[media] a8293: improve LNB register programming logic

On power-on LNB power supply voltage is disabled, due to that no
need to disable it during probe. Tone is supply is hard-coded as
external tone coming from the demodulator. Program both voltage
and tone on set_voltage(). Use register cache to prevent unneeded
programming.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/dvb-frontends/a8293.c b/drivers/media/dvb-frontends/a8293.c
index d99ea4d61315f6dcbf7b90223ea8c351ad2ea1ef..ef2b47c4c17bda86809bfbbffa09b9292d8162a5 100644 (file)
--- a/drivers/media/dvb-frontends/a8293.c
+++ b/drivers/media/dvb-frontends/a8293.c
@@ -31,30 +31,42 @@ static int a8293_set_voltage(struct dvb_frontend *fe,
        struct a8293_dev *dev = fe->sec_priv;
        struct i2c_client *client = dev->client;
        int ret;
+       u8 reg0, reg1;
 
        dev_dbg(&client->dev, "fe_sec_voltage=%d\n", fe_sec_voltage);
 
        switch (fe_sec_voltage) {
        case SEC_VOLTAGE_OFF:
                /* ENB=0 */
-               dev->reg[0] = 0x10;
+               reg0 = 0x10;
                break;
        case SEC_VOLTAGE_13:
                /* VSEL0=1, VSEL1=0, VSEL2=0, VSEL3=0, ENB=1*/
-               dev->reg[0] = 0x31;
+               reg0 = 0x31;
                break;
        case SEC_VOLTAGE_18:
                /* VSEL0=0, VSEL1=0, VSEL2=0, VSEL3=1, ENB=1*/
-               dev->reg[0] = 0x38;
+               reg0 = 0x38;
                break;
        default:
                ret = -EINVAL;
                goto err;
        }
+       if (reg0 != dev->reg[0]) {
+               ret = i2c_master_send(client, &reg0, 1);
+               if (ret < 0)
+                       goto err;
+               dev->reg[0] = reg0;
+       }
 
-       ret = i2c_master_send(client, &dev->reg[0], 1);
-       if (ret < 0)
-               goto err;
+       /* TMODE=0, TGATE=1 */
+       reg1 = 0x82;
+       if (reg1 != dev->reg[1]) {
+               ret = i2c_master_send(client, &reg1, 1);
+               if (ret < 0)
+                       goto err;
+               dev->reg[1] = reg1;
+       }
 
        usleep_range(1500, 50000);
        return 0;
@@ -85,18 +97,6 @@ static int a8293_probe(struct i2c_client *client,
        if (ret < 0)
                goto err_kfree;
 
-       /* ENB=0 */
-       dev->reg[0] = 0x10;
-       ret = i2c_master_send(client, &dev->reg[0], 1);
-       if (ret < 0)
-               goto err_kfree;
-
-       /* TMODE=0, TGATE=1 */
-       dev->reg[1] = 0x82;
-       ret = i2c_master_send(client, &dev->reg[1], 1);
-       if (ret < 0)
-               goto err_kfree;
-
        /* override frontend ops */
        fe->ops.set_voltage = a8293_set_voltage;
        fe->sec_priv = dev;