Re: support IRQ from GPIO trough OF and GPIOLIB

[Henk Stegeman <henk.stegeman@gmail.com>]

I just saw that I missed an earlier very useful a suggestion from Grant Lik=
ely:

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@gmail.com> wr=
ote:
> I forgot to include my =A0changes in arch/powerpc/include/asm/gpio.h:
>
> diff --git a/arch/powerpc/include/asm/gpio.h b/arch/powerpc/include/asm/g=
pio.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)
> =A0 =A0 =A0 =A0return __gpio_cansleep(gpio);
> =A0}
>
> -/*
> - * Not implemented, yet.
> - */
> =A0static inline int gpio_to_irq(unsigned int gpio)
> =A0{
> - =A0 =A0 =A0 return -ENOSYS;
> + =A0 =A0 =A0 return __gpio_to_irq(gpio);
> =A0}
>
> =A0static inline int irq_to_gpio(unsigned int irq)
>
>
> On Thu, Mar 5, 2009 at 12:15 PM, Henk Stegeman <henk.stegeman@gmail.com> =
wrote:
>> Hello,
>>
>> I have an SPI device that sends an IRQ to the CPU (MPC5200) via GPIO (GP=
T6):
>>
>> gpt6: timer@660 { =A0 =A0 =A0 // General Purpose Timer GPT6 in GPIO mode=
 for
>> SMC4000IO sample irq.
>> =A0 =A0 =A0 =A0compatible =3D "fsl,mpc5200b-gpt-gpio","fsl,mpc5200-gpt-g=
pio";
>> =A0 =A0 =A0 =A0cell-index =3D <6>;
>> =A0 =A0 =A0 =A0reg =3D <0x660 0x10>;
>> =A0 =A0 =A0 =A0interrupts =3D <1 15 0>;
>> =A0 =A0 =A0 =A0interrupt-parent =3D <&mpc5200_pic>;
>> =A0 =A0 =A0 =A0gpio-controller;
>> =A0 =A0 =A0 =A0#gpio-cells =3D <2>;
>> };
>>
>> spi@f00 {
>> =A0 =A0 =A0 =A0#address-cells =3D <1>;
>> =A0 =A0 =A0 =A0#size-cells =3D <0>;
>> =A0 =A0 =A0 =A0compatible =3D "fsl,mpc5200b-spi","fsl,mpc5200-spi";
>> =A0 =A0 =A0 =A0reg =3D <0xf00 0x20>;
>> =A0 =A0 =A0 =A0interrupts =3D <2 13 0 2 14 0>;
>> =A0 =A0 =A0 =A0interrupt-parent =3D <&mpc5200_pic>;
>> =A0 =A0 =A0 =A0gpios =3D <&gpt4 0 0>;
>>
>> =A0 =A0 =A0 =A0io-controller@0 {
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0compatible =3D "microkey,smc4000io";
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0linux,modalias =3D "of_smc4000io";
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0spi-max-frequency =3D <1000000>;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0spi-cpha;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0reg =3D <0>;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0// gpios: first is IRQ to cpu
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0gpios =3D <&gpt6 0 0>;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0word-delay-us =3D <0>;
>> =A0 =A0 =A0 =A0};
>> };
>>
>> 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 =3D <1 15 0>)?
>> =A0The effect is that if the IRQ is not specified in the DTS the
>> gpio_to_irq returns NO_IRQ.
>> =A0(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? =A0(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,
>> =A0}
>> =A0EXPORT_SYMBOL(of_gpio_simple_xlate);
>>
>> +static int of_mm_gpio_to_irq(struct gpio_chip *gc, unsigned int gpio)
>> +{
>> + =A0 =A0 =A0 struct of_mm_gpio_chip *mm_gc;
>> + =A0 =A0 =A0 struct of_gpio_chip *of_gc;
>> +
>> + =A0 =A0 =A0 of_gc =3D container_of(gc, struct of_gpio_chip, gc);
>> + =A0 =A0 =A0 mm_gc =3D container_of(of_gc, struct of_mm_gpio_chip, of_g=
c);
>> + =A0 =A0 =A0 return mm_gc->irq;
>> +
>> +}
>> +
>> =A0/**
>> =A0* of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
>> =A0* @np: =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0device node of the GPIO chip
>> @@ -188,6 +199,9 @@ int of_mm_gpiochip_add(struct device_node *np,
>>
>> =A0 =A0 =A0 =A0gc->base =3D -1;
>>
>> + =A0 =A0 =A0 mm_gc->irq =3D irq_of_parse_and_map(np, 0);
>> + =A0 =A0 =A0 gc->to_irq =3D of_mm_gpio_to_irq;
>> +
>> =A0 =A0 =A0 =A0if (!of_gc->xlate)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0of_gc->xlate =3D 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 {
>> =A0 =A0 =A0 =A0struct of_gpio_chip of_gc;
>> =A0 =A0 =A0 =A0void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
>> =A0 =A0 =A0 =A0void __iomem *regs;
>> + =A0 =A0 =A0 int irq;
>> =A0};
>>
>> =A0static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_=
chip *gc)
>>
>