[ Upstream commit b16c310115 ]
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 0b5ef3429d ("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: 3f2b167349 ("pwm: mtk-disp: Implement atomic API .get_state()")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Tested-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit eb411c0cf5 upstream.
This fix is basically the same as 9bce02ef0d ("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: bccaa3f917 ("pwm: meson: Add clock source configuration for Meson-AXG")
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 c73a310762
("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: c375bcbaab ("pwm: meson: Read the full hardware state in meson_pwm_get_state()")
Reported-by: Munehisa Kamata <kamatam@amazon.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20230310191405.2606296-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add the PWM chip using devm_pwmchip_add() to avoid having to manually
remove it. This is useful for subsequent patches adding platform device
support.
Signed-off-by: Ben Dooks <ben.dooks@sifive.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The dwc_pwm_probe() assigns dev to be &pci->dev but then uses &pci->dev
throughout the function. Change these all to the 'dev' variable to make
lines shorter.
Signed-off-by: Ben Dooks <ben.dooks@sifive.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The call to regmap_update_bits() which was responsible for clearing
the PWM output enable register bit was recently dropped in favor of
a call to regmap_clear_bits(), thereby simplifying the code.
Similarly, the call to regmap_update_bits() which sets the same bit
can be simplified with a call to regmap_set_bits().
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The registers are readable, so it's possible to implement the
.get_state() callback for this PWM.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
After a check of the manual it becomes obvious that the calculations in
.apply() are totally bogus:
FreqPWMOutx was always written as zero, so the period was fixed at
3413333.33 ns. However state->period wasn't checked at all.
The lower 10 bits of duty_cycle were just used as DutyPWMOutx. So if
a duty cycle of 512 ns (or 1536 ns) was requested, it actually
programmed 1710000 ns. Other values were wrong by the same factor.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
lp3943 is a platform driver that doesn't use any symbol provided in
<linux/i2c.h>. So drop the include.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The ARR (auto reload register) and CMP (compare) registers are
successively written. The status bits to check the update of these
registers are polled together with regmap_read_poll_timeout().
The condition to end the loop may become true, even if one of the
register isn't correctly updated.
So ensure both status bits are set before clearing them.
Fixes: e70a540b4e ("pwm: Add STM32 LPTimer PWM driver")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Commit 2cfe9bbec5 added support for the
RGB and green PWM controlled LEDs on the HiFive Unmatched board
managed by the leds-pwm-multicolor and leds-pwm drivers respectively.
All three colours of the RGB LED and the green LED run from different
lines of the same PWM, but with the same period so this works fine when
the LED drivers are loaded one after the other.
Unfortunately it does expose a race in the PWM driver when both LED
drivers are loaded at roughly the same time. Here is an example:
| Thread A | Thread B |
| led_pwm_mc_probe | led_pwm_probe |
| devm_fwnode_pwm_get | |
| pwm_sifive_request | |
| ddata->user_count++ | |
| | devm_fwnode_pwm_get |
| | pwm_sifive_request |
| | ddata->user_count++ |
| ... | ... |
| pwm_state_apply | pwm_state_apply |
| pwm_sifive_apply | pwm_sifive_apply |
Now both calls to pwm_sifive_apply will see that ddata->approx_period,
initially 0, is different from the requested period and the clock needs
to be updated. But since ddata->user_count >= 2 both calls will fail
with -EBUSY, which will then cause both LED drivers to fail to probe.
Fix it by letting the first call to pwm_sifive_apply update the clock
even when ddata->user_count != 1.
Fixes: 9e37a53eb0 ("pwm: sifive: Add a driver for SiFive SoC PWM")
Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Pull pwm updates from Thierry Reding:
"Various changes across the board, mostly improvements and cleanups"
* tag 'pwm/for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (42 commits)
pwm: pca9685: Convert to i2c's .probe_new()
pwm: sun4i: Propagate errors in .get_state() to the caller
pwm: Handle .get_state() failures
pwm: sprd: Propagate errors in .get_state() to the caller
pwm: rockchip: Propagate errors in .get_state() to the caller
pwm: mtk-disp: Propagate errors in .get_state() to the caller
pwm: imx27: Propagate errors in .get_state() to the caller
pwm: cros-ec: Propagate errors in .get_state() to the caller
pwm: crc: Propagate errors in .get_state() to the caller
leds: qcom-lpg: Propagate errors in .get_state() to the caller
drm/bridge: ti-sn65dsi86: Propagate errors in .get_state() to the caller
pwm/tracing: Also record trace events for failed API calls
pwm: Make .get_state() callback return an error code
pwm: pxa: Enable for MMP platform
pwm: pxa: Add reference manual link and limitations
pwm: pxa: Use abrupt shutdown mode
pwm: pxa: Remove clk enable/disable from pxa_pwm_config
pwm: pxa: Set duty cycle to 0 when disabling PWM
pwm: pxa: Remove pxa_pwm_enable/disable
pwm: mediatek: Add support for MT7986
...
.get_state() might fail in some cases. To make it possible that a driver
signals such a failure change the prototype of .get_state() to return an
error code.
This patch was created using coccinelle and the following semantic patch:
@p1@
identifier getstatefunc;
identifier driver;
@@
struct pwm_ops driver = {
...,
.get_state = getstatefunc
,...
};
@p2@
identifier p1.getstatefunc;
identifier chip, pwm, state;
@@
-void
+int
getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state)
{
...
- return;
+ return 0;
...
}
plus the actual change of the prototype in include/linux/pwm.h (plus some
manual fixing of indentions and empty lines).
So for now all drivers return success unconditionally. They are adapted
in the following patches to make the changes easier reviewable.
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221130152148.2769768-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
According to MT7622 Reference Manual for Development Board v1.0 the PWM
unit found in the MT7622 SoC also comes with the PWM_CK_26M_SEL register
at offset 0x210 just like other modern MediaTek ARM64 SoCs.
And also MT7622 sets that register to 0x00000001 on reset which is
described as 'Select 26M fix CLK as BCLK' in the datasheet.
Hence set has_ck_26m_sel to true also for MT7622 which results in the
driver writing 0 to the PWM_CK_26M_SEL register which is described as
'Select bus CLK as BCLK'.
Fixes: 0c0ead7623 ("pwm: mediatek: Always use bus clock")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/Y1iF2slvSblf6bYK@makrotopia.org
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
