[PATCH 2/2][v4] gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function

[PATCH 2/2][v4] gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function

[Rojhalat Ibrahim]

Add a set_multiple function to the MPC8xxx GPIO chip driver and thereby allow
for actual performance improvements when setting multiple outputs
simultaneously. In my case the time needed to configure an FPGA goes down from
48 s to 20 s.

Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
---
This patch depends on my previous patch "gpiolib: allow simultaneous setting
of multiple GPIO outputs".

Change log:
  v4: - change interface of the set_multiple driver function to use
        unsigned long as type for the bit fields
      - use generic bitops (which also use unsigned long for bit fields)
  v3: - change commit message
  v2: - add this patch (v1 included only changes to gpiolib)

 drivers/gpio/gpio-mpc8xxx.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
index d7d6d72..d1ff879 100644
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -105,6 +105,32 @@ static void mpc8xxx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
 }
 
+static void mpc8xxx_gpio_set_multiple(struct gpio_chip *gc,
+				      unsigned long *mask, unsigned long *bits)
+{
+	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
+	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
+
+	for (i = 0; i < gc->ngpio; i++) {
+		if (*mask == 0)
+			break;
+		if (__test_and_clear_bit(i, mask)) {
+			if (test_bit(i, bits))
+				mpc8xxx_gc->data |= mpc8xxx_gpio2mask(i);
+			else
+				mpc8xxx_gc->data &= ~mpc8xxx_gpio2mask(i);
+		}
+	}
+
+	out_be32(mm->regs + GPIO_DAT, mpc8xxx_gc->data);
+
+	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
+}
+
 static int mpc8xxx_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 {
 	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
@@ -344,6 +370,7 @@ static void __init mpc8xxx_add_controller(struct device_node *np)
 	gc->get = of_device_is_compatible(np, "fsl,mpc8572-gpio") ?
 		mpc8572_gpio_get : mpc8xxx_gpio_get;
 	gc->set = mpc8xxx_gpio_set;
+	gc->set_multiple = mpc8xxx_gpio_set_multiple;
 	gc->to_irq = mpc8xxx_gpio_to_irq;
 
 	ret = of_mm_gpiochip_add(np, mm_gc);

--
1.8.5.5

Re: [PATCH 2/2][v4] gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function

[Alexandre Courbot]

On Tue, Jun 3, 2014 at 12:29 AM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
> Add a set_multiple function to the MPC8xxx GPIO chip driver and thereby allow
> for actual performance improvements when setting multiple outputs
> simultaneously. In my case the time needed to configure an FPGA goes down from
> 48 s to 20 s.
>
> Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
> ---
> This patch depends on my previous patch "gpiolib: allow simultaneous setting
> of multiple GPIO outputs".
>
> Change log:
>   v4: - change interface of the set_multiple driver function to use
>         unsigned long as type for the bit fields
>       - use generic bitops (which also use unsigned long for bit fields)
>   v3: - change commit message
>   v2: - add this patch (v1 included only changes to gpiolib)
>
>  drivers/gpio/gpio-mpc8xxx.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
>
> diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
> index d7d6d72..d1ff879 100644
> --- a/drivers/gpio/gpio-mpc8xxx.c
> +++ b/drivers/gpio/gpio-mpc8xxx.c
> @@ -105,6 +105,32 @@ static void mpc8xxx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>         spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
>  }
>
> +static void mpc8xxx_gpio_set_multiple(struct gpio_chip *gc,
> +                                     unsigned long *mask, unsigned long *bits)
> +{
> +       struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
> +       struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
> +       unsigned long flags;
> +       int i;
> +
> +       spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
> +
> +       for (i = 0; i < gc->ngpio; i++) {
> +               if (*mask == 0)
> +                       break;

Ok, so this works because presentely you can only have 32 GPIOs max on
this chip. But you cannot be sure that future revisions won't extend
that number ; and if this happens this function won't work as-is
anymore. I won't take much more code to make it more generic, so
please do it now to avoid hours of horrendous debugging to your future
self.

> +               if (__test_and_clear_bit(i, mask)) {
> +                       if (test_bit(i, bits))
> +                               mpc8xxx_gc->data |= mpc8xxx_gpio2mask(i);
> +                       else
> +                               mpc8xxx_gc->data &= ~mpc8xxx_gpio2mask(i);
> +               }
> +       }
> +
> +       out_be32(mm->regs + GPIO_DAT, mpc8xxx_gc->data);
> +
> +       spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
> +}
> +
>  static int mpc8xxx_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
>  {
>         struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
> @@ -344,6 +370,7 @@ static void __init mpc8xxx_add_controller(struct device_node *np)
>         gc->get = of_device_is_compatible(np, "fsl,mpc8572-gpio") ?
>                 mpc8572_gpio_get : mpc8xxx_gpio_get;
>         gc->set = mpc8xxx_gpio_set;
> +       gc->set_multiple = mpc8xxx_gpio_set_multiple;
>         gc->to_irq = mpc8xxx_gpio_to_irq;
>
>         ret = of_mm_gpiochip_add(np, mm_gc);
>
> --
> 1.8.5.5

Re: [PATCH 2/2][v4] gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function

[Alexandre Courbot]

On Sat, Jun 7, 2014 at 10:34 PM, Alexandre Courbot <gnurou@gmail.com> wrote:
> On Tue, Jun 3, 2014 at 12:29 AM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
>> Add a set_multiple function to the MPC8xxx GPIO chip driver and thereby allow
>> for actual performance improvements when setting multiple outputs
>> simultaneously. In my case the time needed to configure an FPGA goes down from
>> 48 s to 20 s.
>>
>> Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
>> ---
>> This patch depends on my previous patch "gpiolib: allow simultaneous setting
>> of multiple GPIO outputs".
>>
>> Change log:
>>   v4: - change interface of the set_multiple driver function to use
>>         unsigned long as type for the bit fields
>>       - use generic bitops (which also use unsigned long for bit fields)
>>   v3: - change commit message
>>   v2: - add this patch (v1 included only changes to gpiolib)
>>
>>  drivers/gpio/gpio-mpc8xxx.c | 27 +++++++++++++++++++++++++++
>>  1 file changed, 27 insertions(+)
>>
>> diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
>> index d7d6d72..d1ff879 100644
>> --- a/drivers/gpio/gpio-mpc8xxx.c
>> +++ b/drivers/gpio/gpio-mpc8xxx.c
>> @@ -105,6 +105,32 @@ static void mpc8xxx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>>         spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
>>  }
>>
>> +static void mpc8xxx_gpio_set_multiple(struct gpio_chip *gc,
>> +                                     unsigned long *mask, unsigned long *bits)
>> +{
>> +       struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
>> +       struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
>> +       unsigned long flags;
>> +       int i;
>> +
>> +       spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
>> +
>> +       for (i = 0; i < gc->ngpio; i++) {
>> +               if (*mask == 0)
>> +                       break;
>
> Ok, so this works because presentely you can only have 32 GPIOs max on
> this chip. But you cannot be sure that future revisions won't extend
> that number ; and if this happens this function won't work as-is
> anymore. I won't take much more code to make it more generic, so
> please do it now to avoid hours of horrendous debugging to your future
> self.

Looking at it twice you only have one data register, so there is
probably not much you can do for the moment - please ignore my
previous comment.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>