Re: [PATCH v3 2/2] i2c: stm32f7: Add SMBus Host-Notify protocol support

From: Pierre Yves MORDRET
Date: Tue Aug 04 2020 - 11:01:31 EST

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In reply to: Alain Volmat: "[PATCH v3 2/2] i2c: stm32f7: Add SMBus Host-Notify protocol support"
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Hi Alain

Look good for me

Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxx>

Best Regards

On 8/3/20 7:17 AM, Alain Volmat wrote:
> Rely on the core functions to implement the host-notify
> protocol via the a I2C slave device.
>
> Signed-off-by: Alain Volmat <alain.volmat@xxxxxx>
> ---
> v3: identical to v2
> v2: fix slot #0 usage condition within stm32f7_i2c_get_free_slave_id
>
> drivers/i2c/busses/Kconfig | 1 +
> drivers/i2c/busses/i2c-stm32f7.c | 110 +++++++++++++++++++++++++++++++++------
> 2 files changed, 96 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 735bf31a3fdf..ae8671727a4c 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -1036,6 +1036,7 @@ config I2C_STM32F7
> tristate "STMicroelectronics STM32F7 I2C support"
> depends on ARCH_STM32 || COMPILE_TEST
> select I2C_SLAVE
> + select I2C_SMBUS
> help
> Enable this option to add support for STM32 I2C controller embedded
> in STM32F7 SoCs.
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index bff3479fe122..223c238c3c09 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/i2c.h>
> +#include <linux/i2c-smbus.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/iopoll.h>
> @@ -50,6 +51,7 @@
>
> /* STM32F7 I2C control 1 */
> #define STM32F7_I2C_CR1_PECEN BIT(23)
> +#define STM32F7_I2C_CR1_SMBHEN BIT(20)
> #define STM32F7_I2C_CR1_WUPEN BIT(18)
> #define STM32F7_I2C_CR1_SBC BIT(16)
> #define STM32F7_I2C_CR1_RXDMAEN BIT(15)
> @@ -150,7 +152,7 @@
>
> #define STM32F7_I2C_MAX_LEN 0xff
> #define STM32F7_I2C_DMA_LEN_MIN 0x16
> -#define STM32F7_I2C_MAX_SLAVE 0x2
> +#define STM32F7_I2C_MAX_SLAVE 0x3
>
> #define STM32F7_I2C_DNF_DEFAULT 0
> #define STM32F7_I2C_DNF_MAX 16
> @@ -301,6 +303,8 @@ struct stm32f7_i2c_msg {
> * @fmp_creg: register address for clearing Fast Mode Plus bits
> * @fmp_mask: mask for Fast Mode Plus bits in set register
> * @wakeup_src: boolean to know if the device is a wakeup source
> + * @smbus_mode: states that the controller is configured in SMBus mode
> + * @host_notify_client: SMBus host-notify client
> */
> struct stm32f7_i2c_dev {
> struct i2c_adapter adap;
> @@ -327,6 +331,8 @@ struct stm32f7_i2c_dev {
> u32 fmp_creg;
> u32 fmp_mask;
> bool wakeup_src;
> + bool smbus_mode;
> + struct i2c_client *host_notify_client;
> };
>
> /*
> @@ -1321,10 +1327,18 @@ static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
> int i;
>
> /*
> - * slave[0] supports 7-bit and 10-bit slave address
> - * slave[1] supports 7-bit slave address only
> + * slave[0] support only SMBus Host address (0x8)
> + * slave[1] supports 7-bit and 10-bit slave address
> + * slave[2] supports 7-bit slave address only
> */
> - for (i = STM32F7_I2C_MAX_SLAVE - 1; i >= 0; i--) {
> + if (i2c_dev->smbus_mode && (slave->addr == 0x08)) {
> + if (i2c_dev->slave[0])
> + goto fail;
> + *id = 0;
> + return 0;
> + }
> +
> + for (i = STM32F7_I2C_MAX_SLAVE - 1; i > 0; i--) {
> if (i == 1 && (slave->flags & I2C_CLIENT_TEN))
> continue;
> if (!i2c_dev->slave[i]) {
> @@ -1333,6 +1347,7 @@ static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
> }
> }
>
> +fail:
> dev_err(dev, "Slave 0x%x could not be registered\n", slave->addr);
>
> return -EINVAL;
> @@ -1776,7 +1791,13 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
> if (!stm32f7_i2c_is_slave_registered(i2c_dev))
> stm32f7_i2c_enable_wakeup(i2c_dev, true);
>
> - if (id == 0) {
> + switch (id) {
> + case 0:
> + /* Slave SMBus Host */
> + i2c_dev->slave[id] = slave;
> + break;
> +
> + case 1:
> /* Configure Own Address 1 */
> oar1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR1);
> oar1 &= ~STM32F7_I2C_OAR1_MASK;
> @@ -1789,7 +1810,9 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
> oar1 |= STM32F7_I2C_OAR1_OA1EN;
> i2c_dev->slave[id] = slave;
> writel_relaxed(oar1, i2c_dev->base + STM32F7_I2C_OAR1);
> - } else if (id == 1) {
> + break;
> +
> + case 2:
> /* Configure Own Address 2 */
> oar2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR2);
