Commit 6af07719 authored by Alain Volmat's avatar Alain Volmat Committed by Wolfram Sang
Browse files

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: default avatarAlain Volmat <alain.volmat@st.com>
Reviewed-by: default avatarPierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 2a71593d

drivers/i2c/busses/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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.

drivers/i2c/busses/i2c-stm32f7.c

+96 −16
Original line number Diff line number Diff line
@@ -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;

};



/*
@@ -1321,11 +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 |

	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);

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