Commit graph

6 commits

Author SHA1 Message Date
Fabrice Gasnier
6534865953 pwm: stm32-lp: Add check in case requested period cannot be achieved
[ Upstream commit c91e3234c6035baf5a79763cb4fcd5d23ce75c2b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-11 18:21:17 +02:00
Fabrice Gasnier
2c2059c0b8 pwm: stm32-lp: Remove useless loop in stm32_pwm_lp_remove()
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>
2018-08-20 11:32:25 +02:00
Gerald Baeza
f6ea025f6e pwm: stm32: LPTimer: Use 3 cells ->of_xlate()
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>
2018-03-28 00:54:56 +02:00
Benjamin Gaignard
d7a131d3a4 pwm: stm32: Adopt SPDX identifier
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>
2018-03-27 23:22:31 +02:00
Axel Lin
f83e2ae260 pwm: stm32-lp: Remove pwm_is_enabled() check before calling pwm_disable()
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>
2017-11-15 11:02:06 +01:00
Fabrice Gasnier
e70a540b4e pwm: Add STM32 LPTimer PWM driver
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>
2017-09-04 14:49:09 +01:00