteration:
> 	while (16 - 0 > 1) {
> 		i = 0 + (16 - 0) / 2 //= 8
> 		b = 8
> 	}
> 
> 2nd iteration:
> 	while (16 - 8 > 1) {
> 		i = 8 + (16 - 8) / 2 //= 12
> 		b = 12
> 	}
> 
> 3rd iteration:
> 	while (16 - 12 > 1) {
> 		i = 12 + (16 - 12) / 2 //= 14
> 		b = 14
> 	}
> 
> 4th iteration:
> 	while (16 - 14 > 1) {
> 		i = 14 + (16 - 14) / 2 //= 15
> 		b = 15
> 	}
> 
> 5th iteration:
> 	while (16 - 15 > 1) { //false

Indeed, you're right -- "> 1" is the crucial part that I missed.

> 	}
> 
> 	return b (15) - last element in the array
> 	
> 
> >>+static struct max77693_led *ldev_to_led(struct led_classdev *ldev)
> >>+{
> >>+	return container_of(ldev, struct max77693_led, ldev);
> >>+}
> >>+
> >>+static u32 max77693_torch_timeout_from_reg(u8 reg)
> >>+{
> >
> >I might limit reg to ARRAY_SIZE(...) as well. Up to you.
> 
> It is already aligned during validation of platform data.

Ack.

