Re: [PATCH 3/5] gpio/omap: Add DT support to GPIO driver

[Javier Martinez Canillas <martinez.javier@gmail.com>]

On Fri, Apr 12, 2013 at 12:47 AM, Stephen Warren <swarren@wwwdotorg.org> wrote:
> On 04/11/2013 04:16 PM, Linus Walleij wrote:
>> On Thu, Apr 11, 2013 at 10:30 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>> On 04/10/2013 03:28 PM, Linus Walleij wrote:
>>
>>>> So the only reason I'm rambing on about this is that it breaks the
>>>
>>> I'm not sure I understand this paragraph; what is "it" in the line above.
>>>
>>> If "it" is this patch, then should "breaks" be re-establishes?
>>
>> No I'm replying to Javier Martinez Canillas mail in this thread:
>> http://marc.info/?l=linux-arm-kernel&m=136334655902407&w=2
>> which is stating a question to grand, and contains the below
>> hunk:
>>
>>> +static int gpio_irq_request(struct irq_data *d)
>>> +{
>>> +       struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
>>> +
>>> +       return gpio_request(irq_to_gpio(bank, d->irq), "gpio-irq");
>>> +}
>>
>> irq_to_gpio(). Notice that. not my_funny_driver_irq_to_gpio().
>
> OK, right. sorry for being so confused/confusing.
>
> Yes, that code should certainly call e.g. omap_gpio__irq_to_gpio() not
> irq_to_gpio(). Probably gpio_irq_request() wants renaming to something
> more like omap_gpio__irq_request() too, so the names don't look like
> they'd clash with global functions. (__ added for clarity but probably
> only one _ at a time)

Stephen, Linus,

Is the following inlined patch [1] what you were thinking that would
be the right approach?

With this patch an explicit call to call gpio_request() before a call
to chip->irq_set_type() is needed. I've tested both with DT and
without DT where a explicit call to gpio_request() is made and it
works in both cases. So it shouldn't have a functional change for
non-DT cases as far as I know.

If you agree with [1] then I'll split in two patches (one that adds
the irq_request function pointer to irq_chip and another one that adds
the implementation for gpio-omap) and send as a patch-set. I just
thought that it would be easier for you if I posted here an inlined
patch so you could have context.

Thanks a lot for your feedback and best regards,
Javier

[1]
diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 685e850..e035e64 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -811,6 +811,13 @@ static void gpio_unmask_irq(struct irq_data *d)
 	spin_unlock_irqrestore(&bank->lock, flags);
 }

+static int omap_gpio_irq_request(struct irq_data *d)
+{
+	struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
+
+	return omap_gpio_request(&bank->chip, d->hwirq);
+}
+
 static struct irq_chip gpio_irq_chip = {
 	.name		= "GPIO",
 	.irq_shutdown	= gpio_irq_shutdown,
@@ -819,6 +826,7 @@ static struct irq_chip gpio_irq_chip = {
 	.irq_unmask	= gpio_unmask_irq,
 	.irq_set_type	= gpio_irq_type,
 	.irq_set_wake	= gpio_wake_enable,
+	.irq_request    = omap_gpio_irq_request,
 };

 /*---------------------------------------------------------------------*/
@@ -1028,6 +1036,7 @@ omap_mpuio_alloc_gc(struct gpio_bank *bank,
unsigned int irq_start,
 	ct->chip.irq_mask = irq_gc_mask_set_bit;
 	ct->chip.irq_unmask = irq_gc_mask_clr_bit;
 	ct->chip.irq_set_type = gpio_irq_type;
+	ct->chip.irq_request = omap_gpio_irq_request;

 	if (bank->regs->wkup_en)
 		ct->chip.irq_set_wake = gpio_wake_enable,
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 0e8e3a6..85596cc 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -303,6 +303,7 @@ struct irq_chip {
 	void		(*irq_shutdown)(struct irq_data *data);
 	void		(*irq_enable)(struct irq_data *data);
 	void		(*irq_disable)(struct irq_data *data);
+	int             (*irq_request)(struct irq_data *data);

 	void		(*irq_ack)(struct irq_data *data);
 	void		(*irq_mask)(struct irq_data *data);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index fa17855..a4bd4f7 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -588,6 +588,12 @@ int __irq_set_trigger(struct irq_desc *desc,
unsigned int irq,
 			unmask = 1;
 	}

+	if (chip->irq_request) {
+			ret = chip->irq_request(&desc->irq_data);
+			if (ret)
+				return ret;
+	}
+
 	/* caller masked out all except trigger mode flags */
 	ret = chip->irq_set_type(&desc->irq_data, flags);