Refactor the recv. Add comments. Change fist_send flag names.

git-svn-id: https://src.develer.com/svnoss/bertos/branches/i2c@4085 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/bertos/cpu/cortex-m3/drv/i2c_lm3s.c b/bertos/cpu/cortex-m3/drv/i2c_lm3s.c
index 29b120ed0b3904538bf9efd455575099cbb0140b..afc6a60b2947ee4ad8f74e73fd5c279b0dd16cd8 100644 (file)
--- a/bertos/cpu/cortex-m3/drv/i2c_lm3s.c
+++ b/bertos/cpu/cortex-m3/drv/i2c_lm3s.c
@@ -48,6 +48,7 @@
 #include <cpu/detect.h>
 #include <cpu/irq.h>
 #include <cpu/types.h>
+#include <cpu/power.h>
 
 #include <io/lm3s.h>
 
@@ -64,12 +65,29 @@ struct I2cHardware
        uint32_t sys_gpio;
        uint32_t pin_mask;
        uint32_t gpio_base;
-       bool first_send;
+       bool first_xtranf;
 };
 
+#define WAIT_BUSY(base) \
+       do { \
+               while (HWREG(base + I2C_O_MCS) & I2C_MCS_BUSY ) \
+                       cpu_relax(); \
+       } while (0);
+
+
+/*
+ * The start is not performed when we call the start function
+ * because the hardware should know the first data byte to send.
+ * Generally to perform a byte send we should write the slave address
+ * in slave address register and the first byte to send in data registry.
+ * After then we can perform the start write procedure, and send really
+ * the our data. To use common bertos i2c api the really start will be
+ * performed when the user "put" or "send" its data. These tricks are hide
+ * from the driver implementation.
+ */
 static void i2c_lm3s_start(struct I2c *i2c, uint16_t slave_addr)
 {
-       i2c->hw->first_send = true;
+       i2c->hw->first_xtranf = true;
 
        if (I2C_TEST_START(i2c->flags) == I2C_START_W)
                HWREG(i2c->hw->base + I2C_O_MSA) = slave_addr & ~BV(0);
@@ -87,14 +105,15 @@ INLINE bool wait_addrAck(I2c *i2c, uint32_t mode_mask)
                if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
                        return false;
 
-               if (status & I2C_MCS_ADRACK)
+               if(status & I2C_MCS_ADRACK)
                {
                        HWREG(i2c->hw->base + I2C_O_MCS) = mode_mask;
-                       while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
-                       continue;
+                       WAIT_BUSY(i2c->hw->base);
                }
                else
                        break;
+
+               cpu_relax();
        }
        return true;
 }
@@ -103,7 +122,7 @@ static void i2c_lm3s_put(I2c *i2c, const uint8_t data)
 {
        HWREG(i2c->hw->base + I2C_O_MDR) = data;
 
-       if (i2c->hw->first_send)
+       if (i2c->hw->first_xtranf)
        {
                HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN | I2C_MCS_START;
                while( HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
@@ -113,90 +132,67 @@ static void i2c_lm3s_put(I2c *i2c, const uint8_t data)
                        LOG_ERR("Start timeout\n");
                        i2c->errors |= I2C_START_TIMEOUT;
                        HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
-                       while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
+                       WAIT_BUSY(i2c->hw->base);
                        return;
                }
 
-               i2c->hw->first_send = false;
+               i2c->hw->first_xtranf = false;
        }
        else
        {
                HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN;
-               while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
+               WAIT_BUSY(i2c->hw->base);
        }
 
        if ((i2c->xfer_size == 1) && (I2C_TEST_STOP(i2c->flags) == I2C_STOP))
        {
                HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
-               while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
+               WAIT_BUSY(i2c->hw->base);
        }
 }
 
 static uint8_t i2c_lm3s_get(I2c *i2c)
 {
-       if ((i2c->xfer_size == 1) && (i2c->hw->first_send))
+       uint8_t data;
+       if (i2c->hw->first_xtranf)
        {
-               HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN | I2C_MCS_START;
-               while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
-
+               uint32_t start_mode;
+               if (i2c->xfer_size == 1)
+                       start_mode = I2C_MCS_RUN | I2C_MCS_START;
+               else
+                       start_mode = I2C_MCS_ACK | I2C_MCS_RUN | I2C_MCS_START;
 
-               if (!wait_addrAck(i2c, I2C_MCS_RUN | I2C_MCS_START))
+               HWREG(i2c->hw->base + I2C_O_MCS) = start_mode;
+               WAIT_BUSY(i2c->hw->base);
+               if (!wait_addrAck(i2c, start_mode))
                {
                        LOG_ERR("Start timeout\n");
                        i2c->errors |= I2C_START_TIMEOUT;
                        HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
+                       WAIT_BUSY(i2c->hw->base);
                        return 0xFF;
                }
 
-               uint8_t data = HWREG(i2c->hw->base + I2C_O_MDR);
-
-               if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
-               {
-                       HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
-                       while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
-               }
-
-               i2c->hw->first_send = false;
-               return data;
+               data = HWREG(i2c->hw->base + I2C_O_MDR);
+               i2c->hw->first_xtranf = false;
        }
        else
        {
-               if (i2c->hw->first_send)
-               {
-                       HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_ACK | I2C_MCS_RUN | I2C_MCS_START;
-                       while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
-
-                       if (!wait_addrAck(i2c, I2C_MCS_ACK | I2C_MCS_RUN | I2C_MCS_START))
-                       {
-                               LOG_ERR("Start timeout\n");
-                               i2c->errors |= I2C_START_TIMEOUT;
-                               HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
-                               return 0xFF;
-                       }
-
-                       i2c->hw->first_send = false;
-                       return HWREG(i2c->hw->base + I2C_O_MDR);
-               }
+               if (i2c->xfer_size > 1)
+                       HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_ACK | I2C_MCS_RUN;
                else
-               {
-                       if (i2c->xfer_size > 1)
-                               HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_ACK | I2C_MCS_RUN;
-                       else
-                               HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN;
-
-                       while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
-                       uint8_t data = HWREG(i2c->hw->base + I2C_O_MDR);
+                       HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN;
 
-                       if ((i2c->xfer_size == 1) && (I2C_TEST_STOP(i2c->flags) == I2C_STOP))
-                       {
-                               HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
-                               while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
-                       }
+               WAIT_BUSY(i2c->hw->base);
+               data = HWREG(i2c->hw->base + I2C_O_MDR);
+       }
 
-                       return data;
-               }
+       if ((i2c->xfer_size == 1) && (I2C_TEST_STOP(i2c->flags) == I2C_STOP))
+       {
+               HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
+               WAIT_BUSY(i2c->hw->base);
        }
-       return 0xFF;
+       return data;
 }
 
 MOD_DEFINE(i2c);