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Subject[RFC PATCH v2 03/16] ACPI: Allow drivers to match using Device Tree compatible property
Date
We have lots of existing Device Tree enabled drivers and allocating
separate _HID for each is not feasible. Instead we allocate special _HID
"PRP0001" that means that the match should be done using Device Tree
compatible property using driver's .of_match_table instead.

If there is a need to distinguish from where the device is enumerated
(DT/ACPI) driver can check dev->of_node or ACPI_COMPATION(dev).

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/acpi/property.c | 34 ++++++++++++++++++
drivers/acpi/scan.c | 91 +++++++++++++++++++++++++++++++++++++++++++------
include/acpi/acpi_bus.h | 1 +
include/linux/acpi.h | 8 ++---
4 files changed, 118 insertions(+), 16 deletions(-)

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index e50964012da8..c6c3ab6f68c3 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -76,6 +76,37 @@ static bool acpi_properties_format_valid(const union acpi_object *properties)
return true;
}

+static void acpi_init_of_compatible(struct acpi_device *adev)
+{
+ const union acpi_object *of_compatible;
+ struct acpi_hardware_id *hwid;
+ bool acpi_of = false;
+
+ /*
+ * Check if the special PRP0001 ACPI ID is present and in that
+ * case we fill in Device Tree compatible properties for this
+ * device.
+ */
+ list_for_each_entry(hwid, &adev->pnp.ids, list) {
+ if (!strcmp(hwid->id, "PRP0001")) {
+ acpi_of = true;
+ break;
+ }
+ }
+
+ if (!acpi_of)
+ return;
+
+ if (acpi_dev_get_property_array(adev, "compatible", ACPI_TYPE_STRING,
+ &of_compatible)) {
+ acpi_handle_warn(adev->handle,
+ "PRP0001 requires compatible property\n");
+ return;
+ }
+
+ adev->data.of_compatible = of_compatible;
+}
+
void acpi_init_properties(struct acpi_device *adev)
{
struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
@@ -119,6 +150,8 @@ void acpi_init_properties(struct acpi_device *adev)

adev->data.pointer = buf.pointer;
adev->data.properties = properties;
+
+ acpi_init_of_compatible(adev);
return;
}

@@ -130,6 +163,7 @@ void acpi_init_properties(struct acpi_device *adev)
void acpi_free_properties(struct acpi_device *adev)
{
ACPI_FREE((void *)adev->data.pointer);
+ adev->data.of_compatible = NULL;
adev->data.pointer = NULL;
adev->data.properties = NULL;
}
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index f4aabf9c0aad..0c8e751cbe6b 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -124,17 +124,43 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
if (list_empty(&acpi_dev->pnp.ids))
return 0;

- len = snprintf(modalias, size, "acpi:");
- size -= len;
+ /*
+ * If the device has PRP0001 we expose DT compatible modalias
+ * instead.
+ */
+ if (acpi_dev->data.of_compatible) {
+ const union acpi_object *of_compatible, *obj;
+ int i;
+
+ len = snprintf(modalias, size, "of:Nprp0001Tacpi");
+
+ of_compatible = acpi_dev->data.of_compatible;
+ for (i = 0; i < of_compatible->package.count; i++) {
+ obj = &of_compatible->package.elements[i];

- list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
- count = snprintf(&modalias[len], size, "%s:", id->id);
- if (count < 0)
- return -EINVAL;
- if (count >= size)
- return -ENOMEM;
- len += count;
- size -= count;
+ count = snprintf(&modalias[len], size, "C%s",
+ obj->string.pointer);
+ if (count < 0)
+ return -EINVAL;
+ if (count >= size)
+ return -ENOMEM;
+
+ len += count;
+ size -= count;
+ }
+ } else {
+ len = snprintf(modalias, size, "acpi:");
+ size -= len;
+
+ list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
+ count = snprintf(&modalias[len], size, "%s:", id->id);
+ if (count < 0)
+ return -EINVAL;
+ if (count >= size)
+ return -ENOMEM;
+ len += count;
+ size -= count;
+ }
}

modalias[len] = '\0';
@@ -864,6 +890,51 @@ int acpi_match_device_ids(struct acpi_device *device,
}
EXPORT_SYMBOL(acpi_match_device_ids);

+/* Performs match for special "PRP0001" shoehorn ACPI ID */
+static bool acpi_of_driver_match_device(struct device *dev,
+ const struct device_driver *drv)
+{
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+ const union acpi_object *of_compatible;
+ int i;
+
+ /*
+ * If the ACPI device does not have corresponding compatible
+ * property or the driver in question does not have DT matching
+ * table we consider the match succesful (matches the ACPI ID).
+ */
+ of_compatible = adev->data.of_compatible;
+ if (!drv->of_match_table || !of_compatible)
+ return true;
+
+ /* Now we can look for the driver DT compatible strings */
+ for (i = 0; i < of_compatible->package.count; i++) {
+ const struct of_device_id *id;
+ const union acpi_object *obj;
+
+ obj = &of_compatible->package.elements[i];
+
+ for (id = drv->of_match_table; id->compatible[0]; id++)
+ if (!strcasecmp(obj->string.pointer, id->compatible))
+ return true;
+ }
+
+ return false;
+}
+
+bool acpi_driver_match_device(struct device *dev,
+ const struct device_driver *drv)
+{
+ const struct acpi_device_id *id;
+
+ id = acpi_match_device(drv->acpi_match_table, dev);
+ if (!id)
+ return false;
+
+ return acpi_of_driver_match_device(dev, drv);
+}
+EXPORT_SYMBOL_GPL(acpi_driver_match_device);
+
static void acpi_free_power_resources_lists(struct acpi_device *device)
{
int i;
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 620b4f89c87b..65866e23e3e9 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -341,6 +341,7 @@ struct acpi_device_physical_node {
struct acpi_device_data {
const union acpi_object *pointer;
const union acpi_object *properties;
+ const union acpi_object *of_compatible;
};

/* Device */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 288abbdf2fb4..37a5280a64a5 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -424,12 +424,8 @@ extern int acpi_nvs_for_each_region(int (*func)(__u64, __u64, void *),
const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids,
const struct device *dev);

-static inline bool acpi_driver_match_device(struct device *dev,
- const struct device_driver *drv)
-{
- return !!acpi_match_device(drv->acpi_match_table, dev);
-}
-
+extern bool acpi_driver_match_device(struct device *dev,
+ const struct device_driver *drv);
int acpi_device_uevent_modalias(struct device *, struct kobj_uevent_env *);
int acpi_device_modalias(struct device *, char *, int);

--
2.1.0


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