pwm: vt8500: Implement .apply() callback

To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply(). This just pushes down a slightly
optimized variant of how legacy drivers are handled in the core.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
index 480bfc2..7170a31 100644 (file)
--- a/drivers/pwm/pwm-vt8500.c
+++ b/drivers/pwm/pwm-vt8500.c
@@ -70,7 +70,7 @@ static inline void vt8500_pwm_busy_wait(struct vt8500_chip *vt8500, int nr, u8 b
 }
 
 static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-               int duty_ns, int period_ns)
+               u64 duty_ns, u64 period_ns)
 {
        struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
        unsigned long long c;
@@ -102,8 +102,8 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
        }
 
        c = (unsigned long long)pv * duty_ns;
-       do_div(c, period_ns);
-       dc = c;
+
+       dc = div64_u64(c, period_ns);
 
        writel(prescale, vt8500->base + REG_SCALAR(pwm->hwpwm));
        vt8500_pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_SCALAR_UPDATE);
@@ -176,11 +176,54 @@ static int vt8500_pwm_set_polarity(struct pwm_chip *chip,
        return 0;
 }
 
+static int vt8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+                           const struct pwm_state *state)
+{
+       int err;
+       bool enabled = pwm->state.enabled;
+
+       if (state->polarity != pwm->state.polarity) {
+               /*
+                * Changing the polarity of a running PWM is only allowed when
+                * the PWM driver implements ->apply().
+                */
+               if (enabled) {
+                       vt8500_pwm_disable(chip, pwm);
+
+                       enabled = false;
+               }
+
+               err = vt8500_pwm_set_polarity(chip, pwm, state->polarity);
+               if (err)
+                       return err;
+       }
+
+       if (!state->enabled) {
+               if (enabled)
+                       vt8500_pwm_disable(chip, pwm);
+
+               return 0;
+       }
+
+       /*
+        * We cannot skip calling ->config even if state->period ==
+        * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
+        * because we might have exited early in the last call to
+        * pwm_apply_state because of !state->enabled and so the two values in
+        * pwm->state might not be configured in hardware.
+        */
+       err = vt8500_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+       if (err)
+               return err;
+
+       if (!enabled)
+               err = vt8500_pwm_enable(chip, pwm);
+
+       return err;
+}
+
 static const struct pwm_ops vt8500_pwm_ops = {
-       .enable = vt8500_pwm_enable,
-       .disable = vt8500_pwm_disable,
-       .config = vt8500_pwm_config,
-       .set_polarity = vt8500_pwm_set_polarity,
+       .apply = vt8500_pwm_apply,
        .owner = THIS_MODULE,
 };