I2C Repeated Start Implementation

Executing "i2c stop" and "i2c start" for repeated start condition does
NOT work for LP3979. For LP3979, I've implemented repeated start
condition.

We need to consider using this as the standard repeated start condition.

diff --git a/drivers/i2c/soft_i2c.c b/drivers/i2c/soft_i2c.c
index e0cf1e1..39fceff 100644 (file)
--- a/drivers/i2c/soft_i2c.c
+++ b/drivers/i2c/soft_i2c.c
@@ -140,6 +140,28 @@ static void send_start(void)
 }
 
 /*-----------------------------------------------------------------------
+ * REPEATED START: Low -> High -> Low on SDA while SCL is High
+ */
+static void send_repeated_start(void)
+{
+       I2C_SOFT_DECLARATIONS   /* intentional without ';' */
+
+       I2C_DELAY;
+       I2C_SCL(0);
+       I2C_DELAY;
+       I2C_SDA(0);
+       I2C_DELAY;
+
+       I2C_DELAY;
+       I2C_SDA(1);
+       I2C_DELAY;
+       I2C_SCL(1);
+       I2C_DELAY;
+       I2C_SDA(0);
+       I2C_DELAY;
+}
+
+/*-----------------------------------------------------------------------
  * STOP: Low -> High on SDA while SCL is High
  */
 static void send_stop(void)
@@ -380,7 +402,7 @@ int  i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
                 * stop/start sequence.
                 */
 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
-               send_start();
+               send_repeated_start();
 #else
                send_stop();
                send_start();