[PATCH v2] gpio: sch: Fix Oops on module load on Asus Eee PC 1201

[Colin Pitrat <colin.pitrat@gmail.com>]

This fixes the issue descirbe in bug 117531. 
It's a regression introduced in linux 4.5 that causes a Oops at load of
gpio_sch and prevents powering off the computer.

The patch consist in reverting commit 737c8fccf1c5b2aae3c6d9a66dce17e35fc39b71 
(a.k.a 'gpio: sch: use gpiochip data pointer') that causes this regression.
However, although it does work for me, I'm not sure of the impact of reverting
only this part of the patch.

Contrary to previous patch sent that reverted two changes, this one only
reverts the source of the issue, that is the replacement of to_sch_gpio macro
by gpiochip_get_data.

Signed-off-by: Colin Pitrat <colin.pitrat@gmail.com>

---
 drivers/gpio/gpio-sch.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpio/gpio-sch.c b/drivers/gpio/gpio-sch.c
index e85e753..a8a333ad 100644
--- a/drivers/gpio/gpio-sch.c
+++ b/drivers/gpio/gpio-sch.c
@@ -41,6 +41,8 @@ struct sch_gpio {
 	unsigned short resume_base;
 };
 
+#define to_sch_gpio(gc)	container_of(gc, struct sch_gpio, chip)
+
 static unsigned sch_gpio_offset(struct sch_gpio *sch, unsigned gpio,
 				unsigned reg)
 {
@@ -63,7 +65,7 @@ static unsigned sch_gpio_bit(struct sch_gpio *sch, unsigned gpio)
 
 static int sch_gpio_reg_get(struct gpio_chip *gc, unsigned gpio, unsigned reg)
 {
-	struct sch_gpio *sch = gpiochip_get_data(gc);
+	struct sch_gpio *sch = to_sch_gpio(gc);
 	unsigned short offset, bit;
 	u8 reg_val;
 
@@ -78,7 +80,7 @@ static int sch_gpio_reg_get(struct gpio_chip *gc, unsigned gpio, unsigned reg)
 static void sch_gpio_reg_set(struct gpio_chip *gc, unsigned gpio, unsigned reg,
 			     int val)
 {
-	struct sch_gpio *sch = gpiochip_get_data(gc);
+	struct sch_gpio *sch = to_sch_gpio(gc);
 	unsigned short offset, bit;
 	u8 reg_val;
 
@@ -95,7 +97,7 @@ static void sch_gpio_reg_set(struct gpio_chip *gc, unsigned gpio, unsigned reg,
 
 static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
 {
-	struct sch_gpio *sch = gpiochip_get_data(gc);
+	struct sch_gpio *sch = to_sch_gpio(gc);
 
 	spin_lock(&sch->lock);
 	sch_gpio_reg_set(gc, gpio_num, GIO, 1);
@@ -110,7 +112,7 @@ static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
 
 static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
 {
-	struct sch_gpio *sch = gpiochip_get_data(gc);
+	struct sch_gpio *sch = to_sch_gpio(gc);
 
 	spin_lock(&sch->lock);
 	sch_gpio_reg_set(gc, gpio_num, GLV, val);
@@ -120,7 +122,7 @@ static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
 static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
 				  int val)
 {
-	struct sch_gpio *sch = gpiochip_get_data(gc);
+	struct sch_gpio *sch = to_sch_gpio(gc);
 
 	spin_lock(&sch->lock);
 	sch_gpio_reg_set(gc, gpio_num, GIO, 0);
-- 
2.8.2