V4L/DVB (11700): tda10048: Added option to block i2c gate control from other drivers.

Currently, DVB-T is broken and this fixes it.

The PVRUSB2 has an odd I2C bus configuration where opening the i2c gate
on the digital and analog demod causes the tuner to fail. This needs
to be protected against for the PVRUSB2.
Signed-off-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/tda10048.c

@@ -689,6 +689,9 @@ static int tda10048_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
 	struct tda10048_state *state = fe->demodulator_priv;
 	dprintk(1, "%s(%d)\n", __func__, enable);
 
+	if (state->config->disable_gate_access)
+		return 0;
+
 	if (enable)
 		return tda10048_writereg(state, TDA10048_CONF_C4_1,
 			tda10048_readreg(state, TDA10048_CONF_C4_1) | 0x02);

drivers/media/dvb/frontends/tda10048.h

@@ -57,6 +57,9 @@ struct tda10048_config {
 #define TDA10048_CLK_4000  4000
 #define TDA10048_CLK_16000 16000
 	u16 clk_freq_khz;
+
+	/* Disable I2C gate access */
+	u8 disable_gate_access;
 };
 
 #if defined(CONFIG_DVB_TDA10048) || \