diff options
| author | Chris Pascoe <c.pascoe@itee.uq.edu.au> | 2007-11-20 08:17:54 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@infradead.org> | 2008-01-25 19:02:37 -0200 |
| commit | a1dcd9de648c8cf21abaeca7f77885665eed4117 (patch) | |
| tree | f35cdf7d007056445a0603a12fb20d3eed5ec7ba /drivers | |
| parent | 702a67624e4bc9c7056418b576af928940b7dbb9 (diff) | |
V4L/DVB (6656): zl10353: store frequencies in 0.1kHz to eliminate rounding errors
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 'drivers')
| -rw-r--r-- | drivers/media/dvb/dvb-usb/cxusb.c | 2 | ||||
| -rw-r--r-- | drivers/media/dvb/frontends/zl10353.c | 15 | ||||
| -rw-r--r-- | drivers/media/dvb/frontends/zl10353.h | 8 |
3 files changed, 14 insertions, 11 deletions
diff --git a/drivers/media/dvb/dvb-usb/cxusb.c b/drivers/media/dvb/dvb-usb/cxusb.c index c44b9799efa..deeb3871a2a 100644 --- a/drivers/media/dvb/dvb-usb/cxusb.c +++ b/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/drivers/media/dvb/frontends/zl10353.c b/drivers/media/dvb/frontends/zl10353.c index 1736c6ac39c..091fbcced00 100644 --- a/drivers/media/dvb/frontends/zl10353.c +++ b/drivers/media/dvb/frontends/zl10353.c @@ -123,9 +123,10 @@ 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; @@ -143,7 +144,9 @@ 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); @@ -153,8 +156,8 @@ 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; @@ -170,7 +173,7 @@ 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/drivers/media/dvb/frontends/zl10353.h b/drivers/media/dvb/frontends/zl10353.h index 2660cec93f8..fc734c22b5f 100644 --- a/drivers/media/dvb/frontends/zl10353.h +++ b/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 */ |