summaryrefslogtreecommitdiff
path: root/drivers/pwm
AgeCommit message (Collapse)Author
2025-04-25pwm: fsl-ftm: Handle clk_get_rate() returning 0Uwe Kleine-König
[ Upstream commit 928446a5302eee30ebb32075c0db5dda5a138fb7 ] Considering that the driver doesn't enable the used clocks (and also that clk_get_rate() returns 0 if CONFIG_HAVE_CLK is unset) better check the return value of clk_get_rate() for being non-zero before dividing by it. Fixes: 3479bbd1e1f8 ("pwm: fsl-ftm: More relaxed permissions for updating period") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Link: https://lore.kernel.org/r/b68351a51017035651bc62ad3146afcb706874f0.1743501688.git.u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-25pwm: rcar: Improve register calculationUwe Kleine-König
[ Upstream commit e7327c193014a4d8666e9c1cda09cf2c060518e8 ] There were several issues in the function rcar_pwm_set_counter(): - The u64 values period_ns and duty_ns were cast to int on function call which might loose bits on 32 bit architectures. Fix: Make parameters to rcar_pwm_set_counter() u64 - The algorithm divided by the result of a division which looses precision. Fix: Make use of mul_u64_u64_div_u64() - The calculated values were just masked to fit the respective register fields which again might loose bits. Fix: Explicitly check for overlow Implement the respective fixes. A side effect of fixing the 2nd issue is that there is no division by 0 if clk_get_rate() returns 0. Fixes: ed6c1476bf7f ("pwm: Add support for R-Car PWM Timer") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Link: https://lore.kernel.org/r/ab3dac794b2216cc1cc56d65c93dd164f8bd461b.1743501688.git.u.kleine-koenig@baylibre.com [ukleinek: Added an explicit #include <linux/bitfield.h> to please the 0day build bot] Link: https://lore.kernel.org/oe-kbuild-all/202504031354.VJtxScP5-lkp@intel.com/ Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-25pwm: mediatek: Prevent divide-by-zero in pwm_mediatek_config()Josh Poimboeuf
[ Upstream commit 7ca59947b5fcf94e7ea4029d1bd0f7c41500a161 ] With CONFIG_COMPILE_TEST && !CONFIG_HAVE_CLK, pwm_mediatek_config() has a divide-by-zero in the following line: do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm])); due to the fact that the !CONFIG_HAVE_CLK version of clk_get_rate() returns zero. This is presumably just a theoretical problem: COMPILE_TEST overrides the dependency on RALINK which would select COMMON_CLK. Regardless it's a good idea to check for the error explicitly to avoid divide-by-zero. Fixes the following warning: drivers/pwm/pwm-mediatek.o: warning: objtool: .text: unexpected end of section Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/fb56444939325cc173e752ba199abd7aeae3bf12.1742852847.git.jpoimboe@kernel.org [ukleinek: s/CONFIG_CLK/CONFIG_HAVE_CLK/] Fixes: caf065f8fd58 ("pwm: Add MediaTek PWM support") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Link: https://lore.kernel.org/r/9e78a0796acba3435553ed7db1c7965dcffa6215.1743501688.git.u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21pwm: stm32: Add check for clk_enable()Mingwei Zheng
[ Upstream commit e8c59791ebb60790c74b2c3ab520f04a8a57219a ] Add check for the return value of clk_enable() to catch the potential error. Fixes: 19f1016ea960 ("pwm: stm32: Fix enable count for clk in .probe()") Signed-off-by: Mingwei Zheng <zmw12306@gmail.com> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com> Link: https://lore.kernel.org/r/20241215224752.220318-1-zmw12306@gmail.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21pwm: stm32-lp: Add check for clk_enable()Mingwei Zheng
[ Upstream commit cce16e7f6216227964cda25f5f23634bce2c500f ] Add check for the return value of clk_enable() to catch the potential error. We used APP-Miner to find it. Fixes: e70a540b4e02 ("pwm: Add STM32 LPTimer PWM driver") Signed-off-by: Mingwei Zheng <zmw12306@gmail.com> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com> Link: https://lore.kernel.org/r/20241206215318.3402860-1-zmw12306@gmail.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14pwm: imx27: Workaround of the pwm output bug when decrease the duty cycleClark Wang
