Hi Benjamin,
Thanks for the patch! Always nice to see new CEC drivers.
On 16/05/17 11:01, 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.gaign...@linaro.org>
Since Yannick wrote the original driver, shouldn't there be a Signed-off-by
from him as well?
> ---
> drivers/media/platform/Kconfig | 11 +
> drivers/media/platform/Makefile | 2 +
> drivers/media/platform/stm32/Makefile | 1 +
> drivers/media/platform/stm32/stm32-cec.c | 368
> +++++++++++++++++++++++++++++++
> 4 files changed, 382 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 ac026ee..72efe34 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -519,4 +519,15 @@ 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 CEC_CORE && (ARCH_STM32 || COMPILE_TEST)
> + select REGMAP
> + select REGMAP_MMIO
> + ---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..a40a6eb
> --- /dev/null
> +++ b/drivers/media/platform/stm32/stm32-cec.c
> @@ -0,0 +1,368 @@
> +/*
> + * STM32 CEC driver
> + * Copyright (C) STMicroelectronic SA 2017
Isn't it STMicroelectronics instead of STMicroelectronic?
> + *
> + * 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 | SFT | BRDNOGEN)
> +
> +#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;
> + u8 rx_msg[CEC_MAX_MSG_SIZE];
> + u8 tx_msg[CEC_MAX_MSG_SIZE];
> + int rx_len;
> + int tx_len;
> + 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_len)
> + regmap_write(cec->regmap, CEC_TXDR,
> + cec->tx_msg[cec->tx_cnt++]);
> +
> + /* TXEOM is set to command transmission of the last byte */
> + if (cec->tx_cnt == cec->tx_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_len = 0;
> + return;
> + }
> +
> + if (cec->irq_status & RXBR) {
> + u32 val;
> +
> + regmap_read(cec->regmap, CEC_RXDR, &val);
> + cec->rx_msg[cec->rx_len++] = val & 0xFF;
Wouldn't it be safer to handle this IRQ and the TXBR interrupt in
stm32_cec_irq_handler()? This can be done in atomic context and these are
more time-sensitive.
> + }
> +
> + if (cec->irq_status & RXEND) {
> + struct cec_msg msg = {};
> +
> + msg.len = cec->rx_len;
> + memcpy(msg.msg, cec->rx_msg, msg.len);
Most drivers just embed a cec_msg struct in the top-level struct (stm32_cec
in this case). That way there is no need to have your own copies of the length
and message data (rx_len and rx_msg in this case).
Actually, the same applies to the tx part, just embed a cec_msg tx_msg.
> + cec_received_msg(cec->adap, &msg);
> +
> + cec->rx_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;
> +
> + 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,
> + (1 << logical_addr) << 16);
Since this is a mask I assume that this CEC implementation can handle multiple
logical addresses? In that case you should allow that when you call
cec_allocate_adapter:
instead of '1' use CEC_MAX_LOG_ADDRS as the last argument.
> +
> + 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 */
> + memcpy(cec->tx_msg, msg->msg, msg->len);
> +
> + cec->tx_len = msg->len;
> + cec->tx_cnt = 0;
> +
> + /*
> + * If the CEC message consists of only one byte,
> + * TXEOM must be set before of TXSOM.
> + */
> + if (cec->tx_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[0]);
> + cec->tx_cnt++;
> +
> + return 0;
> +}
> +
> +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,
> +};
> +
> +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;
> +
> + 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->adap = cec_allocate_adapter(&stm32_cec_adap_ops, cec,
> + CEC_NAME,
> + CEC_CAP_LOG_ADDRS | CEC_CAP_PASSTHROUGH |
> + CEC_CAP_PHYS_ADDR | CEC_CAP_TRANSMIT, 1);
Add CEC_CAP_RC.
Add a comment that CEC_CAP_PHYS_ADDR is temporary until this driver is
switched to using a cec_notifier.
There is no CEC bus monitoring support for this hardware?
> + 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);
> +
> + cec_delete_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.gaign...@st.com>");
> +MODULE_AUTHOR("Yannick Fertre <yannick.fer...@st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Consumer Electronics Control");
> +MODULE_LICENSE("GPL v2");
>
Regards,
Hans
