Re: [PATCH v3 1/2] platform: Add Amlogic Meson AO CEC Controller driver

From: Hans Verkuil
Date: Fri Jul 28 2017 - 08:58:53 EST

On 07/27/2017 05:20 PM, Neil Armstrong wrote:
> The Amlogic SoC embeds a standalone CEC controller, this patch adds a driver
> for such controller.
> The controller does not need HPD to be active, and could support up to max
> 5 logical addresses, but only 1 is handled since the Suspend firmware can
> make use of this unique logical address to wake up the device.
>
> The Suspend firmware configuration will be added in an other patchset.
>
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> ---
> drivers/media/platform/Kconfig | 11 +
> drivers/media/platform/Makefile | 2 +
> drivers/media/platform/meson/Makefile | 1 +
> drivers/media/platform/meson/ao-cec.c | 744 ++++++++++++++++++++++++++++++++++
> 4 files changed, 758 insertions(+)
> create mode 100644 drivers/media/platform/meson/Makefile
> create mode 100644 drivers/media/platform/meson/ao-cec.c
>
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 1313cd5..1e67381 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -536,6 +536,17 @@ menuconfig CEC_PLATFORM_DRIVERS
>
> if CEC_PLATFORM_DRIVERS
>
> +config VIDEO_MESON_AO_CEC
> + tristate "Amlogic Meson AO CEC driver"
> + depends on ARCH_MESON || COMPILE_TEST
> + select CEC_CORE
> + select CEC_NOTIFIER
> + ---help---
> + This is a driver for Amlogic Meson SoCs AO CEC interface. It uses the
> + generic CEC framework interface.
> + CEC bus is present in the HDMI connector and enables communication
> + between compatible devices.
> +
> config VIDEO_SAMSUNG_S5P_CEC
> tristate "Samsung S5P CEC driver"
> depends on PLAT_S5P || ARCH_EXYNOS || COMPILE_TEST
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index 9beadc7..a52d7b6 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -86,3 +86,5 @@ obj-$(CONFIG_VIDEO_MEDIATEK_MDP) += mtk-mdp/
> obj-$(CONFIG_VIDEO_MEDIATEK_JPEG) += mtk-jpeg/
>
> obj-$(CONFIG_VIDEO_QCOM_VENUS) += qcom/venus/
> +
> +obj-y += meson/
> diff --git a/drivers/media/platform/meson/Makefile b/drivers/media/platform/meson/Makefile
> new file mode 100644
> index 0000000..597beb8
> --- /dev/null
> +++ b/drivers/media/platform/meson/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_VIDEO_MESON_AO_CEC) += ao-cec.o
> diff --git a/drivers/media/platform/meson/ao-cec.c b/drivers/media/platform/meson/ao-cec.c
> new file mode 100644
> index 0000000..5c3607c
> --- /dev/null
> +++ b/drivers/media/platform/meson/ao-cec.c
> @@ -0,0 +1,744 @@
> +/*
> + * Driver for Amlogic Meson AO CEC Controller
> + *
> + * Copyright (C) 2015 Amlogic, Inc. All rights reserved
> + * Copyright (C) 2017 BayLibre, SAS
> + * Author: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> + *
> + * SPDX-License-Identifier: GPL-2.0+
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +#include <linux/interrupt.h>
> +#include <linux/reset.h>
> +#include <media/cec.h>
> +#include <media/cec-notifier.h>
