linux-kernel - Re: [RFC PATCH] gpiolib-acpi: Add ACPI5 event model support to gpio.

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Message-ID: <27194841.b5MO8Pt3Ve@vostro.rjw.lan>
Date:	Fri, 25 Jan 2013 13:25:03 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Mathias Nyman <mathias.nyman@...ux.intel.com>
Cc:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Linus <linus.walleij@...aro.org>, grant.likely@...retlab.ca,
	linux-acpi@...r.kernel.org, Zhang Rui <rui.zhang@...el.com>,
	tianyu.lan@...el.com, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] gpiolib-acpi: Add ACPI5 event model support to gpio.

On Friday, January 25, 2013 01:48:25 PM Mathias Nyman wrote:
> Add ability to handle ACPI events signalled by GPIO interrupts.
> 
> ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
> handled by ACPI event methods which need to be called from the GPIO
> controller's interrupt handler. acpi_gpio_request_interrupt() finds out which
> gpio pins have acpi event methods and assigns interrupt handlers that calls
> the acpi event methods for those pins.
> 
> Partially based on work by Rui Zhang <rui.zhang@...el.com>
> 
> Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> ---
>  drivers/gpio/gpiolib-acpi.c |   80 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/acpi_gpio.h   |    4 ++
>  2 files changed, 84 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index cbad6e9..b6ab041 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -15,6 +15,7 @@
>  #include <linux/export.h>
>  #include <linux/acpi_gpio.h>
>  #include <linux/acpi.h>
> +#include <linux/interrupt.h>
>  
>  static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
>  {
> @@ -52,3 +53,82 @@ int acpi_get_gpio(char *path, int pin)
>  	return chip->base + pin;
>  }
>  EXPORT_SYMBOL_GPL(acpi_get_gpio);
> +
> +
> +static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
> +{
> +	acpi_handle handle = data;
> +
> +	acpi_evaluate_object(handle, NULL, NULL, NULL);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/**
> + * acpi_gpio_request_interrupt() - Register isr for gpio controller ACPI events
> + * @chip:      gpio chip representation of the gpio controller
> + *
> + * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
> + * handled by ACPI event methods which need to be called from the GPIO
> + * controller's interrupt handler. acpi_gpio_request_interrupt finds out which
> + * gpio pins have acpi event methods and assigns interrupt handlers that calls
> + * the acpi event methods for those pins.
> + */
> +
> +void acpi_gpio_request_interrupt(struct gpio_chip *chip)
> +{
> +	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_resource *res;
> +	acpi_handle handle, ev_handle;
> +	acpi_status status;
> +	unsigned int pin, irq;
> +	char ev_name[5];
> +
> +	if (!chip->dev || !chip->to_irq)
> +		return;
> +
> +	handle = ACPI_HANDLE(chip->dev);
> +	if (!handle)
> +		return;
> +
> +	status = acpi_get_event_resources(handle, &buf);
> +	if (ACPI_FAILURE(status))
> +		return;
> +
> +	/* If a gpio interrupt has an acpi event handler method, then
> +	 * set up an interrupt handler that calls the acpi event handler
> +	 */
> +
> +	for (res = buf.pointer;
> +	     res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
> +	     res = ACPI_NEXT_RESOURCE(res)) {
> +
> +		if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
> +		    res->data.gpio.connection_type !=
> +		    ACPI_RESOURCE_GPIO_TYPE_INT)
> +			continue;
> +
> +		pin = res->data.gpio.pin_table[0];
> +		if (pin > chip->ngpio)
> +			continue;
> +
> +		sprintf(ev_name, "_%c%02X",
> +		res->data.gpio.triggering ? 'E' : 'L', pin);
> +
> +		status = acpi_get_handle(handle, ev_name, &ev_handle);
> +		if (ACPI_FAILURE(status))
> +			continue;
> +
> +		irq = chip->to_irq(chip, pin);
> +		if (irq < 0)
> +			continue;
> +
> +		/* Assume BIOS sets the triggering, so no flags */
> +		devm_request_threaded_irq(chip->dev, irq, NULL,
> +					  acpi_gpio_irq_handler,
> +					  0,
> +					  "GPIO-signaled-ACPI-event",
> +					  ev_handle);
> +	}
> +}
> +EXPORT_SYMBOL(acpi_gpio_request_interrupt);
> diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
> index 91615a3..43c541d 100644
> --- a/include/linux/acpi_gpio.h
> +++ b/include/linux/acpi_gpio.h
> @@ -2,10 +2,12 @@
>  #define _LINUX_ACPI_GPIO_H_
>  
>  #include <linux/errno.h>
> +#include <linux/gpio.h>
>  
>  #ifdef CONFIG_GPIO_ACPI
>  
>  int acpi_get_gpio(char *path, int pin);
> +void acpi_gpio_request_interrupt(struct gpio_chip *chip);
>  
>  #else /* CONFIG_GPIO_ACPI */
>  
> @@ -14,6 +16,8 @@ static inline int acpi_get_gpio(char *path, int pin)
>  	return -ENODEV;
>  }
>  
> +static inline void acpi_gpio_request_interrupt(struct gpio_chip *chip) { }
> +
>  #endif /* CONFIG_GPIO_ACPI */
>  
>  #endif /* _LINUX_ACPI_GPIO_H_ */
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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