From: asterix <asterix@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Tue, 27 Jul 2010 16:13:01 +0000 (+0000)
Subject: Split long function. Add comments.
X-Git-Tag: 2.6.0~288^2~13
X-Git-Url: https://codewiz.org/gitweb?a=commitdiff_plain;h=b1fde66b00840e9fb6738774e1e9bcd0b3065b1d;p=bertos.git

Split long function. Add comments.

git-svn-id: https://src.develer.com/svnoss/bertos/branches/i2c@4082 38d2e660-2303-0410-9eaa-f027e97ec537
---

diff --git a/bertos/cpu/cortex-m3/drv/i2c_stm32.c b/bertos/cpu/cortex-m3/drv/i2c_stm32.c
index 9807de11..24c3e185 100644
--- a/bertos/cpu/cortex-m3/drv/i2c_stm32.c
+++ b/bertos/cpu/cortex-m3/drv/i2c_stm32.c
@@ -81,7 +81,11 @@ INLINE uint32_t get_status(struct stm32_i2c *base)
 	return ((base->SR1 | (base->SR2 << 16)) & 0x00FFFFFF);
 }
 
-
+/*
+ * This fuction read the status registers of the i2c device
+ * and waint until the selec event happen. If occur one error
+ * the funtions return false.
+ */
 INLINE bool wait_event(I2c *i2c, uint32_t event)
 {
 	while (true)
@@ -101,126 +105,136 @@ INLINE bool wait_event(I2c *i2c, uint32_t event)
 	return true;
 }
 
-static void i2c_stm32_start(struct I2c *i2c, uint16_t slave_addr)
-{
-	i2c->hw->cached = false;
-
-	if (I2C_TEST_START(i2c->flags) == I2C_START_W)
-	{
-		/*
-		 * Loop on the select write sequence: when the eeprom is busy
-		 * writing previously sent data it will reply to the SLA_W
-		 * control byte with a NACK.  In this case, we must
-		 * keep trying until the eeprom responds with an ACK.
-		 */
-		ticks_t start = timer_clock();
-		while (true)
-		{
-			i2c->hw->base->CR1 |= CR1_ACK_SET | CR1_START_SET;
-
-			if(!wait_event(i2c, I2C_EVENT_MASTER_MODE_SELECT))
-			{
-				LOG_ERR("ARBIT lost\n");
-				i2c->errors |= I2C_ARB_LOST;
-				break;
-			}
-
-			i2c->hw->base->DR = slave_addr & OAR1_ADD0_RESET;
-
-			if(wait_event(i2c, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
-				break;
-
-			if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
-			{
-				LOG_ERR("Timeout on I2C START\n");
-				i2c->errors |= I2C_START_TIMEOUT;
-				i2c->hw->base->CR1 |= CR1_STOP_SET;
-				break;
-			}
-		}
 
-	}
-	else /* (I2C_TEST_START(i2c->flags) == I2C_START_R) */
+INLINE void start_w(struct I2c *i2c, uint16_t slave_addr)
+{
+	/*
+	 * Loop on the select write sequence: when the eeprom is busy
+	 * writing previously sent data it will reply to the SLA_W
+	 * control byte with a NACK.  In this case, we must
+	 * keep trying until the eeprom responds with an ACK.
+	 */
+	ticks_t start = timer_clock();
+	while (true)
 	{
-		i2c->hw->base->CR1 |= CR1_START_SET;
+		i2c->hw->base->CR1 |= CR1_ACK_SET | CR1_START_SET;
 
 		if(!wait_event(i2c, I2C_EVENT_MASTER_MODE_SELECT))
 		{
 			LOG_ERR("ARBIT lost\n");
 			i2c->errors |= I2C_ARB_LOST;
-			i2c->hw->base->CR1 |= CR1_STOP_SET;
-			return;
+			break;
 		}
 
-		i2c->hw->base->DR = (slave_addr | OAR1_ADD0_SET);
+		i2c->hw->base->DR = slave_addr & OAR1_ADD0_RESET;
 
-		if (i2c->xfer_size == 2)
-			i2c->hw->base->CR1 |= CR1_ACK_SET | CR1_POS_SET;
+		if(wait_event(i2c, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
+			break;
 
-		if(!wait_event(i2c, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))
+		if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
 		{
-			LOG_ERR("SLAR NACK:%08lx\n", get_status(i2c->hw->base));
-			i2c->errors |= I2C_NO_ACK;
+			LOG_ERR("Timeout on I2C START\n");
+			i2c->errors |= I2C_START_TIMEOUT;
 			i2c->hw->base->CR1 |= CR1_STOP_SET;
-			return;
+			break;
 		}
+	}
+}
 
-		if (i2c->xfer_size == 1)
-		{
-			i2c->hw->base->CR1 &= CR1_ACK_RESET;
-
-			cpu_flags_t irq;
-			IRQ_SAVE_DISABLE(irq);
+INLINE bool start_and_addr(struct I2c *i2c, uint16_t slave_addr)
+{
+	i2c->hw->base->CR1 |= CR1_START_SET;
+	if(!wait_event(i2c, I2C_EVENT_MASTER_MODE_SELECT))
+	{
+		LOG_ERR("ARBIT lost\n");
+		i2c->errors |= I2C_ARB_LOST;
+		i2c->hw->base->CR1 |= CR1_STOP_SET;
+		return false;
+	}
 
