i2c: stm32_v2: implement slave support

This patch adds I2C Slave support conforming to the syscalls and funcs,
only for the STM32 V2 I2C Driver for the moment.

It is capable of handling multi-master bus setups.

Signed-off-by: Neil Armstrong <[email protected]>
Signed-off-by: Daniel Wagenknecht <[email protected]>

Author: Daniel Wagenknecht

drivers/i2c/Kconfig.stm32

@@ -27,9 +27,13 @@ config I2C_STM32_V2
 	select HAS_DTS_I2C
 	select USE_STM32_LL_I2C
 	select USE_STM32_LL_RCC if SOC_SERIES_STM32F0X || SOC_SERIES_STM32F3X
+	select I2C_STM32_INTERRUPT if I2C_SLAVE
+	default n
 	help
 	  Enable I2C support on the STM32 F0, F3 and L4X family of processors.
 	  This driver also supports the F7 and L0 series.
+	  If I2C_SLAVE is enabled it selects I2C_STM32_INTERRUPT, since slave mode
+	  is only supported by this driver with interrupts enabled.
 
 config I2C_STM32_INTERRUPT
 	bool "STM32 MCU I2C Interrupt Support"

drivers/i2c/i2c_ll_stm32.c

@@ -18,7 +18,7 @@
 #define SYS_LOG_LEVEL CONFIG_SYS_LOG_I2C_LEVEL
 #include <logging/sys_log.h>
 
-static int i2c_stm32_runtime_configure(struct device *dev, u32_t config)
+int i2c_stm32_runtime_configure(struct device *dev, u32_t config)
 {
 	const struct i2c_stm32_config *cfg = DEV_CFG(dev);
 	struct i2c_stm32_data *data = DEV_DATA(dev);
@@ -53,9 +53,11 @@ static int i2c_stm32_runtime_configure(struct device *dev, u32_t config)
 static int i2c_stm32_transfer(struct device *dev, struct i2c_msg *msg,
 			      u8_t num_msgs, u16_t slave)
 {
+#if defined(CONFIG_I2C_STM32_V1)
 	const struct i2c_stm32_config *cfg = DEV_CFG(dev);
-	struct i2c_msg *current, *next;
 	I2C_TypeDef *i2c = cfg->i2c;
+#endif
+	struct i2c_msg *current, *next;
 	int ret = 0;
 
 	/* Check for validity of all messages, to prevent having to abort
@@ -108,7 +110,9 @@ static int i2c_stm32_transfer(struct device *dev, struct i2c_msg *msg,
 	}
 
 	/* Send out messages */
+#if defined(CONFIG_I2C_STM32_V1)
 	LL_I2C_Enable(i2c);
+#endif
 
 	current = msg;
 
@@ -135,15 +139,19 @@ static int i2c_stm32_transfer(struct device *dev, struct i2c_msg *msg,
 		current++;
 		num_msgs--;
 	};
-
+#if defined(CONFIG_I2C_STM32_V1)
 	LL_I2C_Disable(i2c);
-
+#endif
 	return ret;
 }
 
 static const struct i2c_driver_api api_funcs = {
 	.configure = i2c_stm32_runtime_configure,
 	.transfer = i2c_stm32_transfer,
+#if defined(CONFIG_I2C_SLAVE) && defined(CONFIG_I2C_STM32_V2)
+	.slave_register = i2c_stm32_slave_register,
+	.slave_unregister = i2c_stm32_slave_unregister,
+#endif
 };
 
 static int i2c_stm32_init(struct device *dev)

drivers/i2c/i2c_ll_stm32.h

@@ -34,26 +34,40 @@ struct i2c_stm32_data {
 		unsigned int flags;
 #endif
 		unsigned int is_write;
+		unsigned int is_arlo;
 		unsigned int is_nack;
 		unsigned int is_err;
 		struct i2c_msg *msg;
 		unsigned int len;
 		u8_t *buf;
 	} current;
+#ifdef CONFIG_I2C_SLAVE
+	bool master_active;
+	struct i2c_slave_config *slave_cfg;
+	bool slave_attached;
+#endif
 };
 
 s32_t stm32_i2c_msg_write(struct device *dev, struct i2c_msg *msg, u8_t *flg,
 			  u16_t sadr);
 s32_t stm32_i2c_msg_read(struct device *dev, struct i2c_msg *msg, u8_t *flg,
 			 u16_t sadr);
 s32_t stm32_i2c_configure_timing(struct device *dev, u32_t clk);
+int i2c_stm32_runtime_configure(struct device *dev, u32_t config);
 
 void stm32_i2c_event_isr(void *arg);
 void stm32_i2c_error_isr(void *arg);
 #ifdef CONFIG_I2C_STM32_COMBINED_INTERRUPT
 void stm32_i2c_combined_isr(void *arg);
 #endif
 
+#ifdef CONFIG_I2C_SLAVE
+int i2c_stm32_slave_register(struct device *dev,
+			     struct i2c_slave_config *config);
+int i2c_stm32_slave_unregister(struct device *dev,
+			       struct i2c_slave_config *config);
+#endif
+
 #define DEV_DATA(dev) ((struct i2c_stm32_data * const)(dev)->driver_data)
 #define DEV_CFG(dev)	\
 ((const struct i2c_stm32_config * const)(dev)->config->config_info)