[ Upstream commit a25351e4c7740eb22561a3ee4ef17611c6f410b0 ] Implement workaround for ERR051198 (https://www.nxp.com/docs/en/errata/IMX8MN_0N14Y.pdf) PWM output may not function correctly if the FIFO is empty when a new SAR value is programmed. Description: When the PWM FIFO is empty, a new value programmed to the PWM Sample register (PWM_PWMSAR) will be directly applied even if the current timer period has not expired. If the new SAMPLE value programmed in the PWM_PWMSAR register is less than the previous value, and the PWM counter register (PWM_PWMCNR) that contains the current COUNT value is greater than the new programmed SAMPLE value, the current period will not flip the level. This may result in an output pulse with a duty cycle of 100%. Workaround: Program the current SAMPLE value in the PWM_PWMSAR register before updating the new duty cycle to the SAMPLE value in the PWM_PWMSAR register. This will ensure that the new SAMPLE value is modified during a non-empty FIFO, and can be successfully updated after the period expires. Write the old SAR value before updating the new duty cycle to SAR. This avoids writing the new value into an empty FIFO. This only resolves the issue when the PWM period is longer than 2us (or <500kHz) because write register is not quick enough when PWM period is very short. Reproduce steps: cd /sys/class/pwm/pwmchip1/pwm0 echo 2000000000 > period # It is easy to observe by using long period echo 1000000000 > duty_cycle echo 1 > enable echo 8000 > duty_cycle # One full high pulse will be seen by scope Fixes: 166091b1894d ("[ARM] MXC: add pwm driver for i.MX SoCs") Reviewed-by: Jun Li <jun.li@nxp.com> Signed-off-by: Clark Wang <xiaoning.wang@nxp.com> Signed-off-by: Frank Li <Frank.Li@nxp.com> Link: https://lore.kernel.org/r/20241008194123.1943141-1-Frank.Li@nxp.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-14pwm: imx-tpm: Use correct MODULO value for EPWM modeErik Schumacher
commit cc6a931d1f3b412263d515fd93b21fc0ca5147fe upstream. The modulo register defines the period of the edge-aligned PWM mode (which is the only mode implemented). The reference manual states: "The EPWM period is determined by (MOD + 0001h) ..." So the value that is written to the MOD register must therefore be one less than the calculated period length. Return -EINVAL if the calculated length is already zero. A correct MODULO value is particularly relevant if the PWM has to output a high frequency due to a low period value. Fixes: 738a1cfec2ed ("pwm: Add i.MX TPM PWM driver support") Cc: stable@vger.kernel.org Signed-off-by: Erik Schumacher <erik.schumacher@iris-sensing.com> Link: https://lore.kernel.org/r/1a3890966d68b9f800d457cbf095746627495e18.camel@iris-sensing.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-03pwm: atmel-tcb: Fix race condition and convert to guardsUwe Kleine-König
[ Upstream commit 37f7707077f5ea2515bf4b1dc7fad43f8e12993e ] The hardware only supports a single period length for both PWM outputs. So atmel_tcb_pwm_config() checks the configuration of the other output if it's compatible with the currently requested setting. The register values are then actually updated in atmel_tcb_pwm_enable(). To make this race free the lock must be held during the whole process, so grab the lock in .apply() instead of individually in atmel_tcb_pwm_disable() and atmel_tcb_pwm_enable() which then also covers atmel_tcb_pwm_config(). To simplify handling, use the guard helper to let the compiler care for unlocking. Otherwise unlocking would be more difficult as there is more than one exit path in atmel_tcb_pwm_apply(). Fixes: 9421bade0765 ("pwm: atmel: add Timer Counter Block PWM driver") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> Link: https://lore.kernel.org/r/20240709101806.52394-3-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03pwm: atmel-tcb: Don't track polarity in driver dataUwe Kleine-König
