gpio: sch: Fix Oops on module load on Asus Eee PC 1201

This fixes the issue descirbe in bug 117531
(https://bugzilla.kernel.org/show_bug.cgi?id=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 issue is that sch_gpio_reg_set is called in sch_gpio_probe before
gpio_chip data is initialized with the pointer to the sch_gpio struct. As
sch_gpio_reg_set calls gpiochip_get_data, it returns NULL which causes
the Oops.

The patch follows Mika's advice (https://lkml.org/lkml/2016/5/9/61) and
consists in modifying sch_gpio_reg_get and sch_gpio_reg_set to take a
sch_gpio struct directly instead of a gpio_chip, which avoids the call to
gpiochip_get_data.

Thanks Mika for your patience with me :-)

Cc: stable@vger.kernel.org
Signed-off-by: Colin Pitrat <colin.pitrat@gmail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 10 insertions, 11 deletions

diff --git a/drivers/gpio/gpio-sch.c b/drivers/gpio/gpio-sch.c
index e85e7539cf5d..eb43ae4835c1 100644
--- a/drivers/gpio/gpio-sch.c
+++ b/drivers/gpio/gpio-sch.c
@@ -61,9 +61,8 @@ static unsigned sch_gpio_bit(struct sch_gpio *sch, unsigned gpio)
         return gpio % 8;
 }
 
-static int sch_gpio_reg_get(struct gpio_chip *gc, unsigned gpio, unsigned reg)
+static int sch_gpio_reg_get(struct sch_gpio *sch, unsigned gpio, unsigned reg)
 {
-        struct sch_gpio *sch = gpiochip_get_data(gc);
         unsigned short offset, bit;
         u8 reg_val;
 
@@ -75,10 +74,9 @@ static int sch_gpio_reg_get(struct gpio_chip *gc, unsigned gpio, unsigned reg)
         return reg_val;
 }
 
-static void sch_gpio_reg_set(struct gpio_chip *gc, unsigned gpio, unsigned reg,
+static void sch_gpio_reg_set(struct sch_gpio *sch, unsigned gpio, unsigned reg,
                              int val)
 {
-        struct sch_gpio *sch = gpiochip_get_data(gc);
         unsigned short offset, bit;
         u8 reg_val;
 
@@ -98,14 +96,15 @@ static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
         struct sch_gpio *sch = gpiochip_get_data(gc);
 
         spin_lock(&sch->lock);
-        sch_gpio_reg_set(gc, gpio_num, GIO, 1);
+        sch_gpio_reg_set(sch, gpio_num, GIO, 1);
         spin_unlock(&sch->lock);
         return 0;
 }
 
 static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
 {
-        return sch_gpio_reg_get(gc, gpio_num, GLV);
+        struct sch_gpio *sch = gpiochip_get_data(gc);
+        return sch_gpio_reg_get(sch, gpio_num, GLV);
 }
 
 static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
@@ -113,7 +112,7 @@ static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
         struct sch_gpio *sch = gpiochip_get_data(gc);
 
         spin_lock(&sch->lock);
-        sch_gpio_reg_set(gc, gpio_num, GLV, val);
+        sch_gpio_reg_set(sch, gpio_num, GLV, val);
         spin_unlock(&sch->lock);
 }
 
@@ -123,7 +122,7 @@ static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
         struct sch_gpio *sch = gpiochip_get_data(gc);
 
         spin_lock(&sch->lock);
-        sch_gpio_reg_set(gc, gpio_num, GIO, 0);
+        sch_gpio_reg_set(sch, gpio_num, GIO, 0);
         spin_unlock(&sch->lock);
 
         /*
@@ -182,13 +181,13 @@ static int sch_gpio_probe(struct platform_device *pdev)
                  * GPIO7 is configured by the CMC as SLPIOVR
                  * Enable GPIO[9:8] core powered gpios explicitly
                  */
-                sch_gpio_reg_set(&sch->chip, 8, GEN, 1);
-                sch_gpio_reg_set(&sch->chip, 9, GEN, 1);
+                sch_gpio_reg_set(sch, 8, GEN, 1);
+                sch_gpio_reg_set(sch, 9, GEN, 1);
                 /*
                  * SUS_GPIO[2:0] enabled by default
                  * Enable SUS_GPIO3 resume powered gpio explicitly
                  */
-                sch_gpio_reg_set(&sch->chip, 13, GEN, 1);
+                sch_gpio_reg_set(sch, 13, GEN, 1);
                 break;
 
         case PCI_DEVICE_ID_INTEL_ITC_LPC: