From 6af077194600d5445f802ce4587a3254a215a851 Mon Sep 17 00:00:00 2001 From: Alain Volmat Date: Mon, 3 Aug 2020 07:17:56 +0200 Subject: [PATCH] i2c: stm32f7: Add SMBus Host-Notify protocol support Rely on the core functions to implement the host-notify protocol via the a I2C slave device. Signed-off-by: Alain Volmat Reviewed-by: Pierre-Yves MORDRET Signed-off-by: Wolfram Sang --- drivers/i2c/busses/Kconfig | 1 + drivers/i2c/busses/i2c-stm32f7.c | 112 ++++++++++++++++++++++++++----- 2 files changed, 97 insertions(+), 16 deletions(-) diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 38639d53a171..46a24faef352 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -1025,6 +1025,7 @@ 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..425eff5b18e0 100644 --- a/drivers/i2c/busses/i2c-stm32f7.c +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -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; }; /* @@ -1321,11 +1327,19 @@ 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 (i == 1 && (slave->flags & I2C_CLIENT_TEN)) + 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 == 2 && (slave->flags & I2C_CLIENT_TEN)) continue; if (!i2c_dev->slave[i]) { *id = 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); -- GitLab