> >>+	return max77693_torch_timeouts[reg];
> >>+}
> >>+
> >>+static u8 max77693_led_vsys_to_reg(u32 mv)
> >>+{
> >>+	return ((mv - MAX77693_FLASH_VSYS_MIN) / MAX77693_FLASH_VSYS_STEP) << 2;
> >>+}
> >>+
> >>+static u8 max77693_led_vout_to_reg(u32 mv)
> >>+{
> >>+	return (mv - MAX77693_FLASH_VOUT_MIN) / MAX77693_FLASH_VOUT_STEP +
> >>+		MAX77693_FLASH_VOUT_RMIN;
> >>+}
> >>+
> >>+/* split composite current @i into two @iout according to @imax weights */
> >
> >Are there dependencies between the two LEDs or are they entirely
> >independent? If they're independent (with the possible exception of strobe),
> >then I'd expose them individually.
> 
> They are independent.
> 
> >>+static void max77693_calc_iout(u32 iout[2], u32 i, u32 imax[2])
> >>+{
> >>+	u64 t = i;
> >>+
> >>+	t *= imax[1];
> >>+	do_div(t, imax[0] + imax[1]);
> >>+
> >>+	iout[1] = (u32)t / MAX77693_FLASH_IOUT_STEP * MAX77693_FLASH_IOUT_STEP;
> >>+	iout[0] = i - iout[1];
> >>+}
> >>+
> >>+static int max77693_set_mode(struct max77693_led *led, unsigned int mode)
> >>+{
> >>+	struct max77693_led_platform_data *p = led->pdata;
> >>+	struct regmap *rmap = led->regmap;
> >>+	int ret, v = 0;
> >>+
> >>+	if (mode & MAX77693_MODE_TORCH) {
> >>+		if (p->trigger[TORCH1] & MAX77693_LED_TRIG_SOFT)
> >>+			v |= MAX77693_FLASH_EN_ON << MAX77693_TORCH_EN1_SHIFT;
> >>+		if (p->trigger[TORCH2] & MAX77693_LED_TRIG_SOFT)
> >>+			v |= MAX77693_FLASH_EN_ON << MAX77693_TORCH_EN2_SHIFT;
> >>+	}
> >>+
> >>+	if (mode & MAX77693_MODE_FLASH) {
> >>+		if (p->trigger[FLASH1] & MAX77693_LED_TRIG_SOFT)
> >>+			v |= MAX77693_FLASH_EN_ON << MAX77693_FLASH_EN1_SHIFT;
> >>+		if (p->trigger[FLASH2] & MAX77693_LED_TRIG_SOFT)
> >>+			v |= MAX77693_FLASH_EN_ON << MAX77693_FLASH_EN2_SHIFT;
> >>+	} else if (mode & MAX77693_MODE_FLASH_EXTERNAL) {
> >>+		if (p->trigger[FLASH1] & MAX77693_LED_TRIG_EXT)
> >>+			v |= MAX77693_FLASH_EN_FLASH << MAX77693_FLASH_EN1_SHIFT;
> >>+		if (p->trigger[FLASH2] & MAX77693_LED_TRIG_EXT)
> >>+			v |= MAX77693_FLASH_EN_FLASH << MAX77693_FLASH_EN2_SHIFT;
> >>+		/*
> >>+		 * Enable hw triggering also for torch mode, as some camera
> >>+		 * sensors use torch led to fathom ambient light conditions
> >>+		 * before strobing the flash.
> >>+		 */
> >>+		if (p->trigger[TORCH1] & MAX77693_LED_TRIG_EXT)
> >>+			v |= MAX77693_FLASH_EN_TORCH << MAX77693_TORCH_EN1_SHIFT;
> >>+		if (p->trigger[TORCH2] & MAX77693_LED_TRIG_EXT)
> >>+			v |= MAX77693_FLASH_EN_TORCH << MAX77693_TORCH_EN2_SHIFT;
> >>+	}
> >>+
> >>+	/* Reset the register only prior setting flash modes */
> >>+	if (mode != MAX77693_MODE_TORCH) {
> >>+		ret = max77693_write_reg(rmap, MAX77693_LED_REG_FLASH_EN, 0);
> >
> >A single wrie for strobe. Looks good!
> >
> >>+		if (ret < 0)
> >>+			return ret;
> >>+	}
> >>+
> >>+	return max77693_write_reg(rmap, MAX77693_LED_REG_FLASH_EN, v);
> >>+}
> >>+
> >>+static int max77693_add_mode(struct max77693_led *led, unsigned int mode)
> >>+{
> >>+	int ret;
> >>+
> >>+	/* Once enabled torch mode is active until turned off */
> >>+	if ((mode == MAX77693_MODE_TORCH) &&
> >>+	    (led->mode_flags & MAX77693_MODE_TORCH))
> >>+		return 0;
> >>+
> >>+	/*
> >>+	 * FLASH_EXTERNAL mode activates HW triggered flash and torch
> >>+	 * modes in the device. The related register settings interfere
> >>+	 * with SW triggerred modes, thus clear them to ensure proper
> >>+	 * device configuration.
> >>+	 */
> >>+	if (mode == MAX77693_MODE_FLASH_EXTERNAL)
> >>+		led->mode_flags &= (~MAX77693_MODE_TORCH &
