V4L/DVB (5960): Add module parameter to enable SFN workaround

In some areas in the world the broadcasters are not using the same
cellid for each transmitter in a SFN. The DiBcom has problems with
that setup. The module parameter buggy_sfn_workaround makes it re-usable.

Signed-off-by: Matt Doran <matt.doran@papercut.biz>
Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 17 insertions, 5 deletions

diff --git a/drivers/media/dvb/frontends/dib3000mc.c b/drivers/media/dvb/frontends/dib3000mc.c
index 38d2322cbaf6..f0096de2279e 100644
--- a/drivers/media/dvb/frontends/dib3000mc.c
+++ b/drivers/media/dvb/frontends/dib3000mc.c
@@ -13,10 +13,6 @@
 
 #include <linux/kernel.h>
 #include <linux/i2c.h>
-//#include <linux/init.h>
-//#include <linux/delay.h>
-//#include <linux/string.h>
-//#include <linux/slab.h>
 
 #include "dvb_frontend.h"
 
@@ -26,6 +22,10 @@ static int debug;
 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "turn on debugging (default: 0)");
 
+static int buggy_sfn_workaround;
+module_param(buggy_sfn_workaround, int, 0644);
+MODULE_PARM_DESC(debug, "Enable work-around for buggy SFNs (default: 0)");
+
 #define dprintk(args...) do { if (debug) { printk(KERN_DEBUG "DiB3000MC/P:"); printk(args); printk("\n"); } } while (0)
 
 struct dib3000mc_state {
@@ -42,6 +42,8 @@ struct dib3000mc_state {
         fe_bandwidth_t current_bandwidth;
 
         u16 dev_id;
+
+        u8 sfn_workaround_active :1;
 };
 
 static u16 dib3000mc_read_word(struct dib3000mc_state *state, u16 reg)
@@ -591,7 +593,14 @@ static int dib3000mc_tune(struct dvb_frontend *demod, struct dvb_frontend_parame
         dib3000mc_set_channel_cfg(state, ch, 0);
 
         // activates isi
-        dib3000mc_write_word(state, 29, 0x1073);
+        if (state->sfn_workaround_active) {
+                dprintk("SFN workaround is active\n");
+                dib3000mc_write_word(state, 29, 0x1273);
+                dib3000mc_write_word(state, 108, 0x4000); // P_pha3_force_pha_shift
+        } else {
+                dib3000mc_write_word(state, 29, 0x1073);
+                dib3000mc_write_word(state, 108, 0x0000); // P_pha3_force_pha_shift
+        }
 
         dib3000mc_set_adp_cfg(state, (u8)ch->u.ofdm.constellation);
         if (ch->u.ofdm.transmission_mode == TRANSMISSION_MODE_8K) {
@@ -679,6 +688,9 @@ static int dib3000mc_set_frontend(struct dvb_frontend* fe,
         state->current_bandwidth = fep->u.ofdm.bandwidth;
         dib3000mc_set_bandwidth(state, BANDWIDTH_TO_KHZ(fep->u.ofdm.bandwidth));
 
+        /* maybe the parameter has been changed */
+        state->sfn_workaround_active = buggy_sfn_workaround;
+
         if (fe->ops.tuner_ops.set_params) {
                 fe->ops.tuner_ops.set_params(fe, fep);
                 msleep(100);