From: Antti Palosaari Date: Mon, 2 Dec 2013 04:39:24 +0000 (-0300) Subject: [media] m88ts2022: reimplement synthesizer calculations X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c19314b09bc0839736f2c74422b21de36a86e7b7;p=linux-beck.git [media] m88ts2022: reimplement synthesizer calculations Used synthesizer is very typical integer-N PLL, with configurable reference frequency divider, output frequency divider and of course N itself. Most common method to calculate values is first select output divider, then calculate VCO frequency and finally calculate PLL N from VCO frequency. Do it that way. Also make some cleanups for filter logic and signal strength. Signed-off-by: Antti Palosaari Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/tuners/m88ts2022.c b/drivers/media/tuners/m88ts2022.c index 4b3eec28fb76..b11e740aec1d 100644 --- a/drivers/media/tuners/m88ts2022.c +++ b/drivers/media/tuners/m88ts2022.c @@ -175,27 +175,33 @@ static int m88ts2022_set_params(struct dvb_frontend *fe) { struct m88ts2022_priv *priv = fe->tuner_priv; struct dtv_frontend_properties *c = &fe->dtv_property_cache; - int ret = 0, div; - u8 buf[3], u8tmp, cap_code, lpf_mxdiv, div_max, div_min; - u16 N_reg, N, K; - u32 lpf_gm, lpf_coeff, gdiv28, frequency_khz, frequency_offset; - u32 freq_3db; + int ret; + unsigned int frequency_khz, frequency_offset_khz, f_3db_hz; + unsigned int f_ref_khz, f_vco_khz, div_ref, div_out, pll_n, gdiv28; + u8 buf[3], u8tmp, cap_code, lpf_gm, lpf_mxdiv, div_max, div_min; + u16 u16tmp; dev_dbg(&priv->i2c->dev, "%s: frequency=%d symbol_rate=%d rolloff=%d\n", __func__, c->frequency, c->symbol_rate, c->rolloff); + /* + * Integer-N PLL synthesizer + * kHz is used for all calculations to keep calculations within 32-bit + */ + f_ref_khz = DIV_ROUND_CLOSEST(priv->cfg->clock, 1000); + div_ref = DIV_ROUND_CLOSEST(f_ref_khz, 2000); if (c->symbol_rate < 5000000) - frequency_offset = 3000000; /* 3 MHz */ + frequency_offset_khz = 3000; /* 3 MHz */ else - frequency_offset = 0; + frequency_offset_khz = 0; - frequency_khz = c->frequency + (frequency_offset / 1000); + frequency_khz = c->frequency + frequency_offset_khz; if (frequency_khz < 1103000) { - div = 2; + div_out = 4; u8tmp = 0x1b; } else { - div = 1; + div_out = 2; u8tmp = 0x0b; } @@ -205,30 +211,30 @@ static int m88ts2022_set_params(struct dvb_frontend *fe) if (ret) goto err; - K = DIV_ROUND_CLOSEST((priv->cfg->clock / 2), 1000000); - N = 1ul * frequency_khz * K * div * 2 / (priv->cfg->clock / 1000); - N += N % 2; + 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; - if (N < 4095) - N_reg = N - 1024; - else if (N < 6143) - N_reg = N + 1024; + if (pll_n < 4095) + u16tmp = pll_n - 1024; + else if (pll_n < 6143) + u16tmp = pll_n + 1024; else - N_reg = N + 3072; + u16tmp = pll_n + 3072; - buf[0] = (N_reg >> 8) & 0x3f; - buf[1] = (N_reg >> 0) & 0xff; - buf[2] = K - 8; + buf[0] = (u16tmp >> 8) & 0x3f; + buf[1] = (u16tmp >> 0) & 0xff; + buf[2] = div_ref - 8; ret = m88ts2022_wr_regs(priv, 0x01, buf, 3); if (ret) goto err; - priv->frequency_khz = 1ul * N * (priv->cfg->clock / 1000) / K / div / 2; - dev_dbg(&priv->i2c->dev, - "%s: frequency=%d offset=%d K=%d N=%d div=%d\n", + "%s: frequency=%u offset=%d