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path: root/drivers/pwm/pwm-atmel.c
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2024-02-15pwm: atmel: Make use of devm_pwmchip_alloc() functionUwe Kleine-König1-8/+5
This prepares the pwm-atmel 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/f2a83af5660de461b4dcaf76929e9813bddfeff1.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: atmel: Make use of pwmchip_parent() accessorUwe Kleine-König1-4/+4
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/f8ca10033204111e4eb2e7a4dad0bd1f7586c735.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: atmel: Change prototype of a helper to prepare further changesUwe Kleine-König1-9/+12
This prepares the driver for further changes that will make it harder to determine the pwm_chip from a given atmel_pwm_chip. To just not have to do that, rework atmel_pwm_enable_clk_if_on() to take a pwm_chip. Link: https://lore.kernel.org/r/c9a92f77760e401debfe0c9bfc086222f31fb3c4.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: atmel: Don't use pwm consumer APIUwe Kleine-König1-8/+5
Lowlevel driver callbacks are not supposed to use the consumer API functions. Currently this works, but with the upcoming locking changes this probably results in dead locks. Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Link: https://lore.kernel.org/r/20240129085627.2386470-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2023-10-13pwm: Manage owner assignment implicitly for driversUwe Kleine-König1-1/+0
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>
2023-10-06pwm: atmel: Remove redundant of_match_ptr()Ruan Jinjie1-1/+1
The driver depends on CONFIG_OF, it is not necessary to use of_match_ptr() here. Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-28pwm: atmel: Simplify using devm functionsUwe Kleine-König1-26/+7
For all resources used by the driver there is a devm variant to allocate these. This simplifies the error path in the probe callback and allows to drop the remove callback. While at it also use dev_err_probe() to compact returning an error. With the remove callback gone, there is no user of driver data left, so the call to platform_set_drvdata() can also be dropped. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-24pwm: atmel: Enable clk when pwm already enabled in bootloaderGuiting Shen1-2/+45
The driver would never call clk_enable() if the PWM channel was already enabled in bootloader which lead to dump the warning message "the PWM clock already disabled" when turning off the PWM channel. Add atmel_pwm_enable_clk_if_on() in probe function to enable clock if the PWM channel was already enabled in bootloader. Signed-off-by: Guiting Shen <aarongt.shen@gmail.com> Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-24pwm: Explicitly include correct DT includesRob Herring1-1/+0
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>
2023-06-16docs: update some straggling Documentation/arm referencesJonathan Corbet1-1/+1
The Arm documentation has moved to Documentation/arch/arm; update the last remaining references to match. Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Chen-Yu Tsai <wens@csie.org> Cc: Samuel Holland <samuel@sholland.org> Cc: Thierry Reding <thierry.reding@gmail.com> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # for pwm Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-03-30pwm: atmel: Convert to platform remove callback returning voidUwe Kleine-König1-4/+2
The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06pwm: Make .get_state() callback return an error codeUwe Kleine-König1-2/+4
.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>
2022-02-24pwm: atmel: Remove redundant initialization of variable timeoutColin Ian King1-1/+1
The variable timeout is being initialized with a value that is never read, it is being re-assigned the same value later on. Remove the redundant initialization and keep the latter assignment because it's closer to the use of the variable. Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-11-05pwm: atmel: Drop unused headerUwe Kleine-König1-1/+0
Since commit 52eaba4cedbd ("pwm: atmel: Rework tracking updates pending in hardware") the driver doesn't make use of mutexes any more, so the header defining these doesn't need to be included. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-09-02pwm: atmel: Rework tracking updates pending in hardwareUwe Kleine-König1-23/+79
This improves the driver's behavior in several ways: - The lock is held for shorter periods and so a channel that is currently waited for doesn't block disabling another channel. - It's easier to understand because the procedure is split into more semantic units and documentation is improved - A channel is only set to pending when such an event is actually scheduled in hardware (by writing the CUPD register). - Also wait in .get_state() to report the last configured state instead of (maybe) the previous one. This fixes the read back duty cycle and so prevents a warning being emitted when PWM_DEBUG is on. Tested on an AriettaG25. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25pwm: Simplify all drivers with explicit of_pwm_n_cells = 3Uwe Kleine-König1-2/+0
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>
2021-04-23pwm: atmel: Improve duty cycle calculation in .apply()Uwe Kleine-König1-7/+16
