> From: linux-acpi-ow...@vger.kernel.org
> [mailto:linux-acpi-ow...@vger.kernel.org] On Behalf Of Mika Westerberg
> Sent: Friday, September 13, 2013 11:15 PM
>
> GPIO operation regions is a new feature introduced in ACPI 5.0
> specification. In practise it means that now ASL code can toggle GPIOs with
> the help of the OS GPIO driver.
>
> An imaginary example of such ASL code:
>
> Device (\SB.GPIO)
> {
> // _REG is called when the operation region handler is
> // installed.
> Method (_REG)
> {
> ...
> }
>
> OperationRegion (GPOP, GeneralPurposeIo, 0, 0xc)
> Field (GPOP, ByteAcc, NoLock, Preserve)
> {
> Connection
> (
> GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
> IoRestrictionOutputOnly, "\\_SB.GPIO",
> 0x00, ResourceConsumer,,)
> {
> 0x0005
> }
> ),
> PWR0, 1
> }
>
> ...
> }
>
> Device (\SB.DEV0)
> {
> ...
>
> Method (_PS0, 0, Serialized)
> {
> // Toggle the GPIO
> Store (1, \SB.GPIO.PWR0)
> }
>
> Method (_PS3, 0, Serialized)
> {
> Store (0, \SB.GPIO.PRW0)
> }
> }
>
> The device \SB.DEV0 is powered on by asserting \SB.GPIO.PWR0 GPIO line. So
> when the OS calls _PS0 or _PS3, that GPIO line should be set to 1 or 0 by
> the actual GPIO driver.
>
> In order to support GPIO operation regions we install ACPI address space
> handler for the device (provided that it has an ACPI handle). This handler
> uses the standard GPIO APIs to toggle the pin according to what the ASL
> code does.
>
> Since there is need to attach more data to the ACPI object, we create a new
> structure acpi_gpio_chip_data that contains data for both GPIO operation
> regions and for ACPI event handling and make the event handling code to use
> this new structure.
>
> Signed-off-by: Mika Westerberg <mika.westerb...@linux.intel.com>
> ---
> drivers/gpio/gpiolib-acpi.c | 131
> ++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 126 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index e12a08e..f52536a 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -24,6 +24,17 @@ struct acpi_gpio_evt_pin {
> unsigned int irq;
> };
>
> +struct acpi_gpio_chip_data {
> + /*
> + * acpi_install_address_space_handler() wants to put the connection
> + * information at the start of the context structure we pass it, in
> + * case we are dealing with GPIO operation regions.
> + */
> + struct acpi_connection_info ci;
> + struct gpio_chip *chip;
> + struct list_head *evt_pins;
> +};
> +
> static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
> {
> if (!gc->dev)
> @@ -86,7 +97,7 @@ static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void
> *data)
> return IRQ_HANDLED;
> }
>
> -static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
> +static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
> {
> /* The address of this function is used as a key. */
> }
> @@ -127,12 +138,16 @@ static void acpi_gpiochip_request_interrupts(struct
> gpio_chip *chip)
> if (ACPI_SUCCESS(status)) {
> evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
> if (evt_pins) {
> + struct acpi_gpio_chip_data *data;
> +
> INIT_LIST_HEAD(evt_pins);
> - status = acpi_attach_data(handle, acpi_gpio_evt_dh,
> - evt_pins);
> + status = acpi_get_data(handle, acpi_gpio_chip_dh,
> + (void **)&data);
> if (ACPI_FAILURE(status)) {
> kfree(evt_pins);
> evt_pins = NULL;
> + } else {
> + data->evt_pins = evt_pins;
> }
> }
> }
> @@ -293,6 +308,7 @@ static void acpi_gpiochip_free_interrupts(struct
> gpio_chip *chip)
> acpi_status status;
> struct list_head *evt_pins;
> struct acpi_gpio_evt_pin *evt_pin, *ep;
> + struct acpi_gpio_chip_data *data;
>
> if (!chip->dev || !chip->to_irq)
> return;
> @@ -301,28 +317,133 @@ static void acpi_gpiochip_free_interrupts(struct
