Re: [PATCH v6 2/2] cec: add STM32 cec driver

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On 05/31/17 14:13, Benjamin Gaignard wrote:
> This patch add cec driver for STM32 platforms.
> cec hardware block isn't not always used with hdmi so
> cec notifier is not implemented. That will be done later
> when STM32 DSI driver will be available.
> 
> Driver compliance has been tested with cec-ctl and cec-compliance
> tools.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
> Signed-off-by: Yannick Fertre <yannick.fertre@xxxxxx>
> ---
> version 6:
> - fix duplicate constant in define 
> - add monitor mode
> 
>  drivers/media/platform/Kconfig           |  12 +
>  drivers/media/platform/Makefile          |   2 +
>  drivers/media/platform/stm32/Makefile    |   1 +
>  drivers/media/platform/stm32/stm32-cec.c | 369 +++++++++++++++++++++++++++++++
>  4 files changed, 384 insertions(+)
>  create mode 100644 drivers/media/platform/stm32/Makefile
>  create mode 100644 drivers/media/platform/stm32/stm32-cec.c
> 
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 041cb80..52280bc 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -521,4 +521,16 @@ config VIDEO_STI_HDMI_CEC
>           CEC bus is present in the HDMI connector and enables communication
>           between compatible devices.
>  
> +config VIDEO_STM32_HDMI_CEC
> +       tristate "STMicroelectronics STM32 HDMI CEC driver"
> +       depends on ARCH_STM32 || COMPILE_TEST
> +       select REGMAP
> +       select REGMAP_MMIO
> +       select CEC_CORE
> +       ---help---
> +         This is a driver for STM32 interface. It uses the
> +         generic CEC framework interface.
> +         CEC bus is present in the HDMI connector and enables communication
> +         between compatible devices.
> +
>  endif #CEC_PLATFORM_DRIVERS
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index 63303d6..7cd9965 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -44,6 +44,8 @@ obj-$(CONFIG_VIDEO_STI_HDMI_CEC) 	+= sti/cec/
>  
>  obj-$(CONFIG_VIDEO_STI_DELTA)		+= sti/delta/
>  
> +obj-$(CONFIG_VIDEO_STM32_HDMI_CEC) 	+= stm32/
> +
>  obj-$(CONFIG_BLACKFIN)                  += blackfin/
>  
>  obj-$(CONFIG_ARCH_DAVINCI)		+= davinci/
> diff --git a/drivers/media/platform/stm32/Makefile b/drivers/media/platform/stm32/Makefile
> new file mode 100644
> index 0000000..632b04c
> --- /dev/null
> +++ b/drivers/media/platform/stm32/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_VIDEO_STM32_HDMI_CEC) += stm32-cec.o
> diff --git a/drivers/media/platform/stm32/stm32-cec.c b/drivers/media/platform/stm32/stm32-cec.c
> new file mode 100644
> index 0000000..f7a8fd9
> --- /dev/null
> +++ b/drivers/media/platform/stm32/stm32-cec.c
> @@ -0,0 +1,369 @@
> +/*
> + * STM32 CEC driver
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include <media/cec.h>
> +
> +#define CEC_NAME	"stm32-cec"
> +