> +
> +/* CEC Registers */
> +
> +/*
> + * [2:1] cntl_clk
> + * - 0 = Disable clk (Power-off mode)
> + * - 1 = Enable gated clock (Normal mode)
> + * - 2 = Enable free-run clk (Debug mode)
> + */
> +#define CEC_GEN_CNTL_REG 0x00
> +
> +#define CEC_GEN_CNTL_RESET BIT(0)
> +#define CEC_GEN_CNTL_CLK_DISABLE 0
> +#define CEC_GEN_CNTL_CLK_ENABLE 1
> +#define CEC_GEN_CNTL_CLK_ENABLE_DBG 2
> +#define CEC_GEN_CNTL_CLK_CTRL_MASK GENMASK(2, 1)
> +
> +/*
> + * [7:0] cec_reg_addr
> + * [15:8] cec_reg_wrdata
> + * [16] cec_reg_wr
> + * - 0 = Read
> + * - 1 = Write
> + * [23] bus free
> + * [31:24] cec_reg_rddata
> + */
> +#define CEC_RW_REG 0x04
> +
> +#define CEC_RW_ADDR GENMASK(7, 0)
> +#define CEC_RW_WR_DATA GENMASK(15, 8)
> +#define CEC_RW_WRITE_EN BIT(16)
> +#define CEC_RW_BUS_BUSY BIT(23)
> +#define CEC_RW_RD_DATA GENMASK(31, 24)
> +
> +/*
> + * [1] tx intr
> + * [2] rx intr
> + */
> +#define CEC_INTR_MASKN_REG 0x08
> +#define CEC_INTR_CLR_REG 0x0c
> +#define CEC_INTR_STAT_REG 0x10
> +
> +#define CEC_INTR_TX BIT(1)
> +#define CEC_INTR_RX BIT(2)
> +
> +/* CEC Commands */
> +
> +#define CEC_TX_MSG_0_HEADER 0x00
> +#define CEC_TX_MSG_1_OPCODE 0x01
> +#define CEC_TX_MSG_2_OP1 0x02
> +#define CEC_TX_MSG_3_OP2 0x03
> +#define CEC_TX_MSG_4_OP3 0x04
> +#define CEC_TX_MSG_5_OP4 0x05
> +#define CEC_TX_MSG_6_OP5 0x06
> +#define CEC_TX_MSG_7_OP6 0x07
> +#define CEC_TX_MSG_8_OP7 0x08
> +#define CEC_TX_MSG_9_OP8 0x09
> +#define CEC_TX_MSG_A_OP9 0x0A
> +#define CEC_TX_MSG_B_OP10 0x0B
> +#define CEC_TX_MSG_C_OP11 0x0C
> +#define CEC_TX_MSG_D_OP12 0x0D
> +#define CEC_TX_MSG_E_OP13 0x0E
> +#define CEC_TX_MSG_F_OP14 0x0F
> +#define CEC_TX_MSG_LENGTH 0x10
> +#define CEC_TX_MSG_CMD 0x11
> +#define CEC_TX_WRITE_BUF 0x12
> +#define CEC_TX_CLEAR_BUF 0x13
> +#define CEC_RX_MSG_CMD 0x14
> +#define CEC_RX_CLEAR_BUF 0x15
> +#define CEC_LOGICAL_ADDR0 0x16
> +#define CEC_LOGICAL_ADDR1 0x17
> +#define CEC_LOGICAL_ADDR2 0x18
> +#define CEC_LOGICAL_ADDR3 0x19
> +#define CEC_LOGICAL_ADDR4 0x1A
> +#define CEC_CLOCK_DIV_H 0x1B
> +#define CEC_CLOCK_DIV_L 0x1C
> +#define CEC_QUIESCENT_25MS_BIT7_0 0x20
> +#define CEC_QUIESCENT_25MS_BIT11_8 0x21
> +#define CEC_STARTBITMINL2H_3MS5_BIT7_0 0x22
> +#define CEC_STARTBITMINL2H_3MS5_BIT8 0x23
> +#define CEC_STARTBITMAXL2H_3MS9_BIT7_0 0x24
> +#define CEC_STARTBITMAXL2H_3MS9_BIT8 0x25
> +#define CEC_STARTBITMINH_0MS6_BIT7_0 0x26
> +#define CEC_STARTBITMINH_0MS6_BIT8 0x27
> +#define CEC_STARTBITMAXH_1MS0_BIT7_0 0x28
> +#define CEC_STARTBITMAXH_1MS0_BIT8 0x29
> +#define CEC_STARTBITMINTOT_4MS3_BIT7_0 0x2A
> +#define CEC_STARTBITMINTOT_4MS3_BIT9_8 0x2B
> +#define CEC_STARTBITMAXTOT_4MS7_BIT7_0 0x2C
> +#define CEC_STARTBITMAXTOT_4MS7_BIT9_8 0x2D
> +#define CEC_LOGIC1MINL2H_0MS4_BIT7_0 0x2E
> +#define CEC_LOGIC1MINL2H_0MS4_BIT8 0x2F
> +#define CEC_LOGIC1MAXL2H_0MS8_BIT7_0 0x30
> +#define CEC_LOGIC1MAXL2H_0MS8_BIT8 0x31
> +#define CEC_LOGIC0MINL2H_1MS3_BIT7_0 0x32
> +#define CEC_LOGIC0MINL2H_1MS3_BIT8 0x33
