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pwm: Ensure pwm_apply_state() doesn't modify the state argument

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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/gpio/gpio-mvebu.c
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;

6
drivers/pwm/core.c
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;

2
drivers/pwm/pwm-atmel-hlcdc.c
View File

@ -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;

2
drivers/pwm/pwm-atmel.c
View File

@ -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;

2
drivers/pwm/pwm-bcm-iproc.c
View File

@ -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);

2
drivers/pwm/pwm-cros-ec.c
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;

4
drivers/pwm/pwm-fsl-ftm.c
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;

2
drivers/pwm/pwm-hibvt.c
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);

4
drivers/pwm/pwm-imx-tpm.c
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;

2
drivers/pwm/pwm-imx27.c
View File

@ -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);

2
drivers/pwm/pwm-jz4740.c
View File

@ -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;

2
drivers/pwm/pwm-lpss.c
View File

@ -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;

4
drivers/pwm/pwm-meson.c
View File

@ -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);

2
drivers/pwm/pwm-rcar.c
View File

@ -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;

4
drivers/pwm/pwm-rockchip.c
View File

@ -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;

2
drivers/pwm/pwm-sifive.c
View File

@ -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;

2
drivers/pwm/pwm-sprd.c
View File

@ -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);

2
drivers/pwm/pwm-stm32-lp.c
View File

@ -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;

4
drivers/pwm/pwm-stm32.c
View File

@ -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;

4
drivers/pwm/pwm-sun4i.c
View File

@ -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;

2
drivers/pwm/pwm-zx.c
View File

@ -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;

4
include/linux/pwm.h
View File

@ -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);
/**