In the calculation of the register value determining the duty cycle the requested period is used instead of the actually implemented period which results in suboptimal settings. The following example assumes an input clock of 133333333 Hz on one of the SoCs with 16 bit period. When the following state is to be applied: .period = 414727681 .duty_cycle = 652806 the following register values used to be calculated: PRES = 10 CPRD = 54000 CDTY = 53916 which yields an actual duty cycle of a bit more than 645120 ns. The setting PRES = 10 CPRD = 54000 CDTY = 53915 however yields a duty of 652800 ns which is between the current result and the requested value and so is a better approximation. The reason for this error is that for the calculation of CDTY the requested period was used instead of the actually implemented one. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-04-23pwm: atmel: Fix duty cycle calculation in .get_state()Uwe Kleine-König1-1/+1
The CDTY register contains the number of inactive cycles. .apply() does this correctly, however .get_state() got this wrong. Fixes: 651b510a74d4 ("pwm: atmel: Implement .get_state()") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-04-09pwm: atmel: Free resources only after pwmchip_remove()Uwe Kleine-König1-1/+3
Before pwmchip_remove() returns the PWM is expected to be functional. So remove the pwmchip before disabling the clock. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-03-22pwm: Always allocate PWM chip base ID dynamicallyUwe Kleine-König1-1/+0
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>
2020-12-17pwm: atmel: Convert to devm_platform_ioremap_resource()Yangtao Li1-3/+1
Use devm_platform_ioremap_resource() to simplify code. Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-08pwm: atmel: Implement .get_state()Uwe Kleine-König1-0/+40
This function reads back the configured parameters from the hardware. As .apply() rounds down (mostly) I'm rounding up in .get_state() to achieve that applying a state just read from hardware is a no-op. Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-08pwm: atmel: Use register accessors for channelsUwe Kleine-König1-2/+2
This makes it a bit easier when instrumenting register access to only have to add code in one place. Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-08pwm: atmel: Document known weaknesses of both hardware and softwareUwe Kleine-König1-0/+10
This documents the my findings while reading through the driver and the reference manual. Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-08pwm: atmel: Replace loop in prescale calculation by ad-hoc calculationUwe Kleine-König1-7/+17
The calculated values are the same with the modified algorithm. The only difference is that the calculation is a bit more efficient. Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-08pwm: atmel: Use a constant for maximum prescale valueUwe Kleine-König1-5/+3
The maximal prescale value is 10 for all supported variants. So drop the member in the variant description and introduce a global constant instead. This reduces the size of the variant descriptions and the .apply() callback can be compiled a bit more effectively. Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-08pwm: atmel: Add a hint where to find hardware documentationUwe Kleine-König1-0/+3
Most Microchip (formerly Atmel) chips have publicly available manuals. A comprehensive list is already contained in the documentation folder. Reference this list in the header of the driver to allow reviewers to find the relevant manuals. Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21pwm: atmel: Consolidate driver data initializationThierry Reding1-4/+2
This helps readability by separating the driver-specific bits from the PWM framework bits. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21pwm: atmel: Remove unneeded check for match dataThierry Reding1-6/+2
Since the driver is now exclusively DT, it only binds if it finds a match in the of_device_id table. But in that case the associated data can never be NULL, so drop the unnecessary check. While at it, drop the extra local variable and store the pointer to this per-SoC data in the driver data directly. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21pwm: atmel: Remove platform_device_id and use only dt bindingsKamel Bouhara1-32/+3
Since commit 26202873bb51 ("avr32: remove support for AVR32 architecture") there is no more user of platform_device_id and we should only use dt bindings Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21pwm: Ensure pwm_apply_state() doesn't modify the state argumentUwe Kleine-König1-1/+1
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>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 191Thomas Gleixner1-2/+1
Based on 1 normalized pattern(s): licensed under gplv2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 99 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Steve Winslow <swinslow@gmail.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170027.163048684@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-04pwm: atmel: Remove useless symbolic definitionsThierry Reding1-14/+6
The values that these symbols define are only assigned to the per-SoC structure where the context is clear, so there's no need for the extra symbolic name. Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04pwm: atmel: Add support for SAM9X60's PWM controllerClaudiu Beznea1-0/+19
Add support for SAM9X60's PWM controller. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04pwm: atmel: Rename objects of type atmel_pwm_dataClaudiu Beznea1-7/+7
Rename objects of type atmel_pwm_data to contain chip name instead of version number. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04pwm: atmel: Add support for controllers with 32 bit countersClaudiu Beznea1-11/+23
