leds: pca963x: Add support for suspend and resume

This implements power management for pca9633 which enables
device sleep and resume on system-wide sleep/hibernation

Signed-off-by: Amitesh Singh <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/leds/leds-pca963x.c

···
 #define PCA963X_LED_PWM		0x2	/* Controlled through PWM */
 #define PCA963X_LED_GRP_PWM	0x3	/* Controlled through PWM/GRPPWM */
 
+#define PCA963X_MODE1_SLEEP	0x04    /* Normal mode or Low Power mode, oscillator off */
 #define PCA963X_MODE2_OUTDRV	0x04	/* Open-drain or totem pole */
 #define PCA963X_MODE2_INVRT	0x10	/* Normal or inverted direction */
 #define PCA963X_MODE2_DMBLNK	0x20	/* Enable blinking */
···
 	return ret;
 }
 
+static int pca963x_suspend(struct device *dev)
+{
+	struct pca963x *chip = dev_get_drvdata(dev);
+	u8 reg;
+
+	reg = i2c_smbus_read_byte_data(chip->client, PCA963X_MODE1);
+	reg = reg | BIT(PCA963X_MODE1_SLEEP);
+	i2c_smbus_write_byte_data(chip->client, PCA963X_MODE1, reg);
+
+	return 0;
+}
+
+static int pca963x_resume(struct device *dev)
+{
+	struct pca963x *chip = dev_get_drvdata(dev);
+	u8 reg;
+
+	reg = i2c_smbus_read_byte_data(chip->client, PCA963X_MODE1);
+	reg = reg & ~BIT(PCA963X_MODE1_SLEEP);
+	i2c_smbus_write_byte_data(chip->client, PCA963X_MODE1, reg);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(pca963x_pm, pca963x_suspend, pca963x_resume);
+
 static const struct of_device_id of_pca963x_match[] = {
 	{ .compatible = "nxp,pca9632", },
 	{ .compatible = "nxp,pca9633", },
···
 	.driver = {
 		.name	= "leds-pca963x",
 		.of_match_table = of_pca963x_match,
+		.pm = pm_sleep_ptr(&pca963x_pm)
 	},
 	.probe = pca963x_probe,
 	.id_table = pca963x_id,