The probe function in the gpio-backlight driver is quite short. If we
pull gpio_backlight_initial_power_state() into probe we can drop two
more fields from struct gpio_backlight and shrink the driver code.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Instead of dereferencing pdev each time, use a helper variable for
the associated device pointer.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Now that the last user of platform data (sh ecovec24) defines a proper
GPIO lookup and sets the 'default-on' device property, we can drop the
platform_data-specific GPIO handling and unify a big chunk of code.

The only field used from the platform data is now the fbdev pointer.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

The GPIO backlight driver currently requests the line 'as is', without
acively setting its direction. This can lead to problems: if the line
is in input mode by default, we won't be able to drive it later when
updating the status and also reading its initial value doesn't make
sense for backlight setting.

Request the line 'as is' initially, so that we can read its value
without affecting it but then change the direction to output explicitly
when setting the initial brightness.

Also: check the current direction and only read the value if it's output.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Remove a double newline from the driver.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

We no longer use any symbols from of_gpio.h. Remove this include.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

The default-on property - or the def_value via legacy pdata) should be
handled as:
if it is 1, the backlight must be enabled (kept enabled)
if it is 0, the backlight must be disabled (kept disabled)

This only works for the case when default-on is set. If it is not set then
the brightness of the backlight is set to 0. Now if the backlight is
enabled by external driver (graphics) the backlight will stay disabled since
the brightness is configured as 0. The backlight will not turn on.

In order to minimize screen flickering during device boot:

The initial brightness should be set to 1.

If booted in non DT mode or no phandle link to the backlight node:
follow the def_value/default-on to select UNBLANK or POWERDOWN

If in DT boot we have phandle link then leave the GPIO in a state which the
bootloader left it and let the user of the backlight to configure it
further.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Pull backlight updates from Lee Jones:
 "New Functionality:
   - Provide support for ACPI enumeration; gpio_backlight

  Fix-ups:
   - SPDX fixups; pwm_bl
   - Fix linear	brightness levels to include number available; pwm_bl"

* tag 'backlight-next-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: pwm_bl: Fix heuristic to determine number of brightness levels
  backlight: gpio_backlight: Enable ACPI enumeration
  backlight: pwm_bl: Convert to use SPDX identifier

ACPI allows to enumerate specific devices by using compatible strings.
Enable that enumeration for GPIO based backlight devices.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>