[media] saa7164: Improvements for I2C handling

Workaround oddball I2C issues caused by using newer
SILABS devices.

Signed-off-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/pci/saa7164/saa7164-api.c b/drivers/media/pci/saa7164/saa7164-api.c
index 97bbd0a13d62136adbbd6815b5cbe62d63b7dd1c..d9e21e736d1f7de258fbbf6e88626879dc41e76a 100644 (file)
--- a/drivers/media/pci/saa7164/saa7164-api.c
+++ b/drivers/media/pci/saa7164/saa7164-api.c
@@ -1385,7 +1385,8 @@ int saa7164_api_i2c_read(struct saa7164_i2c *bus, u8 addr, u32 reglen, u8 *reg,
         *       08... register address
         */
        memset(buf, 0, sizeof(buf));
-       memcpy((buf + 2 * sizeof(u32) + 0), reg, reglen);
+       if (reg)
+               memcpy((buf + 2 * sizeof(u32) + 0), reg, reglen);
        *((u32 *)(buf + 0 * sizeof(u32))) = reglen;
        *((u32 *)(buf + 1 * sizeof(u32))) = datalen;
 
@@ -1473,6 +1474,14 @@ int saa7164_api_i2c_write(struct saa7164_i2c *bus, u8 addr, u32 datalen,
         *       04-07 dest bytes to write
         *       08... register address
         */
+       if (datalen == 1) {
+               /* Workaround for issues with i2c components
+                * that issue writes with no data. IE: SI2168/2157
+                * Increase reglen by 1, strobe out an additional byte,
+                * ignored by SI2168/2157.
+                */
+               datalen++;
+       }
        *((u32 *)(buf + 0 * sizeof(u32))) = reglen;
        *((u32 *)(buf + 1 * sizeof(u32))) = datalen - reglen;
        memcpy((buf + 2 * sizeof(u32)), data, datalen);