diff options
| author | Chuck Ritola <cjritola@gmail.com> | 2021-12-31 03:53:27 +0000 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2022-11-25 09:55:55 +0000 |
| commit | e6431a0c0d711af71a0628689463af4ec19c82f8 (patch) | |
| tree | 7792d60720e7de2fe650e3f582280cb8f7a5def1 /drivers/media/usb | |
| parent | b5411dd4d506c373d4957e0b6c1c8e822dc8e511 (diff) | |
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>
Diffstat (limited to 'drivers/media/usb')
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx-dvb.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-dvb.c b/drivers/media/usb/em28xx/em28xx-dvb.c index 185e89c18d68..9fce59979e3b 100644 --- a/drivers/media/usb/em28xx/em28xx-dvb.c +++ b/drivers/media/usb/em28xx/em28xx-dvb.c @@ -1204,6 +1204,12 @@ 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); |