Commit e6431a0c authored by Chuck Ritola's avatar Chuck Ritola Committed by Mauro Carvalho Chehab

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: default avatarChuck Ritola <cjritola@gmail.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
parent b5411dd4
...@@ -7,20 +7,148 @@ ...@@ -7,20 +7,148 @@
#include "a8293.h" #include "a8293.h"
#define A8293_FLAG_ODT 0x10
struct a8293_dev { struct a8293_dev {
struct i2c_client *client; struct i2c_client *client;
u8 reg[2]; u8 reg[2];
int volt_slew_nanos_per_mv;
}; };
static int a8293_set_voltage(struct dvb_frontend *fe, /*
enum fe_sec_voltage fe_sec_voltage) * 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, &reg0, 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, &reg0, 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, &reg1, 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; struct a8293_dev *dev = fe->sec_priv;
struct i2c_client *client = dev->client; struct i2c_client *client = dev->client;
int ret; int ret;
u8 reg0, reg1; 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) { switch (fe_sec_voltage) {
case SEC_VOLTAGE_OFF: case SEC_VOLTAGE_OFF:
...@@ -62,6 +190,26 @@ static int a8293_set_voltage(struct dvb_frontend *fe, ...@@ -62,6 +190,26 @@ static int a8293_set_voltage(struct dvb_frontend *fe,
return ret; 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) static int a8293_probe(struct i2c_client *client)
{ {
struct a8293_dev *dev; struct a8293_dev *dev;
...@@ -77,6 +225,7 @@ static int a8293_probe(struct i2c_client *client) ...@@ -77,6 +225,7 @@ static int a8293_probe(struct i2c_client *client)
} }
dev->client = client; dev->client = client;
dev->volt_slew_nanos_per_mv = pdata->volt_slew_nanos_per_mv;
/* check if the SEC is there */ /* check if the SEC is there */
ret = i2c_master_recv(client, buf, 2); ret = i2c_master_recv(client, buf, 2);
......
...@@ -18,9 +18,12 @@ ...@@ -18,9 +18,12 @@
/** /**
* struct a8293_platform_data - Platform data for the a8293 driver * struct a8293_platform_data - Platform data for the a8293 driver
* @dvb_frontend: DVB frontend. * @dvb_frontend: DVB frontend.
* @volt_slew_nanos_per_mv: Slew rate when increasing LNB voltage,
* in nanoseconds per millivolt.
*/ */
struct a8293_platform_data { struct a8293_platform_data {
struct dvb_frontend *dvb_frontend; struct dvb_frontend *dvb_frontend;
int volt_slew_nanos_per_mv;
}; };
#endif /* A8293_H */ #endif /* A8293_H */
...@@ -1204,6 +1204,12 @@ static int em28178_dvb_init_pctv_461e(struct em28xx *dev) ...@@ -1204,6 +1204,12 @@ static int em28178_dvb_init_pctv_461e(struct em28xx *dev)
/* attach SEC */ /* attach SEC */
a8293_pdata.dvb_frontend = dvb->fe[0]; 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, dvb->i2c_client_sec = dvb_module_probe("a8293", NULL,
&dev->i2c_adap[dev->def_i2c_bus], &dev->i2c_adap[dev->def_i2c_bus],
0x08, &a8293_pdata); 0x08, &a8293_pdata);
......
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