From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Provide a way for device drivers using GPIOs described by ACPI
GpioIo resources in _CRS to tell the GPIO subsystem what names
(connection IDs) to associate with specific GPIO pins defined
in there.
To do that, a driver needs to define a mapping table as a
NULL-terminated array of struct acpi_gpio_mapping objects
that each contain a name, a pointer to an array of pin data
(struct acpi_gpio_params) objects and the size of that array.
Each struct acpi_gpio_params object consists of three fields,
crs_entry_index, pin_index, active_low, representing the index of
the target GpioIo()/GpioInt() resource in _CRS starting from zero,
the index of the target pin in that resource starting from zero,
and the active-low flag for that pin, respectively.
Next, the mapping table needs to be passed as the second argument to
acpi_dev_add_driver_gpios() that will register it with the ACPI device
object pointed to by its first argument. That object must represent
the ACPI namespace node containing the _CRS object referred to by the
GPIO mapping. That should be done in the driver's .probe() routine.
On removal, the driver should unregister its GPIO mapping table
by calling acpi_dev_remove_driver_gpios() on the ACPI device
object where that table was previously registered.
Included are fixes from Mika Westerberg.
Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
---
On top of the device-properties branch of the linux-pm.git tree at kernel.org.
---
drivers/gpio/gpiolib-acpi.c | 43 +++++++++++++++++++++++++++++++++++++++++--
include/acpi/acpi_bus.h | 3 +++
include/linux/acpi.h | 30 ++++++++++++++++++++++++++++++
3 files changed, 74 insertions(+), 2 deletions(-)
Index: linux-pm/include/acpi/acpi_bus.h
===================================================================
--- linux-pm.orig/include/acpi/acpi_bus.h
+++ linux-pm/include/acpi/acpi_bus.h
@@ -345,6 +345,8 @@ struct acpi_device_data {
const union acpi_object *of_compatible;
};
+struct acpi_gpio_mapping;
+
/* Device */
struct acpi_device {
int device_type;
@@ -366,6 +368,7 @@ struct acpi_device {
struct acpi_scan_handler *handler;
struct acpi_hotplug_context *hp;
struct acpi_driver *driver;
+ const struct acpi_gpio_mapping *driver_gpios;
void *driver_data;
struct device dev;
unsigned int physical_node_count;
Index: linux-pm/include/linux/acpi.h
===================================================================
--- linux-pm.orig/include/linux/acpi.h
+++ linux-pm/include/linux/acpi.h
@@ -672,6 +672,36 @@ do {
\
#endif
#endif
+struct acpi_gpio_params {
+ unsigned int crs_entry_index;
+ unsigned int pin_index;
+ bool active_low;
+};
+
+struct acpi_gpio_mapping {
+ const char *name;
+ const struct acpi_gpio_params *data;
+ unsigned int size;
+};
+
+#if defined(CONFIG_ACPI) && defined(CONFIG_GPIOLIB)
+int acpi_dev_add_driver_gpios(struct acpi_device *adev,
+ const struct acpi_gpio_mapping *gpios);
+
+static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev)
+{
+ if (adev)
+ adev->driver_gpios = NULL;
+}
+#else
+static inline int acpi_dev_add_driver_gpios(struct acpi_device *adev,
+ const struct acpi_gpio_mapping *gpios)
+{
+ return -ENXIO;
+}
+static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev) {}
+#endif
+
/* Device properties */
#define MAX_ACPI_REFERENCE_ARGS 8
Index: linux-pm/drivers/gpio/gpiolib-acpi.c
===================================================================
--- linux-pm.orig/drivers/gpio/gpiolib-acpi.c
+++ linux-pm/drivers/gpio/gpiolib-acpi.c
@@ -287,6 +287,41 @@ void acpi_gpiochip_free_interrupts(struc
}
}
+int acpi_dev_add_driver_gpios(struct acpi_device *adev,
+ const struct acpi_gpio_mapping *gpios)
+{
+ if (adev && gpios) {
+ adev->driver_gpios = gpios;
+ return 0;
+ }
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);
+
+static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
+ const char *name, int index,
+ struct acpi_reference_args *args)
+{
+ const struct acpi_gpio_mapping *gm;
+
+ if (!adev->driver_gpios)
+ return false;
+
+ for (gm = adev->driver_gpios; gm->name; gm++)
+ if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
+ const struct acpi_gpio_params *par = gm->data + index;
+
+ args->adev = adev;
+ args->args[0] = par->crs_entry_index;
+ args->args[1] = par->pin_index;
+ args->args[2] = par->active_low;
+ args->nargs = 3;
+ return true;
+ }
+
+ return false;
+}
+
struct acpi_gpio_lookup {
struct acpi_gpio_info info;
int index;
@@ -372,8 +407,12 @@ struct gpio_desc *acpi_get_gpiod_by_inde
memset(&args, 0, sizeof(args));
ret = acpi_dev_get_property_reference(adev, propname, NULL,
index, &args);
- if (ret)
- return ERR_PTR(ret);
+ if (ret) {
+ bool found = acpi_get_driver_gpio_data(adev, propname,
+ index, &args);
+ if (!found)
+ return ERR_PTR(ret);
+ }
/*
* The property was found and resolved so need to
--
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