The I2C to the Atmel is very fussy, and locks up easily on
Pi0-3 particularly on reads.
If running at 100kHz on Pi3, reading the ID register generally
locks up the Atmel, but splitting the register select write and
read into two transactions is reliable.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-10-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The I2C to the Atmel is very fussy, and locks up easily on
Pi0-3 particularly on reads.
The LCD power status is controlled solely by this driver, so
rather than reading it back from the Atmel, use the regmap cache
to avoid reading values.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-9-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The driver was implementing a get_brightness function that
tried to read back the PWM setting of the display to report
as the current brightness.
The controller on the display does not support that, therefore
we end up reporting a brightness of 0, and that confuses
systemd's backlight service.
Remove the hook so that the framework returns the current
brightness automatically.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-8-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
We need independent control of the resets for the panel&bridge,
vs the touch controller.
Expose the reset lines that are on the Atmel's port C via the GPIO
API so that they can be controlled appropriately.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-7-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The Atmel was doing a load of automatic sequencing of
control lines, however it was combining the touch controller's
reset with the bridge/panel control.
Change to control the control signals directly rather than
through the automatic POWERON control.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-6-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The initial state of the Atmel is not defined, so ensure the
backlight PWM is set to 0 by default.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-5-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The driver was using the regmap lock to serialise the
individual accesses, but we really need to protect the
timings of enabling the regulators, including any communication
with the Atmel.
Use a mutex within the driver to control overall accesses to
the Atmel, instead of the regmap lock.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-4-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The Atmel is doing some things in the I2C ISR, during which
period it will not respond to further commands. This is
particularly true of the POWERON command.
Increase delays appropriately, and retry should I2C errors be
reported.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-3-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There's no reason why 2 Raspberry Pi DSI displays can't be
attached to a Pi Compute Module, so the backlight names need to
be unique.
Use the parent dev_name. It's not as readable, but is unique.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-2-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This regulator/backlight driver handles the ATTINY88 present on the
RPi 7" touchscreen panel and exposes the power/backlight interfaces.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Eric Anholt <eric@anholt.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
To: dri-devel@lists.freedesktop.org
Link: https://lore.kernel.org/r/20200809105938.6388-2-marex@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Dave Stevenson
Marek Vasut