[media] stb0899: store successful inversion for next run

Usually, inversion doesn't change in a system. Storing the last
successful inversion value speeds up tuning of DVB-S2 transponders.
Signed-off-by: Reinhard Nißl <rnissl@gmx.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb-frontends/stb0899_algo.c

@@ -1488,9 +1488,15 @@ enum stb0899_status stb0899_dvbs2_algo(struct stb0899_state *state)
 
 		offsetfreq = offsetfreq / ((1 << 30) / 1000);
 		offsetfreq *= (internal->master_clk / 1000000);
+
+		/* store current inversion for next run */
 		reg = STB0899_READ_S2REG(STB0899_S2DEMOD, DMD_CNTRL2);
 		if (STB0899_GETFIELD(SPECTRUM_INVERT, reg))
-			offsetfreq *= -1;
+			internal->inversion = IQ_SWAP_ON;
+		else
+			internal->inversion = IQ_SWAP_OFF;
+
+		offsetfreq *= internal->inversion;
 
 		internal->freq = internal->freq - offsetfreq;
 		internal->srate = stb0899_dvbs2_get_srate(state);

drivers/media/dvb-frontends/stb0899_drv.c

@@ -1618,19 +1618,18 @@ static struct dvb_frontend_ops stb0899_ops = {
 struct dvb_frontend *stb0899_attach(struct stb0899_config *config, struct i2c_adapter *i2c)
 {
 	struct stb0899_state *state = NULL;
-	enum stb0899_inversion inversion;
 
 	state = kzalloc(sizeof (struct stb0899_state), GFP_KERNEL);
 	if (state == NULL)
 		goto error;
 
-	inversion				= config->inversion;
 	state->verbose				= &verbose;
 	state->config				= config;
 	state->i2c				= i2c;
 	state->frontend.ops			= stb0899_ops;
 	state->frontend.demodulator_priv	= state;
-	state->internal.inversion		= inversion;
+	/* use configured inversion as default -- we'll later autodetect inversion */
+	state->internal.inversion		= config->inversion;
 
 	stb0899_wakeup(&state->frontend);
 	if (stb0899_get_dev_id(state) == -ENODEV) {