> +/* CEC registers  */
> +#define CEC_CR		0x0000 /* Control Register */
> +#define CEC_CFGR	0x0004 /* ConFiGuration Register */
> +#define CEC_TXDR	0x0008 /* Rx data Register */
> +#define CEC_RXDR	0x000C /* Rx data Register */
> +#define CEC_ISR		0x0010 /* Interrupt and status Register */
> +#define CEC_IER		0x0014 /* Interrupt enable Register */
> +
> +#define TXEOM		BIT(2)
> +#define TXSOM		BIT(1)
> +#define CECEN		BIT(0)
> +
> +#define LSTN		BIT(31)
> +#define OAR		GENMASK(30, 16)
> +#define SFTOP		BIT(8)
> +#define BRDNOGEN	BIT(7)
> +#define LBPEGEN		BIT(6)
> +#define BREGEN		BIT(5)
> +#define BRESTP		BIT(4)
> +#define RXTOL		BIT(3)
> +#define SFT		GENMASK(2, 0)
> +#define FULL_CFG	(LSTN | SFTOP | BRDNOGEN | LBPEGEN | BREGEN | BRESTP \
> +			 | RXTOL)
> +
> +#define TXACKE		BIT(12)
> +#define TXERR		BIT(11)
> +#define TXUDR		BIT(10)
> +#define TXEND		BIT(9)
> +#define TXBR		BIT(8)
> +#define ARBLST		BIT(7)
> +#define RXACKE		BIT(6)
> +#define RXOVR		BIT(2)
> +#define RXEND		BIT(1)
> +#define RXBR		BIT(0)
> +
> +#define ALL_TX_IT	(TXEND | TXBR | TXACKE | TXERR | TXUDR | ARBLST)
> +#define ALL_RX_IT	(RXEND | RXBR | RXACKE | RXOVR)
> +
> +struct stm32_cec {
> +	struct cec_adapter	*adap;
> +	struct device		*dev;
> +	struct clk		*clk_cec;
> +	struct clk		*clk_hdmi_cec;
> +	struct reset_control	*rstc;
> +	struct regmap		*regmap;
> +	int			irq;
> +	u32			irq_status;
> +	struct cec_msg		rx_msg;
> +	struct cec_msg		tx_msg;
> +	int			tx_cnt;
> +};
> +
> +static void cec_hw_init(struct stm32_cec *cec)
> +{
> +	regmap_update_bits(cec->regmap, CEC_CR, TXEOM | TXSOM | CECEN, 0);
> +
> +	regmap_update_bits(cec->regmap, CEC_IER, ALL_TX_IT | ALL_RX_IT,
> +			   ALL_TX_IT | ALL_RX_IT);
> +
> +	regmap_update_bits(cec->regmap, CEC_CFGR, FULL_CFG, FULL_CFG);
> +}
> +
> +static void stm32_tx_done(struct stm32_cec *cec, u32 status)
> +{
> +	if (status & (TXERR | TXUDR)) {
> +		cec_transmit_done(cec->adap, CEC_TX_STATUS_ERROR,
> +				  0, 0, 0, 1);
> +		return;
> +	}
> +
> +	if (status & ARBLST) {
> +		cec_transmit_done(cec->adap, CEC_TX_STATUS_ARB_LOST,
> +				  1, 0, 0, 0);
> +		return;
> +	}
> +
> +	if (status & TXACKE) {
> +		cec_transmit_done(cec->adap, CEC_TX_STATUS_NACK,
> +				  0, 1, 0, 0);
> +		return;
> +	}
> +
> +	if (cec->irq_status & TXBR) {
> +		/* send next byte */
> +		if (cec->tx_cnt < cec->tx_msg.len)
> +			regmap_write(cec->regmap, CEC_TXDR,
> +				     cec->tx_msg.msg[cec->tx_cnt++]);
> +
> +		/* TXEOM is set to command transmission of the last byte */
> +		if (cec->tx_cnt == cec->tx_msg.len)
> +			regmap_update_bits(cec->regmap, CEC_CR, TXEOM, TXEOM);
> +	}
> +
> +	if (cec->irq_status & TXEND)
> +		cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
> +}
> +
> +static void stm32_rx_done(struct stm32_cec *cec, u32 status)
> +{
> +	if (cec->irq_status & (RXACKE | RXOVR)) {
> +		cec->rx_msg.len = 0;
> +		return;
> +	}
> +