[ Upstream commit 28a1dadc49e2902d0a7a2e8c699a15f93b1b6f40 ] struct atmel_tcb_pwm_device::polarity is only used in atmel_tcb_pwm_enable and atmel_tcb_pwm_disable(). These functions are only called by atmel_tcb_pwm_apply() after the member variable was assigned to state->polarity. So the value assigned in atmel_tcb_pwm_request() is never used and the member can be dropped from struct atmel_tcb_pwm_device. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: 37f7707077f5 ("pwm: atmel-tcb: Fix race condition and convert to guards") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03pwm: atmel-tcb: Unroll atmel_tcb_pwm_set_polarity() into only callerUwe Kleine-König
[ Upstream commit 9a6ac822a2153d583b0da95b8693e954b5f4203a ] atmel_tcb_pwm_set_polarity() is only called once and effectively wraps an assignment only. Replace the function call by the respective assignment. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: 37f7707077f5 ("pwm: atmel-tcb: Fix race condition and convert to guards") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03pwm: atmel-tcb: Put per-channel data into driver dataUwe Kleine-König
[ Upstream commit 78dca23bd6706dd6a3cdb5c0052f48794b4d2bed ] This simplifies the code, reduces the number of memory allocations and pointer dereferences. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: 37f7707077f5 ("pwm: atmel-tcb: Fix race condition and convert to guards") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03pwm: stm32: Always do lazy disablingUwe Kleine-König
[ Upstream commit 7346e7a058a2c9aa9ff1cc699c7bf18a402d9f84 ] When the state changes from enabled to disabled, polarity, duty_cycle and period are not configured in hardware and TIM_CCER_CCxE is just cleared. However if the state changes from one disabled state to another, all parameters are written to hardware because the early exit from stm32_pwm_apply() is only taken if the pwm is currently enabled. This yields surprises like: Applying { .period = 1, .duty_cycle = 0, .enabled = false } succeeds if the pwm is initially on, but fails if it's already off because 1 is a too small period. Update the check for lazy disable to always exit early if the target state is disabled, no matter what is currently configured. Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Link: https://lore.kernel.org/r/20240703110010.672654-2-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05pwm: stm32: Refuse too small period requestsUwe Kleine-König
commit c45fcf46ca2368dafe7e5c513a711a6f0f974308 upstream. If period_ns is small, prd might well become 0. Catch that case because otherwise with regmap_write(priv->regmap, TIM_ARR, prd - 1); a few lines down quite a big period is configured. Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm") Cc: stable@vger.kernel.org Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Link: https://lore.kernel.org/r/b86f62f099983646f97eeb6bfc0117bb2d0c340d.1718979150.git.u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-12pwm: sti: Simplify probe function using devm functionsUwe Kleine-König
[ Upstream commit 5bb0b194aeee5d5da6881232f4e9989b35957c25 ] Instead of of_clk_get_by_name() use devm_clk_get_prepared() which has several advantages: - Combines getting the clock and a call to clk_prepare(). The latter can be dropped from sti_pwm_probe() accordingly. - Cares for calling clk_put() which is missing in both probe's error path and the remove function. - Cares for calling clk_unprepare() which can be dropped from the error paths and the remove function. (Note that not all error path got this right.) With additionally using devm_pwmchip_add() instead of pwmchip_add() the remove callback can be dropped completely. With it the last user of platform_get_drvdata() goes away and so platform_set_drvdata() can be dropped from the probe function, too. Fixes: 378fe115d19d ("pwm: sti: Add new driver for ST's PWM IP") Link: https://lore.kernel.org/r/81f0e1d173652f435afda6719adaed1922fe059a.1710068192.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12pwm: sti: Prepare removing pwm_chip from driver dataUwe Kleine-König
