leds: cht-wcove: Add suspend/resume handling

When LED1 is showing the tablet is charging and then the device gets
suspended followed by unplugging the charger, then it will incorrectly
still show it is charging.

To avoid this turn both LEDs off on suspend, just like the PMIC always
turns them off when the tablet is powered off (even if the tablet is
charging). If hw-control is supported for LED1, then restore the
initial hw-control settings to let the hw control LED1 while suspended.

To restore the state the LEDs had before suspending, save it before
turning the LEDs off and restore it on resume.
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230430195952.862527-3-hdegoede@redhat.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/leds/leds-cht-wcove.c

@@ -17,6 +17,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <linux/suspend.h>
 
 #define CHT_WC_LED1_CTRL		0x5e1f
 #define CHT_WC_LED1_FSM			0x5e20
@@ -69,6 +70,7 @@ struct cht_wc_led {
 	const struct cht_wc_led_regs *regs;
 	struct regmap *regmap;
 	struct mutex mutex;
+	struct cht_wc_led_saved_regs saved_regs;
 };
 
 struct cht_wc_leds {
@@ -364,12 +366,43 @@ static void cht_wc_leds_disable(struct platform_device *pdev)
 		cht_wc_led_restore_regs(&leds->leds[0], &leds->led1_initial_regs);
 }
 
+/* On suspend save current settings and turn LEDs off */
+static int cht_wc_leds_suspend(struct device *dev)
+{
+	struct cht_wc_leds *leds = dev_get_drvdata(dev);
+	int i, ret;
+
+	for (i = 0; i < CHT_WC_LED_COUNT; i++) {
+		ret = cht_wc_led_save_regs(&leds->leds[i], &leds->leds[i].saved_regs);
+		if (ret < 0)
+			return ret;
+	}
+
+	cht_wc_leds_disable(to_platform_device(dev));
+	return 0;
+}
+
+/* On resume restore the saved settings */
+static int cht_wc_leds_resume(struct device *dev)
+{
+	struct cht_wc_leds *leds = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < CHT_WC_LED_COUNT; i++)
+		cht_wc_led_restore_regs(&leds->leds[i], &leds->leds[i].saved_regs);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(cht_wc_leds_pm, cht_wc_leds_suspend, cht_wc_leds_resume);
+
 static struct platform_driver cht_wc_leds_driver = {
 	.probe = cht_wc_leds_probe,
 	.remove_new = cht_wc_leds_remove,
 	.shutdown = cht_wc_leds_disable,
 	.driver = {
 		.name = "cht_wcove_leds",
+		.pm = pm_sleep_ptr(&cht_wc_leds_pm),
 	},
 };
 module_platform_driver(cht_wc_leds_driver);