usb: typec: ucsi: ccg: enable runtime pm support

The change enables runtime pm support to UCSI CCG driver.
Added ucsi_resume() function to enable notification after
system reusme. Exported both ucsi_resume() and ucsi_send_command()
symbols in ucsi.c for modular build.
Signed-off-by: Ajay Gupta <ajayg@nvidia.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/usb/typec/ucsi/ucsi.c

@@ -206,7 +206,17 @@ int ucsi_send_command(struct ucsi *ucsi, struct ucsi_control *ctrl,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(ucsi_send_command);
 
+int ucsi_resume(struct ucsi *ucsi)
+{
+	struct ucsi_control ctrl;
+
+	/* Restore UCSI notification enable mask after system resume */
+	UCSI_CMD_SET_NTFY_ENABLE(ctrl, UCSI_ENABLE_NTFY_ALL);
+	return ucsi_send_command(ucsi, &ctrl, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(ucsi_resume);
 /* -------------------------------------------------------------------------- */
 
 void ucsi_altmode_update_active(struct ucsi_connector *con)

drivers/usb/typec/ucsi/ucsi.h

@@ -430,6 +430,7 @@ int ucsi_send_command(struct ucsi *ucsi, struct ucsi_control *ctrl,
 		      void *retval, size_t size);
 
 void ucsi_altmode_update_active(struct ucsi_connector *con);
+int ucsi_resume(struct ucsi *ucsi);
 
 #if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
 struct typec_altmode *

drivers/usb/typec/ucsi/ucsi_ccg.c

@@ -14,6 +14,8 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
 
 #include <asm/unaligned.h>
 #include "ucsi.h"
@@ -210,6 +212,7 @@ static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
 	if (quirks && quirks->max_read_len)
 		max_read_len = quirks->max_read_len;
 
+	pm_runtime_get_sync(uc->dev);
 	while (rem_len > 0) {
 		msgs[1].buf = &data[len - rem_len];
 		rlen = min_t(u16, rem_len, max_read_len);
@@ -218,12 +221,14 @@ static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
 		status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 		if (status < 0) {
 			dev_err(uc->dev, "i2c_transfer failed %d\n", status);
+			pm_runtime_put_sync(uc->dev);
 			return status;
 		}
 		rab += rlen;
 		rem_len -= rlen;
 	}
 
+	pm_runtime_put_sync(uc->dev);
 	return 0;
 }
 
@@ -249,13 +254,16 @@ static int ccg_write(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
 	msgs[0].len = len + sizeof(rab);
 	msgs[0].buf = buf;
 
+	pm_runtime_get_sync(uc->dev);
 	status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 	if (status < 0) {
 		dev_err(uc->dev, "i2c_transfer failed %d\n", status);
+		pm_runtime_put_sync(uc->dev);
 		kfree(buf);
 		return status;
 	}
 
+	pm_runtime_put_sync(uc->dev);
 	kfree(buf);
 	return 0;
 }
@@ -1134,6 +1142,10 @@ static int ucsi_ccg_probe(struct i2c_client *client,
 	if (status)
 		dev_err(uc->dev, "cannot create sysfs group: %d\n", status);
 
+	pm_runtime_set_active(uc->dev);
+	pm_runtime_enable(uc->dev);
+	pm_runtime_idle(uc->dev);
+
 	return 0;
 }
 
@@ -1143,6 +1155,7 @@ static int ucsi_ccg_remove(struct i2c_client *client)
 
 	cancel_work_sync(&uc->work);
 	ucsi_unregister_ppm(uc->ucsi);
+	pm_runtime_disable(uc->dev);
 	free_irq(uc->irq, uc);
 	sysfs_remove_group(&uc->dev->kobj, &ucsi_ccg_attr_group);
 
@@ -1155,9 +1168,34 @@ static const struct i2c_device_id ucsi_ccg_device_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, ucsi_ccg_device_id);
 
+static int ucsi_ccg_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ucsi_ccg *uc = i2c_get_clientdata(client);
+
+	return ucsi_resume(uc->ucsi);
+}
+
+static int ucsi_ccg_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int ucsi_ccg_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+static const struct dev_pm_ops ucsi_ccg_pm = {
+	.resume = ucsi_ccg_resume,
+	.runtime_suspend = ucsi_ccg_runtime_suspend,
+	.runtime_resume = ucsi_ccg_runtime_resume,
+};
+
 static struct i2c_driver ucsi_ccg_driver = {
 	.driver = {
 		.name = "ucsi_ccg",
+		.pm = &ucsi_ccg_pm,
 	},
 	.probe = ucsi_ccg_probe,
 	.remove = ucsi_ccg_remove,