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Add support for Amlogic S4 PWM.
Signed-off-by: Junyi Zhao <junyi.zhao@amlogic.com>
Signed-off-by: Kelvin Zhang <kelvin.zhang@amlogic.com>
Reviewed-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240613-s4-pwm-v8-1-b5bd0a768282@amlogic.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
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While calculating frequency for the given period u64 numbers are
multiplied before division what can lead to overflow in theory so use
secure mul_u64_u64_div_u64() which handles overflow correctly.
Fixes: 329db102a26d ("pwm: meson: make full use of common clock framework")
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-4-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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clk_round_rate() can return not only zero if requested frequency can not
be provided but also negative error code so add check for it too.
Also change type of variable holding clk_round_rate() result from
unsigned long to long. It's safe due to clk_round_rate() returns long.
Fixes: 329db102a26d ("pwm: meson: make full use of common clock framework")
Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-3-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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Drop checking state argument for NULL pointer in meson_pwm_get_state()
due to it is called only from pwm core with always valid arguments.
Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-2-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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Introduce a new compatible support in the Amlogic PWM driver.
The PWM HW is actually the same for all SoCs supported so far. A specific
compatible is needed only because the clock sources of the PWMs are
hard-coded in the driver.
It is better to have the clock source described in DT but this changes the
bindings so a new compatible must be introduced.
When all supported platform have migrated to the new compatible, support
for the legacy ones may be removed from the driver.
The addition of this new compatible makes the old ones obsolete, as
described in the DT documentation.
Adding a callback to setup the clock will also make it easier to add
support for the new PWM HW found in a1, s4, c3 and t7 SoC families.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20240221151154.26452-6-jbrunet@baylibre.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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Meson8 pwm type always has 4 input clocks. Some inputs may be grounded,
like in the AO domain of some SoCs.
Drop the parent number parameter and make this is constant.
This is also done to make the addition of generic meson8 compatible easier.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20240221151154.26452-4-jbrunet@baylibre.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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This prepares the pwm-meson driver to further changes of the pwm core
outlined in the commit introducing devm_pwmchip_alloc(). There is no
intended semantical change and the driver should behave as before.
Link: https://lore.kernel.org/r/6cc57880e910e6ffd8df15bc4a41c42fe9523293.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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struct pwm_chip::dev is about to change. To not have to touch this
driver in the same commit as struct pwm_chip::dev, use the accessor
function provided for exactly this purpose.
Link: https://lore.kernel.org/r/02d5f32001c4d0817fa79f5831cfd16b7e345f00.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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This prepares the driver for further changes that will make it harder to
determine the pwm_chip from a given meson_pwm. To just not have to do
that, rework meson_pwm_calc(), meson_pwm_enable(), meson_pwm_disable()
and meson_pwm_init_channels() to take a pwm_chip.
Link: https://lore.kernel.org/r/157084e1dd464da0097edba880240868c1c0b27e.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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Using dev_err_probe() emitting an error message mentioning a return
value and returning that value can be done in a single statement. Make
use of that to simplify the probe part of the driver. This has the
additional advantage to emit the symbolic name for the error instead of
the integer error value.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Instead of requiring each driver to care for assigning the owner member
of struct pwm_ops, handle that implicitly using a macro. Note that the
owner member has to be moved to struct pwm_chip, as the ops structure
usually lives in read-only memory and so cannot be modified.
The upside is that new low level drivers cannot forget the assignment and
save one line each. The pwm-crc driver didn't assign .owner, that's not
a problem in practice though as the driver cannot be compiled as a
module.
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # Intel LPSS
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> # pwm-{bcm,brcm}*.c
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> # sun4i
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> # pwm-visconti
Acked-by: Heiko Stuebner <heiko@sntech.de> # pwm-rockchip
Acked-by: Michael Walle <michael@walle.cc> # pwm-sl28cpld
Acked-by: Neil Armstrong <neil.armstrong@linaro.org> # pwm-meson
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230804142707.412137-2-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>
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The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Newer versions of the PWM block use a core clock with external mux,
divider, and gate. These components either don't exist any longer in
the PWM block, or they are bypassed.
To minimize needed changes for supporting the new version, the internal
divider and gate should be handled by CCF too.
I didn't see a good way to split the patch, therefore it's somewhat
bigger. What it does:
- The internal mux is handled by CCF already. Register also internal
divider and gate with CCF, so that we have one representation of the
input clock: [mux] parent of [divider] parent of [gate]
- Now that CCF selects an appropriate mux parent, we don't need the
DT-provided default parent any longer. Accordingly we can also omit
setting the mux parent directly in the driver.
