linux-stable.git/drivers/pwm, branch linux-6.3.y

pwm: mtk-disp: Configure double buffering before reading in .get_state()

2023-05-11T14:17:35+00:00

[ Upstream commit b16c310115f2084b8826a35b77ef42bab6786d9f ]

The DISP_PWM controller's default behavior is to always use register
double buffering: all reads/writes are then performed on shadow
registers instead of working registers and this becomes an issue
in case our chosen configuration in Linux is different from the
default (or from the one that was pre-applied by the bootloader).

An example of broken behavior is when the controller is configured
to use shadow registers, but this driver wants to configure it
otherwise: what happens is that the .get_state() callback is called
right after registering the pwmchip and checks whether the PWM is
enabled by reading the DISP_PWM_EN register;
At this point, if shadow registers are enabled but their content
was not committed before booting Linux, we are *not* reading the
current PWM enablement status, leading to the kernel knowing that
the hardware is actually enabled when, in reality, it's not.

The aforementioned issue emerged since this driver was fixed with
commit 0b5ef3429d8f ("pwm: mtk-disp: Fix the parameters calculated
by the enabled flag of disp_pwm") making it to read the enablement
status from the right register.

Configure the controller in the .get_state() callback to avoid
this desync issue and get the backlight properly working again.

Fixes: 3f2b16734914 ("pwm: mtk-disp: Implement atomic API .get_state()")
Signed-off-by: AngeloGioacchino Del Regno 
Reviewed-by: Nícolas F. R. A. Prado 
Tested-by: Nícolas F. R. A. Prado 
Reviewed-by: Alexandre Mergnat 
Tested-by: Alexandre Mergnat 
Signed-off-by: Thierry Reding 
Signed-off-by: Sasha Levin

pwm: mtk-disp: Disable shadow registers before setting backlight values

2023-05-11T14:17:35+00:00

[ Upstream commit 36dd7f530ae7d9ce9e853ffb8aa337de65c6600b ]

If shadow registers usage is not desired, disable that before performing
any write to CON0/1 registers in the .apply() callback, otherwise we may
lose clkdiv or period/width updates.

Fixes: cd4b45ac449a ("pwm: Add MediaTek MT2701 display PWM driver support")
Signed-off-by: AngeloGioacchino Del Regno 
Reviewed-by: Nícolas F. R. A. Prado 
Tested-by: Nícolas F. R. A. Prado 
Reviewed-by: Alexandre Mergnat 
Tested-by: Alexandre Mergnat 
Signed-off-by: Thierry Reding 
Signed-off-by: Sasha Levin

pwm: meson: Fix g12a ao clk81 name

2023-05-11T14:16:50+00:00

commit 9e4fa80ab7ef9eb4f7b1ea9fc31e0eb040e85e25 upstream.

Fix the name of the aoclk81 clock. Apparently name aoclk81 as used by
the vendor driver was changed when mainlining the g12a clock driver.

Fixes: f41efceb46e6 ("pwm: meson: Add clock source configuration for Meson G12A")
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit 
Reviewed-by: Martin Blumenstingl 
Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman

pwm: meson: Fix axg ao mux parents

2023-05-11T14:16:49+00:00

commit eb411c0cf59ae6344b34bc6f0d298a22b300627e upstream.

This fix is basically the same as 9bce02ef0dfa ("pwm: meson: Fix the
G12A AO clock parents order"). Vendor driver referenced there has
xtal as first parent also for axg ao. In addition fix the name
of the aoclk81 clock. Apparently name aoclk81 as used by the vendor
driver was changed when mainlining the axg clock driver.

Fixes: bccaa3f917c9 ("pwm: meson: Add clock source configuration for Meson-AXG")
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit 
Reviewed-by: Martin Blumenstingl 
Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman

pwm: Zero-initialize the pwm_state passed to driver's .get_state()

2023-03-23T13:44:43+00:00

This is just to ensure that .usage_power is properly initialized and
doesn't contain random stack data. The other members of struct pwm_state
should get a value assigned in a successful call to .get_state(). So in
the absence of bugs in driver implementations, this is only a safe-guard
and no fix.

Reported-by: Munehisa Kamata 
Link: https://lore.kernel.org/r/20230310214004.2619480-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: meson: Explicitly set .polarity in .get_state()

2023-03-23T13:44:42+00:00

The driver only supports normal polarity. Complete the implementation of
.get_state() by setting .polarity accordingly.

This fixes a regression that was possible since commit c73a3107624d
("pwm: Handle .get_state() failures") which stopped to zero-initialize
the state passed to the .get_state() callback. This was reported at
https://forum.odroid.com/viewtopic.php?f=177&t=46360 . While this was an
unintended side effect, the real issue is the driver's callback not
setting the polarity.

There is a complicating fact, that the .apply() callback fakes support
for inversed polarity. This is not (and cannot) be matched by
.get_state(). As fixing this isn't easy, only point it out in a comment
to prevent authors of other drivers from copying that approach.

Fixes: c375bcbaabdb ("pwm: meson: Read the full hardware state in meson_pwm_get_state()")
Reported-by: Munehisa Kamata 
Acked-by: Martin Blumenstingl 
Link: https://lore.kernel.org/r/20230310191405.2606296-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: sprd: Explicitly set .polarity in .get_state()

2023-03-23T13:44:42+00:00

The driver only supports normal polarity. Complete the implementation of
.get_state() by setting .polarity accordingly.

Fixes: 8aae4b02e8a6 ("pwm: sprd: Add Spreadtrum PWM support")
Link: https://lore.kernel.org/r/20230228135508.1798428-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: iqs620a: Explicitly set .polarity in .get_state()

2023-03-23T13:44:41+00:00

The driver only supports normal polarity. Complete the implementation of
.get_state() by setting .polarity accordingly.

Fixes: 6f0841a8197b ("pwm: Add support for Azoteq IQS620A PWM generator")
Reviewed-by: Jeff LaBundy 
Link: https://lore.kernel.org/r/20230228135508.1798428-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: cros-ec: Explicitly set .polarity in .get_state()

2023-03-23T13:44:41+00:00

The driver only supports normal polarity. Complete the implementation of
.get_state() by setting .polarity accordingly.

Reviewed-by: Guenter Roeck 
Fixes: 1f0d3bb02785 ("pwm: Add ChromeOS EC PWM driver")
Link: https://lore.kernel.org/r/20230228135508.1798428-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: hibvt: Explicitly set .polarity in .get_state()

2023-03-23T13:44:40+00:00

The driver only both polarities. Complete the implementation of
.get_state() by setting .polarity according to the configured hardware
state.

Fixes: d09f00810850 ("pwm: Add PWM driver for HiSilicon BVT SOCs")
Link: https://lore.kernel.org/r/20230228135508.1798428-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding