Used frequency synthesizer is simple Integer-N PLL, with configurable
reference divider, output divider and of course N itself. Old
calculations were working fine, but not so easy to understand.
Signed-off-by: Antti Palosaari <crope@xxxxxx>
---
drivers/media/dvb-frontends/ts2020.c | 76 +++++++++++++++++++++---------------
1 file changed, 44 insertions(+), 32 deletions(-)
diff --git a/drivers/media/dvb-frontends/ts2020.c b/drivers/media/dvb-frontends/ts2020.c
index 90164a3..bc48388 100644
--- a/drivers/media/dvb-frontends/ts2020.c
+++ b/drivers/media/dvb-frontends/ts2020.c
@@ -32,8 +32,8 @@ struct ts2020_priv {
struct i2c_adapter *i2c;
u8 clk_out:2;
u8 clk_out_div:5;
- u32 frequency;
- u32 frequency_div;
+ u32 frequency_div; /* LO output divider switch frequency */
+ u32 frequency_khz; /* actual used LO frequency */
#define TS2020_M88TS2020 0
#define TS2020_M88TS2022 1
u8 tuner;
@@ -233,45 +233,62 @@ static int ts2020_set_params(struct dvb_frontend *fe)
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
struct ts2020_priv *priv = fe->tuner_priv;
int ret;
- u32 frequency = c->frequency;
- s32 offset_khz;
u32 symbol_rate = (c->symbol_rate / 1000);
u32 f3db, gdiv28;
- u16 value, ndiv, lpf_coeff;
- u8 lpf_mxdiv, mlpf_max, mlpf_min, nlpf;
- u8 lo = 0x01, div4 = 0x0;
-
- /* Calculate frequency divider */
- if (frequency < priv->frequency_div) {
- lo |= 0x10;
- div4 = 0x1;
- ndiv = (frequency * 14 * 4) / TS2020_XTAL_FREQ;
- } else
- ndiv = (frequency * 14 * 2) / TS2020_XTAL_FREQ;
- ndiv = ndiv + ndiv % 2;
- ndiv = ndiv - 1024;
+ u16 u16tmp, value, lpf_coeff;
+ u8 buf[3], reg10, lpf_mxdiv, mlpf_max, mlpf_min, nlpf;
+ unsigned int f_ref_khz, f_vco_khz, div_ref, div_out, pll_n;
+ unsigned int frequency_khz = c->frequency;
+
+ /*
+ * Integer-N PLL synthesizer
+ * kHz is used for all calculations to keep calculations within 32-bit
+ */
+ f_ref_khz = TS2020_XTAL_FREQ;
+ div_ref = DIV_ROUND_CLOSEST(f_ref_khz, 2000);
+
+ /* select LO output divider */
+ if (frequency_khz < priv->frequency_div) {
+ div_out = 4;
+ reg10 = 0x10;
+ } else {
+ div_out = 2;
+ reg10 = 0x00;
+ }
+
+ f_vco_khz = frequency_khz * div_out;
+ pll_n = f_vco_khz * div_ref / f_ref_khz;
+ pll_n += pll_n % 2;
+ priv->frequency_khz = pll_n * f_ref_khz / div_ref / div_out;
+
+ pr_debug("frequency=%u offset=%d f_vco_khz=%u pll_n=%u div_ref=%u div_out=%u\n",
+ priv->frequency_khz, priv->frequency_khz - c->frequency,
+ f_vco_khz, pll_n, div_ref, div_out);
if (priv->tuner == TS2020_M88TS2020) {
lpf_coeff = 2766;
- ret = ts2020_writereg(fe, 0x10, 0x80 | lo);
+ reg10 |= 0x01;
+ ret = ts2020_writereg(fe, 0x10, reg10);
} else {
lpf_coeff = 3200;
- ret = ts2020_writereg(fe, 0x10, 0x0b);
+ reg10 |= 0x0b;
+ ret = ts2020_writereg(fe, 0x10, reg10);
ret |= ts2020_writereg(fe, 0x11, 0x40);
}
- /* Set frequency divider */
- ret |= ts2020_writereg(fe, 0x01, (ndiv >> 8) & 0xf);
- ret |= ts2020_writereg(fe, 0x02, ndiv & 0xff);
+ u16tmp = pll_n - 1024;
+ buf[0] = (u16tmp >> 8) & 0xff;
+ buf[1] = (u16tmp >> 0) & 0xff;
+ buf[2] = div_ref - 8;
+
+ ret |= ts2020_writereg(fe, 0x01, buf[0]);
+ ret |= ts2020_writereg(fe, 0x02, buf[1]);
+ ret |= ts2020_writereg(fe, 0x03, buf[2]);
- ret |= ts2020_writereg(fe, 0x03, 0x06);
ret |= ts2020_tuner_gate_ctrl(fe, 0x10);
if (ret < 0)
return -ENODEV;
- /* Tuner Frequency Range */
- ret = ts2020_writereg(fe, 0x10, lo);
-
ret |= ts2020_tuner_gate_ctrl(fe, 0x08);
/* Tuner RF */
@@ -335,11 +352,6 @@ static int ts2020_set_params(struct dvb_frontend *fe)
ret |= ts2020_tuner_gate_ctrl(fe, 0x01);
msleep(80);
- /* calculate offset assuming 96000kHz*/
- offset_khz = (ndiv - ndiv % 2 + 1024) * TS2020_XTAL_FREQ
- / (6 + 8) / (div4 + 1) / 2;
-
- priv->frequency = offset_khz;
return (ret < 0) ? -EINVAL : 0;
}
@@ -347,8 +359,8 @@ static int ts2020_set_params(struct dvb_frontend *fe)
static int ts2020_get_frequency(struct dvb_frontend *fe, u32 *frequency)
{
struct ts2020_priv *priv = fe->tuner_priv;
- *frequency = priv->frequency;
+ *frequency = priv->frequency_khz;
return 0;
}
--
http://palosaari.fi/
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