Commit 71523d18 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Thierry Reding
Browse files

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: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent c9675829

drivers/gpio/gpio-mvebu.c

+1 −1
Original line number Diff line number Diff line
@@ -694,7 +694,7 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip, 
}



static int mvebu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,

			   struct pwm_state *state)

			   const struct pwm_state *state)

{

	struct mvebu_pwm *mvpwm = to_mvebu_pwm(chip);

	struct mvebu_gpio_chip *mvchip = mvpwm->mvchip;

drivers/pwm/core.c

+2 −4
Original line number Diff line number Diff line
@@ -448,11 +448,9 @@ EXPORT_SYMBOL_GPL(pwm_free); 
/**

 * pwm_apply_state() - atomically apply a new state to a PWM device

 * @pwm: PWM device

 * @state: new state to apply. This can be adjusted by the PWM driver

 *	   if the requested config is not achievable, for example,

 *	   ->duty_cycle and ->period might be approximated.

 * @state: new state to apply

 */

int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)

int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)

{

	struct pwm_chip *chip;

	int err;

drivers/pwm/pwm-atmel-hlcdc.c

+1 −1
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip) 
}



static int atmel_hlcdc_pwm_apply(struct pwm_chip *c, struct pwm_device *pwm,

				 struct pwm_state *state)

				 const struct pwm_state *state)

{

	struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);

	struct atmel_hlcdc *hlcdc = chip->hlcdc;

drivers/pwm/pwm-atmel.c

+1 −1
Original line number Diff line number Diff line
@@ -209,7 +209,7 @@ static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm, 
}



static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,

			   struct pwm_state *state)

			   const struct pwm_state *state)

{

	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);

	struct pwm_state cstate;

drivers/pwm/pwm-bcm-iproc.c

+1 −1
Original line number Diff line number Diff line
@@ -115,7 +115,7 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm, 
}



static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,

			    struct pwm_state *state)

			    const struct pwm_state *state)

{

	unsigned long prescale = IPROC_PWM_PRESCALE_MIN;

	struct iproc_pwmc *ip = to_iproc_pwmc(chip);

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