diff options
Diffstat (limited to 'drivers/gpio/gpiolib-acpi.c')
| -rw-r--r-- | drivers/gpio/gpiolib-acpi.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c index 092ea4e5c9a8..bf0f8b476696 100644 --- a/drivers/gpio/gpiolib-acpi.c +++ b/drivers/gpio/gpiolib-acpi.c @@ -16,6 +16,7 @@ #include <linux/export.h> #include <linux/acpi.h> #include <linux/interrupt.h> +#include <linux/mutex.h> #include "gpiolib.h" @@ -26,7 +27,20 @@ struct acpi_gpio_event { unsigned int irq; }; +struct acpi_gpio_connection { + struct list_head node; + struct gpio_desc *desc; +}; + struct acpi_gpio_chip { + /* + * ACPICA requires that the first field of the context parameter + * passed to acpi_install_address_space_handler() is large enough + * to hold struct acpi_connection_info. + */ + struct acpi_connection_info conn_info; + struct list_head conns; + struct mutex conn_lock; struct gpio_chip *chip; struct list_head events; }; @@ -334,6 +348,153 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index, return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT); } +static acpi_status +acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address, + u32 bits, u64 *value, void *handler_context, + void *region_context) +{ + struct acpi_gpio_chip *achip = region_context; + struct gpio_chip *chip = achip->chip; + struct acpi_resource_gpio *agpio; + struct acpi_resource *ares; + acpi_status status; + bool pull_up; + int i; + + status = acpi_buffer_to_resource(achip->conn_info.connection, + achip->conn_info.length, &ares); + if (ACPI_FAILURE(status)) + return status; + + if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) { + ACPI_FREE(ares); + return AE_BAD_PARAMETER; + } + + agpio = &ares->data.gpio; + pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP; + + if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT && + function == ACPI_WRITE)) { + ACPI_FREE(ares); + return AE_BAD_PARAMETER; + } + + for (i = 0; i < agpio->pin_table_length; i++) { + unsigned pin = agpio->pin_table[i]; + struct acpi_gpio_connection *conn; + struct gpio_desc *desc; + bool found; + + desc = gpiochip_get_desc(chip, pin); + if (IS_ERR(desc)) { + status = AE_ERROR; + goto out; + } + + mutex_lock(&achip->conn_lock); + + found = false; + list_for_each_entry(conn, &achip->conns, node) { + if (conn->desc == desc) { + found = true; + break; + } + } + if (!found) { + int ret; + + ret = gpiochip_request_own_desc(desc, "ACPI:OpRegion"); + if (ret) { + status = AE_ERROR; + mutex_unlock(&achip->conn_lock); + goto out; + } + + switch (agpio->io_restriction) { + case ACPI_IO_RESTRICT_INPUT: + gpiod_direction_input(desc); + break; + case ACPI_IO_RESTRICT_OUTPUT: + /* + * ACPI GPIO resources don't contain an + * initial value for the GPIO. Therefore we + * deduce that value from the pull field + * instead. If the pin is pulled up we + * assume default to be high, otherwise + * low. + */ + gpiod_direction_output(desc, pull_up); + break; + default: + /* + * Assume that the BIOS has configured the + * direction and pull accordingly. + */ + break; + } + + conn = kzalloc(sizeof(*conn), GFP_KERNEL); + if (!conn) { + status = AE_NO_MEMORY; + gpiochip_free_own_desc(desc); + mutex_unlock(&achip->conn_lock); + goto out; + } + + conn->desc = desc; + list_add_tail(&conn->node, &achip->conns); + } + + mutex_unlock(&achip->conn_lock); + + if (function == ACPI_WRITE) + gpiod_set_raw_value(desc, !!((1 << i) & *value)); + else + *value |= gpiod_get_raw_value(desc) << i; + } + +out: + ACPI_FREE(ares); + return status; +} + +static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip) +{ + struct gpio_chip *chip = achip->chip; + acpi_handle handle = ACPI_HANDLE(chip->dev); + acpi_status status; + + INIT_LIST_HEAD(&achip->conns); + mutex_init(&achip->conn_lock); + status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO, + acpi_gpio_adr_space_handler, + NULL, achip); + if (ACPI_FAILURE(status)) + dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n"); +} + +static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip) +{ + struct gpio_chip *chip = achip->chip; + acpi_handle handle = ACPI_HANDLE(chip->dev); + struct acpi_gpio_connection *conn, *tmp; + acpi_status status; + + status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO, + acpi_gpio_adr_space_handler); + if (ACPI_FAILURE(status)) { + dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n"); + return; + } + + list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) { + gpiochip_free_own_desc(conn->desc); + list_del(&conn->node); + kfree(conn); + } +} + void acpi_gpiochip_add(struct gpio_chip *chip) { struct acpi_gpio_chip *acpi_gpio; @@ -361,6 +522,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip) } acpi_gpiochip_request_interrupts(acpi_gpio); + acpi_gpiochip_request_regions(acpi_gpio); } void acpi_gpiochip_remove(struct gpio_chip *chip) @@ -379,6 +541,7 @@ void acpi_gpiochip_remove(struct gpio_chip *chip) return; } + acpi_gpiochip_free_regions(acpi_gpio); acpi_gpiochip_free_interrupts(acpi_gpio); acpi_detach_data(handle, acpi_gpio_chip_dh); |