Commit c8062d11 authored by Alain Volmat's avatar Alain Volmat Committed by Wolfram Sang
Browse files

i2c: stm32f7: add SMBus-Alert support 



Add support for the SMBus-Alert protocol to the STM32F7 that has
dedicated control and status logic.

If SMBus-Alert is used, the SMBALERT# pin must be configured as alternate
function for I2C Alert.

Signed-off-by: default avatarAlain Volmat <alain.volmat@foss.st.com>
Reviewed-by: default avatarPierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 168290fb

drivers/i2c/busses/i2c-stm32f7.c

+73 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 


/* STM32F7 I2C control 1 */

#define STM32F7_I2C_CR1_PECEN			BIT(23)

#define STM32F7_I2C_CR1_ALERTEN			BIT(22)

#define STM32F7_I2C_CR1_SMBHEN			BIT(20)

#define STM32F7_I2C_CR1_WUPEN			BIT(18)

#define STM32F7_I2C_CR1_SBC			BIT(16)
@@ -125,6 +126,7 @@ 
				(((n) & STM32F7_I2C_ISR_ADDCODE_MASK) >> 17)

#define STM32F7_I2C_ISR_DIR			BIT(16)

#define STM32F7_I2C_ISR_BUSY			BIT(15)

#define STM32F7_I2C_ISR_ALERT			BIT(13)

#define STM32F7_I2C_ISR_PECERR			BIT(11)

#define STM32F7_I2C_ISR_ARLO			BIT(9)

#define STM32F7_I2C_ISR_BERR			BIT(8)
@@ -138,6 +140,7 @@ 
#define STM32F7_I2C_ISR_TXE			BIT(0)



/* STM32F7 I2C Interrupt Clear */

#define STM32F7_I2C_ICR_ALERTCF			BIT(13)

#define STM32F7_I2C_ICR_PECCF			BIT(11)

#define STM32F7_I2C_ICR_ARLOCF			BIT(9)

#define STM32F7_I2C_ICR_BERRCF			BIT(8)
@@ -278,6 +281,17 @@ struct stm32f7_i2c_msg { 
	u8 smbus_buf[I2C_SMBUS_BLOCK_MAX + 3] __aligned(4);

};



/**

 * struct stm32f7_i2c_alert - SMBus alert specific data

 * @setup: platform data for the smbus_alert i2c client

 * @ara: I2C slave device used to respond to the SMBus Alert with Alert

 * Response Address

 */

struct stm32f7_i2c_alert {

	struct i2c_smbus_alert_setup setup;

	struct i2c_client *ara;

};



/**

 * struct stm32f7_i2c_dev - private data of the controller

 * @adap: I2C adapter for this controller
@@ -310,6 +324,7 @@ struct stm32f7_i2c_msg { 
 * @analog_filter: boolean to indicate enabling of the analog filter

 * @dnf_dt: value of digital filter requested via dt

 * @dnf: value of digital filter to apply

 * @alert: SMBus alert specific data

 */

struct stm32f7_i2c_dev {

	struct i2c_adapter adap;
@@ -341,6 +356,7 @@ struct stm32f7_i2c_dev { 
	bool analog_filter;

	u32 dnf_dt;

	u32 dnf;

	struct stm32f7_i2c_alert *alert;

};



/*
@@ -1624,6 +1640,13 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) 
		f7_msg->result = -EINVAL;

	}



	if (status & STM32F7_I2C_ISR_ALERT) {

		dev_dbg(dev, "<%s>: SMBus alert received\n", __func__);

		writel_relaxed(STM32F7_I2C_ICR_ALERTCF, base + STM32F7_I2C_ICR);

		i2c_handle_smbus_alert(i2c_dev->alert->ara);

		return IRQ_HANDLED;

	}



	if (!i2c_dev->slave_running) {

		u32 mask;

		/* Disable interrupts */
@@ -1990,6 +2013,42 @@ static void stm32f7_i2c_disable_smbus_host(struct stm32f7_i2c_dev *i2c_dev) 
	}

}



static int stm32f7_i2c_enable_smbus_alert(struct stm32f7_i2c_dev *i2c_dev)

{

	struct stm32f7_i2c_alert *alert;

	struct i2c_adapter *adap = &i2c_dev->adap;

	struct device *dev = i2c_dev->dev;

	void __iomem *base = i2c_dev->base;



	alert = devm_kzalloc(dev, sizeof(*alert), GFP_KERNEL);

	if (!alert)

		return -ENOMEM;



	alert->ara = i2c_new_smbus_alert_device(adap, &alert->setup);

	if (IS_ERR(alert->ara))

		return PTR_ERR(alert->ara);



	i2c_dev->alert = alert;



	/* Enable SMBus Alert */

	stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, STM32F7_I2C_CR1_ALERTEN);



	return 0;

}



static void stm32f7_i2c_disable_smbus_alert(struct stm32f7_i2c_dev *i2c_dev)

{

	struct stm32f7_i2c_alert *alert = i2c_dev->alert;

	void __iomem *base = i2c_dev->base;



	if (alert) {

		/* Disable SMBus Alert */

		stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1,

				     STM32F7_I2C_CR1_ALERTEN);

		i2c_unregister_device(alert->ara);

	}

}



static u32 stm32f7_i2c_func(struct i2c_adapter *adap)

{

	struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
@@ -2173,6 +2232,16 @@ static int stm32f7_i2c_probe(struct platform_device *pdev) 
		}

	}



	if (of_property_read_bool(pdev->dev.of_node, "smbus-alert")) {

		ret = stm32f7_i2c_enable_smbus_alert(i2c_dev);

		if (ret) {

			dev_err(i2c_dev->dev,

				"failed to enable SMBus alert protocol (%d)\n",

				ret);

			goto i2c_disable_smbus_host;

		}

	}



	dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);



	pm_runtime_mark_last_busy(i2c_dev->dev);
@@ -2180,6 +2249,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev) 


	return 0;



i2c_disable_smbus_host:

	stm32f7_i2c_disable_smbus_host(i2c_dev);



i2c_adapter_remove:

	i2c_del_adapter(adap);
@@ -2214,6 +2286,7 @@ static int stm32f7_i2c_remove(struct platform_device *pdev) 
{

	struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);



	stm32f7_i2c_disable_smbus_alert(i2c_dev);

	stm32f7_i2c_disable_smbus_host(i2c_dev);



	i2c_del_adapter(&i2c_dev->adap);