[media] saa7134: fix warm Medion 7134 EEPROM read

When saa7134 module driving a Medion 7134 card is reloaded reads of this
card EEPROM (required for automatic detection of tuner model) will be
corrupted due to I2C gate in DVB-T demod being left closed.
This sometimes also happens on first saa7134 module load after a warm
reboot.

Fix this by opening this I2C gate before doing EEPROM read during i2c
initialization.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/pci/saa7134/saa7134-i2c.c b/drivers/media/pci/saa7134/saa7134-i2c.c
index 2dac48fa1386248fe839fff873034bd582afd05a..dca0592c5f47157bae6d1b85a751bb51f7aee6fe 100644 (file)
--- a/drivers/media/pci/saa7134/saa7134-i2c.c
+++ b/drivers/media/pci/saa7134/saa7134-i2c.c
@@ -355,12 +355,43 @@ static struct i2c_client saa7134_client_template = {
 
 /* ----------------------------------------------------------- */
 
+/* On Medion 7134 reading EEPROM needs DVB-T demod i2c gate open */
+static void saa7134_i2c_eeprom_md7134_gate(struct saa7134_dev *dev)
+{
+       u8 subaddr = 0x7, dmdregval;
+       u8 data[2];
+       int ret;
+       struct i2c_msg i2cgatemsg_r[] = { {.addr = 0x08, .flags = 0,
+                                          .buf = &subaddr, .len = 1},
+                                         {.addr = 0x08,
+                                          .flags = I2C_M_RD,
+                                          .buf = &dmdregval, .len = 1}
+                                       };
+       struct i2c_msg i2cgatemsg_w[] = { {.addr = 0x08, .flags = 0,
+                                          .buf = data, .len = 2} };
+
+       ret = i2c_transfer(&dev->i2c_adap, i2cgatemsg_r, 2);
+       if ((ret == 2) && (dmdregval & 0x2)) {
+               pr_debug("%s: DVB-T demod i2c gate was left closed\n",
+                        dev->name);
+
+               data[0] = subaddr;
+               data[1] = (dmdregval & ~0x2);
+               if (i2c_transfer(&dev->i2c_adap, i2cgatemsg_w, 1) != 1)
+                       pr_err("%s: EEPROM i2c gate open failure\n",
+                         dev->name);
+       }
+}
+
 static int
 saa7134_i2c_eeprom(struct saa7134_dev *dev, unsigned char *eedata, int len)
 {
        unsigned char buf;
        int i,err;
 
+       if (dev->board == SAA7134_BOARD_MD7134)
+               saa7134_i2c_eeprom_md7134_gate(dev);
+
        dev->i2c_client.addr = 0xa0 >> 1;
        buf = 0;
        if (1 != (err = i2c_master_send(&dev->i2c_client,&buf,1))) {