- Instead of manually handling the pre-div divider value, let CCF
set the input clock. Targeted input clock frequency is
0xffff * 1/period for best precision.
- For the "inverted pwm disabled" scenario target an input clock
frequency of ULONG_MAX. This ensures that the remaining low pulses
have minimum length.
I don't have hw with the old PWM block, therefore I couldn't test this
patch. With the not yet included extension for the new PWM block
(channel->clk coming directly from get_clk(external_clk)) I didn't
notice any problem. My system uses PWM for the CPU voltage regulator
and for the SDIO 32kHz clock.
Note: The clock gate in the old PWM block is permanently disabled.
This seems to indicate that it's not used by the new PWM block.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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The meson_vclk code from the display driver may change the rate of the
video clock. Therefore better don't use it as pwm mux parent.
After removing this clock from the parent list pwm_gxbb_data and
pwm_g12a_ee_data are the same as pwm_meson8b_data. So we can remove
them.
Reported-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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We'll use struct clk_parent_data for mux/div/gate initialization in the
follow-up patches. As a first step switch the mux from using
parent_names to clk_parent_data.
Suggested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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period >= duty implies that cnt >= duty_cnt. We verified before
that cnt <= 0xffff, therefore we can omit the check here.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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state->period/duty are of type u64, and if their value is greater than
UINT_MAX, then the cast to uint will cause problems. Fix this by
changing the type of the respective local variables to u64.
Fixes: b79c3670e120 ("pwm: meson: Don't duplicate the polarity internally")
Cc: stable@vger.kernel.org
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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I don't see a reason why we should treat the case lo < hi differently
and return 0 as period and duty_cycle. The current logic was added with
c375bcbaabdb ("pwm: meson: Read the full hardware state in
meson_pwm_get_state()"), Martin as original author doesn't remember why
it was implemented this way back then.
So let's handle it as normal use case and also remove the optimization
for lo == 0. I think the improved readability is worth it.
Fixes: c375bcbaabdb ("pwm: meson: Read the full hardware state in meson_pwm_get_state()")
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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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 <hkallweit1@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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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 <hkallweit1@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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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 <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>
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.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>
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The PWM core only calls the apply callback with a valid state pointer,
so don't repeat this check already done in the core.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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The driver tracks per-channel data via struct pwm_device::chip_data and
struct meson_pwm::channels[]. The latter holds the actual data, the former
is only a pointer to the latter. So simplify by using struct
meson_pwm::channels[] consistently.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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In meson_pwm_free() the function pwm_get_chip_data() always returns a
non-NULL pointer because it's only called when the request callback
succeeded and this callback calls pwm_set_chip_data() in this case.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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In .request() pwm_get_chip_data() returns NULL always since commit
e926b12c611c ("pwm: Clear chip_data in pwm_put()"). (And if it didn't
returning 0 would be wrong because then .request() wouldn't reenable
the clk which the other driver code depends on.)
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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With the previous commit there is no need for the lowlevel driver any
more to specify it it uses two or three cells. So simplify accordingly.
The only non-trival change affects the pwm-rockchip driver: It used to only
support three cells if the hardware supports polarity. Now the default
number depends on the device tree which has to match hardware anyhow
(and if it doesn't the error is just a bit delayed as a PWM handle with
an inverted setting is catched when pwm_apply_state() is called).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Since commit 5e5da1e9fbee ("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Use devm_platform_ioremap_resource() to simplify code.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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The variable fin_freq is being initialized with a value that is never
read and it is being updated later with a new value. The initialization
is redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Fix indentation of return block. Smatch warning:
drivers/pwm/pwm-meson.c:139 meson_pwm_request() warn: inconsistent indenting
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Fixes: 211ed630753d ("pwm: Add support for Meson PWM Controller")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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It is surprising for a PWM consumer when the variable holding the
requested state is modified by pwm_apply_state(). Consider for example a
driver doing:
#define PERIOD 5000000
#define DUTY_LITTLE 10
...
struct pwm_state state = {
.period = PERIOD,
.duty_cycle = DUTY_LITTLE,
.polarity = PWM_POLARITY_NORMAL,
.enabled = true,
};
pwm_apply_state(mypwm, &state);
...
state.duty_cycle = PERIOD / 2;
pwm_apply_state(mypwm, &state);
For sure the second call to pwm_apply_state() should still have
state.period = PERIOD and not something the hardware driver chose for a
reason that doesn't necessarily apply to the second call.
