usb: typec: tcpm: husb311: add runtime power save

While TCPM invoke set_vbus(), we checked the vbus and charge status
to disable 24M OSC to save power consumption via a delay worker.

Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Change-Id: I4e5b191d4071b3668413fc7362498d6ea3889b7a

drivers/usb/typec/tcpm/tcpci_husb311.c

@@ -24,12 +24,18 @@
 #define HUSB311_TCPC_TDRP	0xA2
 #define HUSB311_TCPC_DCSRCDRP	0xA3
 
+#define HUSB311_PM_DELAY_S	(3 * HZ)
+
 struct husb311_chip {
 	struct tcpci_data data;
 	struct tcpci *tcpci;
 	struct device *dev;
 	struct regulator *vbus;
+	struct mutex lock; /* lock for sharing chip states */
+	struct delayed_work pm_work;
 	bool vbus_on;
+	bool charge_on;
+	bool suspended;
 };
 
 static int husb311_read8(struct husb311_chip *chip, unsigned int reg, u8 *val)
@@ -58,6 +64,49 @@ static struct husb311_chip *tdata_to_husb311(struct tcpci_data *tdata)
 	return container_of(tdata, struct husb311_chip, data);
 }
 
+static int husb311_disable_osc24m(struct husb311_chip *chip)
+{
+	int ret = 0;
+	u8 pwr;
+
+	/*
+	 * Disable 24M oscillator to save power consumption, and it will be
+	 * enabled automatically when INT occurs.
+	 */
+	ret = husb311_read8(chip, HUSB311_TCPC_POWER, &pwr);
+	if (ret < 0)
+		return ret;
+
+	pwr &= ~BIT(0);
+	ret = husb311_write8(chip, HUSB311_TCPC_POWER, pwr);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static void husb311_pm_work(struct work_struct *work)
+{
+	struct husb311_chip *chip =
+		container_of(work, struct husb311_chip, pm_work.work);
+
+	mutex_lock(&chip->lock);
+
+	if (!chip->vbus_on && !chip->charge_on) {
+		if (chip->suspended)
+			goto exit;
+
+		husb311_disable_osc24m(chip);
+		chip->suspended = 1;
+	} else {
+		if (chip->suspended)
+			chip->suspended = 0;
+	}
+
+exit:
+	mutex_unlock(&chip->lock);
+}
+
 static int husb311_sw_reset(struct husb311_chip *chip)
 {
 	/* soft reset */
@@ -88,24 +137,35 @@ static int husb311_set_vbus(struct tcpci *tcpci, struct tcpci_data *tdata,
 	struct husb311_chip *chip = tdata_to_husb311(tdata);
 	int ret = 0;
 
+	mutex_lock(&chip->lock);
+
 	if (chip->vbus_on == on) {
 		dev_dbg(chip->dev, "vbus is already %s", on ? "On" : "Off");
-		goto done;
+	} else {
+		if (on)
+			ret = regulator_enable(chip->vbus);
+		else
+			ret = regulator_disable(chip->vbus);
+		if (ret < 0) {
+			dev_err(chip->dev, "cannot %s vbus regulator, ret=%d",
+				on ? "enable" : "disable", ret);
+			goto done;
+		}
+
+		chip->vbus_on = on;
+		dev_dbg(chip->dev, "vbus := %s", on ? "On" : "Off");
 	}
 
-	if (on)
-		ret = regulator_enable(chip->vbus);
+	if (chip->charge_on == charge)
+		dev_dbg(chip->dev, "charge is already %s",
+			charge ? "On" : "Off");
 	else
-		ret = regulator_disable(chip->vbus);
-	if (ret < 0) {
-		dev_err(chip->dev, "cannot %s vbus regulator, ret=%d",
-			on ? "enable" : "disable", ret);
-		goto done;
-	}
+		chip->charge_on = charge;
 
-	chip->vbus_on = on;
+	queue_delayed_work(system_freezable_wq, &chip->pm_work, HUSB311_PM_DELAY_S);
 
 done:
+	mutex_unlock(&chip->lock);
 	return ret;
 }
 
@@ -169,6 +229,9 @@ static int husb311_probe(struct i2c_client *client,
 	chip->dev = &client->dev;
 	i2c_set_clientdata(client, chip);
 
+	mutex_init(&chip->lock);
+	INIT_DELAYED_WORK(&chip->pm_work, husb311_pm_work);
+
 	chip->vbus = devm_regulator_get_optional(chip->dev, "vbus");
 	if (IS_ERR(chip->vbus)) {
 		ret = PTR_ERR(chip->vbus);
@@ -209,6 +272,7 @@ static void husb311_remove(struct i2c_client *client)
 	struct husb311_chip *chip = i2c_get_clientdata(client);
 
 	device_init_wakeup(chip->dev, false);
+	cancel_delayed_work_sync(&chip->pm_work);
 	tcpci_unregister_port(chip->tcpci);
 }
 
@@ -216,27 +280,17 @@ static int husb311_pm_suspend(struct device *dev)
 {
 	struct husb311_chip *chip = dev->driver_data;
 	struct i2c_client *client = to_i2c_client(dev);
-	int ret = 0;
-	u8 pwr;
-
-	/*
-	 * Disable 12M oscillator to save power consumption, and it will be
-	 * enabled automatically when INT occur after system resume.
-	 */
-	ret = husb311_read8(chip, HUSB311_TCPC_POWER, &pwr);
-	if (ret < 0)
-		return ret;
-
-	pwr &= ~BIT(0);
-	ret = husb311_write8(chip, HUSB311_TCPC_POWER, pwr);
-	if (ret < 0)
-		return ret;
 
 	if (device_may_wakeup(dev) && !chip->vbus_on)
 		enable_irq_wake(client->irq);
 	else
 		disable_irq(client->irq);
 
+	if (!chip->suspended) {
+		chip->suspended = 1;
+		husb311_disable_osc24m(chip);
+	}
+
 	return 0;
 }