target/linux/bcm27xx/patches-5.15/950-0317-drm-panel-raspberrypi-ts-Insert-delay-before-polling.patch

   1 From f44c81e5ba2742d2d3f10b99f30983491b4a138f Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Tue, 10 Nov 2020 11:21:56 +0000
   4 Subject: [PATCH] drm/panel/raspberrypi-ts: Insert delay before polling
   5  for startup state
   6
   7 In switching to the hardware I2C controller there is an issue
   8 where we seem to not get back the correct state from the Pi
   9 touchscreen.
  10 Insert a delay before polling to avoid this condition.
  11
  12 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  13 ---
  14  drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 1 +
  15  1 file changed, 1 insertion(+)
  16
  17 --- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
  18 +++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
  19 @@ -299,6 +299,7 @@ static int rpi_touchscreen_prepare(struc
  20         int i;
  21
  22         rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
  23 +       usleep_range(20000, 25000);
  24         /* Wait for nPWRDWN to go low to indicate poweron is done. */
  25         for (i = 0; i < 100; i++) {
  26                 if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)