Subject: [PATCH v2 4/5] pinctrl: sunxi: Properly handle level triggered gpio interrupts

From: [email-masked] (Hans de Goede)
Date: Mon, 23 Jun 2014 16:53:02 +0200

Hi,

On 06/17/2014 08:43 PM, Maxime Ripard wrote:
> On Tue, Jun 03, 2014 at 05:13:17PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 06/03/2014 03:30 PM, Maxime Ripard wrote:
>>> On Sat, May 31, 2014 at 04:01:38PM +0200, Hans de Goede wrote:
>>>> For level triggered gpio interrupts we need to use handle_fasteoi_irq,
>>>> like we do with the irq-sunxi-nmi driver. This is necessary to give threaded
>>>> interrupt handlers a chance to actuall clear the source of the interrupt
>>>> (which may involve sleeping waiting for i2c / spi / mmc transfers), before
>>>> acknowledging the interrupt.
>>>>
>>>> Signed-off-by: Hans de Goede <[email-masked]>
>>>> ---
>>>>  drivers/pinctrl/sunxi/pinctrl-sunxi.c | 57 +++++++++++++++++++++++++----------
>>>>  1 file changed, 41 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>>>> index 61d3246..418a430 100644
>>>> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>>>> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>>>> @@ -31,6 +31,11 @@
>>>>  #include "../core.h"
>>>>  #include "pinctrl-sunxi.h"
>>>>
>>>> +static void sunxi_pinctrl_irq_ack(struct irq_data *d);
>>>> +static void sunxi_pinctrl_irq_mask(struct irq_data *d);
>>>> +static void sunxi_pinctrl_irq_unmask(struct irq_data *d);
>>>> +static int sunxi_pinctrl_irq_set_type(struct irq_data *d, unsigned int type);
>>>> +
>>>>  static struct sunxi_pinctrl_group *
>>>>  sunxi_pinctrl_find_group_by_name(struct sunxi_pinctrl *pctl, const char *group)
>>>>  {
>>>> @@ -545,10 +550,29 @@ static int sunxi_pinctrl_irq_request_resources(struct irq_data *d)
>>>>  	return 0;
>>>>  }
>>>>
>>>> -static int sunxi_pinctrl_irq_set_type(struct irq_data *d,
>>>> -				      unsigned int type)
>>>> +static struct irq_chip sunxi_pinctrl_edge_irq_chip = {
>>>> +	.irq_ack		= sunxi_pinctrl_irq_ack,
>>>> +	.irq_mask		= sunxi_pinctrl_irq_mask,
>>>> +	.irq_unmask		= sunxi_pinctrl_irq_unmask,
>>>> +	.irq_request_resources	= sunxi_pinctrl_irq_request_resources,
>>>> +	.irq_set_type		= sunxi_pinctrl_irq_set_type,
>>>> +	.flags			= IRQCHIP_SKIP_SET_WAKE,
>>>> +};
>>>> +
>>>> +static struct irq_chip sunxi_pinctrl_level_irq_chip = {
>>>> +	.irq_eoi		= sunxi_pinctrl_irq_ack,
>>>> +	.irq_mask		= sunxi_pinctrl_irq_mask,
>>>> +	.irq_unmask		= sunxi_pinctrl_irq_unmask,
>>>> +	.irq_request_resources	= sunxi_pinctrl_irq_request_resources,
>>>> +	.irq_set_type		= sunxi_pinctrl_irq_set_type,
>>>> +	.flags			= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_EOI_THREADED
>>>> +				  | IRQCHIP_EOI_IF_HANDLED,
>>>> +};
>>>
>>> Maybe we can just forward declare these two structures, instead of all
>>> their functions.
>>
>> Variables cannot be forward declared, they can be declared extern, but last
>> time I checked extern and static don't mix.
> 
> Actually, you can. It's called a tentative definition, see
> http://c0x.coding-guidelines.com/6.9.2.html and
> http://c0x.coding-guidelines.com/6.2.2.html for the definition of
> internal linkage.

Ah, I've been programming C since 1996, and I did not know about that :)

Good to have learned something new today. I'll do a v3 patch-set with this
fixed (well a v4 really as I accidentally did a second v2, but lets be
consistent and number the next one v3).

Regards,

Hans

> 
> Maxime
> 
>>
>>>
>>>> +
>>>> +static int sunxi_pinctrl_irq_set_type(struct irq_data *d, unsigned int type)
>>>>  {
>>>>  	struct sunxi_pinctrl *pctl = irq_data_get_irq_chip_data(d);
>>>> +	struct irq_desc *desc = container_of(d, struct irq_desc, irq_data);
>>>>  	u32 reg = sunxi_irq_cfg_reg(d->hwirq);
>>>>  	u8 index = sunxi_irq_cfg_offset(d->hwirq);
>>>>  	unsigned long flags;
>>>> @@ -575,6 +599,14 @@ static int sunxi_pinctrl_irq_set_type(struct irq_data *d,
>>>>  		return -EINVAL;
>>>>  	}
>>>>
>>>> +	if (type & IRQ_TYPE_LEVEL_MASK) {
>>>> +		d->chip = &sunxi_pinctrl_level_irq_chip;
>>>> +		desc->handle_irq = handle_fasteoi_irq;
>>>> +	} else {
>>>> +		d->chip = &sunxi_pinctrl_edge_irq_chip;
>>>> +		desc->handle_irq = handle_edge_irq;
>>>
>>> irq_set_chip_and_handler?
>>
>> Does a lookup of the irqdata which we already have here, and
>> that lookup takes a lock which is already held here.
> 
> Ah, yes.
> 
> Thanks,
> Maxime
>