@@ -58,6 +58,7 @@ struct sti_pwm_chip {
struct regmap_field *pwm_int_en;
unsigned long *pwm_periods;
struct pwm_chip chip;
+ struct pwm_device *cur;
void __iomem *mmio;
};
@@ -99,6 +100,24 @@ static void sti_pwm_calc_periods(struct sti_pwm_chip *pc)
}
}
+/* Calculate the number of PWM devices configured with a period. */
+unsigned int sti_pwm_count_configured(struct pwm_chip *chip)
+{
+ struct pwm_device *pwm;
+ unsigned int ncfg = 0;
+ unsigned int i;
+
+ for (i = 0; i < chip->npwm; i++) {
+ pwm = &chip->pwms[i];
+ if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
+ if (pwm_get_period(pwm))
+ ncfg++;
+ }
+ }
+
+ return ncfg;
+}
+
static int sti_pwm_cmp_periods(const void *key, const void *elt)
{
unsigned long i = *(unsigned long *)key;
@@ -124,57 +143,90 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
{
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
struct sti_pwm_compat_data *cdata = pc->cdata;
+ struct pwm_device *cur = pc->cur;
struct device *dev = pc->dev;
- unsigned int prescale, pwmvalx;
+ unsigned int prescale = 0, pwmvalx;
unsigned long *found;
int ret;
-
- /*
- * Search for matching period value. The corresponding index is our
- * prescale value
+ unsigned int ncfg;
+ bool period_same = false;
+
+ ncfg = sti_pwm_count_configured(chip);
+ if (ncfg)
+ period_same = (period_ns == pwm_get_period(cur));
+
+ /* Allow configuration changes if one of the
+ * following conditions satisfy.
+ * 1. No channels have been configured.
+ * 2. Only one channel has been configured and the new request
+ * is for the same channel.
+ * 3. Only one channel has been configured and the new request is
+ * for a new channel and period of the new channel is same as
+ * the current configured period.
+ * 4. More than one channels are configured and period of the new
+ * requestis the same as the current period.
*/
- found = bsearch(&period_ns, &pc->pwm_periods[0],
- cdata->max_prescale + 1, sizeof(unsigned long),
- sti_pwm_cmp_periods);
- if (!found) {
- dev_err(dev, "failed to find matching period\n");
+ if (!ncfg ||
+ ((ncfg == 1) && (pwm->hwpwm == cur->hwpwm)) ||
+ ((ncfg == 1) && (pwm->hwpwm != cur->hwpwm) && period_same) ||
+ ((ncfg > 1) && period_same)) {
+ /* Enable clock before writing to PWM registers. */
+ ret = clk_enable(pc->clk);
+ if (ret)
+ return ret;
+
+ if (!period_same) {
+ /*
+ * Search for matching period value.
+ * The corresponding index is our prescale value.
+ */
+ found = bsearch(&period_ns, &pc->pwm_periods[0],
+ cdata->max_prescale + 1,
+ sizeof(unsigned long),
+ sti_pwm_cmp_periods);
+ if (!found) {
+ dev_err(dev,
+ "failed to find matching period\n");
+ ret = -EINVAL;
+ goto clk_dis;
+ }
+ prescale = found - &pc->pwm_periods[0];
+
+ ret =
+ regmap_field_write(pc->prescale_low,
+ prescale & PWM_PRESCALE_LOW_MASK);
+ if (ret)
+ goto clk_dis;
+
+ ret =
+ regmap_field_write(pc->prescale_high,
+ (prescale & PWM_PRESCALE_HIGH_MASK) >> 4);
+ if (ret)
+ goto clk_dis;
+ }
+
+ /*
+ * When PWMVal == 0, PWM pulse = 1 local clock cycle.
+ * When PWMVal == max_pwm_count,
+ * PWM pulse = (max_pwm_count + 1) local cycles,
+ * that is continuous pulse: signal never goes low.
+ */
+ pwmvalx = cdata->max_pwm_cnt * duty_ns / period_ns;
+
+ ret = regmap_write(pc->regmap, STI_DS_REG(pwm->hwpwm), pwmvalx);
+ if (ret)
+ goto clk_dis;
+
+ ret = regmap_field_write(pc->pwm_int_en, 0);
+
+ pc->cur = pwm;
+
+ dev_dbg(dev, "prescale:%u, period:%lu, duty:%i, pwmvalx:%u\n",
+ prescale, period_ns, duty_ns, pwmvalx);
+ } else {
return -EINVAL;
}
- prescale = found - &pc->pwm_periods[0];
-
- /*
- * When PWMVal == 0, PWM pulse = 1 local clock cycle.
- * When PWMVal == max_pwm_count,
- * PWM pulse = (max_pwm_count + 1) local cycles,
- * that is continuous pulse: signal never goes low.
- */
- pwmvalx = cdata->max_pwm_cnt * duty_ns / period_ns;
-
- dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n",
- prescale, period_ns, duty_ns, pwmvalx);
-
- /* Enable clock before writing to PWM registers */
- ret = clk_enable(pc->clk);
- if (ret)
- return ret;
-
- ret = regmap_field_write(pc->prescale_low,
- prescale & PWM_PRESCALE_LOW_MASK);
- if (ret)
- goto clk_dis;
-
- ret = regmap_field_write(pc->prescale_high,
- (prescale & PWM_PRESCALE_HIGH_MASK) >> 4);
- if (ret)
- goto clk_dis;
-
- ret = regmap_write(pc->regmap, STI_PWMVAL(pwm->hwpwm), pwmvalx);
- if (ret)
- goto clk_dis;
-
- ret = regmap_field_write(pc->pwm_int_en, 0);
-
clk_dis:
clk_disable(pc->clk);
return ret;