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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2019-08-24 17:37:07 +0200
committerThierry Reding <thierry.reding@gmail.com>2019-09-21 03:25:10 +0200
commit71523d1812aca61e32e742e87ec064e3d8c615e1 (patch)
tree20491f0323c9b71d0628741824c4dcf992e22363 /drivers/pwm/pwm-stm32-lp.c
parentc9675829ba4b0e95c613f6d6d83d2b5cb9c5371c (diff)
pwm: Ensure pwm_apply_state() doesn't modify the state argument
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>
Diffstat (limited to 'drivers/pwm/pwm-stm32-lp.c')
-rw-r--r--drivers/pwm/pwm-stm32-lp.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c
index 2211a642066d..21cb260dc2c0 100644
--- a/drivers/pwm/pwm-stm32-lp.c
+++ b/drivers/pwm/pwm-stm32-lp.c
@@ -32,7 +32,7 @@ static inline struct stm32_pwm_lp *to_stm32_pwm_lp(struct pwm_chip *chip)
#define STM32_LPTIM_MAX_PRESCALER 128
static int stm32_pwm_lp_apply(struct pwm_chip *chip, struct pwm_device *pwm,
- struct pwm_state *state)
+ const struct pwm_state *state)
{
struct stm32_pwm_lp *priv = to_stm32_pwm_lp(chip);
unsigned long long prd, div, dty;