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path: root/drivers/pwm/pwm-stm32.c
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2018-06-14Merge tag 'pwm/for-4.18-rc1' of ↵Linus Torvalds
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 Bergmann
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 Gasnier
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 Gasnier
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 Gasnier
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 Gasnier
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 Gasnier
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 Gasnier
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 Gaignard
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 Gaignard
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>