Remove interrupt disablement during backlight setting. It is
way to dangerous and makes platforms instable by having it
miss vblank IRQs leading to the graphics derailing.
The code is using ndelay() which is not available on
platforms such as ARM and will result in 32 * udelay(1)
which is substantial.
Add some code to detect if an interrupt occurs during the
tight loop and in that case just redo it from the top.
Fixes: 5317f37e48 ("backlight: Add Kinetic KTD253 backlight driver")
Cc: Stephan Gerhold <stephan@gerhold.net>
Reported-by: newbyte@disroot.org
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The KTD259 works just like KTD253 so add this compatible
to the driver.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The KTD253 backlight might already be on when the driver
is probed: then we don't really know what the current
ratio is and all light intensity settings will be off
relative to what it was at boot.
To fix this, bring up the backlight OFF then move it to
the default backlight from there so we know the state.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The Kinetic KTD253 backlight driver is controlled with a
single GPIO line, but still supports a range of brightness
settings by sending fast pulses on the line.
This is based off the source code release for the Samsung
GT-S7710 mobile phone.
Cc: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
