> From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-owner@xxxxxxxxxxxxxxx] 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.westerberg@xxxxxxxxxxxxxxx> > --- > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