[ Upstream commit 54272761ce7c475fa30a31b59b0cb89f7652b39e ] This prepares the driver for further changes that will drop struct pwm_chip chip from struct sti_pwm_chip. Use the pwm_chip as driver data instead of the sti_pwm_chip to get access to the pwm_chip in sti_pwm_remove() without using pc->chip. Link: https://lore.kernel.org/r/56d53372aacff6871df4d6c6779c9dac94592696.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Stable-dep-of: 5bb0b194aeee ("pwm: sti: Simplify probe function using devm functions") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12pwm: sti: Convert to platform remove callback returning voidUwe Kleine-König
[ Upstream commit e13cec3617c6ace4fc389b60d2a7d5b305b62683 ] 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> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: 5bb0b194aeee ("pwm: sti: Simplify probe function using devm functions") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-03pwm: img: fix pwm clock lookupZoltan HERPAI
[ Upstream commit 9eb05877dbee03064d3d3483cd6702f610d5a358 ] 22e8e19 has introduced a regression in the imgchip->pwm_clk lookup, whereas the clock name has also been renamed to "imgchip". This causes the driver failing to load: [ 0.546905] img-pwm 18101300.pwm: failed to get imgchip clock [ 0.553418] img-pwm: probe of 18101300.pwm failed with error -2 Fix this lookup by reverting the clock name back to "pwm". Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu> Link: https://lore.kernel.org/r/20240320083602.81592-1-wigyori@uid0.hu Fixes: 22e8e19a46f7 ("pwm: img: Rename variable pointing to driver private data") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26pwm: sti: Fix capture for st,pwm-num-chan < st,capture-num-chanUwe Kleine-König
[ Upstream commit 5f623835584f1c8d1030666796f40c47a448ce0b ] The driver only used the number of pwm channels to set the pwm_chip's npwm member. The result is that if there are more capture channels than PWM channels specified in the device tree, only a part of the capture channel is usable. Fix that by passing the bigger channel count to the pwm framework. This makes it possible that the .apply() callback is called with .hwpwm >= pwm_num_devs, catch that case and return an error code. Fixes: c97267ae831d ("pwm: sti: Add PWM capture callback") Link: https://lore.kernel.org/r/20240204212043.2951852-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26pwm: atmel-hlcdc: Fix clock imbalance related to suspend supportUwe Kleine-König
[ Upstream commit e25ac87d3f831fed002c34aadddaf4ebb4ea45ec ] The suspend callback disables the periph clock when the PWM is enabled and resume reenables this clock if the PWM was disabled before. Judging from the code comment it's suspend that is wrong here. Fix accordingly. Fixes: f9bb9da7c09d ("pwm: atmel-hlcdc: Implement the suspend/resume hooks") Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Link: https://lore.kernel.org/r/b51ea92b0a45eff3dc83b08adefd43d930df996c.1706269232.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26pwm: atmel-hlcdc: Use consistent variable namingUwe Kleine-König
[ Upstream commit aecab554b6ffa9a94ba796031eb39ea20eb60fb3 ] In PWM drivers the variable name "chip" is usually only used for struct pwm_chip pointers. This driver however used "chip" for its driver data and pwm_chip pointers are named "chip", too, when there is no driver data around and "c" otherwise. Instead use "atmel" for driver data and always "chip" for pwm_chips. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> [thierry.reding@gmail.com: replace ddata by atmel] Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: e25ac87d3f83 ("pwm: atmel-hlcdc: Fix clock imbalance related to suspend support") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26pwm: atmel-hlcdc: Convert to platform remove callback returning voidUwe Kleine-König
[ Upstream commit 5fce94170ad8a67b839f3dd8e8e8a87039ba0251 ] 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> Stable-dep-of: e25ac87d3f83 ("pwm: atmel-hlcdc: Fix clock imbalance related to suspend support") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-25pwm: Fix out-of-bounds access in of_pwm_single_xlate()Uwe Kleine-König