> +#define CEC_LOGIC0MAXL2H_1MS7_BIT7_0 0x34
> +#define CEC_LOGIC0MAXL2H_1MS7_BIT8 0x35
> +#define CEC_LOGICMINTOTAL_2MS05_BIT7_0 0x36
> +#define CEC_LOGICMINTOTAL_2MS05_BIT9_8 0x37
> +#define CEC_LOGICMAXHIGH_2MS8_BIT7_0 0x38
> +#define CEC_LOGICMAXHIGH_2MS8_BIT8 0x39
> +#define CEC_LOGICERRLOW_3MS4_BIT7_0 0x3A
> +#define CEC_LOGICERRLOW_3MS4_BIT8 0x3B
> +#define CEC_NOMSMPPOINT_1MS05 0x3C
> +#define CEC_DELCNTR_LOGICERR 0x3E
> +#define CEC_TXTIME_17MS_BIT7_0 0x40
> +#define CEC_TXTIME_17MS_BIT10_8 0x41
> +#define CEC_TXTIME_2BIT_BIT7_0 0x42
> +#define CEC_TXTIME_2BIT_BIT10_8 0x43
> +#define CEC_TXTIME_4BIT_BIT7_0 0x44
> +#define CEC_TXTIME_4BIT_BIT10_8 0x45
> +#define CEC_STARTBITNOML2H_3MS7_BIT7_0 0x46
> +#define CEC_STARTBITNOML2H_3MS7_BIT8 0x47
> +#define CEC_STARTBITNOMH_0MS8_BIT7_0 0x48
> +#define CEC_STARTBITNOMH_0MS8_BIT8 0x49
> +#define CEC_LOGIC1NOML2H_0MS6_BIT7_0 0x4A
> +#define CEC_LOGIC1NOML2H_0MS6_BIT8 0x4B
> +#define CEC_LOGIC0NOML2H_1MS5_BIT7_0 0x4C
> +#define CEC_LOGIC0NOML2H_1MS5_BIT8 0x4D
> +#define CEC_LOGIC1NOMH_1MS8_BIT7_0 0x4E
> +#define CEC_LOGIC1NOMH_1MS8_BIT8 0x4F
> +#define CEC_LOGIC0NOMH_0MS9_BIT7_0 0x50
> +#define CEC_LOGIC0NOMH_0MS9_BIT8 0x51
> +#define CEC_LOGICERRLOW_3MS6_BIT7_0 0x52
> +#define CEC_LOGICERRLOW_3MS6_BIT8 0x53
> +#define CEC_CHKCONTENTION_0MS1 0x54
> +#define CEC_PREPARENXTBIT_0MS05_BIT7_0 0x56
> +#define CEC_PREPARENXTBIT_0MS05_BIT8 0x57
> +#define CEC_NOMSMPACKPOINT_0MS45 0x58
> +#define CEC_ACK0NOML2H_1MS5_BIT7_0 0x5A
> +#define CEC_ACK0NOML2H_1MS5_BIT8 0x5B
> +#define CEC_BUGFIX_DISABLE_0 0x60
> +#define CEC_BUGFIX_DISABLE_1 0x61
> +#define CEC_RX_MSG_0_HEADER 0x80
> +#define CEC_RX_MSG_1_OPCODE 0x81
> +#define CEC_RX_MSG_2_OP1 0x82
> +#define CEC_RX_MSG_3_OP2 0x83
> +#define CEC_RX_MSG_4_OP3 0x84
> +#define CEC_RX_MSG_5_OP4 0x85
> +#define CEC_RX_MSG_6_OP5 0x86
> +#define CEC_RX_MSG_7_OP6 0x87
> +#define CEC_RX_MSG_8_OP7 0x88
> +#define CEC_RX_MSG_9_OP8 0x89
> +#define CEC_RX_MSG_A_OP9 0x8A
> +#define CEC_RX_MSG_B_OP10 0x8B
> +#define CEC_RX_MSG_C_OP11 0x8C
> +#define CEC_RX_MSG_D_OP12 0x8D
> +#define CEC_RX_MSG_E_OP13 0x8E
> +#define CEC_RX_MSG_F_OP14 0x8F
> +#define CEC_RX_MSG_LENGTH 0x90
> +#define CEC_RX_MSG_STATUS 0x91
> +#define CEC_RX_NUM_MSG 0x92
> +#define CEC_TX_MSG_STATUS 0x93
> +#define CEC_TX_NUM_MSG 0x94
> +
> +
> +/* CEC_TX_MSG_CMD definition */
> +#define TX_NO_OP 0 /* No transaction */
> +#define TX_REQ_CURRENT 1 /* Transmit earliest message in buffer */
> +#define TX_ABORT 2 /* Abort transmitting earliest message */
> +#define TX_REQ_NEXT 3 /* Overwrite earliest msg, transmit next */
> +
> +/* tx_msg_status definition */
> +#define TX_IDLE 0 /* No transaction */
> +#define TX_BUSY 1 /* Transmitter is busy */
> +#define TX_DONE 2 /* Message successfully transmitted */
> +#define TX_ERROR 3 /* Message transmitted with error */
> +
> +/* rx_msg_cmd */
> +#define RX_NO_OP 0 /* No transaction */
