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>
---
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,
};
--
2.25.1
