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@amd.com
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@amd.com
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