pwm: atmel-hlcdc: Implement the suspend/resume hooks

Implement the suspend/resume hooks to make sure the PWM device is
restored to a correct state after a suspend.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-atmel-hlcdc.c

@@ -191,6 +191,40 @@ static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = {
 	.div1_clk_erratum = true,
 };
 
+#ifdef CONFIG_PM_SLEEP
+static int atmel_hlcdc_pwm_suspend(struct device *dev)
+{
+	struct atmel_hlcdc_pwm *chip = dev_get_drvdata(dev);
+
+	/* Keep the periph clock enabled if the PWM is still running. */
+	if (pwm_is_enabled(&chip->chip.pwms[0]))
+		clk_disable_unprepare(chip->hlcdc->periph_clk);
+
+	return 0;
+}
+
+static int atmel_hlcdc_pwm_resume(struct device *dev)
+{
+	struct atmel_hlcdc_pwm *chip = dev_get_drvdata(dev);
+	struct pwm_state state;
+	int ret;
+
+	pwm_get_state(&chip->chip.pwms[0], &state);
+
+	/* Re-enable the periph clock it was stopped during suspend. */
+	if (!state.enabled) {
+		ret = clk_prepare_enable(chip->hlcdc->periph_clk);
+		if (ret)
+			return ret;
+	}
+
+	return atmel_hlcdc_pwm_apply(&chip->chip, &chip->chip.pwms[0], &state);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(atmel_hlcdc_pwm_pm_ops,
+			 atmel_hlcdc_pwm_suspend, atmel_hlcdc_pwm_resume);
+
 static const struct of_device_id atmel_hlcdc_dt_ids[] = {
 	{
 		.compatible = "atmel,at91sam9n12-hlcdc",
@@ -280,6 +314,7 @@ static struct platform_driver atmel_hlcdc_pwm_driver = {
 	.driver = {
 		.name = "atmel-hlcdc-pwm",
 		.of_match_table = atmel_hlcdc_pwm_dt_ids,
+		.pm = &atmel_hlcdc_pwm_pm_ops,
 	},
 	.probe = atmel_hlcdc_pwm_probe,
 	.remove = atmel_hlcdc_pwm_remove,