From af9d52555304979c7a3ce254e026bc76bd878f74 Mon Sep 17 00:00:00 2001 From: Antti Palosaari Date: Thu, 26 Mar 2015 10:04:09 -0300 Subject: [PATCH] [media] ts2020: re-implement PLL calculations 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 Signed-off-by: Mauro Carvalho Chehab --- 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 90164a38cd36..bc48388906d3 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; } -- 2.39.2