f_vco_khz=%u pll_n=%u div_ref=%u div_out=%u\n", __func__, priv->frequency_khz, - priv->frequency_khz - c->frequency, K, N, div); + priv->frequency_khz - c->frequency, f_vco_khz, pll_n, + div_ref, div_out); ret = m88ts2022_cmd(fe, 0x10, 5, 0x15, 0x40, 0x00, NULL); if (ret) @@ -284,7 +290,8 @@ static int m88ts2022_set_params(struct dvb_frontend *fe) if (ret) goto err; - gdiv28 = DIV_ROUND_CLOSEST(priv->cfg->clock / 1000000 * 1694, 1000); + /* filters */ + gdiv28 = DIV_ROUND_CLOSEST(f_ref_khz * 1694U, 1000000U); ret = m88ts2022_wr_reg(priv, 0x04, gdiv28); if (ret) @@ -309,35 +316,20 @@ static int m88ts2022_set_params(struct dvb_frontend *fe) gdiv28 = gdiv28 * 207 / (cap_code * 2 + 151); div_max = gdiv28 * 135 / 100; div_min = gdiv28 * 78 / 100; - if (div_max > 63) - div_max = 63; - - freq_3db = 1ul * c->symbol_rate * 135 / 200 + 2000000; - freq_3db += frequency_offset; - if (freq_3db < 7000000) - freq_3db = 7000000; - if (freq_3db > 40000000) - freq_3db = 40000000; - - lpf_coeff = 3200; - lpf_gm = DIV_ROUND_CLOSEST(freq_3db * gdiv28, lpf_coeff * - (priv->cfg->clock / 1000)); - if (lpf_gm > 23) - lpf_gm = 23; - if (lpf_gm < 1) - lpf_gm = 1; - - lpf_mxdiv = DIV_ROUND_CLOSEST(lpf_gm * lpf_coeff * - (priv->cfg->clock / 1000), freq_3db); - - if (lpf_mxdiv < div_min) { - lpf_gm++; - lpf_mxdiv = DIV_ROUND_CLOSEST(lpf_gm * lpf_coeff * - (priv->cfg->clock / 1000), freq_3db); - } + div_max = clamp_val(div_max, 0U, 63U); + + f_3db_hz = c->symbol_rate * 135UL / 200UL; + f_3db_hz += 2000000U + (frequency_offset_khz * 1000U); + f_3db_hz = clamp(f_3db_hz, 7000000U, 40000000U); - if (lpf_mxdiv > div_max) - lpf_mxdiv = div_max; +#define LPF_COEFF 3200U + lpf_gm = DIV_ROUND_CLOSEST(f_3db_hz * gdiv28, LPF_COEFF * f_ref_khz); + lpf_gm = clamp_val(lpf_gm, 1U, 23U); + + lpf_mxdiv = DIV_ROUND_CLOSEST(lpf_gm * LPF_COEFF * f_ref_khz, f_3db_hz); + if (lpf_mxdiv < div_min) + lpf_mxdiv = DIV_ROUND_CLOSEST(++lpf_gm * LPF_COEFF * f_ref_khz, f_3db_hz); + lpf_mxdiv = clamp_val(lpf_mxdiv, 0U, div_max); ret = m88ts2022_wr_reg(priv, 0x04, lpf_mxdiv); if (ret) @@ -492,44 +484,37 @@ static int m88ts2022_get_if_frequency(struct dvb_frontend *fe, u32 *frequency) static int m88ts2022_get_rf_strength(struct dvb_frontend *fe, u16 *strength) { struct m88ts2022_priv *priv = fe->tuner_priv; - u8 u8tmp, gain1, gain2, gain3; - u16 gain, u16tmp; int ret; + u8 u8tmp; + u16 gain, u16tmp; + unsigned int gain1, gain2, gain3; ret = m88ts2022_rd_reg(priv, 0x3d, &u8tmp); if (ret) goto err; gain1 = (u8tmp >> 0) & 0x1f; - if (gain1 > 15) - gain1 = 15; + gain1 = clamp(gain1, 0U, 15U); ret = m88ts2022_rd_reg(priv, 0x21, &u8tmp); if (ret) goto err; gain2 = (u8tmp >> 0) & 0x1f; - if (gain2 < 2) - gain2 = 2; - if (gain2 > 16) - gain2 = 16; + gain2 = clamp(gain2, 2U, 16U); ret = m88ts2022_rd_reg(priv, 0x66, &u8tmp); if (ret) goto err; gain3 = (u8tmp >> 3) & 0x07; - if (gain3 > 6) - gain3 = 6; + gain3 = clamp(gain3, 0U, 6U); gain = gain1 * 265 + gain2 * 338 + gain3 * 285; /* scale value to 0x0000-0xffff */ u16tmp = (0xffff - gain); - if (u16tmp < 59000) - u16tmp = 59000; - else if (u16tmp > 61500) - u16tmp = 61500; + u16tmp = clamp_val(u16tmp, 59000U, 61500U); *strength = (u16tmp - 59000) * 0xffff / (61500 - 59000); err: