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path: root/drivers/pwm/pwm-stm32-lp.c
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* pwm: stm32-lp: Add check in case requested period cannot be achievedFabrice Gasnier2019-09-211-0/+6
| | | | | | | | | | | | | | | LPTimer can use a 32KHz clock for counting. It depends on clock tree configuration. In such a case, PWM output frequency range is limited. Although unlikely, nothing prevents user from requesting a PWM frequency above counting clock (32KHz for instance): - This causes (prd - 1) = 0xffff to be written in ARR register later in the apply() routine. This results in badly configured PWM period (and also duty_cycle). Add a check to report an error is such a case. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Ensure pwm_apply_state() doesn't modify the state argumentUwe Kleine-König2019-09-211-1/+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>
* pwm: stm32-lp: Add power management supportFabrice Gasnier2019-06-251-0/+25
| | | | | | | | | | | 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. Only perform a check here, and handle the pinctrl states. See [1]. [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>
* pwm: stm32-lp: Remove useless loop in stm32_pwm_lp_remove()Fabrice Gasnier2018-08-201-3/+1
| | | | | | | | LPTimer has only one pwm channel (npwm = 1). Remove useless for loop in remove routine. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: stm32: LPTimer: Use 3 cells ->of_xlate()Gerald Baeza2018-03-281-0/+2
| | | | | | | | | STM32 Low-Power Timer supports generic 3 cells PWM to encode PWM number, period and polarity. Signed-off-by: Gerald Baeza <gerald.baeza@st.com> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: stm32: Adopt SPDX identifierBenjamin Gaignard2018-03-271-2/+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>
* pwm: stm32-lp: Remove pwm_is_enabled() check before calling pwm_disable()Axel Lin2017-11-151-2/+1
| | | | | | | | The same checking is done by the implementation of pwm_disable(). Signed-off-by: Axel Lin <axel.lin@ingics.com> Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Add STM32 LPTimer PWM driverFabrice Gasnier2017-09-041-0/+246
Add support for single PWM channel on Low-Power Timer, that can be found on some STM32 platforms. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>