ACPI / property: Drop size_prop from acpi_dev_get_property_reference()

The size_prop argument of the recently added function
acpi_dev_get_property_reference() is not used by the only current
caller of that function and is very unlikely to be used at any time
going forward.

Namely, for a property whose value is a list of items each containing
a references to a device object possibly accompanied by some integers,
the number of items in the list can always be computed as the number
of elements of type ACPI_TYPE_LOCAL_REFERENCE in the property package.
Thus it should never be necessary to provide an additional "cells"
property with a value equal to the number of items in that list.  It
also should never be necessary to provide a "cells" property specifying
how many integers are supposed to be following each reference.

For this reason, drop the size_prop argument from
acpi_dev_get_property_reference() and update its caller accordingly.

Link: http://marc.info/?l=linux-kernel&m=141511255610556&w=2
Suggested-by: Grant Likely <grant.likely@linaro.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index 27add91bc270e2e142b92957cd8e166ce4c4f331..0d083736e25babf920140d9b0c88a84b47d6d729 100644 (file)
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -273,25 +273,21 @@ EXPORT_SYMBOL_GPL(acpi_dev_get_property_array);
  * acpi_dev_get_property_reference - returns handle to the referenced object
  * @adev: ACPI device to get property
  * @name: Name of the property
- * @size_prop: Name of the "size" property in referenced object
  * @index: Index of the reference to return
  * @args: Location to store the returned reference with optional arguments
  *
  * Find property with @name, verifify that it is a package containing at least
  * one object reference and if so, store the ACPI device object pointer to the
- * target object in @args->adev.
+ * target object in @args->adev.  If the reference includes arguments, store
+ * them in the @args->args[] array.
  *
- * If the reference includes arguments (@size_prop is not %NULL) follow the
- * reference and check whether or not there is an integer property @size_prop
- * under the target object and if so, whether or not its value matches the
- * number of arguments that follow the reference.  If there's more than one
- * reference in the property value package, @index is used to select the one to
- * return.
+ * If there's more than one reference in the property value package, @index is
+ * used to select the one to return.
  *
  * Return: %0 on success, negative error code on failure.
  */
-int acpi_dev_get_property_reference(struct acpi_device *adev, const char *name,
-                                   const char *size_prop, size_t index,
+int acpi_dev_get_property_reference(struct acpi_device *adev,
+                                   const char *name, size_t index,
                                    struct acpi_reference_args *args)
 {
        const union acpi_object *element, *end;
@@ -308,7 +304,7 @@ int acpi_dev_get_property_reference(struct acpi_device *adev, const char *name,
         * return that reference then.
         */
        if (obj->type == ACPI_TYPE_LOCAL_REFERENCE) {
-               if (size_prop || index)
+               if (index)
                        return -EINVAL;
 
                ret = acpi_bus_get_device(obj->reference.handle, &device);
@@ -348,42 +344,16 @@ int acpi_dev_get_property_reference(struct acpi_device *adev, const char *name,
                element++;
                nargs = 0;
 
-               if (size_prop) {
-                       const union acpi_object *prop;
-
-                       /*
-                        * Find out how many arguments the refenced object
-                        * expects by reading its size_prop property.
-                        */
-                       ret = acpi_dev_get_property(device, size_prop,
-                                                   ACPI_TYPE_INTEGER, &prop);
-                       if (ret)
-                               return ret;
-
-                       nargs = prop->integer.value;
-                       if (nargs > MAX_ACPI_REFERENCE_ARGS
-                           || element + nargs > end)
-                               return -EPROTO;
+               /* assume following integer elements are all args */
+               for (i = 0; element + i < end; i++) {
+                       int type = element[i].type;
 
-                       /*
-                        * Skip to the start of the arguments and verify
-                        * that they all are in fact integers.
-                        */
-                       for (i = 0; i < nargs; i++)
-                               if (element[i].type != ACPI_TYPE_INTEGER)
-                                       return -EPROTO;
-               } else {
-                       /* assume following integer elements are all args */
-                       for (i = 0; element + i < end; i++) {
-                               int type = element[i].type;
-
-                               if (type == ACPI_TYPE_INTEGER)
-                                       nargs++;
-                               else if (type == ACPI_TYPE_LOCAL_REFERENCE)
-                                       break;
-                               else
-                                       return -EPROTO;
-                       }
+                       if (type == ACPI_TYPE_INTEGER)
+                               nargs++;
+                       else if (type == ACPI_TYPE_LOCAL_REFERENCE)
+                               break;
+                       else
+                               return -EPROTO;
                }
 
                if (idx++ == index) {

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 5a4d061e787e7c2bc27c871d1842cc2713ab8252..ba98bb59a58f23c20a1945d72c6849f267f0e91b 100644 (file)
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -405,7 +405,7 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
                dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
 
                memset(&args, 0, sizeof(args));
-               ret = acpi_dev_get_property_reference(adev, propname, NULL,
+               ret = acpi_dev_get_property_reference(adev, propname,
                                                      index, &args);
                if (ret) {
                        bool found = acpi_get_driver_gpio_data(adev, propname,

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 0902426c4521d5a7db6b32c687c3a338b879e6fc..10f2ed95645c54b2c2379890573d30bce38226d6 100644 (file)
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -718,8 +718,8 @@ int acpi_dev_get_property(struct acpi_device *adev, const char *name,
 int acpi_dev_get_property_array(struct acpi_device *adev, const char *name,
                                acpi_object_type type,
                                const union acpi_object **obj);
-int acpi_dev_get_property_reference(struct acpi_device *adev, const char *name,
-                                   const char *cells_name, size_t index,
+int acpi_dev_get_property_reference(struct acpi_device *adev,
+                                   const char *name, size_t index,
                                    struct acpi_reference_args *args);
 
 int acpi_dev_prop_get(struct acpi_device *adev, const char *propname,