> +#define RX_ACK_CURRENT 1 /* Read earliest message in buffer */
> +#define RX_DISABLE 2 /* Disable receiving latest message */
> +#define RX_ACK_NEXT 3 /* Clear earliest msg, read next */
> +
> +/* rx_msg_status */
> +#define RX_IDLE 0 /* No transaction */
> +#define RX_BUSY 1 /* Receiver is busy */
> +#define RX_DONE 2 /* Message has been received successfully */
> +#define RX_ERROR 3 /* Message has been received with error */
> +
> +/* RX_CLEAR_BUF options */
> +#define CLEAR_START 1
> +#define CLEAR_STOP 0
> +
> +/* CEC_LOGICAL_ADDRx options */
> +#define LOGICAL_ADDR_MASK 0xf
> +#define LOGICAL_ADDR_VALID BIT(4)
> +#define LOGICAL_ADDR_DISABLE 0
> +
> +#define CEC_CLK_RATE 32768
> +
> +struct meson_ao_cec_device {
> + struct platform_device *pdev;
> + void __iomem *base;
> + struct clk *core;
> + spinlock_t cec_reg_lock;
> + struct cec_notifier *notify;
> + struct cec_adapter *adap;
> + struct cec_msg rx_msg;
> +};
> +
> +#define writel_bits_relaxed(mask, val, addr) \
> + writel_relaxed((readl_relaxed(addr) & ~(mask)) | (val), addr)
> +
> +static inline int meson_ao_cec_wait_busy(struct meson_ao_cec_device *ao_cec)
> +{
> + ktime_t timeout = ktime_add_us(ktime_get(), 5000);
> +
> + while (readl_relaxed(ao_cec->base + CEC_RW_REG) & CEC_RW_BUS_BUSY) {
> + if (ktime_compare(ktime_get(), timeout) > 0)
> + return -ETIMEDOUT;
> + }
> +
> + return 0;
> +}
> +
> +static void meson_ao_cec_read(struct meson_ao_cec_device *ao_cec,
> + unsigned long address, u8 *data,
> + int *res)
> +{
> + unsigned long flags;
> + u32 reg = FIELD_PREP(CEC_RW_ADDR, address);
> + int ret = 0;
> +
> + if (res && *res)
> + return;
> +
> + spin_lock_irqsave(&ao_cec->cec_reg_lock, flags);
> +
> + ret = meson_ao_cec_wait_busy(ao_cec);
> + if (ret)
> + goto read_out;
> +
> + writel_relaxed(reg, ao_cec->base + CEC_RW_REG);
> +
> + ret = meson_ao_cec_wait_busy(ao_cec);
> + if (ret)
> + goto read_out;
> +
> + *data = FIELD_GET(CEC_RW_RD_DATA,
> + readl_relaxed(ao_cec->base + CEC_RW_REG));
> +
> +read_out:
> + spin_unlock_irqrestore(&ao_cec->cec_reg_lock, flags);
> +
> + if (res)
> + *res = ret;
> +}
> +
> +static void meson_ao_cec_write(struct meson_ao_cec_device *ao_cec,
> + unsigned long address, u8 data,
> + int *res)
> +{
> + unsigned long flags;
> + u32 reg = FIELD_PREP(CEC_RW_ADDR, address) |
> + FIELD_PREP(CEC_RW_WR_DATA, data) |
> + CEC_RW_WRITE_EN;
> + int ret = 0;
> +
> + if (res && *res)
> + return;
> +
> + spin_lock_irqsave(&ao_cec->cec_reg_lock, flags);
> +
> + ret = meson_ao_cec_wait_busy(ao_cec);
> + if (ret)
> + goto write_out;
> +
> + writel_relaxed(reg, ao_cec->base + CEC_RW_REG);
> +
> +write_out:
> + spin_unlock_irqrestore(&ao_cec->cec_reg_lock, flags);
> +
> + if (ret)
> + *res = ret;

smatch error:

drivers/media/platform/meson/ao-cec.c:301 meson_ao_cec_write() error: we previously assumed 'res' could be null (see line 286)

Obvious typo: if (ret) should be if (res). I'll fix that, no need for
a new version of this patch.

Regards,

Hans