> gpio_chip *chip)
> if (!handle)
> return;
>
> - status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
> + status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&data);
> if (ACPI_FAILURE(status))
> return;
>
> + evt_pins = data->evt_pins;
> + data->evt_pins = NULL;
> +
> list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
> devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
> list_del(&evt_pin->node);
> kfree(evt_pin);
> }
>
> - acpi_detach_data(handle, acpi_gpio_evt_dh);
> kfree(evt_pins);
> }
>
> +static acpi_status
> +acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
> + u32 bits, u64 *value, void *handler_context,
> + void *reqion_context)
> +{
> + struct acpi_gpio_chip_data *data = handler_context;
> + struct gpio_chip *chip = data->chip;
> + struct acpi_resource *ares;
> + int ret, gpio = -EINVAL;
> + unsigned long flags = 0;
> + acpi_status status;
> +
> + status = acpi_buffer_to_resource(data->ci.connection, data->ci.length,
> + &ares);
> + if (ACPI_FAILURE(status))
> + return status;
> +
> + if (ares->type == ACPI_RESOURCE_TYPE_GPIO) {
> + const struct acpi_resource_gpio *agpio = &ares->data.gpio;
> +
> + switch (agpio->io_restriction) {
> + case ACPI_IO_RESTRICT_NONE:
> + flags = GPIOF_DIR_IN | GPIOF_DIR_OUT;
> + break;
> + case ACPI_IO_RESTRICT_INPUT:
> + flags = GPIOF_DIR_IN;
> + break;
> + case ACPI_IO_RESTRICT_OUTPUT:
> + flags = GPIOF_DIR_OUT;
> + break;
> + }
> +
> + gpio = acpi_get_gpio(agpio->resource_source.string_ptr,
> + agpio->pin_table[0]);
> + }
> +
> + ACPI_FREE(ares);
> +
> + if (!gpio_is_valid(gpio)) {
> + dev_err(chip->dev, "GpioOpReg: invalid GPIO resource\n");
> + return AE_ERROR;
> + }
> +
> + ret = gpio_request_one(gpio, flags, "acpi_gpio_adr_space");
> + if (ret) {
> + dev_err(chip->dev, "GpioOpReg: failed to request GPIO\n");
> + return AE_ERROR;
> + }
> +
> + if (function == ACPI_WRITE)
> + gpio_set_value(gpio, (int)*value);
> + else
> + *value = gpio_get_value(gpio);
> +
> + gpio_free(gpio);
> + return AE_OK;
> +}
> +
> void acpi_gpiochip_add(struct gpio_chip *chip)
> {
> + struct acpi_gpio_chip_data *data;
> + acpi_handle handle;
> + acpi_status status;
> +
> + handle = ACPI_HANDLE(chip->dev);
> + if (!handle)
> + return;
> +
> + data = kzalloc(sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return;
> +
> + status = acpi_attach_data(handle, acpi_gpio_chip_dh, data);
> + if (ACPI_FAILURE(status)) {
> + kfree(data);
> + return;
> + }
> +
> + data->chip = chip;
> +
> + status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
> + acpi_gpio_adr_space_handler,
> + NULL, data);
Is it possible to install the handler for ACPI_ROOT_OBJECT?
Can it be achieved by implementing a setup callback?
Maybe you can also eliminate acpi_attach_data usages by doing so.
> + if (ACPI_FAILURE(status)) {
> + acpi_detach_data(handle, acpi_gpio_chip_dh);
> + kfree(data);
> + return;
> + }
> +
> acpi_gpiochip_request_interrupts(chip);
> }
> EXPORT_SYMBOL_GPL(acpi_gpiochip_add);
>
> void acpi_gpiochip_remove(struct gpio_chip *chip)
> {
> + struct acpi_gpio_chip_data *data;
> + acpi_handle handle;
> + acpi_status status;
> +
> + handle = ACPI_HANDLE(chip->dev);
> + if (!handle)
> + return;
> +
> + status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&data);
> + if (ACPI_FAILURE(status))
> + return;
> +
> acpi_gpiochip_free_interrupts(chip);
> + acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
> + acpi_gpio_adr_space_handler);
> + acpi_detach_data(handle, acpi_gpio_chip_dh);
> + kfree(data);
> }
> EXPORT_SYMBOL_GPL(acpi_gpiochip_remove);
> --
> 1.8.4.rc3
>
> --
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