On Wed, Apr 17, 2013 at 1:14 AM, Jon Hunter <jon-hunter@xxxxxx> wrote: > > On 04/16/2013 05:11 PM, Stephen Warren wrote: >> On 04/16/2013 01:27 PM, Jon Hunter wrote: >>> >>> On 04/16/2013 01:40 PM, Stephen Warren wrote: >>>> On 04/15/2013 05:04 PM, Jon Hunter wrote: >> ... >>>>> If some driver is calling gpio_request() directly, then they will most >>>>> likely just call gpio_to_irq() when requesting the interrupt and so the >>>>> xlate function would not be called in this case (mmc drivers are a good >>>>> example). So I don't see that as being a problem. In fact that's the >>>>> benefit of this approach as AFAICT it solves this problem. >>>> >>>> Oh. That assumption seems very fragile. What about drivers that actually >>>> do have platform data (or DT bindings) that provide both the IRQ and >>>> GPIO IDs, and hence don't use gpio_to_irq()? That's entirely possible. >>> >>> Right. In the DT case though, if someone does provide the IRQ and GPIO >>> IDs then at least they would use a different xlate function. Another >>> option to consider would be defining the #interrupt-cells = <3> where we >>> would have ... >>> >>> cell-#1 --> IRQ domain ID >>> cell-#2 --> Trigger type >>> cell-#3 --> GPIO ID >>> >>> Then we could have a generic xlate for 3 cells that would also request >>> the GPIO. Again not sure if people are against a gpio being requested in >>> the xlate but just an idea. Or given that irq_of_parse_and_map() calls >>> the xlate, we could have this function call gpio_request() if the >>> interrupt controller is a gpio and there are 3 cells. >> >> I rather dislike this approach since: >> >> a) It requires changes to the DT bindings, which are already defined. >> Admittedly it's backwards-compatible, but still. >> >> b) There isn't really any need for the DT to represent this; the >> GPIO+IRQ driver itself already knows which IRQ ID is which GPIO ID and >> vice-versa (if the HW has such a concept), so there's no need for the DT >> to contain this information. This seems like pushing Linux's internal >> requirements into the design of the DT binding. > > Yes, so the only alternative is to use irq_to_gpio to avoid this. > >> c) I have the feeling that hooking the of_xlate function for this is a >> bit of an abuse of the function. > > I was wondering about that. So I was grep'ing through the various xlate > implementations and found this [1]. Also you may recall that in the > of_dma_simple_xlate() we call the dma_request_channel() to allocate the > channel, which is very similar. However, I don't wish to get a > reputation as abusing APIs so would be good to know if this really is > abuse or not ;-) > > Cheers > Jon > > [1] http://permalink.gmane.org/gmane.linux.ports.arm.kernel/195124 I was looking at [1] shared by Jon and come up with the following patch that does something similar for OMAP GPIO. This has the advantage that is local to gpio-omap instead changing gpiolib-of and also doesn't require DT changes But I don't want to get a reputation for abusing APIs neither :-) Best regards, Javier >From 23368eb72b125227fcf4b22be19ea70b4ab94556 Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> Date: Wed, 17 Apr 2013 02:03:08 +0200 Subject: [PATCH 1/1] gpio/omap: add custom xlate function handler Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> --- drivers/gpio/gpio-omap.c | 29 ++++++++++++++++++++++++++++- 1 files changed, 28 insertions(+), 1 deletions(-) diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c index 8524ce5..77216f9 100644 --- a/drivers/gpio/gpio-omap.c +++ b/drivers/gpio/gpio-omap.c @@ -1097,6 +1097,33 @@ static void omap_gpio_chip_init(struct gpio_bank *bank) static const struct of_device_id omap_gpio_match[]; static void omap_gpio_init_context(struct gpio_bank *p); +static int omap_gpio_irq_domain_xlate(struct irq_domain *d, + struct device_node *ctrlr, + const u32 *intspec, unsigned int intsize, + irq_hw_number_t *out_hwirq, + unsigned int *out_type) +{ + int ret; + struct gpio_bank *bank = d->host_data; + int gpio = bank->chip.base + intspec[0]; + + if (WARN_ON(intsize < 2)) + return -EINVAL; + + ret = gpio_request_one(gpio, GPIOF_IN, ctrlr->full_name); + if (ret) + return ret; + + *out_hwirq = intspec[0]; + *out_type = (intsize > 1) ? intspec[1] : IRQ_TYPE_NONE; + + return 0; +} + +static struct irq_domain_ops omap_gpio_irq_ops = { + .xlate = omap_gpio_irq_domain_xlate, +}; + static int omap_gpio_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -1144,7 +1171,7 @@ static int omap_gpio_probe(struct platform_device *pdev) bank->domain = irq_domain_add_linear(node, bank->width, - &irq_domain_simple_ops, NULL); + &omap_gpio_irq_ops, bank); if (!bank->domain) return -ENODEV; -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