SAM9X60's PWM controller uses 32 bits counters thus it could generate signals with higher period and duty cycles than the old ones. Prepare the current driver to be able to work with old controllers (that uses 16 bits counters) and with the new SAM9X60's controller, by providing counters information based on compatible string. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04pwm: atmel: Add struct atmel_pwm_dataClaudiu Beznea1-28/+36
Add struct atmel_pwm_data to embed different per controller information. It prepares adding support for another similar controller that needs additional information. At this stage, embed a member of type struct atmel_pwm_registers in it. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-04-06pwm: atmel: Enable PWM on sama5d2Claudiu Beznea1-0/+3
sama5d2 can use the same atmel_pwm_data as sama5d3. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-04-06pwm: atmel: Switch to atomic PWMClaudiu Beznea1-144/+129
The currently Atmel PWM controllers supported by this driver could change period or duty factor without channel disable, for regular channels (sama5d3 support this by using period or duty factor update registers, sam9rl support this by writing channel update register and select the corresponding update: period or duty factor). The chip doesn't support run time changings of signal polarity. To take advantage of atomic PWM framework and let controller works without glitches, in this patch only the duty factor could be changed without disabling PWM channel. For period and signal polarity the atomic PWM is simulated by disabling + enabling the right PWM channel. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-04pwm: Remove .can_sleep from struct pwm_chipThierry Reding1-1/+0
All PWM devices have been marked as "might sleep" since v4.5, there is no longer a need to differentiate on a per-chip basis. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-11pwm: atmel: Use of_device_get_match_data()Thierry Reding1-9/+2
Use of_device_get_match_data() instead of an open-coded variant. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-11pwm: atmel: Fix checkpatch warningsThierry Reding1-6/+7
Avoid an overly long line by moving a comment around, and remove a use of else-after-return. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-11pwm: atmel: Fix disabling of PWM channelsGuillermo Rodriguez1-0/+10
When disabling a PWM channel, the PWM clock was being stopped immediately after writing to PWM_DIS. As a result, the disabling of the PWM channel did not complete properly, and the PWM output might be left at the wrong level. Fix this by waiting for the channel to be effectively disabled (by checking the PWM_SR register) before disabling the clock. Signed-off-by: Guillermo Rodriguez <guille.rodriguez@gmail.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-07-20pwm: Make use of pwm_get_xxx() helpers where appropriateBoris Brezillon1-1/+1
Use the pwm_get_xxx() helpers instead of directly accessing the fields in struct pwm_device. This will allow us to smoothly move to the atomic update approach. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-07-20pwm: Add the pwm_is_enabled() helperBoris Brezillon1-3/+3
Some PWM drivers are testing the PWMF_ENABLED flag. Create a helper function to hide the logic behind enabled test. This will allow us to smoothly move from the current approach to an atomic PWM update approach. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-06-12pwm: atmel: Fix incorrect CDTY value after disablingAlexandre Belloni1-0/+28
pwm-leds calls .config() and .disable() in a row. This exhibits that it may happen that the channel gets disabled before CDTY has been updated with CUPD. The issue gets quite worse with long periods. So, ensure that at least one period has past before disabling the channel by polling ISR. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Tested-by: Gaël PORTAY <gael.portay@gmail.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-06-12pwm: atmel: Fix incorrect CDTY value after enablingAlexandre Belloni1-17/+18
CUPD is not flushed before enabling the channel so it will update CDTY/CPRD just after one period. So we always set CUPD, even when the channel is not enabled. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-09-25pwm: atmel: Fix calculation of prescale valueNikolaus Voss1-13/+11
The prescale value used for calculating the period was incremented afterwards, thus the resulting prescale value is by one too high. This resulted in a PWM frequency only half as high as requested. This patch moves the 64 bit division out of the prescale loop to correct the above issue and make the calculation more efficient. Signed-off-by: Nikolaus Voss <n.voss@weinmann-emt.de> Tested-by: Bo Shen <voice.shen@atmel.com> Acked-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-21pwm: atmel: set pwm_chip can_sleep flagAlexandre Belloni1-0/+1
atmel_pwm_config() calls clk_get_rate() which might sleep, so we need to set pwm_chip can_sleep flag. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-03-18pwm: atmel: correct CDTY calculationAlexandre Belloni1-1/+1
From the datasheet, the actual duty cycle is: (period - (1 / clk) * CDTY) / period This actually correct the polarity of the PWM and solves the issue that pwm-leds exhibits: when setting a duty cycle of 0 and then disabling a channel, the level was wrong (1 when the polarity was normal and 0 when the polarity was inversed). Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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