Set the carrier offset correctly using the default mclk values.
Add function m88rs2000_get_mclk to calculate the mclk value
against crystal frequency which will later be used for
other functions.
Add function m88rs2000_set_carrieroffset to calculate
and set the offset value.
variable offset becomes a signed value.
Register 0x86 is set the appropriate value according to
remainder value of frequency % 192857 calculation as
shown.
Signed-off-by: Malcolm Priestley <tvbox...@gmail.com>
Cc: sta...@vger.kernel.org # v3.9+
---
drivers/media/dvb-frontends/m88rs2000.c | 77 ++++++++++++++++++++++++---------
drivers/media/dvb-frontends/m88rs2000.h | 2 +
2 files changed, 59 insertions(+), 20 deletions(-)
diff --git a/drivers/media/dvb-frontends/m88rs2000.c
b/drivers/media/dvb-frontends/m88rs2000.c
index 4da5272..8091653 100644
--- a/drivers/media/dvb-frontends/m88rs2000.c
+++ b/drivers/media/dvb-frontends/m88rs2000.c
@@ -110,6 +110,52 @@ static u8 m88rs2000_readreg(struct m88rs2000_state *state,
u8 reg)
return b1[0];
}
+static u32 m88rs2000_get_mclk(struct dvb_frontend *fe)
+{
+ struct m88rs2000_state *state = fe->demodulator_priv;
+ u32 mclk;
+ u8 reg;
+ /* Must not be 0x00 or 0xff */
+ reg = m88rs2000_readreg(state, 0x86);
+ if (!reg || reg == 0xff)
+ return 0;
+
+ reg /= 2;
+ reg += 1;
+
+ mclk = (u32)(reg * RS2000_FE_CRYSTAL_KHZ + 28 / 2) / 28;
+
+ return mclk;
+}
+
+static int m88rs2000_set_carrieroffset(struct dvb_frontend *fe, s16 offset)
+{
+ struct m88rs2000_state *state = fe->demodulator_priv;
+ u32 mclk;
+ s32 tmp;
+ u8 reg;
+ int ret;
+
+ mclk = m88rs2000_get_mclk(fe);
+ if (!mclk)
+ return -EINVAL;
+
+ tmp = (offset * 4096 + (s32)mclk / 2) / (s32)mclk;
+ if (tmp < 0)
+ tmp += 4096;
+
+ /* Carrier Offset */
+ ret = m88rs2000_writereg(state, 0x9c, (u8)(tmp >> 4));
+
+ reg = m88rs2000_readreg(state, 0x9d);
+ reg &= 0xf;
+ reg |= (u8)(tmp & 0xf) << 4;
+
+ ret |= m88rs2000_writereg(state, 0x9d, reg);
+
+ return ret;
+}
+
static int m88rs2000_set_symbolrate(struct dvb_frontend *fe, u32 srate)
{
struct m88rs2000_state *state = fe->demodulator_priv;
@@ -540,9 +586,8 @@ static int m88rs2000_set_frontend(struct dvb_frontend *fe)
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
fe_status_t status;
int i, ret = 0;
- s32 tmp;
u32 tuner_freq;
- u16 offset = 0;
+ s16 offset = 0;
u8 reg;
state->no_lock_count = 0;
@@ -567,26 +612,18 @@ static int m88rs2000_set_frontend(struct dvb_frontend *fe)
if (ret < 0)
return -ENODEV;
- offset = tuner_freq - c->frequency;
+ offset = (s16)((s32)tuner_freq - c->frequency);
- /* calculate offset assuming 96000kHz*/
- tmp = offset;
- tmp *= 65536;
-
- tmp = (2 * tmp + 96000) / (2 * 96000);
- if (tmp < 0)
- tmp += 65536;
-
- offset = tmp & 0xffff;
-
- ret = m88rs2000_writereg(state, 0x9a, 0x30);
- /* Unknown usually 0xc6 sometimes 0xc1 */
- reg = m88rs2000_readreg(state, 0x86);
- ret |= m88rs2000_writereg(state, 0x86, reg);
- /* Offset lower nibble always 0 */
- ret |= m88rs2000_writereg(state, 0x9c, (offset >> 8));
- ret |= m88rs2000_writereg(state, 0x9d, offset & 0xf0);
+ /* default mclk value 96.4285 * 2 * 1000 = 192857 */
+ if (((c->frequency % 192857) >= (192857 - 3000)) ||
+ (c->frequency % 192857) <= 3000)
+ ret = m88rs2000_writereg(state, 0x86, 0xc2);
+ else
+ ret = m88rs2000_writereg(state, 0x86, 0xc6);
+ ret |= m88rs2000_set_carrieroffset(fe, offset);
+ if (ret < 0)
+ return -ENODEV;
/* Reset Demod */
ret = m88rs2000_tab_set(state, fe_reset);
diff --git a/drivers/media/dvb-frontends/m88rs2000.h
b/drivers/media/dvb-frontends/m88rs2000.h
index 14ce31e..0a50ea9 100644
--- a/drivers/media/dvb-frontends/m88rs2000.h
+++ b/drivers/media/dvb-frontends/m88rs2000.h
@@ -53,6 +53,8 @@ static inline struct dvb_frontend *m88rs2000_attach(
}
#endif /* CONFIG_DVB_M88RS2000 */
+#define RS2000_FE_CRYSTAL_KHZ 27000
+
enum {
DEMOD_WRITE = 0x1,
WRITE_DELAY = 0x10,
--
1.8.5.2
--
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