From: Uwe Kleine-König Date: Sat, 24 Aug 2019 15:37:07 +0000 (+0200) Subject: pwm: Ensure pwm_apply_state() doesn't modify the state argument X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=71523d1812aca61e32e742e87ec064e3d8c615e1;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: Thierry Reding --- diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c index 869d47f89599..6c0687694341 100644 --- a/drivers/gpio/gpio-mvebu.c +++ b/drivers/gpio/gpio-mvebu.c @@ -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; diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 449ba161877d..6ad51aa60c03 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -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; diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c index d13a83f430ac..dcbc0489dfd4 100644 --- a/drivers/pwm/pwm-atmel-hlcdc.c +++ b/drivers/pwm/pwm-atmel-hlcdc.c @@ -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; diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c index e5e1eaf372fa..53bc7b9b3581 100644 --- a/drivers/pwm/pwm-atmel.c +++ b/drivers/pwm/pwm-atmel.c @@ -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; diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c index d961a8207b1c..56c38cfae92c 100644 --- a/drivers/pwm/pwm-bcm-iproc.c +++ b/drivers/pwm/pwm-bcm-iproc.c @@ -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); diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c index 98f6ac6cf6ab..db5faa79c33f 100644 --- a/drivers/pwm/pwm-cros-ec.c +++ b/drivers/pwm/pwm-cros-ec.c @@ -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; 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; diff --git a/drivers/pwm/pwm-hibvt.c b/drivers/pwm/pwm-hibvt.c index 753bd58111e4..ad205fdad372 100644 --- a/drivers/pwm/pwm-hibvt.c +++ b/drivers/pwm/pwm-hibvt.c @@ -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); diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c index e8385c1cf342..9145f6160649 100644 --- a/drivers/pwm/pwm-imx-tpm.c +++ b/drivers/pwm/pwm-imx-tpm.c @@ -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; diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c index 91c23cbbc167..ae11d8577f18 100644 --- a/drivers/pwm/pwm-imx27.c +++ b/drivers/pwm/pwm-imx27.c @@ -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); diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c index 9d444d012f92..9d78cc21cb12 100644 --- a/drivers/pwm/pwm-jz4740.c +++ b/drivers/pwm/pwm-jz4740.c @@ -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; diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c index 4098a4601691..75bbfe5f3bc2 100644 --- a/drivers/pwm/pwm-lpss.c +++ b/drivers/pwm/pwm-lpss.c @@ -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; diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c index 3cbff5cbb789..6245bbdb6e6c 100644 --- a/drivers/pwm/pwm-meson.c +++ b/drivers/pwm/pwm-meson.c @@ -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); diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c index c8cd43f91efc..852eb2347954 100644 --- a/drivers/pwm/pwm-rcar.c +++ b/drivers/pwm/pwm-rcar.c @@ -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; diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c index 83c7627868d8..73352e6fbccb 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -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; diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index bb4f02ce4f94..cc63f9baa481 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -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; 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); 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; diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c index 740e2dec8313..359b08596d9e 100644 --- a/drivers/pwm/pwm-stm32.c +++ b/drivers/pwm/pwm-stm32.c @@ -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; diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c index 39007a7c0d83..6f5840a1a82d 100644 --- a/drivers/pwm/pwm-sun4i.c +++ b/drivers/pwm/pwm-sun4i.c @@ -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; diff --git a/drivers/pwm/pwm-zx.c b/drivers/pwm/pwm-zx.c index e24f4be35316..e2c21cc34a96 100644 --- a/drivers/pwm/pwm-zx.c +++ b/drivers/pwm/pwm-zx.c @@ -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; diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 24632a7a7d11..b2c9c460947d 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -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); /**