> +	if (cec->irq_status & RXBR) {
> +		u32 val;
> +
> +		regmap_read(cec->regmap, CEC_RXDR, &val);
> +		cec->rx_msg.msg[cec->rx_msg.len++] = val & 0xFF;
> +	}
> +
> +	if (cec->irq_status & RXEND) {
> +		cec_received_msg(cec->adap, &cec->rx_msg);
> +		cec->rx_msg.len = 0;
> +	}
> +}
> +
> +static irqreturn_t stm32_cec_irq_thread(int irq, void *arg)
> +{
> +	struct stm32_cec *cec = arg;
> +
> +	if (cec->irq_status & ALL_TX_IT)
> +		stm32_tx_done(cec, cec->irq_status);
> +
> +	if (cec->irq_status & ALL_RX_IT)
> +		stm32_rx_done(cec, cec->irq_status);
> +
> +	cec->irq_status = 0;
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t stm32_cec_irq_handler(int irq, void *arg)
> +{
> +	struct stm32_cec *cec = arg;
> +
> +	regmap_read(cec->regmap, CEC_ISR, &cec->irq_status);
> +
> +	regmap_update_bits(cec->regmap, CEC_ISR,
> +			   ALL_TX_IT | ALL_RX_IT,
> +			   ALL_TX_IT | ALL_RX_IT);
> +
> +	return IRQ_WAKE_THREAD;
> +}
> +
> +static int stm32_cec_adap_enable(struct cec_adapter *adap, bool enable)
> +{
> +	struct stm32_cec *cec = adap->priv;
> +	int ret = 0;
> +
> +	if (enable) {
> +		ret = clk_enable(cec->clk_cec);
> +		if (ret)
> +			dev_err(cec->dev, "fail to enable cec clock\n");
> +
> +		clk_enable(cec->clk_hdmi_cec);
> +		regmap_update_bits(cec->regmap, CEC_CR, CECEN, CECEN);
> +	} else {
> +		clk_disable(cec->clk_cec);
> +		clk_disable(cec->clk_hdmi_cec);
> +		regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
> +	}
> +
> +	return ret;
> +}
> +
> +static int stm32_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
> +{
> +	struct stm32_cec *cec = adap->priv;
> +	u32 oar = (1 << logical_addr) << 16;
> +
> +	regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
> +
> +	if (logical_addr == CEC_LOG_ADDR_INVALID)
> +		regmap_update_bits(cec->regmap, CEC_CFGR, OAR, 0);
> +	else
> +		regmap_update_bits(cec->regmap, CEC_CFGR, oar, oar);
> +
> +	regmap_update_bits(cec->regmap, CEC_CR, CECEN, CECEN);
> +
> +	return 0;
> +}
> +
> +static int stm32_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
> +				   u32 signal_free_time, struct cec_msg *msg)
> +{
> +	struct stm32_cec *cec = adap->priv;
> +
> +	/* Copy message */
> +	cec->tx_msg = *msg;
> +	cec->tx_cnt = 0;
> +
> +	/*
> +	 * If the CEC message consists of only one byte,
> +	 * TXEOM must be set before of TXSOM.
> +	 */
> +	if (cec->tx_msg.len == 1)
> +		regmap_update_bits(cec->regmap, CEC_CR, TXEOM, TXEOM);
> +
> +	/* TXSOM is set to command transmission of the first byte */
> +	regmap_update_bits(cec->regmap, CEC_CR, TXSOM, TXSOM);
> +
> +	/* Write the header (first byte of message) */
> +	regmap_write(cec->regmap, CEC_TXDR, cec->tx_msg.msg[0]);
> +	cec->tx_cnt++;
> +
> +	return 0;
> +}
> +
> +static int stm32_cec_monitor_all(struct cec_adapter *adap, bool enable)
> +{
> +	/* By default LSTN bit is set in CEC_CFGR so we are always listening */
> +	return 0;
> +}