> >>+				    ~MAX77693_MODE_FLASH);
> >>+
> >>+	led->mode_flags |= mode;
> >>+
> >>+	ret = max77693_set_mode(led, led->mode_flags);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	/*
> >>+	 * Clear flash mode flag after setting the mode to avoid
> >>+	 * spurous flash strobing on each successive torch mode
> >>+	 * setting.
> >>+	 */
> >>+	if ((mode == MAX77693_MODE_FLASH) ||
> >>+	    (mode == MAX77693_MODE_FLASH_EXTERNAL))
> >>+		led->mode_flags &= ~mode;
> >>+
> >>+	return 0;
> >>+}
> >>+
> >>+static int max77693_clear_mode(struct max77693_led *led, unsigned int mode)
> >>+{
> >>+	led->mode_flags &= ~mode;
> >>+
> >>+	return max77693_set_mode(led, led->mode_flags);
> >>+}
> >>+
> >>+static int max77693_set_torch_current(struct max77693_led *led,
> >>+					u32 micro_amp)
> >>+{
> >>+	struct max77693_led_platform_data *p = led->pdata;
> >>+	struct regmap *rmap = led->regmap;
> >>+	u32 iout[2];
> >>+	u8 v, iout1_reg, iout2_reg;
> >>+	int ret;
> >>+
> >>+	max77693_calc_iout(iout, micro_amp, &p->iout[TORCH1]);
> >>+	iout1_reg = max77693_led_iout_to_reg(iout[0]);
> >>+	iout2_reg = max77693_led_iout_to_reg(iout[1]);
> >>+
> >>+	v = iout1_reg | (iout2_reg << MAX77693_TORCH_IOUT_BITS);
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_ITORCH, v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	return 0;
> >>+}
> >>+
> >>+static int max77693_set_flash_current(struct max77693_led *led,
> >>+					u32 micro_amp)
> >>+{
> >>+	struct max77693_led_platform_data *p = led->pdata;
> >>+	struct regmap *rmap = led->regmap;
> >>+	u32 iout[2];
> >>+	u8 iout1_reg, iout2_reg;
> >>+	int ret;
> >>+
> >>+	max77693_calc_iout(iout, micro_amp, &p->iout[FLASH1]);
> >>+	iout1_reg = max77693_led_iout_to_reg(iout[0]);
> >>+	iout2_reg = max77693_led_iout_to_reg(iout[1]);
> >>+
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_IFLASH1, iout1_reg);
> >>+	if (ret < 0)
> >>+		goto error_ret;
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_IFLASH2, iout2_reg);
> >>+	if (ret < 0)
> >>+		goto error_ret;
> >>+
> >>+error_ret:
> >>+	return ret;
> >>+}
> >>+
> >>+static int max77693_set_timeout(struct max77693_led *led,
> >>+				u32 timeout)
> >>+{
> >>+	struct max77693_led_platform_data *p = led->pdata;
> >>+	struct regmap *rmap = led->regmap;
> >>+	u8 v;
> >>+
> >>+	v = max77693_flash_timeout_to_reg(timeout);
> >>+
> >>+	if (p->trigger_type[FLASH] == MAX77693_LED_TRIG_TYPE_LEVEL)
> >>+		v |= MAX77693_FLASH_TIMER_LEVEL;
> >>+
> >>+	return max77693_write_reg(rmap, MAX77693_LED_REG_FLASH_TIMER, v);
> >>+}
> >>+
> >>+static int max77693_strobe_status_get(struct max77693_led *led)
> >>+{
> >>+	struct regmap *rmap = led->regmap;
> >>+	u8 v;
> >>+	int ret;
> >>+
> >>+	ret = max77693_read_reg(rmap, MAX77693_LED_REG_FLASH_INT_STATUS, &v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	return !!(v & MAX77693_LED_STATUS_FLASH_ON);
> >>+}
> >>+
> >>+static int max77693_int_flag_get(struct max77693_led *led, u8 *v)
> >>+{
> >>+	struct regmap *rmap = led->regmap;
> >>+
> >>+	return max77693_read_reg(rmap, MAX77693_LED_REG_FLASH_INT, v);
> >>+}
> >>+
> >>+static int max77693_setup(struct max77693_led *led)
> >>+{
> >>+	struct max77693_led_platform_data *p = led->pdata;
> >>+	struct regmap *rmap = led->regmap;
> >>+	int ret;
> >>+	u8 v;
> >>+
> >>+	ret = max77693_set_torch_current(led, p->iout[TORCH1] +
> >>+						p->iout[TORCH2]);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	ret = max77693_set_flash_current(led, p->iout[FLASH1] +
