* [PATCH] pch_gpio: transform mutex into spinlock
@ 2011-06-21 14:17 Alexander Stein
2011-06-27 22:47 ` Grant Likely
0 siblings, 1 reply; 3+ messages in thread
From: Alexander Stein @ 2011-06-21 14:17 UTC (permalink / raw)
To: Grant Likely; +Cc: linux-kernel, Tomoya MORINAGA, Alexander Stein
gpio_chip.can_sleep is 0, but gpio_set_value & friends lock a mutex. Thus
those functions are not callable from interrupt context.
Changing mutex into spinlock.
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
---
I just noticed that the patch introduced at
http://marc.info/?l=linux-kernel&m=130863151431202&w=2
also added a spinlock. I think those two spinlock can be merged into one.
drivers/gpio/pch_gpio.c | 19 +++++++++++--------
1 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/gpio/pch_gpio.c b/drivers/gpio/pch_gpio.c
index 36919e7..262c200 100644
--- a/drivers/gpio/pch_gpio.c
+++ b/drivers/gpio/pch_gpio.c
@@ -62,15 +62,16 @@ struct pch_gpio {
struct device *dev;
struct gpio_chip gpio;
struct pch_gpio_reg_data pch_gpio_reg;
- struct mutex lock;
+ struct spinlock lock;
};
static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
{
u32 reg_val;
+ unsigned long flags;
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->lock, flags);
reg_val = ioread32(&chip->reg->po);
if (val)
reg_val |= (1 << nr);
@@ -78,7 +79,7 @@ static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
reg_val &= ~(1 << nr);
iowrite32(reg_val, &chip->reg->po);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->lock, flags);
}
static int pch_gpio_get(struct gpio_chip *gpio, unsigned nr)
@@ -94,8 +95,9 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
u32 pm;
u32 reg_val;
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->lock, flags);
pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS;
pm |= (1 << nr);
iowrite32(pm, &chip->reg->pm);
@@ -107,7 +109,7 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
reg_val &= ~(1 << nr);
iowrite32(reg_val, &chip->reg->po);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->lock, flags);
return 0;
}
@@ -116,12 +118,13 @@ static int pch_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
{
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
u32 pm;
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->lock, flags);
pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS; /*bits 0-11*/
pm &= ~(1 << nr);
iowrite32(pm, &chip->reg->pm);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->lock, flags);
return 0;
}
@@ -194,7 +197,7 @@ static int __devinit pch_gpio_probe(struct pci_dev *pdev,
chip->reg = chip->base;
pci_set_drvdata(pdev, chip);
- mutex_init(&chip->lock);
+ spin_lock_init(&chip->lock);
pch_gpio_setup(chip);
ret = gpiochip_add(&chip->gpio);
if (ret) {
--
1.7.3.4
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] pch_gpio: transform mutex into spinlock
2011-06-21 14:17 [PATCH] pch_gpio: transform mutex into spinlock Alexander Stein
@ 2011-06-27 22:47 ` Grant Likely
2011-06-28 1:02 ` Tomoya MORINAGA
0 siblings, 1 reply; 3+ messages in thread
From: Grant Likely @ 2011-06-27 22:47 UTC (permalink / raw)
To: Alexander Stein; +Cc: linux-kernel, Tomoya MORINAGA
On Tue, Jun 21, 2011 at 04:17:27PM +0200, Alexander Stein wrote:
> gpio_chip.can_sleep is 0, but gpio_set_value & friends lock a mutex. Thus
> those functions are not callable from interrupt context.
> Changing mutex into spinlock.
>
> Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Tomoya, what do you think of this patch?
> ---
> I just noticed that the patch introduced at
> http://marc.info/?l=linux-kernel&m=130863151431202&w=2
> also added a spinlock. I think those two spinlock can be merged into one.
