[linux-dvb] Handling of frontend automatic inversion?

[Jon Burgess <mplayer@jburgess.uklinux.net>]

Attached are two patches which tweak the handling of the INVERSION_AUTO 
by the grundig_29504-401 and tda1004x frontends.

When reading through the grundig datasheet some time ago I noticed that 
the driver already enables the "automatic TPS update" feature of the 
frontend. I believe that this feature allows the frontend to determine 
the correct inversion setting automatically, but the driver doesn't 
claim to support this feature. The patch for this frontend adds support 
for setting this mode (but the auto TPS mode was already permenantly 
enabled anyway).

The tda1004x driver claims to support auto inversion, but was rejecting 
it as an invalid parameter if the application (e.g. scan) tried to use 
it. I assume that this frontend uses the same auto-TPS mechanism as the 
grundig frontend.

The datasheet that i've found seems a bit light on technical information 
but it does claim:
 "For maximum ease of use, the TDA10045 features fully automatic
  transmission parameter detection"

Does anyone have a more detailed register guide to confirm whether this 
feature is actually enabled? I'll try tuning with both inversion on and 
off and see whether it really does get it correct.

	Jon


diff -urw dvb-kernel-cvs/linux/drivers/media/dvb/frontends/tda1004x.c dvb-kernel/linux/drivers/media/dvb/frontends/tda1004x.c
--- dvb-kernel-cvs/linux/drivers/media/dvb/frontends/tda1004x.c	2003-09-11 17:35:55.000000000 +0100
+++ dvb-kernel/linux/drivers/media/dvb/frontends/tda1004x.c	2003-09-14 00:09:15.000000000 +0100
@@ -681,6 +681,7 @@
 	// set inversion
 	switch (fe_params->inversion) {
 	case INVERSION_OFF:
+	case INVERSION_AUTO:
 		tda1004x_write_mask(i2c, tda_state, TDA1004X_CONFC1, 0x20, 0);
 		break;
 
--- dvb-kernel-cvs/linux/drivers/media/dvb/frontends/grundig_29504-401.c	2003-09-11 17:35:55.000000000 +0100
+++ dvb-kernel/linux/drivers/media/dvb/frontends/grundig_29504-401.c	2003-09-14 00:19:02.000000000 +0100
@@ -45,7 +45,8 @@
 /*      .frequency_tolerance = ???,*/
 /*      .symbol_rate_tolerance = ???,*/
 	.notifier_delay = 0,
-	.caps = FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
+	.caps = FE_CAN_INVERSION_AUTO |
+	      FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
 	      FE_CAN_FEC_5_6 | FE_CAN_FEC_7_8 |
 	      FE_CAN_QPSK | FE_CAN_QAM_16 | FE_CAN_QAM_64 |
 	      FE_CAN_MUTE_TS /*| FE_CAN_CLEAN_SETUP*/
@@ -179,7 +180,8 @@
 	int bw = p->bandwidth - BANDWIDTH_8_MHZ;
 
 	if (param->inversion != INVERSION_ON &&
-	    param->inversion != INVERSION_OFF)
+	    param->inversion != INVERSION_OFF &&
+	    param->inversion != INVERSION_AUTO)
 		return -EINVAL;
 
 	if (bw < 0 || bw > 2)