> >>+						p->iout[FLASH2]);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	if (p->timeout[TORCH] > 0)
> >>+		v = max77693_torch_timeout_to_reg(p->timeout[TORCH]);
> >>+	else
> >>+		v = MAX77693_TORCH_NO_TIMER;
> >>+	if (p->trigger_type[TORCH] == MAX77693_LED_TRIG_TYPE_LEVEL)
> >>+		v |= MAX77693_FLASH_TIMER_LEVEL;
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_ITORCHTIMER, v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	v = max77693_flash_timeout_to_reg(p->timeout[FLASH]);
> >>+	if (p->trigger_type[FLASH] == MAX77693_LED_TRIG_TYPE_LEVEL)
> >>+		v |= MAX77693_FLASH_TIMER_LEVEL;
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_FLASH_TIMER, v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	if (p->low_vsys > 0)
> >>+		v = max77693_led_vsys_to_reg(p->low_vsys) |
> >>+						MAX77693_FLASH_LOW_BATTERY_EN;
> >>+	else
> >>+		v = 0;
> >>+
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_MAX_FLASH1, v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_MAX_FLASH2, 0);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	if (p->boost_mode[FLASH1] == MAX77693_LED_BOOST_FIXED ||
> >>+	    p->boost_mode[FLASH2] == MAX77693_LED_BOOST_FIXED)
> >>+		v = MAX77693_FLASH_BOOST_FIXED;
> >>+	else
> >>+		v = p->boost_mode[FLASH1] | (p->boost_mode[FLASH2] << 1);
> >>+	if (p->boost_mode[FLASH1] && p->boost_mode[FLASH2])
> >>+		v |= MAX77693_FLASH_BOOST_LEDNUM_2;
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_VOUT_CNTL, v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	v = max77693_led_vout_to_reg(p->boost_vout);
> >>+	ret = max77693_write_reg(rmap, MAX77693_LED_REG_VOUT_FLASH1, v);
> >>+	if (ret < 0)
> >>+		return ret;
> >>+
> >>+	return max77693_set_mode(led, MAX77693_MODE_OFF);
> >>+}
> >>+
> >>+/* LED subsystem callbacks */
> >>+
> >>+static void max77693_brightness_set_work(struct work_struct *work)
> >>+{
> >>+	struct max77693_led *led =
> >>+		container_of(work, struct max77693_led, work_brightness_set);
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+
> >>+	if (led->torch_brightness == 0) {
> >>+		ret = max77693_clear_mode(led, MAX77693_MODE_TORCH);
> >>+		if (ret < 0)
> >>+			dev_dbg(&led->pdev->dev,
> >>+				"Failed to clear torch mode (%d)\n",
> >>+				ret);
> >>+		goto unlock;
> >>+	}
> >>+
> >>+	ret = max77693_set_torch_current(led, led->torch_brightness *
> >>+						MAX77693_TORCH_IOUT_STEP);
> >>+	if (ret < 0) {
> >>+		dev_dbg(&led->pdev->dev, "Failed to set torch current (%d)\n",
> >>+			ret);
> >>+		goto unlock;
> >>+	}
> >>+
> >>+	ret = max77693_add_mode(led, MAX77693_MODE_TORCH);
> >>+	if (ret < 0)
> >>+		dev_dbg(&led->pdev->dev, "Failed to set torch mode (%d)\n",
> >>+			ret);
> >>+unlock:
> >>+	mutex_unlock(&led->lock);
> >>+}
> >>+
> >>+static void max77693_led_brightness_set(struct led_classdev *led_cdev,
> >>+				enum led_brightness value)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+
> >>+	led->torch_brightness = value;
> >>+	schedule_work(&led->work_brightness_set);
> >
> >Is there a reason not to do this right now (but in a work queue instead)?
> 
> Almost all the drivers in the LED subsystem do it that way.
> I think that it is caused by the fact that setting led brightness
> should be as fast as possible and non-blocking. The led may be
> used e.g. for HD LED (see ledtrig-ide) and activated many times
> per second, and thus it could have impact on the system performance
> if it wasn't run in a work queue.

