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path: root/drivers/pwm/pwm-stm32.c
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2020-01-20pwm: stm32: Remove automatic output enableFabrice Gasnier1-3/+1
Don't use AOE (automatic output enable) by default. In case of break events, PWM is automatically re-enabled on next PWM cycle otherwise. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-10-21pwm: stm32: Pass breakinput instead of its valuesThierry Reding1-11/+8
Instead of passing the individual values of the breakpoint, pass a pointer to the breakpoint. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-10-21pwm: stm32: Remove clutter from ternary operatorThierry Reding1-12/+9
Remove usage of the ternary operator to assign values for register fields. Instead, parameterize the register and field offset macros and pass the index to them. This removes clutter and improves readability. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-10-21pwm: stm32: Validate breakinput data from DTThierry Reding1-0/+8
Both index and level can only be either 0 or 1 and the filter value is limited to values between (and including) 0 and 15. Validate that the device tree node contains values that are within these ranges. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-10-21pwm: stm32: Add power management supportFabrice Gasnier1-0/+38
Add suspend/resume PM sleep ops. When going to low power, enforce the PWM channel isn't active. Let the PWM consumers disable it during their own suspend sequence, see [1]. So, perform a check here, and handle the pinctrl states. Also restore the break inputs upon resume, as registers content may be lost when going to low power mode. [1] https://lkml.org/lkml/2019/2/5/770 Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-10-21pwm: stm32: Split breakinput apply routine to ease PM supportFabrice Gasnier1-19/+31
Split breakinput routine that configures STM32 timers 'break' safety feature upon probe, into two routines: - stm32_pwm_apply_breakinputs() sets all the break inputs into registers. - stm32_pwm_probe_breakinputs() probes the device tree break input settings before calling stm32_pwm_apply_breakinputs() This is a precursor patch to ease PM support. Registers content may get lost during low power. So, break input settings applied upon probe need to be restored upon resume (e.g. by calling stm32_pwm_apply_breakinputs()). Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21pwm: Ensure pwm_apply_state() doesn't modify the state argumentUwe Kleine-König1-2/+2
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>
2019-06-25pwm: stm32: Use 3 cells ->of_xlate()Fabrice Gasnier1-0/+2
STM32 Timers support generic 3 cells PWM to encode PWM number, period and polarity. Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-06-14Merge tag 'pwm/for-4.18-rc1' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm Pull pwm updates from Thierry Reding: "This contains a couple of fixes and cleanups for the Meson and ACPI/LPSS drivers as well as capture support for STM32. Note that given the cross- subsystem changes, the STM32 patches were merged through the MFD and PWM trees, both sharing an immutable branch" * tag 'pwm/for-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: pwm: stm32: Fix build warning with CONFIG_DMA_ENGINE disabled pwm: stm32: Enforce dependency on CONFIG_MFD_STM32_TIMERS ACPI / LPSS: Add missing prv_offset setting for byt/cht PWM devices pwm: lpss: platform: Save/restore the ctrl register over a suspend/resume dt-bindings: mfd: stm32-timers: Add support for dmas pwm: simplify getting .drvdata pwm: meson: Fix allocation of PWM channel array
2018-06-06pwm: stm32: Fix build warning with CONFIG_DMA_ENGINE disabledArnd Bergmann1-3/+1
Without dmaengine support, we get a harmless warning about an unused function: drivers/pwm/pwm-stm32.c:166:12: error: 'stm32_pwm_capture' defined but not used [-Werror=unused-function] Changing the #ifdef to an IS_ENABLED() check shuts up that warning and is slightly nicer to read. Fixes: 53e38fe73f94 ("pwm: stm32: Add capture support") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-06-04pwm: stm32: Initialize raw local variablesFabrice Gasnier1-1/+1
This removes build warning when COMPILE_TEST=y and MFD_STM32_TIMERS=n in drivers/pwm/pwm-stm32.c. In function 'stm32_pwm_capture' 'raw_prd' and 'raw_dty' may be used uninitialized in this function [-Wmaybe-uninitialized] Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Acked-by: Thierry Reding <thierry.reding@gmail.com> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2018-05-16pwm: stm32: Use input prescaler to improve period captureFabrice Gasnier1-2/+61
Using input prescaler, capture unit will trigger DMA once every configurable /2, /4 or /8 events (rising edge). This helps improve period (only) capture accuracy at high rates. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2018-05-16pwm: stm32: Improve capture by tuning counter prescalerFabrice Gasnier1-1/+23
Currently, capture is based on timeout window to configure prescaler. PWM capture framework provides 1s window at the time of writing. There's place for improvement, after input signal has been captured once: - Finer tune counter clock prescaler, by using 1st capture result (with arbitrary margin). - Do a 2nd capture, with scaled capture window. This increases accuracy, especially at high rates. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2018-05-16pwm: stm32: Add capture supportFabrice Gasnier1-0/+176
Add support for PMW input mode on pwm-stm32. STM32 timers support period and duty cycle capture as long as they have at least two PWM channels. One capture channel is used for period (rising-edge), one for duty-cycle (falling-edge). When there's only one channel available, only period can be captured. Duty-cycle is simply zero'ed in such a case. Capture requires exclusive access (e.g. no pwm output running at the same time, to protect common prescaler). Timer DMA burst mode (from MFD core) is being used, to take two snapshots of capture registers (upon each period rising edge). Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2018-03-28pwm: stm32: Protect common prescaler for all channelsFabrice Gasnier1-1/+17
There may be a race, when configuring two PWM channels, with different prescaler values, when there's no active channel yet. Add mutex lock to avoid concurrent access on PWM apply state. This is also precursor patch for PWM capture support. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-03-28pwm: stm32: Remove unused struct deviceFabrice Gasnier1-1/+0
dev is never assigned or used. Remove it. Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-03-27pwm: stm32: Adopt SPDX identifierBenjamin Gaignard1-2/+1
Add SPDX identifier to make it easier to determine the license of the file. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> Acked-by: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-25pwm: Add driver for STM32 plaftormBenjamin Gaignard1-0/+397
This driver adds support for PWM driver on STM32 platform. The SoC have multiple instances of the hardware IP and each of them could have small differences: number of channels, complementary output, auto reload register size... version 9: - fix commit message header - remove one space MODULE_ALIAS version 8: - fix comments done by Thierry on version 7 version 6: - change st,breakinput parameter to make it usuable for stm32f7 too. version 4: - detect at probe time hardware capabilities - fix comments done on v2 and v3 - use PWM atomic ops version 2: - only keep one comptatible - use DT parameters to discover hardware block configuration Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
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