So declare the state argument as a pointer to a const type and adapt all
drivers' .apply callbacks.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Add links to the datasheet and a short summary how the hardware works.
The goal is to make it easier for other developers to understand why the
pwm-meson driver is implemented the way it is.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Co-authored-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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meson_pwm_apply() has to consider the PWM polarity when disabling the
output.
With enabled=false and polarity=PWM_POLARITY_NORMAL the output needs to
be LOW. The driver already supports this.
With enabled=false and polarity=PWM_POLARITY_INVERSED the output needs
to be HIGH. Implement this in the driver by internally enabling the
output with the same settings that we already use for "period == duty".
This fixes a PWM API violation which expects that the driver honors the
polarity also for enabled=false. Due to the IP block not supporting this
natively we only get "an as close as possible" to 100% HIGH signal (in
my test setup with input clock of 24MHz and measuring the output with a
logic analyzer at 24MHz sampling rate I got a duty cycle of 99.998475%
on a Khadas VIM).
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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The PWM core already caches the "current struct pwm_state" as the
"current state of the hardware registers" inside struct pwm_device.
Drop the struct pwm_state from struct meson_pwm_channel in favour of the
struct pwm_state in struct pwm_device. While here also drop any checks
based on the pwm_state because the PWM core already takes care of this.
No functional changes intended.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Update the meson_pwm_get_state() implementation to take care of all
information in the registers instead of only reading the "enabled"
state.
The PWM output is only enabled if two conditions are met:
1. the per-channel clock is enabled
2. the PWM output is enabled
Calculate the PWM period and duty cycle using the reverse formula which
we already have in meson_pwm_calc() and update struct pwm_state with the
results.
As result of this /sys/kernel/debug/pwm now shows the PWM state set by
the bootloader (or firmware) after booting Linux.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Replace the loop to calculate the pre-divider and count with two
separate div64_u64() calculations. This makes the code easier to read
and improves the precision.
Three example cases:
1) 32.768kHz LPO clock for the SDIO wifi chip on Khadas VIM
clock input: 500MHz (FCLK_DIV4)
period: 30518ns
duty cycle: 15259ns
old algorithm: pre_div=0, cnt=15259
new algorithm: pre_div=0, cnt=15259
(no difference in calculated values)
2) PWM LED on Khadas VIM
clock input: 24MHz (XTAL)
period: 7812500ns
duty cycle: 7812500ns
old algorithm: pre_div=2, cnt=62004
new algorithm: pre_div=2, cnt=62500
Using a scope (24MHz sampling rate) shows the actual difference:
- old: 7753000ns, off by -59500ns (0.7616%)
- new: 7815000ns, off by +2500ns (0.032%)
3) Theoretical case where pre_div is different
clock input: 24MHz (XTAL)
period: 2730624ns
duty cycle: 1365312ns
old algorithm: pre_div=1, cnt=32768
new algorithm: pre_div=0, cnt=65534
Using a scope (24MHz sampling rate) shows the actual difference:
- old: 2731000ns
- new: 2731000ns
(my scope is not precise enough to measure the difference if there's
any)
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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All existing PWM drivers (except pwm-meson and two other ones) call
pwm_set_chip_data() from their pwm_ops.request() callback. Now that we
can access the struct meson_pwm_channel from struct meson_pwm we can do
the same.
Move the call to pwm_set_chip_data() to meson_pwm_request() and drop the
custom meson_pwm_add_channels(). This makes the implementation
consistent with other drivers and makes it slightly more obvious
thatpwm_get_chip_data() cannot be used from pwm_ops.get_state() (because
that's called by the PWM core before pwm_ops.request()).
No functional changes intended.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Introduce struct meson_pwm_channel_data which contains the per-channel
offsets for the PWM register and REG_MISC_AB bits. Replace the existing
switch (pwm->hwpwm) statements with an access to the new struct.
This simplifies the code and will make it easier to implement
pwm_ops.get_state() because the switch-case which all per-channel
registers and offsets (as previously implemented in meson_pwm_enable())
doesn't have to be duplicated.
No functional changes intended.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Make struct meson_pwm_channel accessible from struct meson_pwm.