-			(void)i2c->hw->base->SR2;
+	i2c->hw->base->DR = (slave_addr | OAR1_ADD0_SET);
 
-			if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
-				i2c->hw->base->CR1 |= CR1_STOP_SET;
+	if (i2c->xfer_size == 2)
+		i2c->hw->base->CR1 |= CR1_ACK_SET | CR1_POS_SET;
 
-			IRQ_RESTORE(irq);
+	if(!wait_event(i2c, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))
+	{
+		LOG_ERR("SLAR NACK:%08lx\n", get_status(i2c->hw->base));
+		i2c->errors |= I2C_NO_ACK;
+		i2c->hw->base->CR1 |= CR1_STOP_SET;
+		return false;
+	}
 
-			WAIT_RXNE(i2c->hw->base);
+	return true;
+}
 
-			i2c->hw->cache[0] = i2c->hw->base->DR;
-			i2c->hw->cached = true;
+INLINE void start_r(struct I2c *i2c, uint16_t slave_addr)
+{
+	if (!start_and_addr(i2c, slave_addr))
+		return;
+	/*
+	 * Due to the hardware receive bytes from slave in automatically mode
+	 * we should manage contextually all cases that we want to read one, two or more
+	 * than two bytes. To comply this behaviour to our api we shoul bufferd some byte
+	 * to hide all special case that needs to use this device.
+	 */
+	if (i2c->xfer_size == 1)
+	{
+		i2c->hw->base->CR1 &= CR1_ACK_RESET;
 
-			if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
-				while (i2c->hw->base->CR1 & CR1_STOP_SET);
+		cpu_flags_t irq;
 
-			i2c->hw->base->CR1 |= CR1_ACK_SET;
+		IRQ_SAVE_DISABLE(irq);
+		(void)i2c->hw->base->SR2;
+		if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
+			i2c->hw->base->CR1 |= CR1_STOP_SET;
+		IRQ_RESTORE(irq);
 
-		}
-		else if (i2c->xfer_size == 2)
-		{
-			cpu_flags_t irq;
-			IRQ_SAVE_DISABLE(irq);
+		WAIT_RXNE(i2c->hw->base);
 
-			(void)i2c->hw->base->SR2;
+		i2c->hw->cache[0] = i2c->hw->base->DR;
+		i2c->hw->cached = true;
 
-			i2c->hw->base->CR1 &= CR1_ACK_RESET;
+		if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
+			while (i2c->hw->base->CR1 & CR1_STOP_SET);
 
-			IRQ_RESTORE(irq);
+		i2c->hw->base->CR1 |= CR1_ACK_SET;
+	}
+	else if (i2c->xfer_size == 2)
+	{
+		cpu_flags_t irq;
 
-			WAIT_BTF(i2c->hw->base);
+		IRQ_SAVE_DISABLE(irq);
+		(void)i2c->hw->base->SR2;
+		i2c->hw->base->CR1 &= CR1_ACK_RESET;
+		IRQ_RESTORE(irq);
 
-			IRQ_SAVE_DISABLE(irq);
+		WAIT_BTF(i2c->hw->base);
 
-			if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
-				i2c->hw->base->CR1 |= CR1_STOP_SET;
+		IRQ_SAVE_DISABLE(irq);
+		if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
+			i2c->hw->base->CR1 |= CR1_STOP_SET;
+		/*
+		 * We store read bytes like a fifo..
+		 */
+		i2c->hw->cache[1] = i2c->hw->base->DR;
+		i2c->hw->cache[0] = i2c->hw->base->DR;
+		i2c->hw->cached = true;
+		IRQ_RESTORE(irq);
 
-			/*
-			 * We store read bytes like a fifo..
-			 */
-			i2c->hw->cache[1] = i2c->hw->base->DR;
-			i2c->hw->cache[0] = i2c->hw->base->DR;
-			i2c->hw->cached = true;
+		i2c->hw->base->CR1 &= CR1_POS_RESET;
+		i2c->hw->base->CR1 |= CR1_ACK_SET;
+	}
+}
 
-			IRQ_RESTORE(irq);
+static void i2c_stm32_start(struct I2c *i2c, uint16_t slave_addr)
+{
+	i2c->hw->cached = false;
 
-			i2c->hw->base->CR1 &= CR1_POS_RESET;
-			i2c->hw->base->CR1 |= CR1_ACK_SET;
-		}
-	}
+	if (I2C_TEST_START(i2c->flags) == I2C_START_W)
+		start_w(i2c, slave_addr);
+	else /* (I2C_TEST_START(i2c->flags) == I2C_START_R) */
+		start_r(i2c, slave_addr);
 }
 
 static void i2c_stm32_put(I2c *i2c, const uint8_t data)