hi Alex, On 2022/3/18 下午8:15, Alex Elder wrote:
On 3/18/22 4:57 AM, Song Chen wrote: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@xxxxxx>I had another comment suggestion but you've been through enough. Thanks for working this to completion.
sorry about that, i probably missed it somehow. Thanks for the understanding.
Song
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>--- 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.cindex 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, };
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