Fair enough. But the expectation is that the V4L2 control's value has taken
effect when the set control handler returns. That is also what virtually all
existing implementations do.

Could this be handled in the LED framework instead so that the V4L2 controls
would function synchronously?

I'm ok for postponing this as long as we agree on how it'd be fixed. Perhaps
someone from the LED framework side to comment.

> >>+}
> >>+
> >>+static int max77693_led_flash_strobe_get(struct led_classdev *led_cdev)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+	ret = max77693_strobe_status_get(led);
> >>+	mutex_unlock(&led->lock);
> >>+
> >>+	return ret;
> >>+}
> >>+
> >>+static int max77693_led_flash_fault_get(struct led_classdev *led_cdev,
> >>+					u32 *fault)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+	u8 v;
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+
> >>+	ret = max77693_int_flag_get(led, &v);
> >>+	if (ret < 0)
> >>+		goto unlock;
> >>+
> >>+	*fault = 0;
> >>+
> >>+	if (v & MAX77693_LED_FLASH_INT_FLED2_OPEN ||
> >>+	    v & MAX77693_LED_FLASH_INT_FLED1_OPEN)
> >>+		*fault |= LED_FAULT_OVER_VOLTAGE;
> >>+	if (v & MAX77693_LED_FLASH_INT_FLED2_SHORT ||
> >>+	    v & MAX77693_LED_FLASH_INT_FLED1_SHORT)
> >>+		*fault |= LED_FAULT_SHORT_CIRCUIT;
> >>+	if (v & MAX77693_LED_FLASH_INT_OVER_CURRENT)
> >>+		*fault |= LED_FAULT_OVER_CURRENT;
> >>+unlock:
> >>+	mutex_unlock(&led->lock);
> >>+	return ret;
> >>+}
> >>+
> >>+static int max77693_led_flash_strobe_set(struct led_classdev *led_cdev,
> >>+						bool state)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+	struct led_flash *flash = led_cdev->flash;
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+
> >>+	if (flash->external_strobe) {
> >>+		ret = -EBUSY;
> >>+		goto unlock;
> >>+	}
> >>+
> >>+	if (!state) {
> >>+		ret = max77693_clear_mode(led, MAX77693_MODE_FLASH);
> >>+		goto unlock;
> >>+	}
> >>+
> >>+	ret = max77693_add_mode(led, MAX77693_MODE_FLASH);
> >>+	if (ret < 0)
> >>+		goto unlock;
> >>+unlock:
> >>+	mutex_unlock(&led->lock);
> >>+	return ret;
> >>+}
> >>+
> >>+static int max77693_led_external_strobe_set(struct led_classdev *led_cdev,
> >>+						bool enable)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+
> >>+	if (enable)
> >>+		ret = max77693_add_mode(led, MAX77693_MODE_FLASH_EXTERNAL);
> >>+	else
> >>+		ret = max77693_clear_mode(led, MAX77693_MODE_FLASH_EXTERNAL);
> >>+
> >>+	mutex_unlock(&led->lock);
> >>+
> >>+	return ret;
> >>+}
> >>+
> >>+static int max77693_led_flash_brightness_set(struct led_classdev *led_cdev,
> >>+						u32 brightness)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+
> >>+	ret = max77693_set_flash_current(led, brightness);
> >>+	if (ret < 0)
> >>+		goto unlock;
> >>+unlock:
> >>+	mutex_unlock(&led->lock);
> >>+	return ret;
> >>+}
> >>+
> >>+static int max77693_led_flash_timeout_set(struct led_classdev *led_cdev,
> >>+						u32 timeout)
> >>+{
> >>+	struct max77693_led *led = ldev_to_led(led_cdev);
> >>+	int ret;
> >>+
> >>+	mutex_lock(&led->lock);
> >>+
> >>+	ret = max77693_set_timeout(led, timeout);
> >>+	if (ret < 0)
> >>+		goto unlock;
> >>+
> >>+unlock:
> >>+	mutex_unlock(&led->lock);
> >>+	return ret;
> >>+}
> >>+
> >>+static void max77693_led_parse_dt(struct max77693_led_platform_data *p,
> >>+			    struct device_node *node)
> >>+{
> >>+	of_property_read_u32_array(node, "maxim,iout", p->iout, 4);
> >
> >How about separate current for flash and torch modes? They are the same
> >LEDs; just the mode is different.
> 
> There are separate currents - 2 for torch and 2 for flash mode.

True. But shouldn't they be two different properties as, well, these are
different properties of individual hardware devices? :-)

> >>+	of_property_read_u32_array(node, "maxim,trigger", p->trigger, 4);
> >>+	of_property_read_u32_array(node, "maxim,trigger-type", p->trigger_type,
> >>+									2);
> >>+	of_property_read_u32_array(node, "maxim,timeout", p->timeout, 2);
> >>+	of_property_read_u32_array(node, "maxim,boost-mode", p->boost_mode, 2);
> >>+	of_property_read_u32(node, "maxim,boost-vout", &p->boost_vout);
> >>+	of_property_read_u32(node, "maxim,vsys-min", &p->low_vsys);
> >
> >Are these values specific to the maxim chip? I'd suppose e.g. timeout and
> >iout are something that can be found pretty much in any flash controller.
> 
> Besides the two they are specific. And what with timeout and iout
> if they are common for all flash controllers?

They should be defined in a way which is not specific to the chip itself.
That would also change the property names. I'm not sure how much of this is
already done on the LED side.

