summaryrefslogtreecommitdiff
path: root/drivers/pwm/pwm-atmel.c
AgeCommit message (Collapse)Author
2021-11-05pwm: atmel: Drop unused headerUwe Kleine-König
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-König
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-König
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-König
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-König
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-König
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-König
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 Li
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-König
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-König
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-König
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-König
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-König
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-König
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 Reding
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 Reding
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 Bouhara
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-König
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 Gleixner
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 Reding
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 Beznea
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 Beznea
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 Beznea
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 Beznea
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 Beznea
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 Beznea
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 Reding
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 Reding
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 Reding
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 Rodriguez
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 Brezillon
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 Brezillon
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 Belloni
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 Belloni
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 Voss
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 Belloni
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 Belloni
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>
2014-03-18pwm: atmel: Fix polarity handlingAlexandre Belloni
When atmel_pwm_config() calculates and then sets the prescaler, it is overwriting the channel's CMR register so we are losing the CPOL configuration. As atmel_pwm_config() is always called before enabling a channel, inverting the polarity doesn't work. Fix that by reading CMR first and only overwriting the prescaler bits. 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>
2013-12-20pwm: atmel-pwm: Do not unprepare clock after successful registrationBo Shen
When the PWM controller is registered successfully, the clock can not unprepare, so fix it. Signed-off-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-12-17pwm: atmel-pwm: Add Atmel PWM controller driverBo Shen
Add a PWM framework driver for the PWM controller found on Atmel SoCs. Signed-off-by: Bo Shen <voice.shen@atmel.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> [thierry.reding: coding style and other minor cleanups] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
generated by cgit (git 2.34.1) at 2024-06-10 06:53:26 +0000