PWM core has a limitation: per-channel data can only be set after
pwmchip_add() is called. However, pwmchip_add() internally calls
pwm_ops.get_state(). If pwm_ops.get_state() needs access to the
per-channel data it has to obtain it from struct pwm_chip and struct
pwm_device's hwpwm information.
Add a struct meson_pwm_channel for each PWM channel to struct meson_pwm
so the pwm_ops.get_state() callback can be implemented as it needs
access to the clock from struct meson_pwm_channel.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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meson_pwm_calc() is the last function that accepts a struct
meson_pwm_channel. meson_pwm_enable(), meson_pwm_disable() and
meson_pwm_apply() for example are all taking a struct pwm_device as
parameter. When they need the struct meson_pwm_channel these functions
simply call pwm_get_chip_data() internally.
Make meson_pwm_calc() consistent with the other functions in the
meson-pwm driver by passing struct pwm_device to it as well. The value
of the "id" parameter is actually pwm->hwpwm, but the driver never read
the "id" parameter, which is why there's no replacement for it in the
new code.
No functional changes.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Let meson_pwm_calc() use the polarity from struct pwm_state directly.
This removes a level of indirection where meson_pwm_apply() first had to
set a driver-internal inverter mask which was then only used by
meson_pwm_calc().
Instead of adding the polarity as parameter to meson_pwm_calc() switch
to struct pwm_state directly to make it easier to see where the
parameters are actually coming from.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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MISC_CLK_SEL_WIDTH is only used in one place where it's converted into
a bit-mask. Rename and change the macro to be a bit-mask so that
conversion is not needed anymore. No functional changes intended.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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meson_pwm_calc() ensures that "lo" is always less than 16 bits wide
(otherwise it would overflow into the "hi" part of the REG_PWM_{A,B}
register).
Use GENMASK and FIELD_PREP for the lo and hi values to make it easier to
spot how wide these are internally. Additionally this is a preparation
step for the .get_state() implementation where the GENMASK() for lo and
hi becomes handy because it can be used with FIELD_GET() to extract the
values from the register REG_PWM_{A,B} register.
No functional changes intended.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Simplify the code which fetches the input clock for a PWM channel by
using devm_clk_get_optional().
This comes with a small functional change: previously all errors except
EPROBE_DEFER were ignored. Now all other errors are also treated as
errors. If no input clock is present devm_clk_get_optional() will return
NULL instead of an error which matches the behavior of the old code.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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This is a preparation for a future cleanup. Pass struct pwm_device
instead of passing the individual values required by each function as
these can be obtained for each struct pwm_device instance.
As a nice side-effect the driver now uses "switch (pwm->hwpwm)"
everywhere. Before some functions used "switch (id)" while others used
"switch (pwm->hwpwm)".
No functional changes.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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The Amlogic G12A and G12B Documentation is wrong, the AO xtal and clk81
clock source order is reversed, and validated when adding DVFS support
by using the PWM AO D output to control the CPU supply voltage.
The vendor tree also uses the reversed xtal and clk81 order at [1].
[1] https://github.com/hardkernel/linux/blob/odroidn2-4.9.y/drivers/amlogic/pwm/pwm_meson.c#L462
Fixes: f41efceb46e6 ("pwm: meson: Add clock source configuration for Meson G12A")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"Nothing out of the ordinary this cycle.
The bulk of this is a collection of fixes for existing drivers and
some cleanups. There's one new driver for i.MX SoCs and addition of
support for some new variants to existing drivers"
* tag 'pwm/for-5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
pwm: meson: Add clock source configuration for Meson G12A
dt-bindings: pwm: Update bindings for the Meson G12A Family
pwm: samsung: Don't uses devm_*() functions in ->request()
pwm: Clear chip_data in pwm_put()
pwm: Add i.MX TPM PWM driver support
dt-bindings: pwm: Add i.MX TPM PWM binding
pwm: imx27: Use devm_platform_ioremap_resource() to simplify code
pwm: meson: Use the spin-lock only to protect register modifications
pwm: meson: Don't disable PWM when setting duty repeatedly
pwm: meson: Consider 128 a valid pre-divider
pwm: sysfs: fix typo "its" -> "it's"
pwm: tiehrpwm: Enable compilation for ARCH_K3
dt-bindings: pwm: tiehrpwm: Add TI AM654 SoC specific compatible
pwm: tiehrpwm: Update shadow register for disabling PWMs
pwm: img: Turn final 'else if' into 'else' in img_pwm_config
pwm: Fix deadlock warning when removing PWM device
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