commit a297d07b9a1e4fb8cda25a4a2363a507d294b7c9 upstream. With args->args_count == 2 args->args[2] is not defined. Actually the flags are contained in args->args[1]. Fixes: 3ab7b6ac5d82 ("pwm: Introduce single-PWM of_xlate function") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/243908750d306e018a3d4bf2eb745d53ab50f663.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-25pwm: jz4740: Don't use dev_err_probe() in .request()Uwe Kleine-König
commit 9320fc509b87b4d795fb37112931e2f4f8b5c55f upstream. dev_err_probe() is only supposed to be used in probe functions. While it probably doesn't hurt, both the EPROBE_DEFER handling and calling device_set_deferred_probe_reason() are conceptually wrong in the request callback. So replace the call by dev_err() and a separate return statement. This effectively reverts commit c0bfe9606e03 ("pwm: jz4740: Simplify with dev_err_probe()"). Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20240106141302.1253365-2-u.kleine-koenig@pengutronix.de Fixes: c0bfe9606e03 ("pwm: jz4740: Simplify with dev_err_probe()") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-25pwm: stm32: Fix enable count for clk in .probe()Philipp Zabel
[ Upstream commit 19f1016ea9600ed89bc24247c36ff5934ad94fbb ] Make the driver take over hardware state without disabling in .probe() and enable the clock for each enabled channel. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> [ukleinek: split off from a patch that also implemented .get_state()] Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm") Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-25pwm: stm32: Use hweight32 in stm32_pwm_detect_channelsPhilipp Zabel
[ Upstream commit 41fa8f57c0d269243fe3bde2bce71e82c884b9ad ] Use hweight32() to count the CCxE bits in stm32_pwm_detect_channels(). Since the return value is assigned to chip.npwm, change it to unsigned int as well. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: 19f1016ea960 ("pwm: stm32: Fix enable count for clk in .probe()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-25pwm: stm32: Use regmap_clear_bits and regmap_set_bits where applicableUwe Kleine-König
[ Upstream commit 632ae5d7eb348b3ef88552ec0999260b6f9d6ab1 ] Found using coccinelle and the following semantic patch: @@ expression map, reg, bits; @@ - regmap_update_bits(map, reg, bits, bits) + regmap_set_bits(map, reg, bits) @@ expression map, reg, bits; @@ - regmap_update_bits(map, reg, bits, 0) + regmap_clear_bits(map, reg, bits) Tested-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Link: https://lore.kernel.org/r/20221115111347.3705732-6-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> Stable-dep-of: 19f1016ea960 ("pwm: stm32: Fix enable count for clk in .probe()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20pwm: brcmstb: Utilize appropriate clock APIs in suspend/resumeFlorian Fainelli
[ Upstream commit e9bc4411548aaa738905d37851a0146c16b3bb21 ] The suspend/resume functions currently utilize clk_disable()/clk_enable() respectively which may be no-ops with certain clock providers such as SCMI. Fix this to use clk_disable_unprepare() and clk_prepare_enable() respectively as we should. Fixes: 3a9f5957020f ("pwm: Add Broadcom BCM7038 PWM controller support") Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20pwm: sti: Reduce number of allocations and drop usage of chip_dataUwe Kleine-König
[ Upstream commit 2d6812b41e0d832919d72c72ebddf361df53ba1b ] Instead of using one allocation per capture channel, use a single one. Also store it in driver data instead of chip data. This has several advantages: - driver data isn't cleared when pwm_put() is called - Reduces memory fragmentation Also register the pwm chip only after the per capture channel data is initialized as the capture callback relies on this initialization and it might be called even before pwmchip_add() returns. It would be still better to have struct sti_pwm_compat_data and the per-channel data struct sti_cpt_ddata in a single memory chunk, but that's not easily possible because the number of capture channels isn't known yet when the driver data struct is allocated. Fixes: e926b12c611c ("pwm: Clear chip_data in pwm_put()") Reported-by: George Stark <gnstark@sberdevices.ru> Fixes: c97267ae831d ("pwm: sti: Add PWM capture callback") Link: https://lore.kernel.org/r/20230705080650.2353391-7-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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19pwm: lpc32xx: Remove handling of PWM channelsVladimir Zapolskiy
