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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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