On 3/2/2015 2:27 AM, Suravee Suthikulpanit wrote:
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. Also, certain classes of devices
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.

To support loadable module, current design uses _HID or _CID to match device's
modalias. With the new way of matching with _CLS this would requires 
modification
to the current ACPI modalias key to include _CLS. This patch appends PCI-defined
class-code to the existing ACPI modalias as following.

     acpi:<HID>:<CID1>:<CID2>:..:<CIDn>:<bbsspp>:
E.g:
     # cat /sys/devices/platform/AMDI0600:00/modalias
     acpi:AMDI0600:010601:

where bb is th base-class code, ss is te sub-class code, and pp is the
programming interface code

Since there would not be _HID/_CID in the ACPI matching table of the driver,
this patch adds a field to acpi_device_id to specify the matching _CLS.

     static const struct acpi_device_id ahci_acpi_match[] = {
         { "", 0, PCI_CLASS_STORAGE_SATA_AHCI },
         {},
     };

In this case, the corresponded entry in modules.alias file would be:

     alias acpi*:010601:* ahci_platform

Signed-off-by: Suravee Suthikulpanit<suravee.suthikulpa...@amd.com>
---
  drivers/acpi/acpica/acutils.h     |  3 ++
  drivers/acpi/acpica/nsxfname.c    | 20 +++++++++--
  drivers/acpi/acpica/utids.c       | 71 +++++++++++++++++++++++++++++++++++++++
  drivers/acpi/scan.c               | 17 ++++++++--
  include/acpi/acnames.h            |  1 +
  include/acpi/actypes.h            |  4 ++-
  include/linux/mod_devicetable.h   |  1 +
  scripts/mod/devicetable-offsets.c |  1 +
  scripts/mod/file2alias.c          | 13 +++++--
  9 files changed, 123 insertions(+), 8 deletions(-)

[....]
>
diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
index b034f10..50d8019 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -1148,7 +1148,7 @@ struct acpi_device_info {
        u32 name;               /* ACPI object Name */
        acpi_object_type type;  /* ACPI object Type */
        u8 param_count;         /* If a method, required parameter count */
-       u8 valid;               /* Indicates which optional fields are valid */
+       u16 valid;              /* Indicates which optional fields are valid */
        u8 flags;               /* Miscellaneous info */
        u8 highest_dstates[4];  /* _sx_d values: 0xFF indicates not valid */
        u8 lowest_dstates[5];   /* _sx_w values: 0xFF indicates not valid */
@@ -1158,6 +1158,7 @@ struct acpi_device_info {
        struct acpi_pnp_device_id unique_id;    /* _UID value */
        struct acpi_pnp_device_id subsystem_id; /* _SUB value */
        struct acpi_pnp_device_id_list compatible_id_list;      /* _CID list <must 
be last> */
+       struct acpi_pnp_device_id cls;  /* _CLS value */
  };

Please disregard this patch. I found out a mistake on my part here. I have sent out V5 here (https://lkml.org/lkml/2015/3/6/24)

Thank you,

Suravee

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