[ Upstream commit 4aae44f65827f0213a7361cf9c32cfe06114473f ] Because LPC32xx PWM controllers have only a single output which is registered as the only PWM device/channel per controller, it is known in advance that pwm->hwpwm value is always 0. On basis of this fact simplify the code by removing operations with pwm->hwpwm, there is no controls which require channel number as input. Even though I wasn't aware at the time when I forward ported that patch, this fixes a null pointer dereference as lpc32xx->chip.pwms is NULL before devm_pwmchip_add() is called. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Vladimir Zapolskiy <vz@mleia.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Fixes: 3d2813fb17e5 ("pwm: lpc32xx: Don't modify HW state in .probe() after the PWM chip was registered") Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19pwm: atmel-tcb: Fix resource freeing in error path and removeUwe Kleine-König
[ Upstream commit c11622324c023415fb69196c5fc3782d2b8cced0 ] Several resources were not freed in the error path and the remove function. Add the forgotten items. Fixes: 34cbcd72588f ("pwm: atmel-tcb: Add sama5d2 support") Fixes: 061f8572a31c ("pwm: atmel-tcb: Switch to new binding") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19pwm: atmel-tcb: Harmonize resource allocation orderUwe Kleine-König
[ Upstream commit 0323e8fedd1ef25342cf7abf3a2024f5670362b8 ] Allocate driver data as first resource in the probe function. This way it can be used during allocation of the other resources (instead of assigning these to local variables first and update driver data only when it's allocated). Also as driver data is allocated using a devm function this should happen first to have the order of freeing resources in the error path and the remove function in reverse. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Stable-dep-of: c11622324c02 ("pwm: atmel-tcb: Fix resource freeing in error path and remove") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19pwm: atmel-tcb: Convert to platform remove callback returning voidUwe Kleine-König
[ Upstream commit 9609284a76978daf53a54e05cff36873a75e4d13 ] 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> Stable-dep-of: c11622324c02 ("pwm: atmel-tcb: Fix resource freeing in error path and remove") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-23pwm: meson: fix handling of period/duty if greater than UINT_MAXHeiner Kallweit
commit 87a2cbf02d7701255f9fcca7e5bd864a7bb397cf upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23pwm: meson: modify and simplify calculation in meson_pwm_get_stateHeiner Kallweit
commit 6b9352f3f8a1a35faf0efc1ad1807ee303467796 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19pwm: mtk_disp: Fix the disable flow of disp_pwmShuijing Li
[ Upstream commit bc13d60e4e1e945b34769a4a4c2b172e8552abe5 ] There is a flow error in the original mtk_disp_pwm_apply() function. If this function is called when the clock is disabled, there will be a chance to operate the disp_pwm register, resulting in disp_pwm exception. Fix this accordingly. Fixes: 888a623db5d0 ("pwm: mtk-disp: Implement atomic API .apply()") Signed-off-by: Shuijing Li <shuijing.li@mediatek.com> Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com> Tested-by: Fei Shao <fshao@chromium.org> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19pwm: ab8500: Fix error code in probe()Dan Carpenter
[ Upstream commit cdcffafc4d845cc0c6392cba168c7a942734cce7 ] This code accidentally return positive EINVAL instead of negative -EINVAL. Fixes: eb41f334589d ("pwm: ab8500: Fix register offset calculation to not depend on probe order") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19pwm: sysfs: Do not apply state to already disabled PWMsMarek Vasut
