[PATCH 4.6 039/203] gpio: sch: Fix Oops on module load on Asus Eee PC 1201

Greg Kroah-Hartman
2016-07-25T21:40:20Z

From: Colin Pitrat <colin.pitrat@gmail.com>

commit 87041a58d3b19455d39baed2a5e5bb43b58fb915 upstream.

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 :-)

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpio/gpio-sch.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)

--- a/drivers/gpio/gpio-sch.c
+++ b/drivers/gpio/gpio-sch.c
@@ -61,9 +61,8 @@ static unsigned sch_gpio_bit(struct sch_
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_
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
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_chi
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
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 platfor
* 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;