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-rw-r--r--drivers/gpio/gpiolib-acpi.c163
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);