[ Upstream commit 38ba83598633373f47951384cfc389181c8d1bed ] If the PWM is exported but not enabled, do not call pwm_class_apply_state(). First of all, in this case, period may still be unconfigured and this would make pwm_class_apply_state() return -EINVAL, and then suspend would fail. Second, it makes little sense to apply state onto PWM that is not enabled before suspend. Failing case: " $ echo 1 > /sys/class/pwm/pwmchip4/export $ echo mem > /sys/power/state ... pwm pwmchip4: PM: dpm_run_callback(): pwm_class_suspend+0x1/0xa8 returns -22 pwm pwmchip4: PM: failed to suspend: error -22 PM: Some devices failed to suspend, or early wake event detected " Working case: " $ echo 1 > /sys/class/pwm/pwmchip4/export $ echo 100 > /sys/class/pwm/pwmchip4/pwm1/period $ echo 10 > /sys/class/pwm/pwmchip4/pwm1/duty_cycle $ echo mem > /sys/power/state ... " Do not call pwm_class_apply_state() in case the PWM is disabled to fix this issue. Fixes: 7fd4edc57bbae ("pwm: sysfs: Add suspend/resume support") Signed-off-by: Marek Vasut <marex@denx.de> Fixes: ef2bf4997f7d ("pwm: Improve args checking in pwm_apply_state()") Reviewed-by: Brian Norris <briannorris@chromium.org> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19pwm: imx-tpm: force 'real_period' to be zero in suspendFancy Fang
[ Upstream commit 661dfb7f46298e53f6c3deaa772fa527aae86193 ] During suspend, all the tpm registers will lose values. So the 'real_period' value of struct 'imx_tpm_pwm_chip' should be forced to be zero to force the period update code can be executed after system resume back. Signed-off-by: Fancy Fang <chen.fang@nxp.com> Signed-off-by: Clark Wang <xiaoning.wang@nxp.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Fixes: 738a1cfec2ed ("pwm: Add i.MX TPM PWM driver support") Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-11pwm: mtk-disp: Configure double buffering before reading in .get_state()AngeloGioacchino Del Regno
[ Upstream commit b16c310115f2084b8826a35b77ef42bab6786d9f ] The DISP_PWM controller's default behavior is to always use register double buffering: all reads/writes are then performed on shadow registers instead of working registers and this becomes an issue in case our chosen configuration in Linux is different from the default (or from the one that was pre-applied by the bootloader). An example of broken behavior is when the controller is configured to use shadow registers, but this driver wants to configure it otherwise: what happens is that the .get_state() callback is called right after registering the pwmchip and checks whether the PWM is enabled by reading the DISP_PWM_EN register; At this point, if shadow registers are enabled but their content was not committed before booting Linux, we are *not* reading the current PWM enablement status, leading to the kernel knowing that the hardware is actually enabled when, in reality, it's not. The aforementioned issue emerged since this driver was fixed with commit 0b5ef3429d8f ("pwm: mtk-disp: Fix the parameters calculated by the enabled flag of disp_pwm") making it to read the enablement status from the right register. Configure the controller in the .get_state() callback to avoid this desync issue and get the backlight properly working again. Fixes: 3f2b16734914 ("pwm: mtk-disp: Implement atomic API .get_state()") Signed-off-by: AngeloGioacchino Del Regno <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>
2023-05-11pwm: mtk-disp: Disable shadow registers before setting backlight valuesAngeloGioacchino Del Regno
[ Upstream commit 36dd7f530ae7d9ce9e853ffb8aa337de65c6600b ] If shadow registers usage is not desired, disable that before performing any write to CON0/1 registers in the .apply() callback, otherwise we may lose clkdiv or period/width updates. Fixes: cd4b45ac449a ("pwm: Add MediaTek MT2701 display PWM driver support") Signed-off-by: AngeloGioacchino Del Regno <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>
2023-05-11pwm: meson: Fix g12a ao clk81 nameHeiner Kallweit
