support IRQ from GPIO trough OF and GPIOLIB

[Henk Stegeman]

I just saw that I missed an earlier very useful a suggestion from Grant Likely:

http://ozlabs.org/pipermail/linuxppc-dev/2009-February/068357.html

By defining the irq in the dts directly I don't need the gpio irq
support anymore.


On Thu, Mar 5, 2009 at 12:20 PM, Henk Stegeman <henk.stegeman at gmail.com> wrote:
> I forgot to include my  changes in arch/powerpc/include/asm/gpio.h:
>
> diff --git a/arch/powerpc/include/asm/gpio.h b/arch/powerpc/include/asm/gpio.h
> index ea04632..38762ed 100644
> --- a/arch/powerpc/include/asm/gpio.h
> +++ b/arch/powerpc/include/asm/gpio.h
> @@ -38,12 +38,9 @@ static inline int gpio_cansleep(unsigned int gpio)
>        return __gpio_cansleep(gpio);
>  }
>
> -/*
> - * Not implemented, yet.
> - */
>  static inline int gpio_to_irq(unsigned int gpio)
>  {
> -       return -ENOSYS;
> +       return __gpio_to_irq(gpio);
>  }
>
>  static inline int irq_to_gpio(unsigned int irq)
>
>
> On Thu, Mar 5, 2009 at 12:15 PM, Henk Stegeman <henk.stegeman at gmail.com> wrote:
>> Hello,
>>
>> I have an SPI device that sends an IRQ to the CPU (MPC5200) via GPIO (GPT6):
>>
>> gpt6: timer at 660 {       // General Purpose Timer GPT6 in GPIO mode for
>> SMC4000IO sample irq.
>>        compatible = "fsl,mpc5200b-gpt-gpio","fsl,mpc5200-gpt-gpio";
>>        cell-index = <6>;
>>        reg = <0x660 0x10>;
>>        interrupts = <1 15 0>;
>>        interrupt-parent = <&mpc5200_pic>;
>>        gpio-controller;
>>        #gpio-cells = <2>;
>> };
>>
>> spi at f00 {
>>        #address-cells = <1>;
>>        #size-cells = <0>;
>>        compatible = "fsl,mpc5200b-spi","fsl,mpc5200-spi";
>>        reg = <0xf00 0x20>;
>>        interrupts = <2 13 0 2 14 0>;
>>        interrupt-parent = <&mpc5200_pic>;
>>        gpios = <&gpt4 0 0>;
>>
>>        io-controller at 0 {
>>                compatible = "microkey,smc4000io";
>>                linux,modalias = "of_smc4000io";
>>                spi-max-frequency = <1000000>;
>>                spi-cpha;
>>                reg = <0>;
>>                // gpios: first is IRQ to cpu
>>                gpios = <&gpt6 0 0>;
>>                word-delay-us = <0>;
>>        };
>> };
>>
>> I've got it working for a mm_gpio, but it's probably not the right
>> approach, I have the following questions to get to the right solution:
>> - Should gpiolib's gpio_to_irq function indeed return the IRQ that was
>> specified at the GPIO by the DTS (interrupts = <1 15 0>)?
>>  The effect is that if the IRQ is not specified in the DTS the
>> gpio_to_irq returns NO_IRQ.
>>  (On the MPC5200 the IRQ is fixed for GPT6, so instead the cell-index
>> could also be used to return a gpio's IRQ)
>> - If a GPIO controller supports several GPIOs but one IRQ, is it
>> defined what gpio_to_irq should return?
>> - Is it okay for gpio_to_irq to return NO_IRQ?  (returned by
>> irq_of_parse_and_map) if irq is not defined?
>>
>>
>> Henk.
>>
>> diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
>> index 6eea601..81927d7 100644
>> --- a/drivers/of/gpio.c
>> +++ b/drivers/of/gpio.c
>> @@ -150,6 +150,17 @@ int of_gpio_simple_xlate(struct of_gpio_chip
>> *of_gc, struct device_node *np,
>>  }
>>  EXPORT_SYMBOL(of_gpio_simple_xlate);
>>
>> +static int of_mm_gpio_to_irq(struct gpio_chip *gc, unsigned int gpio)
>> +{
>> +       struct of_mm_gpio_chip *mm_gc;
>> +       struct of_gpio_chip *of_gc;
>> +
>> +       of_gc = container_of(gc, struct of_gpio_chip, gc);
>> +       mm_gc = container_of(of_gc, struct of_mm_gpio_chip, of_gc);
>> +       return mm_gc->irq;
>> +
>> +}
>> +
>>  /**
>>  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
>>  * @np:                device node of the GPIO chip
>> @@ -188,6 +199,9 @@ int of_mm_gpiochip_add(struct device_node *np,
>>
>>        gc->base = -1;
>>
>> +       mm_gc->irq = irq_of_parse_and_map(np, 0);
>> +       gc->to_irq = of_mm_gpio_to_irq;
>> +
>>        if (!of_gc->xlate)
>>                of_gc->xlate = of_gpio_simple_xlate;
>>
>> diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
>> index fc2472c..17fe9ed 100644
>> --- a/include/linux/of_gpio.h
>> +++ b/include/linux/of_gpio.h
>> @@ -54,6 +54,7 @@ struct of_mm_gpio_chip {
>>        struct of_gpio_chip of_gc;
>>        void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
>>        void __iomem *regs;
>> +       int irq;
>>  };
>>
>>  static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
>>
>