> >>+}
> >>+
> >>+static void clamp_align(u32 *v, u32 min, u32 max, u32 step)
> >>+{
> >>+	*v = clamp_val(*v, min, max);
> >>+	if (step > 1)
> >>+		*v = (*v - min) / step * step + min;
> >>+}
> >>+
> >>+static void max77693_led_validate_platform_data(
> >>+					struct max77693_led_platform_data *p)
> >>+{
> >>+	u32 max;
> >>+	int i;
> >>+
> >>+	for (i = 0; i < 2; ++i)
> >
> >How about using ARRAY_SIZE() here, too?
> 
> OK.
> 
> >
> >>+		clamp_align(&p->boost_mode[i], MAX77693_LED_BOOST_NONE,
> >>+			    MAX77693_LED_BOOST_FIXED, 1);
> >>+	/* boost, if enabled, should be the same on both leds */
> >>+	if (p->boost_mode[0] != MAX77693_LED_BOOST_NONE &&
> >>+	    p->boost_mode[1] != MAX77693_LED_BOOST_NONE)
> >>+		p->boost_mode[1] = p->boost_mode[0];
> >>+
> >>+	max = (p->boost_mode[FLASH1] && p->boost_mode[FLASH2]) ?
> >>+		  MAX77693_FLASH_IOUT_MAX_2LEDS : MAX77693_FLASH_IOUT_MAX_1LED;
> >>+
> >>+	clamp_align(&p->iout[FLASH1], MAX77693_FLASH_IOUT_MIN,
> >>+		    max, MAX77693_FLASH_IOUT_STEP);
> >>+	clamp_align(&p->iout[FLASH2], MAX77693_FLASH_IOUT_MIN,
> >>+		    max, MAX77693_FLASH_IOUT_STEP);
> >>+	clamp_align(&p->iout[TORCH1], MAX77693_TORCH_IOUT_MIN,
> >>+		    MAX77693_TORCH_IOUT_MAX, MAX77693_TORCH_IOUT_STEP);
> >>+	clamp_align(&p->iout[TORCH2], MAX77693_TORCH_IOUT_MIN,
> >>+		    MAX77693_TORCH_IOUT_MAX, MAX77693_TORCH_IOUT_STEP);
> >>+
> >>+	for (i = 0; i < 4; ++i)
> >>+		clamp_align(&p->trigger[i], 0, 7, 1);

You can just use clamp() here. Same elsewhere where step == 1.

> >>+	for (i = 0; i < 2; ++i)
> >>+		clamp_align(&p->trigger_type[i], MAX77693_LED_TRIG_TYPE_EDGE,
> >>+			    MAX77693_LED_TRIG_TYPE_LEVEL, 1);
> >
> >ARRAY_SIZE() would be nicer than using numeric values for the loop
> >condition.
> >
> >>+	clamp_align(&p->timeout[FLASH], MAX77693_FLASH_TIMEOUT_MIN,
> >>+		    MAX77693_FLASH_TIMEOUT_MAX, MAX77693_FLASH_TIMEOUT_STEP);
> >>+
> >>+	if (p->timeout[TORCH]) {
> >>+		clamp_align(&p->timeout[TORCH], MAX77693_TORCH_TIMEOUT_MIN,
> >>+			    MAX77693_TORCH_TIMEOUT_MAX, 1);
> >>+		p->timeout[TORCH] = max77693_torch_timeout_from_reg(
> >>+			      max77693_torch_timeout_to_reg(p->timeout[TORCH]));
> >>+	}
> >>+
> >>+	clamp_align(&p->boost_vout, MAX77693_FLASH_VOUT_MIN,
> >>+		    MAX77693_FLASH_VOUT_MAX, MAX77693_FLASH_VOUT_STEP);
> >>+
> >>+	if (p->low_vsys) {

Extra braces.

