tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

drm/bridge: ps8640: Add double reset T4 and T5 to power-on sequence

Browse Source 
The double reset power-on sequence is a workaround for the hardware
flaw in some chip that SPI Clock output glitch and cause internal MPU
unable to read firmware correctly. The sequence is suggested in ps8640
application note.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Rock Chiu <rock.chiu@paradetech.corp-partner.google.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220815093905.134164-1-hsinyi@chromium.org
This commit is contained in:
Hsin-Yi Wang
2022-08-15 17:39:07 +08:00
committed by Douglas Anderson
parent da09daf881
commit 55453c0914
1 changed files with 5 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/gpu/drm/bridge/parade-ps8640.c
+5
View File
@@ -375,6 +375,11 @@ static int __maybe_unused ps8640_resume(struct device *dev)
gpiod_set_value(ps_bridge->gpio_reset, 1);
usleep_range(2000, 2500);
gpiod_set_value(ps_bridge->gpio_reset, 0);
/* Double reset for T4 and T5 */
msleep(50);
gpiod_set_value(ps_bridge->gpio_reset, 1);
msleep(50);
gpiod_set_value(ps_bridge->gpio_reset, 0);
/*
* Mystery 200 ms delay for the "MCU to be ready". It's unclear if