>
> drivers/gpio/pch_gpio.c | 19 +++++++++++--------
> 1 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpio/pch_gpio.c b/drivers/gpio/pch_gpio.c
> index 36919e7..262c200 100644
> --- a/drivers/gpio/pch_gpio.c
> +++ b/drivers/gpio/pch_gpio.c
> @@ -62,15 +62,16 @@ struct pch_gpio {
> struct device *dev;
> struct gpio_chip gpio;
> struct pch_gpio_reg_data pch_gpio_reg;
> - struct mutex lock;
> + struct spinlock lock;
> };
>
> static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
> {
> u32 reg_val;
> + unsigned long flags;
> struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
>
> - mutex_lock(&chip->lock);
> + spin_lock_irqsave(&chip->lock, flags);
> reg_val = ioread32(&chip->reg->po);
> if (val)
> reg_val |= (1 << nr);
> @@ -78,7 +79,7 @@ static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
> reg_val &= ~(1 << nr);
>
> iowrite32(reg_val, &chip->reg->po);
> - mutex_unlock(&chip->lock);
> + spin_unlock_irqrestore(&chip->lock, flags);
> }
>
> static int pch_gpio_get(struct gpio_chip *gpio, unsigned nr)
> @@ -94,8 +95,9 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
> struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
> u32 pm;
> u32 reg_val;
> + unsigned long flags;
>
> - mutex_lock(&chip->lock);
> + spin_lock_irqsave(&chip->lock, flags);
> pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS;
> pm |= (1 << nr);
> iowrite32(pm, &chip->reg->pm);
> @@ -107,7 +109,7 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
> reg_val &= ~(1 << nr);
> iowrite32(reg_val, &chip->reg->po);
>
> - mutex_unlock(&chip->lock);
> + spin_unlock_irqrestore(&chip->lock, flags);
>
> return 0;
> }
> @@ -116,12 +118,13 @@ static int pch_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
> {
> struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
> u32 pm;
> + unsigned long flags;
>
> - mutex_lock(&chip->lock);
> + spin_lock_irqsave(&chip->lock, flags);
> pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS; /*bits 0-11*/
> pm &= ~(1 << nr);
> iowrite32(pm, &chip->reg->pm);
> - mutex_unlock(&chip->lock);
> + spin_unlock_irqrestore(&chip->lock, flags);
>
> return 0;
> }
> @@ -194,7 +197,7 @@ static int __devinit pch_gpio_probe(struct pci_dev *pdev,
>
> chip->reg = chip->base;
> pci_set_drvdata(pdev, chip);
> - mutex_init(&chip->lock);
> + spin_lock_init(&chip->lock);
> pch_gpio_setup(chip);
> ret = gpiochip_add(&chip->gpio);
> if (ret) {
> --
> 1.7.3.4
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] pch_gpio: transform mutex into spinlock
2011-06-27 22:47 ` Grant Likely
@ 2011-06-28 1:02 ` Tomoya MORINAGA
0 siblings, 0 replies; 3+ messages in thread
From: Tomoya MORINAGA @ 2011-06-28 1:02 UTC (permalink / raw)
To: Grant Likely; +Cc: Alexander Stein, linux-kernel, toshiharu-linux
(2011/06/28 7:47), Grant Likely wrote:
> On Tue, Jun 21, 2011 at 04:17:27PM +0200, Alexander Stein wrote:
>> gpio_chip.can_sleep is 0, but gpio_set_value& friends lock a mutex. Thus
>> those functions are not callable from interrupt context.
>> Changing mutex into spinlock.
>>
>> Signed-off-by: Alexander Stein<alexander.stein@systec-electronic.com>
>
> Tomoya, what do you think of this patch?
>
Seeing some upstreamed GPIO driver, Alexander's comment looks right.
Best Regards,
tomoya
OKI SEMICONDUCTOR CO., LTD.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-06-28 1:03 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2011-06-21 14:17 [PATCH] pch_gpio: transform mutex into spinlock Alexander Stein
2011-06-27 22:47 ` Grant Likely
2011-06-28 1:02 ` Tomoya MORINAGA
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