> >>+		clamp_align(&p->low_vsys, MAX77693_FLASH_VSYS_MIN,
> >>+			    MAX77693_FLASH_VSYS_MAX, MAX77693_FLASH_VSYS_STEP);
> >>+	}
> >>+}
> >>+
> >>+static int max77693_led_get_platform_data(struct max77693_led *led)
> >>+{
> >>+	struct max77693_led_platform_data *p;
> >>+	struct device *dev = &led->pdev->dev;
> >>+
> >>+	if (dev->of_node) {
> >>+		p = devm_kzalloc(dev, sizeof(*led->pdata), GFP_KERNEL);
> >>+		if (!p)
> >>+			return -ENOMEM;
> >
> >Check for p can be moved out of the if as it's the same for both.
> >
> >You could also use led->pdata directly. Up to you.
> >
> >>+		max77693_led_parse_dt(p, dev->of_node);
> >>+	} else {
> >>+		p = dev_get_platdata(dev);
> >>+		if (!p)
> >>+			return -ENODEV;
> >>+	}
> >>+	led->pdata = p;
> >>+
> >>+	max77693_led_validate_platform_data(p);
> >>+
> >>+	return 0;
> >>+}
> >>+
> >>+static struct led_flash led_flash = {
> >>+	.ops = {
> >>+		.brightness_set		= max77693_led_flash_brightness_set,
> >>+		.strobe_set		= max77693_led_flash_strobe_set,
> >>+		.strobe_get		= max77693_led_flash_strobe_get,
> >>+		.timeout_set		= max77693_led_flash_timeout_set,
> >>+		.external_strobe_set	= max77693_led_external_strobe_set,
> >>+		.fault_get		= max77693_led_flash_fault_get,
> >>+	},
> >>+	.has_flash_led = true,
> >>+};
> >>+
> >>+static void max77693_init_led_controls(struct led_classdev *led_cdev,
> >>+					struct max77693_led_platform_data *p)
> >>+{
> >>+	struct led_flash *flash = led_cdev->flash;
> >>+	struct led_ctrl *c;
> >>+
> >>+	/*
> >>+	 * brightness_ctrl and fault_flags are used only
> >>+	 * for initializing related V4L2 controls.
> >>+	 */
> >>+#ifdef CONFIG_V4L2_FLASH
> >>+	flash->fault_flags = V4L2_FLASH_FAULT_OVER_VOLTAGE |
> >>+			     V4L2_FLASH_FAULT_SHORT_CIRCUIT |
> >>+			     V4L2_FLASH_FAULT_OVER_CURRENT;
> >>+
> >>+	c = &led_cdev->brightness_ctrl;
> >>+	c->min = (p->iout[TORCH1] != 0 && p->iout[TORCH2] != 0) ?
> >>+					MAX77693_TORCH_IOUT_MIN * 2 :
> >>+					MAX77693_TORCH_IOUT_MIN;
> >>+	c->max = p->iout[TORCH1] + p->iout[TORCH2];
> >>+	c->step = MAX77693_TORCH_IOUT_STEP;
> >>+	c->val = p->iout[TORCH1] + p->iout[TORCH2];
> >
> >Can you control the current for the two flash LEDs separately?
> 
> Yes.
> 
> >If yes, this
> >should be also available on the V4L2 flash API. The lm3560 driver does this,
> >for example. (It creates two sub-devices since we can only control a single
> >LED using a single sub-device, at least for the time being.)
> 
> So, should I propose new V4L2 flash API for controlling more than
> one led? Probably similar improvement should be applied to the
> LED subsystem.

As said, the V4L2 API exposes two sub-devices currently. That's just a hack,
though; I think we need extensions in the V4L2 core API to support this
properly: controls are per-(sub)device and we certainly do not want controls
such as V4L2_CID_FLASH2_INTENSITY. But I don't think it's an excuse for e.g.
LED API not to do it. :-)

One option would be to use a matrix control but I'm not sure how much I like
that option either: there's nothing in the API that suggests that the index
is the LED number, for instance. That is still the only realistic
possibility right now. Actually --- this is what I'd suggest right now. Cc
Hans.

What I'm worried about is that, as this will affect the user space API in a
way or another very probably, changing it later on could be a problem. That
has been proved multiple times and people are often afraid of even trying to
do so. So if we can think of a way how to meaningfully extend the LED API
now into this direction and get an acceptance from the LED API developers,
that would be highly appreciated.

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@xxxxxx	XMPP: sailus@xxxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/