Ah, if it is always on, then you can just specify the CAP and drop this
callback. Test it first, just to make sure I didn't overlook some logic
in the CEC core code :-)

> +
> +static const struct cec_adap_ops stm32_cec_adap_ops = {
> +	.adap_enable = stm32_cec_adap_enable,
> +	.adap_log_addr = stm32_cec_adap_log_addr,
> +	.adap_transmit = stm32_cec_adap_transmit,
> +	.adap_monitor_all_enable = stm32_cec_monitor_all,
> +};
> +
> +static const struct regmap_config stm32_cec_regmap_cfg = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = sizeof(u32),
> +	.max_register = 0x14,
> +	.fast_io = true,
> +};
> +
> +static int stm32_cec_probe(struct platform_device *pdev)
> +{
> +	struct resource *res;
> +	struct stm32_cec *cec;
> +	void __iomem *mmio;
> +	int ret;
> +	u32 caps = CEC_CAP_LOG_ADDRS | CEC_CAP_PASSTHROUGH |
> +		   CEC_CAP_TRANSMIT | CEC_CAP_RC | CEC_CAP_PHYS_ADDR |
> +		   CEC_MODE_MONITOR_ALL;

I would move 'caps' up as the first item.

Regards,

	Hans

> +
> +	cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
> +	if (!cec)
> +		return -ENOMEM;
> +
> +	cec->dev = &pdev->dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	mmio = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(mmio))
> +		return PTR_ERR(mmio);
> +
> +	cec->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "cec", mmio,
> +						&stm32_cec_regmap_cfg);
> +
> +	if (IS_ERR(cec->regmap))
> +		return PTR_ERR(cec->regmap);
> +
> +	cec->irq = platform_get_irq(pdev, 0);
> +	if (cec->irq < 0)
> +		return cec->irq;
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
> +					stm32_cec_irq_handler,
> +					stm32_cec_irq_thread,
> +					0,
> +					pdev->name, cec);
> +	if (ret)
> +		return ret;
> +
> +	cec->clk_cec = devm_clk_get(&pdev->dev, "cec");
> +	if (IS_ERR(cec->clk_cec)) {
> +		dev_err(&pdev->dev, "Cannot get cec clock\n");
> +		return PTR_ERR(cec->clk_cec);
> +	}
> +
> +	ret = clk_prepare(cec->clk_cec);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to prepare cec clock\n");
> +		return ret;
> +	}
> +
> +	cec->clk_hdmi_cec = devm_clk_get(&pdev->dev, "hdmi-cec");
> +	if (!IS_ERR(cec->clk_hdmi_cec)) {
> +		ret = clk_prepare(cec->clk_hdmi_cec);
> +		if (ret) {
> +			dev_err(&pdev->dev, "Unable to prepare hdmi-cec clock\n");
> +			return ret;
> +		}
> +	}
> +
> +	/*
> +	 * CEC_CAP_PHYS_ADDR caps should be removed when a cec notifier is
> +	 * available for example when a drm driver can provide edid
> +	 */
> +	cec->adap = cec_allocate_adapter(&stm32_cec_adap_ops, cec,
> +			CEC_NAME, caps,	CEC_MAX_LOG_ADDRS);
> +	ret = PTR_ERR_OR_ZERO(cec->adap);
> +	if (ret)
> +		return ret;
> +
> +	ret = cec_register_adapter(cec->adap, &pdev->dev);
> +	if (ret) {
> +		cec_delete_adapter(cec->adap);
> +		return ret;
> +	}
> +
> +	cec_hw_init(cec);
> +
> +	platform_set_drvdata(pdev, cec);
> +
> +	return 0;
> +}
> +
> +static int stm32_cec_remove(struct platform_device *pdev)
> +{
> +	struct stm32_cec *cec = platform_get_drvdata(pdev);
> +
> +	clk_unprepare(cec->clk_cec);
> +	clk_unprepare(cec->clk_hdmi_cec);
> +
> +	cec_unregister_adapter(cec->adap);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id stm32_cec_of_match[] = {
> +	{ .compatible = "st,stm32-cec" },
> +	{ /* end node */ }
> +};
> +MODULE_DEVICE_TABLE(of, stm32_cec_of_match);
> +
> +static struct platform_driver stm32_cec_driver = {
> +	.probe  = stm32_cec_probe,
> +	.remove = stm32_cec_remove,
> +	.driver = {
> +		.name		= CEC_NAME,
> +		.of_match_table = stm32_cec_of_match,
> +	},
> +};
> +
> +module_platform_driver(stm32_cec_driver);
> +
> +MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@xxxxxx>");
> +MODULE_AUTHOR("Yannick Fertre <yannick.fertre@xxxxxx>");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Consumer Electronics Control");
> +MODULE_LICENSE("GPL v2");
> 

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