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fsl_i2c: Do not generate STOP after read.

__i2c_read always ends with a STOP condition thereby releasing
the bus. It is cleaner to do the STOP magic in i2c_read(), like
i2c_write() does. This may also help future multimaster systems which
wants to hold on to the bus until all transactions are finished.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Joakim Tjernlund 15 年之前
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d1c9e5b379
共有 1 个文件被更改,包括 6 次插入5 次删除
  1. 6 5
      drivers/i2c/fsl_i2c.c

+ 6 - 5
drivers/i2c/fsl_i2c.c

@@ -353,9 +353,10 @@ __i2c_read(u8 *data, int length)
 			writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
 			       &i2c_dev[i2c_bus_num]->cr);
 
-		/* Generate stop on last byte */
+		/* Do not generate stop on last byte */
 		if (i == length - 1)
-			writeb(I2C_CR_MEN | I2C_CR_TXAK, &i2c_dev[i2c_bus_num]->cr);
+			writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
+			       &i2c_dev[i2c_bus_num]->cr);
 
 		data[i] = readb(&i2c_dev[i2c_bus_num]->dr);
 	}
@@ -378,11 +379,11 @@ i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
 	    && i2c_write_addr(dev, I2C_READ_BIT, 1) != 0)
 		i = __i2c_read(data, length);
 
-	if (length && i2c_wait4bus()) /* Wait until STOP */
-		debug("i2c_read: wait4bus timed out\n");
-
 	writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr);
 
+	if (i2c_wait4bus()) /* Wait until STOP */
+		debug("i2c_read: wait4bus timed out\n");
+
 	if (i == length)
 	    return 0;