target/linux/bcm27xx/patches-6.1/950-0354-regulator-rpi-panel-attiny-Don-t-read-the-LCD-power-.patch

   1 From 59431ad65437c29a3728f31428363c83e9e4e45c Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Mon, 29 Nov 2021 18:31:37 +0000
   4 Subject: [PATCH] regulator/rpi-panel-attiny: Don't read the LCD power
   5  status
   6
   7 The I2C to the Atmel is very fussy, and locks up easily on
   8 Pi0-3 particularly on reads.
   9
  10 The LCD power status is controlled solely by this driver, so
  11 rather than reading it back from the Atmel, use the cached
  12 status last set.
  13
  14 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  15 ---
  16  drivers/regulator/rpi-panel-attiny-regulator.c | 18 +-----------------
  17  1 file changed, 1 insertion(+), 17 deletions(-)
  18
  19 --- a/drivers/regulator/rpi-panel-attiny-regulator.c
  20 +++ b/drivers/regulator/rpi-panel-attiny-regulator.c
  21 @@ -144,24 +144,8 @@ static int attiny_lcd_power_disable(stru
  22  static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
  23  {
  24         struct attiny_lcd *state = rdev_get_drvdata(rdev);
  25 -       unsigned int data;
  26 -       int ret, i;
  27
  28 -       mutex_lock(&state->lock);
  29 -
  30 -       for (i = 0; i < 10; i++) {
  31 -               ret = regmap_read(rdev->regmap, REG_PORTC, &data);
  32 -               if (!ret)
  33 -                       break;
  34 -               usleep_range(10000, 12000);
  35 -       }
  36 -
  37 -       mutex_unlock(&state->lock);
  38 -
  39 -       if (ret < 0)
  40 -               return ret;
  41 -
  42 -       return data & PC_RST_BRIDGE_N;
  43 +       return state->port_states[REG_PORTC - REG_PORTA] & PC_RST_BRIDGE_N;
  44  }
  45
  46  static const struct regulator_init_data attiny_regulator_default = {