Fixes a8293 failure to raise LNB voltage in PCTV 461e DVB-S2 Stick affecting multiple users over several years as found here: http://www.linuxquestions.org/questions/linux-hardware-18/pctv-dvb-s2-stick-461e-not-feeding-lnb-4175529374/ https://www.linuxtv.org/wiki/index.php/Pinnacle_PCTV_DVB-S2_Stick_(461e) https://github.com/OpenELEC/OpenELEC.tv/issues/3731 Caused by vIN undervoltage lockout (status register bit 7) when raising LNB to 18V. Addressed by using the higher-precision voltages available on the a8293 to gradually increase (slew) the voltage when voltage increases are requested. Adds volt_slew_nanos_per_mv to a8293_platform_data struct for specifying slew rate. If value is <1 or non-sane (>1600), the original no-slew version for a8293_set_voltage is used. Signed-off-by: Chuck Ritola <cjritola@xxxxxxxxx> --- drivers/media/dvb-frontends/a8293.c | 147 +++++++++++++++++++++++++- drivers/media/dvb-frontends/a8293.h | 2 + drivers/media/usb/em28xx/em28xx-dvb.c | 3 + 3 files changed, 150 insertions(+), 2 deletions(-) diff --git a/drivers/media/dvb-frontends/a8293.c b/drivers/media/dvb-frontends/a8293.c index 57f52c004..f86af43ee 100644 --- a/drivers/media/dvb-frontends/a8293.c +++ b/drivers/media/dvb-frontends/a8293.c @@ -3,16 +3,139 @@ * Allegro A8293 SEC driver * * Copyright (C) 2011 Antti Palosaari <crope@xxxxxx> + * Copyright (C) 2021 Chuck Ritola <cjritola@xxxxxxxxx> */ #include "a8293.h" +#define A8293_FLAG_ODT 0x10 + + struct a8293_dev { struct i2c_client *client; u8 reg[2]; + int volt_slew_nanos_per_mv; }; -static int a8293_set_voltage(struct dvb_frontend *fe, +/* + * When increasing voltage, do so in minimal steps over time, minimizing risk of vIN undervoltage. + */ + +static int a8293_set_voltage_slew(struct a8293_dev *dev, + struct i2c_client *client, + enum fe_sec_voltage fe_sec_voltage, + int min_nanos_per_mv) +{ + int ret; + u8 reg0, reg1; + int new_volt_idx; + const int idx_to_mv[] = {0, 12709, 13042, 13375, 14042, 15042, 18042, 18709, 19042}; + const u8 idx_to_reg[] = {0x00, 0x20, 0x21, 0x22, 0x24, 0x27, 0x28, 0x2A, 0x2B }; + int this_volt_idx; + u8 status; + int prev_volt_idx; + + dev_dbg(&client->dev, "set_voltage_slew fe_sec_voltage=%d\n", fe_sec_voltage); + + /* Read status register to clear any stale faults. */ + ret = i2c_master_recv(client, &status, 1); + if (ret < 0) + goto err; + + /* Determine previous voltage */ + switch (dev->reg[0] & 0x2F) { + case 0x00: + prev_volt_idx = 0; + break; + case 0x20: + prev_volt_idx = 1; + break; + case 0x21: + prev_volt_idx = 2; + break; + case 0x22: + prev_volt_idx = 3; + break; + case 0x24: + prev_volt_idx = 4; + break; + case 0x27: + prev_volt_idx = 5; + break; + case 0x28: + prev_volt_idx = 6; + break; + case 0x2A: + prev_volt_idx = 7; + break; + case 0x2B: + prev_volt_idx = 8; + break; + default: + prev_volt_idx = 0; + } + + /* Determine new voltage */ + switch (fe_sec_voltage) { + case SEC_VOLTAGE_OFF: + new_volt_idx = 0; + break; + case SEC_VOLTAGE_13: + new_volt_idx = 2; + break; + case SEC_VOLTAGE_18: + new_volt_idx = 6; + break; + default: + ret = -EINVAL; + goto err; + } + + /* Slew to new voltage if new voltage is greater than current voltage */ + this_volt_idx = prev_volt_idx; + if (this_volt_idx < new_volt_idx) { + while (this_volt_idx < new_volt_idx) { + int delta_mv = idx_to_mv[this_volt_idx+1] - idx_to_mv[this_volt_idx]; + int min_wait_time = delta_mv * min_nanos_per_mv; + + reg0 = idx_to_reg[this_volt_idx+1]; + reg0 |= A8293_FLAG_ODT; + + ret = i2c_master_send(client, ®0, 1); + if (ret < 0) + goto err; + dev->reg[0] = reg0; + this_volt_idx++; + usleep_range(min_wait_time, min_wait_time * 2); + } + } else { /* Else just set the voltage */ + reg0 = idx_to_reg[new_volt_idx]; + reg0 |= A8293_FLAG_ODT; + ret = i2c_master_send(client, ®0, 1); + if (ret < 0) + goto err; + dev->reg[0] = reg0; + } + + /* TMODE=0, TGATE=1 */ + reg1 = 0x82; + if (reg1 != dev->reg[1]) { + ret = i2c_master_send(client, ®1, 1); + if (ret < 0) + goto err; + dev->reg[1] = reg1; + } + + usleep_range(1500, 5000); + + return 0; +err: + dev_dbg(&client->dev, "failed=%d\n", ret); + return ret; +} + + +static int a8293_set_voltage_noslew(struct dvb_frontend *fe, enum fe_sec_voltage fe_sec_voltage) { struct a8293_dev *dev = fe->sec_priv; @@ -20,7 +143,7 @@ static int a8293_set_voltage(struct dvb_frontend *fe, int ret; u8 reg0, reg1; - dev_dbg(&client->dev, "fe_sec_voltage=%d\n", fe_sec_voltage); + dev_dbg(&client->dev, "set_voltage_noslew fe_sec_voltage=%d\n", fe_sec_voltage); switch (fe_sec_voltage) { case SEC_VOLTAGE_OFF: @@ -62,6 +185,24 @@ static int a8293_set_voltage(struct dvb_frontend *fe, return ret; } +static int a8293_set_voltage(struct dvb_frontend *fe, + enum fe_sec_voltage fe_sec_voltage) +{ + struct a8293_dev *dev = fe->sec_priv; + struct i2c_client *client = dev->client; + int volt_slew_nanos_per_mv = dev->volt_slew_nanos_per_mv; + + dev_dbg(&client->dev, "set_voltage volt_slew_nanos_per_mv=%d\n", volt_slew_nanos_per_mv); + + /* Use slew version if slew rate is set to a sane value */ + if (volt_slew_nanos_per_mv > 0 && volt_slew_nanos_per_mv < 1600) + a8293_set_voltage_slew(dev, client, fe_sec_voltage, volt_slew_nanos_per_mv); + else + a8293_set_voltage_noslew(fe, fe_sec_voltage); + + return 0; +} + static int a8293_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -78,6 +219,7 @@ static int a8293_probe(struct i2c_client *client, } dev->client = client; + dev->volt_slew_nanos_per_mv = pdata->volt_slew_nanos_per_mv; /* check if the SEC is there */ ret = i2c_master_recv(client, buf, 2); @@ -127,5 +269,6 @@ static struct i2c_driver a8293_driver = { module_i2c_driver(a8293_driver); MODULE_AUTHOR("Antti Palosaari <crope@xxxxxx>"); +MODULE_AUTHOR("Chuck Ritola <cjritola@xxxxxxxxx>"); MODULE_DESCRIPTION("Allegro A8293 SEC driver"); MODULE_LICENSE("GPL"); diff --git a/drivers/media/dvb-frontends/a8293.h b/drivers/media/dvb-frontends/a8293.h index 8c09635ef..0a807c022 100644 --- a/drivers/media/dvb-frontends/a8293.h +++ b/drivers/media/dvb-frontends/a8293.h @@ -18,9 +18,11 @@ /** * struct a8293_platform_data - Platform data for the a8293 driver * @dvb_frontend: DVB frontend. + * @volt_slew_nanos_per_mv: Slew rate when increasing LNB voltage, in nanoseconds per millivolt. */ struct a8293_platform_data { struct dvb_frontend *dvb_frontend; + int volt_slew_nanos_per_mv; }; #endif /* A8293_H */ diff --git a/drivers/media/usb/em28xx/em28xx-dvb.c b/drivers/media/usb/em28xx/em28xx-dvb.c index 471bd7466..859f4a33e 100644 --- a/drivers/media/usb/em28xx/em28xx-dvb.c +++ b/drivers/media/usb/em28xx/em28xx-dvb.c @@ -1208,6 +1208,9 @@ static int em28178_dvb_init_pctv_461e(struct em28xx *dev) /* attach SEC */ a8293_pdata.dvb_frontend = dvb->fe[0]; + /* 461e has a tendency to have vIN undervoltage troubles. Slew mitigates this. */ + a8293_pdata.volt_slew_nanos_per_mv = 20; + dvb->i2c_client_sec = dvb_module_probe("a8293", NULL, &dev->i2c_adap[dev->def_i2c_bus], 0x08, &a8293_pdata); -- 2.20.1
