On 12/19/2014 12:47 PM, Suravee Suthikulanit wrote:
On 12/19/2014 8:56 AM, Hanjun Guo wrote:
Hi Suravee,
On 2014年12月18日 07:16, Suravee Suthikulpanit wrote:
From: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Device drivers typically use ACPI _HIDs/_CIDs listed in struct
device_driver
acpi_match_table to match devices. However, for generic drivers, we do
not want to list _HID for all supported devices, and some device classes
do not have _CID (e.g. SATA, USB). Instead, we can leverage ACPI _CLS,
which specifies PCI-defined class code (i.e. base-class, subclass and
programming interface).
This patch adds support for matching ACPI devices using the _CLS method.
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
---
drivers/acpi/scan.c | 73
+++++++++++++++++++++++++++++++++++++++++
include/acpi/acnames.h | 1 +
include/linux/acpi.h | 12 ++++++-
include/linux/device.h | 1 +
include/linux/mod_devicetable.h | 6 ++++
5 files changed, 92 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index d670158..6406648 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -864,6 +864,79 @@ int acpi_match_device_ids(struct acpi_device
*device,
}
EXPORT_SYMBOL(acpi_match_device_ids);
+/**
+ * acpi_match_device_cls - Match a struct device against a ACPI _CLS
method
+ * @dev_cls: A pointer to struct acpi_device_cls object to match
against.
+ * @dev: The ACPI device structure to match.
+ *
+ * Check if @dev has a valid ACPI and _CLS handle. If there is a
+ * struct acpi_device_cls object for that handle, use that object to
match
+ * against the given struct acpi_device_cls object.
+ *
+ * Return 0 on success or error code on failure.
+ */
+int acpi_match_device_cls(const struct acpi_device_cls *dev_cls,
+ const struct device *dev)
+{
+ int ret = -EINVAL;
+ acpi_status status;
+ struct acpi_device *adev;
+ union acpi_object *pkg;
+ struct acpi_device_cls cls;
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct acpi_buffer format = { sizeof("NNN"), "NNN" };
+ struct acpi_buffer state = { 0, NULL };
+ acpi_handle handle = ACPI_HANDLE(dev);
...
+ acpi_handle cls_handle;
+
+ if (!handle || acpi_bus_get_device(handle, &adev))
if handle is not NULL, adev will not NULL too :)
because you get the handle from adev, ACPI_HANDLE() is defined as:
acpi_device_handle(ACPI_COMPANION(dev)), and adev = ACPI_COMPANION(dev);
you may use adev = ACPI_COMPANION(dev) to simplify the code.
Thanks for the pointer.
+ return ret;
+
+ if (!adev->status.present || !dev_cls)
+ return ret;
+
+ status = acpi_get_handle(adev->handle, METHOD_NAME__CLS,
&cls_handle);
do we need this function called here? _CLS is the method under ACPI
device object in DSDT/SSDT, and you will get adev->handle == cls_handle
if I'm not wrong :)
You are right. It is not needed, and we can just evaluate right from the
handle.
+ if (ACPI_FAILURE(status))
+ return ret;
+
+ status = acpi_evaluate_object(cls_handle, "_CLS", NULL, &buffer);
+ if (ACPI_FAILURE(status)) {
+ ACPI_EXCEPTION((AE_INFO, status, "Failed to Evaluat _CLS"));
+ return ret;
+ }
I think you can evaluate _CLS directly with handle here.
Thanks
Hanjun
Yep. I will send out the new patch in a bit.
Thanks,
Suravee
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