V4L/DVB (7575): mt312: add attach-time setting to invert lnb-voltage

Add a setting to config struct for inversion of lnb-voltage.
Needed for support of Avermedia A700 cards.

Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

2 files changed, 9 insertions, 1 deletions

diff --git a/drivers/media/dvb/frontends/mt312.c b/drivers/media/dvb/frontends/mt312.c
index e17a36180f9c..081ca3398c76 100644
--- a/drivers/media/dvb/frontends/mt312.c
+++ b/drivers/media/dvb/frontends/mt312.c
@@ -422,11 +422,16 @@ static int mt312_set_voltage(struct dvb_frontend *fe, const fe_sec_voltage_t v)
 {
         struct mt312_state *state = fe->demodulator_priv;
         const u8 volt_tab[3] = { 0x00, 0x40, 0x00 };
+        u8 val;
 
         if (v > SEC_VOLTAGE_OFF)
                 return -EINVAL;
 
-        return mt312_writereg(state, DISEQC_MODE, volt_tab[v]);
+        val = volt_tab[v];
+        if (state->config->voltage_inverted)
+                val ^= 0x40;
+
+        return mt312_writereg(state, DISEQC_MODE, val);
 }
 
 static int mt312_read_status(struct dvb_frontend *fe, fe_status_t *s)
diff --git a/drivers/media/dvb/frontends/mt312.h b/drivers/media/dvb/frontends/mt312.h
index afe24fd822bd..96338f0c4dd4 100644
--- a/drivers/media/dvb/frontends/mt312.h
+++ b/drivers/media/dvb/frontends/mt312.h
@@ -31,6 +31,9 @@
 struct mt312_config {
         /* the demodulator's i2c address */
         u8 demod_address;
+
+        /* inverted voltage setting */
+        int voltage_inverted:1;
 };
 
 #if defined(CONFIG_DVB_MT312) || (defined(CONFIG_DVB_MT312_MODULE) && defined(MODULE))