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>
This commit is contained in:
Uwe Kleine-König 2019-08-24 17:37:07 +02:00 committed by Thierry Reding
parent c9675829ba
commit 71523d1812
22 changed files with 30 additions and 32 deletions

View File

@ -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;

View File

@ -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;

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@ -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;

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@ -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;

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@ -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);

View File

@ -93,7 +93,7 @@ static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
}
static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
int duty_cycle;

View File

@ -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;

View File

@ -149,7 +149,7 @@ static void hibvt_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
}
static int hibvt_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);

View File

@ -89,7 +89,7 @@ to_imx_tpm_pwm_chip(struct pwm_chip *chip)
static int pwm_imx_tpm_round_state(struct pwm_chip *chip,
struct imx_tpm_pwm_param *p,
struct pwm_state *real_state,
struct pwm_state *state)
const struct pwm_state *state)
{
struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
u32 rate, prescale, period_count, clock_unit;
@ -289,7 +289,7 @@ static int pwm_imx_tpm_apply_hw(struct pwm_chip *chip,
static int pwm_imx_tpm_apply(struct pwm_chip *chip,
struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
struct imx_tpm_pwm_param param;

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@ -209,7 +209,7 @@ static void pwm_imx27_wait_fifo_slot(struct pwm_chip *chip,
}
static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
unsigned long period_cycles, duty_cycles, prescale;
struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);

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@ -88,7 +88,7 @@ static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
}
static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
unsigned long long tmp;

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@ -122,7 +122,7 @@ static inline void pwm_lpss_cond_enable(struct pwm_device *pwm, bool cond)
}
static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
int ret;

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@ -159,7 +159,7 @@ static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
}
static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
unsigned int duty, period, pre_div, cnt, duty_cnt;
@ -265,7 +265,7 @@ static void meson_pwm_disable(struct meson_pwm *meson, struct pwm_device *pwm)
}
static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
struct meson_pwm *meson = to_meson_pwm(chip);

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@ -158,7 +158,7 @@ static void rcar_pwm_disable(struct rcar_pwm_chip *rp)
}
static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
struct pwm_state cur_state;

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@ -99,7 +99,7 @@ static void rockchip_pwm_get_state(struct pwm_chip *chip,
}
static void rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
unsigned long period, duty;
@ -183,7 +183,7 @@ static int rockchip_pwm_enable(struct pwm_chip *chip,
}
static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
struct pwm_state curstate;

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@ -147,7 +147,7 @@ static int pwm_sifive_enable(struct pwm_chip *chip, bool enable)
}
static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
struct pwm_state cur_state;

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@ -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);

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@ -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;

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@ -440,7 +440,7 @@ static void stm32_pwm_disable(struct stm32_pwm *priv, int ch)
}
static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
bool enabled;
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
@ -468,7 +468,7 @@ static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
}
static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
int ret;

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@ -145,7 +145,7 @@ static void sun4i_pwm_get_state(struct pwm_chip *chip,
}
static int sun4i_pwm_calculate(struct sun4i_pwm_chip *sun4i_pwm,
struct pwm_state *state,
const struct pwm_state *state,
u32 *dty, u32 *prd, unsigned int *prsclr)
{
u64 clk_rate, div = 0;
@ -196,7 +196,7 @@ static int sun4i_pwm_calculate(struct sun4i_pwm_chip *sun4i_pwm,
}
static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
struct pwm_state cstate;

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@ -148,7 +148,7 @@ static int zx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
}
static int zx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
const struct pwm_state *state)
{
struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip);
struct pwm_state cstate;

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@ -262,7 +262,7 @@ struct pwm_ops {
int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_capture *result, unsigned long timeout);
int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state);
const struct pwm_state *state);
void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state);
struct module *owner;
@ -316,7 +316,7 @@ struct pwm_capture {
/* PWM user APIs */
struct pwm_device *pwm_request(int pwm_id, const char *label);
void pwm_free(struct pwm_device *pwm);
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);
int pwm_adjust_config(struct pwm_device *pwm);
/**