diff options
Diffstat (limited to 'drivers/media/tuners/r820t.c')
| -rw-r--r-- | drivers/media/tuners/r820t.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/drivers/media/tuners/r820t.c b/drivers/media/tuners/r820t.c index ed9cd6569548..0fa355d1737c 100644 --- a/drivers/media/tuners/r820t.c +++ b/drivers/media/tuners/r820t.c @@ -321,6 +321,20 @@ static int r820t_xtal_capacitor[][2] = { }; /* + * measured with a Racal 6103E GSM test set at 928 MHz with -60 dBm + * input power, for raw results see: + * http://steve-m.de/projects/rtl-sdr/gain_measurement/r820t/ + */ + +static const int r820t_lna_gain_steps[] = { + 0, 9, 13, 40, 38, 13, 31, 22, 26, 31, 26, 14, 19, 5, 35, 13 +}; + +static const int r820t_mixer_gain_steps[] = { + 0, 5, 10, 10, 19, 9, 10, 25, 17, 10, 8, 16, 13, 6, 3, -8 +}; + +/* * I2C read/write code and shadow registers logic */ static void shadow_store(struct r820t_priv *priv, u8 reg, const u8 *val, @@ -1094,6 +1108,78 @@ static int r820t_read_gain(struct r820t_priv *priv) return ((data[3] & 0x0f) << 1) + ((data[3] & 0xf0) >> 4); } +static int r820t_set_gain_mode(struct r820t_priv *priv, + bool set_manual_gain, + int gain) +{ + int rc; + + if (set_manual_gain) { + int i, total_gain = 0; + uint8_t mix_index = 0, lna_index = 0; + u8 data[4]; + + /* LNA auto off */ + rc = r820t_write_reg_mask(priv, 0x05, 0x10, 0x10); + if (rc < 0) + return rc; + + /* Mixer auto off */ + rc = r820t_write_reg_mask(priv, 0x07, 0, 0x10); + if (rc < 0) + return rc; + + rc = r820_read(priv, 0x00, data, sizeof(data)); + if (rc < 0) + return rc; + + /* set fixed VGA gain for now (16.3 dB) */ + rc = r820t_write_reg_mask(priv, 0x0c, 0x08, 0x9f); + if (rc < 0) + return rc; + + for (i = 0; i < 15; i++) { + if (total_gain >= gain) + break; + + total_gain += r820t_lna_gain_steps[++lna_index]; + + if (total_gain >= gain) + break; + + total_gain += r820t_mixer_gain_steps[++mix_index]; + } + + /* set LNA gain */ + rc = r820t_write_reg_mask(priv, 0x05, lna_index, 0x0f); + if (rc < 0) + return rc; + + /* set Mixer gain */ + rc = r820t_write_reg_mask(priv, 0x07, mix_index, 0x0f); + if (rc < 0) + return rc; + } else { + /* LNA */ + rc = r820t_write_reg_mask(priv, 0x05, 0, 0xef); + if (rc < 0) + return rc; + + /* Mixer */ + rc = r820t_write_reg_mask(priv, 0x07, 0x10, 0xef); + if (rc < 0) + return rc; + + /* set fixed VGA gain for now (26.5 dB) */ + rc = r820t_write_reg_mask(priv, 0x0c, 0x0b, 0x9f); + if (rc < 0) + return rc; + } + + return 0; +} + + static int generic_set_freq(struct dvb_frontend *fe, u32 freq /* in HZ */, unsigned bw, @@ -1121,6 +1207,11 @@ static int generic_set_freq(struct dvb_frontend *fe, rc = r820t_set_mux(priv, lo_freq); if (rc < 0) goto err; + + rc = r820t_set_gain_mode(priv, true, 0); + if (rc < 0) + goto err; + rc = r820t_set_pll(priv, lo_freq); if (rc < 0 || !priv->has_lock) goto err; |