[media] au0828: prevent i2c gate from being kept open while in analog mode

The original implementation of the analog support would use an
i2c_gate_ctrl function when using the digital side of the au8522, but on
the analog side we would always just force the gate open and leave it
open all the time.

This can have adverse effects on the xc5000 given the tuner is receiving
all the spurious i2c traffic (a problem which can be exaggerated due to
bugs in the au0828 i2c hardware implementation).

Rework the existing hack to only open/close the gate when actually
talking to the tuner.

This logic might need to be reworked a bit if anybody ever tries to add
support for a board that has the au0828/au8522 but doesn't have digital
support implemented (because the i2c_gate_ctrl callback is being set in
the DVB attach).  However given how few different models are in
circulation, this can be deferred until such a situation arises (if
ever).
Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/au8522_common.c

@@ -99,6 +99,19 @@ int au8522_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
 }
 EXPORT_SYMBOL(au8522_i2c_gate_ctrl);
 
+int au8522_analog_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
+{
+	struct au8522_state *state = fe->demodulator_priv;
+
+	dprintk("%s(%d)\n", __func__, enable);
+
+	if (enable)
+		return au8522_writereg(state, 0x106, 1);
+	else
+		return au8522_writereg(state, 0x106, 0);
+}
+EXPORT_SYMBOL(au8522_analog_i2c_gate_ctrl);
+
 /* Reset the demod hardware and reset all of the configuration registers
    to a default state. */
 int au8522_get_state(struct au8522_state **state, struct i2c_adapter *i2c,

drivers/media/dvb/frontends/au8522_decoder.c

@@ -659,11 +659,6 @@ static int au8522_s_video_routing(struct v4l2_subdev *sd,
 
 	au8522_reset(sd, 0);
 
-	/* Jam open the i2c gate to the tuner.  We do this here to handle the
-	   case where the user went into digital mode (causing the gate to be
-	   closed), and then came back to analog mode */
-	au8522_writereg(state, 0x106, 1);
-
 	if (input == AU8522_COMPOSITE_CH1) {
 		au8522_setup_cvbs_mode(state);
 	} else if (input == AU8522_SVIDEO_CH13) {

drivers/media/dvb/frontends/au8522_dig.c

@@ -777,6 +777,8 @@ struct dvb_frontend *au8522_attach(const struct au8522_config *config,
 	       sizeof(struct dvb_frontend_ops));
 	state->frontend.demodulator_priv = state;
 
+	state->frontend.ops.analog_ops.i2c_gate_ctrl = au8522_analog_i2c_gate_ctrl;
+
 	if (au8522_init(&state->frontend) != 0) {
 		printk(KERN_ERR "%s: Failed to initialize correctly\n",
 			__func__);

drivers/media/dvb/frontends/au8522_priv.h

@@ -82,6 +82,7 @@ int au8522_get_state(struct au8522_state **state, struct i2c_adapter *i2c,
 		     u8 client_address);
 void au8522_release_state(struct au8522_state *state);
 int au8522_i2c_gate_ctrl(struct dvb_frontend *fe, int enable);
+int au8522_analog_i2c_gate_ctrl(struct dvb_frontend *fe, int enable);
 int au8522_led_ctrl(struct au8522_state *state, int led);
 
 /* REGISTERS */

drivers/media/video/au0828/au0828-video.c

@@ -1541,6 +1541,9 @@ static int vidioc_s_frequency(struct file *file, void *priv,
 
 	dev->ctrl_freq = freq->frequency;
 
+	if (dev->dvb.frontend && dev->dvb.frontend->ops.analog_ops.i2c_gate_ctrl)
+		dev->dvb.frontend->ops.analog_ops.i2c_gate_ctrl(dev->dvb.frontend, 1);
+
 	if (dev->std_set_in_tuner_core == 0) {
 	  /* If we've never sent the standard in tuner core, do so now.  We
 	     don't do this at device probe because we don't want to incur
@@ -1552,6 +1555,9 @@ static int vidioc_s_frequency(struct file *file, void *priv,
 
 	v4l2_device_call_all(&dev->v4l2_dev, 0, tuner, s_frequency, freq);
 
+	if (dev->dvb.frontend && dev->dvb.frontend->ops.analog_ops.i2c_gate_ctrl)
+		dev->dvb.frontend->ops.analog_ops.i2c_gate_ctrl(dev->dvb.frontend, 0);
+
 	au0828_analog_stream_reset(dev);
 
 	return 0;