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[media] m88rs2000: add m88rs2000_set_carrieroffset

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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 <tvboxspy@gmail.com>
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Malcolm Priestley 2013-12-24 13:17:12 -03:00 committed by Mauro Carvalho Chehab
parent 58f087c9b6
commit 06af15d1b6
2 changed files with 59 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
drivers/media/dvb-frontends/m88rs2000.c
View File

@ -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);

2
drivers/media/dvb-frontends/m88rs2000.h
View File

@ -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,