media: dvb-frontends: a8293: fix LNB powerup failure in PCTV 461e
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. Link: https://lore.kernel.org/linux-media/20211231035326.6759-1-cjritola@gmail.com [mchehab: fixed some coding style issues] Signed-off-by: Chuck Ritola <cjritola@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Chuck Ritola
Mauro Carvalho Chehab
parent
b5411dd4d5
commit
e6431a0c0d
3 changed files with 161 additions and 3 deletions
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@ -7,12 +7,139 @@
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#include "a8293.h"
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#define A8293_FLAG_ODT 0x10
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struct a8293_dev {
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struct i2c_client *client;
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u8 reg[2];
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int volt_slew_nanos_per_mv;
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};
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static int a8293_set_voltage(struct dvb_frontend *fe,
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/*
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* When increasing voltage, do so in minimal steps over time, minimizing
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* risk of vIN undervoltage.
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*/
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static int a8293_set_voltage_slew(struct a8293_dev *dev,
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struct i2c_client *client,
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enum fe_sec_voltage fe_sec_voltage,
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int min_nanos_per_mv)
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{
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int ret;
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u8 reg0, reg1;
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int new_volt_idx;
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const int idx_to_mv[] = {
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0, 12709, 13042, 13375, 14042, 15042, 18042, 18709, 19042
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};
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const u8 idx_to_reg[] = {
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0x00, 0x20, 0x21, 0x22, 0x24, 0x27, 0x28, 0x2A, 0x2B
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};
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int this_volt_idx;
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u8 status;
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int prev_volt_idx;
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dev_dbg(&client->dev, "set_voltage_slew fe_sec_voltage=%d\n",
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fe_sec_voltage);
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/* Read status register to clear any stale faults. */
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ret = i2c_master_recv(client, &status, 1);
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if (ret < 0)
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goto err;
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/* Determine previous voltage */
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switch (dev->reg[0] & 0x2F) {
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case 0x00:
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prev_volt_idx = 0;
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break;
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case 0x20:
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prev_volt_idx = 1;
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break;
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case 0x21:
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prev_volt_idx = 2;
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break;
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case 0x22:
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prev_volt_idx = 3;
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break;
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case 0x24:
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prev_volt_idx = 4;
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break;
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case 0x27:
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prev_volt_idx = 5;
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break;
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case 0x28:
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prev_volt_idx = 6;
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break;
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case 0x2A:
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prev_volt_idx = 7;
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break;
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case 0x2B:
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prev_volt_idx = 8;
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break;
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default:
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prev_volt_idx = 0;
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}
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/* Determine new voltage */
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switch (fe_sec_voltage) {
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case SEC_VOLTAGE_OFF:
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new_volt_idx = 0;
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break;
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case SEC_VOLTAGE_13:
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new_volt_idx = 2;
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break;
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case SEC_VOLTAGE_18:
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new_volt_idx = 6;
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break;
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default:
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ret = -EINVAL;
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goto err;
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}
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/* Slew to new voltage if new voltage is greater than current voltage */
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this_volt_idx = prev_volt_idx;
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if (this_volt_idx < new_volt_idx) {
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while (this_volt_idx < new_volt_idx) {
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int delta_mv = idx_to_mv[this_volt_idx+1] - idx_to_mv[this_volt_idx];
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int min_wait_time = delta_mv * min_nanos_per_mv;
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reg0 = idx_to_reg[this_volt_idx+1];
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reg0 |= A8293_FLAG_ODT;
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ret = i2c_master_send(client, ®0, 1);
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if (ret < 0)
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goto err;
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dev->reg[0] = reg0;
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this_volt_idx++;
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usleep_range(min_wait_time, min_wait_time * 2);
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}
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} else { /* Else just set the voltage */
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reg0 = idx_to_reg[new_volt_idx];
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reg0 |= A8293_FLAG_ODT;
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ret = i2c_master_send(client, ®0, 1);
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if (ret < 0)
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goto err;
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dev->reg[0] = reg0;
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}
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/* TMODE=0, TGATE=1 */
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reg1 = 0x82;
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if (reg1 != dev->reg[1]) {
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ret = i2c_master_send(client, ®1, 1);
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if (ret < 0)
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goto err;
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dev->reg[1] = reg1;
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}
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usleep_range(1500, 5000);
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return 0;
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err:
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dev_dbg(&client->dev, "failed=%d\n", ret);
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return ret;
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}
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static int a8293_set_voltage_noslew(struct dvb_frontend *fe,
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enum fe_sec_voltage fe_sec_voltage)
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{
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struct a8293_dev *dev = fe->sec_priv;
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@ -20,7 +147,8 @@ static int a8293_set_voltage(struct dvb_frontend *fe,
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int ret;
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u8 reg0, reg1;
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dev_dbg(&client->dev, "fe_sec_voltage=%d\n", fe_sec_voltage);
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dev_dbg(&client->dev, "set_voltage_noslew fe_sec_voltage=%d\n",
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fe_sec_voltage);
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switch (fe_sec_voltage) {
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case SEC_VOLTAGE_OFF:
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@ -62,6 +190,26 @@ static int a8293_set_voltage(struct dvb_frontend *fe,
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return ret;
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}
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static int a8293_set_voltage(struct dvb_frontend *fe,
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enum fe_sec_voltage fe_sec_voltage)
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{
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struct a8293_dev *dev = fe->sec_priv;
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struct i2c_client *client = dev->client;
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int volt_slew_nanos_per_mv = dev->volt_slew_nanos_per_mv;
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dev_dbg(&client->dev, "set_voltage volt_slew_nanos_per_mv=%d\n",
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volt_slew_nanos_per_mv);
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/* Use slew version if slew rate is set to a sane value */
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if (volt_slew_nanos_per_mv > 0 && volt_slew_nanos_per_mv < 1600)
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a8293_set_voltage_slew(dev, client, fe_sec_voltage,
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volt_slew_nanos_per_mv);
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else
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a8293_set_voltage_noslew(fe, fe_sec_voltage);
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return 0;
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}
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static int a8293_probe(struct i2c_client *client)
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{
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struct a8293_dev *dev;
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@ -77,6 +225,7 @@ static int a8293_probe(struct i2c_client *client)
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}
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dev->client = client;
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dev->volt_slew_nanos_per_mv = pdata->volt_slew_nanos_per_mv;
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/* check if the SEC is there */
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ret = i2c_master_recv(client, buf, 2);
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@ -18,9 +18,12 @@
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/**
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* struct a8293_platform_data - Platform data for the a8293 driver
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* @dvb_frontend: DVB frontend.
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* @volt_slew_nanos_per_mv: Slew rate when increasing LNB voltage,
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* in nanoseconds per millivolt.
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*/
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struct a8293_platform_data {
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struct dvb_frontend *dvb_frontend;
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int volt_slew_nanos_per_mv;
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};
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#endif /* A8293_H */
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@ -1204,6 +1204,12 @@ static int em28178_dvb_init_pctv_461e(struct em28xx *dev)
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/* attach SEC */
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a8293_pdata.dvb_frontend = dvb->fe[0];
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/*
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* 461e has a tendency to have vIN undervoltage troubles.
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* Slew mitigates this.
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*/
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a8293_pdata.volt_slew_nanos_per_mv = 20;
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dvb->i2c_client_sec = dvb_module_probe("a8293", NULL,
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&dev->i2c_adap[dev->def_i2c_bus],
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0x08, &a8293_pdata);
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