staging: greybus: introduce pwm_ops::apply

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.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Song Chen <chensong_2000@189.cn>
Link: https://lore.kernel.org/r/1647597432-27586-1-git-send-email-chensong_2000@189.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
index 891a6a6..ad20ec2 100644 (file)
--- 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,
 };