From 76d8ca245c721c12f79779679699b229e361f4ac Mon Sep 17 00:00:00 2001
From: Sean Wang <sean.wang@mediatek.com>
Date: Mon, 9 Jul 2018 23:56:58 +0800
Subject: [PATCH] serdev: add dev_pm_domain_attach|detach()

In order to open up the required power gate before any operation can be
effectively performed over the serial bus between CPU and serdev, it's
clearly essential to add common attach functions for PM domains to serdev
at the probe phase.

Similarly, the relevant dettach function for the PM domains should be
properly and reversely added at the remove phase.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serdev/core.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index bd47c46ec993..9db93f500b4e 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/serdev.h>
 #include <linux/slab.h>
@@ -350,8 +351,17 @@ EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 static int serdev_drv_probe(struct device *dev)
 {
 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
+	int ret;
 
-	return sdrv->probe(to_serdev_device(dev));
+	ret = dev_pm_domain_attach(dev, true);
+	if (ret)
+		return ret;
+
+	ret = sdrv->probe(to_serdev_device(dev));
+	if (ret)
+		dev_pm_domain_detach(dev, true);
+
+	return ret;
 }
 
 static int serdev_drv_remove(struct device *dev)
@@ -359,6 +369,9 @@ static int serdev_drv_remove(struct device *dev)
 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 	if (sdrv->remove)
 		sdrv->remove(to_serdev_device(dev));
+
+	dev_pm_domain_detach(dev, true);
+
 	return 0;
 }