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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-fsl-ftm.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-fsl-ftm.c')
-rw-r--r--drivers/pwm/pwm-fsl-ftm.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c
index 3c9738617ceb..59272a920479 100644
--- a/drivers/pwm/pwm-fsl-ftm.c
+++ b/drivers/pwm/pwm-fsl-ftm.c
@@ -227,7 +227,7 @@ static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
struct pwm_device *pwm,
- struct pwm_state *newstate)
+ const struct pwm_state *newstate)
{
unsigned int duty;
u32 reg_polarity;
@@ -298,7 +298,7 @@ static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
}
static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
- struct pwm_state *newstate)
+ const struct pwm_state *newstate)
{
struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
struct pwm_state *oldstate = &pwm->state;