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| author | Chris Pascoe <c.pascoe@itee.uq.edu.au> | 2007-11-20 21:17:54 +1000 |
|---|---|---|
| committer | Chris Pascoe <c.pascoe@itee.uq.edu.au> | 2007-11-20 21:17:54 +1000 |
| commit | c5810836461ecca233f23cf834fe738ea36a95c8 (patch) | |
| tree | 03f92fef33151fd7761a16ca064afcb9561eac7e /linux/drivers/media/dvb | |
| parent | 4de1c600c7600abdac0c940ad71f3a07432eeaf2 (diff) | |
| download | mediapointer-dvb-s2-c5810836461ecca233f23cf834fe738ea36a95c8.tar.gz mediapointer-dvb-s2-c5810836461ecca233f23cf834fe738ea36a95c8.tar.bz2 | |
zl10353: store frequencies in 0.1kHz to eliminate rounding errors
From: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Whilst reanalysing my formulas I realised it was no longer possible to get the
right values for a 36.1667MHz IF due to rounding problems.
Storing frequencies in units of 0.1kHz makes it possible to calculate these
again correctly.
Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Diffstat (limited to 'linux/drivers/media/dvb')
| -rw-r--r-- | linux/drivers/media/dvb/dvb-usb/cxusb.c | 2 | ||||
| -rw-r--r-- | linux/drivers/media/dvb/frontends/zl10353.c | 15 | ||||
| -rw-r--r-- | linux/drivers/media/dvb/frontends/zl10353.h | 8 |
3 files changed, 14 insertions, 11 deletions
diff --git a/linux/drivers/media/dvb/dvb-usb/cxusb.c b/linux/drivers/media/dvb/dvb-usb/cxusb.c index 6b6633577..a6196f9ac 100644 --- a/linux/drivers/media/dvb/dvb-usb/cxusb.c +++ b/linux/drivers/media/dvb/dvb-usb/cxusb.c @@ -435,7 +435,7 @@ static struct mt352_config cxusb_mt352_config = { static struct zl10353_config cxusb_zl10353_xc3028_config = { .demod_address = 0x0f, - .if2 = 4560, + .if2 = 45600, .no_tuner = 1, .parallel_ts = 1, }; diff --git a/linux/drivers/media/dvb/frontends/zl10353.c b/linux/drivers/media/dvb/frontends/zl10353.c index e3ba1f23b..276612e00 100644 --- a/linux/drivers/media/dvb/frontends/zl10353.c +++ b/linux/drivers/media/dvb/frontends/zl10353.c @@ -128,9 +128,10 @@ static void zl10353_calc_nominal_rate(struct dvb_frontend *fe, enum fe_bandwidth bandwidth, u16 *nominal_rate) { - u32 adc_clock = 45056; /* 45.056 MHz */ - u8 bw; struct zl10353_state *state = fe->demodulator_priv; + u32 adc_clock = 450560; /* 45.056 MHz */ + u64 value; + u8 bw; if (state->config.adc_clock) adc_clock = state->config.adc_clock; @@ -148,7 +149,9 @@ static void zl10353_calc_nominal_rate(struct dvb_frontend *fe, break; } - *nominal_rate = (bw * (1 << 23) / 7 * 125 + adc_clock / 2) / adc_clock; + value = (bw * (u64)10 * (1 << 23) / 7 * 125 + adc_clock / 2); + do_div(value, adc_clock); + *nominal_rate = value; dprintk("%s: bw %d, adc_clock %d => 0x%x\n", __FUNCTION__, bw, adc_clock, *nominal_rate); @@ -158,8 +161,8 @@ static void zl10353_calc_input_freq(struct dvb_frontend *fe, u16 *input_freq) { struct zl10353_state *state = fe->demodulator_priv; - u32 adc_clock = 45056; /* 45.056 MHz */ - int if2 = 36167; /* 36.167 MHz */ + u32 adc_clock = 450560; /* 45.056 MHz */ + int if2 = 361667; /* 36.1667 MHz */ int ife; u64 value; @@ -175,7 +178,7 @@ static void zl10353_calc_input_freq(struct dvb_frontend *fe, if (ife > adc_clock / 2) ife = adc_clock - ife; } - value = 65536ULL * ife + adc_clock / 2; + value = (u64)65536 * ife + adc_clock / 2; do_div(value, adc_clock); *input_freq = -value; diff --git a/linux/drivers/media/dvb/frontends/zl10353.h b/linux/drivers/media/dvb/frontends/zl10353.h index 2660cec93..fc734c22b 100644 --- a/linux/drivers/media/dvb/frontends/zl10353.h +++ b/linux/drivers/media/dvb/frontends/zl10353.h @@ -29,9 +29,9 @@ struct zl10353_config /* demodulator's I2C address */ u8 demod_address; - /* frequencies in kHz */ - int adc_clock; /* default: 45056 */ - int if2; /* default: 36167 */ + /* frequencies in units of 0.1kHz */ + int adc_clock; /* default: 450560 (45.056 MHz) */ + int if2; /* default: 361667 (36.1667 MHz) */ /* set if no pll is connected to the secondary i2c bus */ int no_tuner; @@ -50,6 +50,6 @@ static inline struct dvb_frontend* zl10353_attach(const struct zl10353_config *c printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __FUNCTION__); return NULL; } -#endif // CONFIG_DVB_ZL10353 +#endif /* CONFIG_DVB_ZL10353 */ #endif /* ZL10353_H */ |