From 71523d1812aca61e32e742e87ec064e3d8c615e1 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Sat, 24 Aug 2019 17:37:07 +0200 Subject: pwm: Ensure pwm_apply_state() doesn't modify the state argument MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Thierry Reding --- drivers/pwm/pwm-sprd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pwm/pwm-sprd.c') diff --git a/drivers/pwm/pwm-sprd.c b/drivers/pwm/pwm-sprd.c index 68c2d9f0411b..be2394227423 100644 --- a/drivers/pwm/pwm-sprd.c +++ b/drivers/pwm/pwm-sprd.c @@ -156,7 +156,7 @@ static int sprd_pwm_config(struct sprd_pwm_chip *spc, struct pwm_device *pwm, } static int sprd_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, - struct pwm_state *state) + const struct pwm_state *state) { struct sprd_pwm_chip *spc = container_of(chip, struct sprd_pwm_chip, chip); -- cgit v1.2.3