Introduce newer .apply function in pwm_ops to replace legacy operations including enable, disable, config and set_polarity.
This guarantees atomic changes of the pwm controller configuration.
Signed-off-by: Song Chen chensong_2000@189.cn
--- v2: 1, define duty_cycle and period as u64 in gb_pwm_config_operation. 2, define duty and period as u64 in gb_pwm_config_request. 3, disable before configuring duty and period if the eventual goal is a disabled state.
v3: Regarding duty_cycle and period, I read more discussion in this thread, min, warn or -EINVAL, seems no perfect way acceptable for everyone. How about we limit their value to INT_MAX and throw a warning at the same time when they are wrong?
v4: 1, explain why legacy operations are replaced. 2, cap the value of period and duty to U32_MAX.
v5: 1, revise commit message.
v6: 1, revise commit message. 2, explain why capping the value of period and duty to U32_MAX in comment. --- drivers/staging/greybus/pwm.c | 64 ++++++++++++++++++++++------------- 1 file changed, 40 insertions(+), 24 deletions(-)
diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c index 891a6a672378..ad20ec24031e 100644 --- a/drivers/staging/greybus/pwm.c +++ b/drivers/staging/greybus/pwm.c @@ -204,43 +204,59 @@ static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) gb_pwm_deactivate_operation(pwmc, pwm->hwpwm); }
-static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, - int duty_ns, int period_ns) +static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) { + int err; + bool enabled = pwm->state.enabled; + u64 period = state->period; + u64 duty_cycle = state->duty_cycle; struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
- return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns); -}; + /* Set polarity */ + if (state->polarity != pwm->state.polarity) { + if (enabled) { + gb_pwm_disable_operation(pwmc, pwm->hwpwm); + enabled = false; + } + err = gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, state->polarity); + if (err) + return err; + }
-static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, - enum pwm_polarity polarity) -{ - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); + if (!state->enabled) { + if (enabled) + gb_pwm_disable_operation(pwmc, pwm->hwpwm); + return 0; + }
- return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity); -}; + /* + * Set period and duty cycle + * + * PWM privodes 64-bit period and duty_cycle, but greybus only accepts + * 32-bit, so their values have to be limited to U32_MAX. + */ + if (period > U32_MAX) + period = U32_MAX;
-static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); + if (duty_cycle > period) + duty_cycle = period;
- return gb_pwm_enable_operation(pwmc, pwm->hwpwm); -}; + err = gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_cycle, period); + if (err) + return err;
-static void gb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); + /* enable/disable */ + if (!enabled) + return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
- gb_pwm_disable_operation(pwmc, pwm->hwpwm); -}; + return 0; +}
static const struct pwm_ops gb_pwm_ops = { .request = gb_pwm_request, .free = gb_pwm_free, - .config = gb_pwm_config, - .set_polarity = gb_pwm_set_polarity, - .enable = gb_pwm_enable, - .disable = gb_pwm_disable, + .apply = gb_pwm_apply, .owner = THIS_MODULE, };