> oar2 &= ~STM32F7_I2C_OAR2_MASK;
> @@ -1802,7 +1825,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
> oar2 |= STM32F7_I2C_OAR2_OA2EN;
> i2c_dev->slave[id] = slave;
> writel_relaxed(oar2, i2c_dev->base + STM32F7_I2C_OAR2);
> - } else {
> + break;
> +
> + default:
> + dev_err(dev, "I2C slave id not supported\n");
> ret = -ENODEV;
> goto pm_free;
> }
> @@ -1843,10 +1869,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
> if (ret < 0)
> return ret;
>
> - if (id == 0) {
> + if (id == 1) {
> mask = STM32F7_I2C_OAR1_OA1EN;
> stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR1, mask);
> - } else {
> + } else if (id == 2) {
> mask = STM32F7_I2C_OAR2_OA2EN;
> stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR2, mask);
> }
> @@ -1911,14 +1937,51 @@ static int stm32f7_i2c_setup_fm_plus_bits(struct platform_device *pdev,
> &i2c_dev->fmp_mask);
> }
>
> +static int stm32f7_i2c_enable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
> +{
> + struct i2c_adapter *adap = &i2c_dev->adap;
> + void __iomem *base = i2c_dev->base;
> + struct i2c_client *client;
> +
> + client = i2c_new_slave_host_notify_device(adap);
> + if (IS_ERR(client))
> + return PTR_ERR(client);
> +
> + i2c_dev->host_notify_client = client;
> +
> + /* Enable SMBus Host address */
> + stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, STM32F7_I2C_CR1_SMBHEN);
> +
> + return 0;
> +}
> +
> +static void stm32f7_i2c_disable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
> +{
> + void __iomem *base = i2c_dev->base;
> +
> + if (i2c_dev->host_notify_client) {
> + /* Disable SMBus Host address */
> + stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1,
> + STM32F7_I2C_CR1_SMBHEN);
> + i2c_free_slave_host_notify_device(i2c_dev->host_notify_client);
> + }
> +}
> +
> static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
> {
> - return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE |
> - I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
> - I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
> - I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
> - I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC |
> - I2C_FUNC_SMBUS_I2C_BLOCK;
> + struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
> +
> + u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE |
> + I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
> + I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
> + I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
> + I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC |
> + I2C_FUNC_SMBUS_I2C_BLOCK;
> +
> + if (i2c_dev->smbus_mode)
> + func |= I2C_FUNC_SMBUS_HOST_NOTIFY;
> +
> + return func;
> }
>
> static const struct i2c_algorithm stm32f7_i2c_algo = {
> @@ -2084,10 +2147,22 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
>
> stm32f7_i2c_hw_config(i2c_dev);
>
> + i2c_dev->smbus_mode = of_property_read_bool(pdev->dev.of_node, "smbus");
> +
> ret = i2c_add_adapter(adap);
> if (ret)
> goto pm_disable;
>
> + if (i2c_dev->smbus_mode) {
> + ret = stm32f7_i2c_enable_smbus_host(i2c_dev);
> + if (ret) {
> + dev_err(i2c_dev->dev,
> + "failed to enable SMBus Host-Notify protocol (%d)\n",
> + ret);
> + goto i2c_adapter_remove;
> + }
> + }
> +
> dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
>
> pm_runtime_mark_last_busy(i2c_dev->dev);
> @@ -2095,6 +2170,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
>
> return 0;
>
> +i2c_adapter_remove:
> + i2c_del_adapter(adap);
> +
> pm_disable:
> pm_runtime_put_noidle(i2c_dev->dev);
> pm_runtime_disable(i2c_dev->dev);
> @@ -2126,6 +2204,8 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
> {
> struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
>
> + stm32f7_i2c_disable_smbus_host(i2c_dev);
> +
> i2c_del_adapter(&i2c_dev->adap);
> pm_runtime_get_sync(i2c_dev->dev);
>
>

Next message: nirinA raseliarison: "Re: kernel BUG at fs/inode.c:531!"
Previous message: Chun-Kuang Hu: "Re: [PATCH v3 5/5] arm: dts: mt7623: add display subsystem related device nodes"
In reply to: Alain Volmat: "[PATCH v3 2/2] i2c: stm32f7: Add SMBus Host-Notify protocol support"
Next in thread: Alain Volmat: "[PATCH v3 1/2] i2c: smbus: add core function handling SMBus host-notify"
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