linux-kernel - [PATCH] ACPI / platform: use ACPI device name instead of _HID.

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Message-Id: <1352203971-9219-1-git-send-email-mika.westerberg@linux.intel.com>
Date:	Tue,  6 Nov 2012 14:12:51 +0200
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	linux-kernel@...r.kernel.org
Cc:	lenb@...nel.org, rjw@...k.pl, linux-acpi@...r.kernel.org,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: [PATCH] ACPI / platform: use ACPI device name instead of _HID._UID

Using _UID makes the ACPI platform bus code to depend on BIOS to get it
right. If it doesn't we fail to create the platform device as the name
should be unique.

The ACPI core already makes an unique name when it first creates the ACPI
device so we can use that same name as the platform device name instead of
trusting that the BIOS sets the _UIDs correctly.

Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>
---
This was suggested by Bjorn Helgaas in another thread. The patch applies on
top of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git
linux-next.

 drivers/acpi/acpi_platform.c |   62 +++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 40 deletions(-)

diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
index a5a2346..dbb31d6 100644
--- a/drivers/acpi/acpi_platform.c
+++ b/drivers/acpi/acpi_platform.c
@@ -120,25 +120,6 @@ static acpi_status acpi_platform_add_resources(struct acpi_resource *res,
 	return AE_OK;
 }
 
-static acpi_status acpi_platform_get_device_uid(struct acpi_device *adev,
-						int *uid)
-{
-	struct acpi_device_info *info;
-	acpi_status status;
-
-	status = acpi_get_object_info(adev->handle, &info);
-	if (ACPI_FAILURE(status))
-		return status;
-
-	status = AE_NOT_EXIST;
-	if ((info->valid & ACPI_VALID_UID) &&
-	     !kstrtoint(info->unique_id.string, 0, uid))
-		status = AE_OK;
-
-	kfree(info);
-	return status;
-}
-
 /**
  * acpi_create_platform_device - Create platform device for ACPI device node
  * @adev: ACPI device node to create a platform device for.
@@ -156,19 +137,12 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev)
 	struct device *parent = NULL;
 	struct resource_info ri;
 	acpi_status status;
-	int devid;
 
 	/* If the ACPI node already has a physical device attached, skip it. */
 	if (adev->physical_node_count)
 		return NULL;
 
-	/* Use the UID of the device as the new platform device id if found. */
-	status = acpi_platform_get_device_uid(adev, &devid);
-	if (ACPI_FAILURE(status))
-		devid = -1;
-
 	memset(&ri, 0, sizeof(ri));
-
 	/* First, count the resources. */
 	status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
 				     acpi_platform_count_resources, &ri);
@@ -214,8 +188,8 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev)
 		}
 		mutex_unlock(&acpi_parent->physical_node_lock);
 	}
-	pdev = platform_device_register_resndata(parent, acpi_device_hid(adev),
-						 devid, ri.res, ri.n, NULL, 0);
+	pdev = platform_device_register_resndata(parent, dev_name(&adev->dev),
+						 -1, ri.res, ri.n, NULL, 0);
 	if (IS_ERR(pdev)) {
 		dev_err(&adev->dev, "platform device creation failed: %ld\n",
 			PTR_ERR(pdev));
@@ -245,17 +219,7 @@ static acpi_status acpi_platform_match(acpi_handle handle, u32 depth,
 	if (adev->physical_node_count)
 		return AE_OK;
 
-	if (!strcmp(pdev->name, acpi_device_hid(adev))) {
-		int devid;
-
-		/* Check that both name and UID match if it exists */
-		status = acpi_platform_get_device_uid(adev, &devid);
-		if (ACPI_FAILURE(status))
-			devid = -1;
-
-		if (pdev->id != devid)
-			return AE_OK;
-
+	if (!strcmp(dev_name(&pdev->dev), dev_name(&adev->dev))) {
 		*(acpi_handle *)return_value = handle;
 		return AE_CTRL_TERMINATE;
 	}
@@ -266,10 +230,28 @@ static acpi_status acpi_platform_match(acpi_handle handle, u32 depth,
 static int acpi_platform_find_device(struct device *dev, acpi_handle *handle)
 {
 	struct platform_device *pdev = to_platform_device(dev);
+	char *name, *tmp, *hid;
+
+	/*
+	 * The platform device is named using the ACPI device name
+	 * _HID:INSTANCE so we strip the INSTANCE out in order to find the
+	 * correct device using its _HID.
+	 */
+	name = kstrdup(dev_name(dev), GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	tmp = name;
+	hid = strsep(&tmp, ":");
+	if (!hid) {
+		kfree(name);
+		return -ENODEV;
+	}
 
 	*handle = NULL;
-	acpi_get_devices(pdev->name, acpi_platform_match, pdev, handle);
+	acpi_get_devices(hid, acpi_platform_match, pdev, handle);
 
+	kfree(name);
 	return *handle ? 0 : -ENODEV;
 }
 
-- 
1.7.10.4

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