commit 9e4fa80ab7ef9eb4f7b1ea9fc31e0eb040e85e25 upstream. Fix the name of the aoclk81 clock. Apparently name aoclk81 as used by the vendor driver was changed when mainlining the g12a clock driver. Fixes: f41efceb46e6 ("pwm: meson: Add clock source configuration for Meson G12A") Cc: stable@vger.kernel.org Signed-off-by: Heiner Kallweit <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>
2023-05-11pwm: meson: Fix axg ao mux parentsHeiner Kallweit
commit eb411c0cf59ae6344b34bc6f0d298a22b300627e upstream. This fix is basically the same as 9bce02ef0dfa ("pwm: meson: Fix the G12A AO clock parents order"). Vendor driver referenced there has xtal as first parent also for axg ao. In addition fix the name of the aoclk81 clock. Apparently name aoclk81 as used by the vendor driver was changed when mainlining the axg clock driver. Fixes: bccaa3f917c9 ("pwm: meson: Add clock source configuration for Meson-AXG") Cc: stable@vger.kernel.org Signed-off-by: Heiner Kallweit <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>
2023-04-13pwm: meson: Explicitly set .polarity in .get_state()Uwe Kleine-König
[ Upstream commit 8caa81eb950cb2e9d2d6959b37d853162d197f57 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13pwm: sprd: Explicitly set .polarity in .get_state()Uwe Kleine-König
[ Upstream commit 2be4dcf6627e1bcbbef8e6ba1811f5127d39202c ] The driver only supports normal polarity. Complete the implementation of .get_state() by setting .polarity accordingly. Fixes: 8aae4b02e8a6 ("pwm: sprd: Add Spreadtrum PWM support") Link: https://lore.kernel.org/r/20230228135508.1798428-5-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13pwm: iqs620a: Explicitly set .polarity in .get_state()Uwe Kleine-König
[ Upstream commit b20b097128d9145fadcea1cbb45c4d186cb57466 ] The driver only supports normal polarity. Complete the implementation of .get_state() by setting .polarity accordingly. Fixes: 6f0841a8197b ("pwm: Add support for Azoteq IQS620A PWM generator") Reviewed-by: Jeff LaBundy <jeff@labundy.com> Link: https://lore.kernel.org/r/20230228135508.1798428-4-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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13pwm: cros-ec: Explicitly set .polarity in .get_state()Uwe Kleine-König
[ Upstream commit 30006b77c7e130e01d1ab2148cc8abf73dfcc4bf ] The driver only supports normal polarity. Complete the implementation of .get_state() by setting .polarity accordingly. Reviewed-by: Guenter Roeck <groeck@chromium.org> Fixes: 1f0d3bb02785 ("pwm: Add ChromeOS EC PWM driver") Link: https://lore.kernel.org/r/20230228135508.1798428-3-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13pwm: hibvt: Explicitly set .polarity in .get_state()Uwe Kleine-König
[ Upstream commit 6f57937980142715e927697a6ffd2050f38ed6f6 ] The driver only both polarities. Complete the implementation of .get_state() by setting .polarity according to the configured hardware state. Fixes: d09f00810850 ("pwm: Add PWM driver for HiSilicon BVT SOCs") Link: https://lore.kernel.org/r/20230228135508.1798428-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13pwm: Make .get_state() callback return an error codeUwe Kleine-König
[ Upstream commit 6c452cff79f8bf1c0146fda598d32061cfd25443 ] .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> Stable-dep-of: 6f5793798014 ("pwm: hibvt: Explicitly set .polarity in .get_state()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-11pwm: stm32-lp: fix the check on arr and cmp registers updateFabrice Gasnier
[ Upstream commit 3066bc2d58be31275afb51a589668f265e419c37 ] 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: e70a540b4e02 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-11pwm: sifive: Always let the first pwm_apply_state succeedEmil Renner Berthing
[ Upstream commit 334c7b13d38321e47d1a51dba0bef9f4c403ec75 ] Commit 2cfe9bbec56ea579135cdd92409fff371841904f 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: 9e37a53eb051 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
generated by cgit v1.2.3 (git 2.0.4) at 2025-08-05 19:53:09 +0000