HID devices are only partially presented to userland. Hotplugged
devices emit events containing a modalias based on the basic bus,
vendor and product entities. However, in practise a hid device can
depend on details such as a single usb interface or a particular item
in a report descriptor.
This patch adds a special interface tag to the hid device id, and
broadcasts it using both uevent and modalias. Matching ids are
introduced for the hid-multitouch driver. As a consequence, generic
hid will no longer match multitouch devices, and udev will
automatically load hid-multitouch instead.
Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
---
drivers/hid/hid-core.c | 28 +++++++++++++++++++++++++---
drivers/hid/hid-multitouch.c | 7 ++++++-
include/linux/hid.h | 7 +++++++
include/linux/mod_devicetable.h | 2 +-
scripts/mod/file2alias.c | 2 ++
5 files changed, 41 insertions(+), 5 deletions(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 8a7b59e..1cf6cb5 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -205,6 +205,10 @@ static int hid_add_usage(struct hid_parser *parser, unsigned usage)
parser->collection_stack_ptr ?
parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
parser->local.usage_index++;
+
+ if (usage == HID_DG_CONTACTID)
+ parser->device->idtags |= HID_IDTAG_MULTITOUCH;
+
return 0;
}
@@ -1154,7 +1158,7 @@ EXPORT_SYMBOL_GPL(hid_input_report);
static bool hid_match_one_id(struct hid_device *hdev,
const struct hid_device_id *id)
{
- return id->bus == hdev->bus &&
+ return id->bus == hdev->bus && id->idtags == hdev->idtags &&
(id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
(id->product == HID_ANY_ID || id->product == hdev->product);
}
@@ -1723,6 +1727,23 @@ static int hid_device_remove(struct device *dev)
return 0;
}
+static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
+ char *buf)
+{
+ struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+ int len;
+
+ len = snprintf(buf, PAGE_SIZE, "hid:b%04Xi%04Xv%08Xp%08X\n",
+ hdev->bus, hdev->idtags, hdev->vendor, hdev->product);
+
+ return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
+}
+
+static struct device_attribute hid_dev_attrs[] = {
+ __ATTR_RO(modalias),
+ __ATTR_NULL,
+};
+
static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct hid_device *hdev = container_of(dev, struct hid_device, dev);
@@ -1740,8 +1761,8 @@ static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
return -ENOMEM;
- if (add_uevent_var(env, "MODALIAS=hid:b%04Xv%08Xp%08X",
- hdev->bus, hdev->vendor, hdev->product))
+ if (add_uevent_var(env, "MODALIAS=hid:b%04Xi%04Xv%08Xp%08X",
+ hdev->bus, hdev->idtags, hdev->vendor, hdev->product))
return -ENOMEM;
return 0;
@@ -1749,6 +1770,7 @@ static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
static struct bus_type hid_bus_type = {
.name = "hid",
+ .dev_attrs = hid_dev_attrs,
.match = hid_bus_match,
.probe = hid_device_probe,
.remove = hid_device_remove,
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 421b16c..80ceab5 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -104,7 +104,7 @@ struct mt_device {
#define MT_DEFAULT_MAXCONTACT 10
#define HID_USB_MT_DEVICE(v, p) \
- HID_USB_DEVICE(v, p)
+ .idtags = HID_IDTAG_MULTITOUCH, HID_USB_DEVICE(v, p)
/*
* these device-dependent functions determine what slot corresponds
@@ -886,6 +886,11 @@ static const struct hid_device_id mt_devices[] = {
HID_USB_MT_DEVICE(USB_VENDOR_ID_XIROKU,
USB_DEVICE_ID_XIROKU_CSR2) },
+ /* Generic MT device */
+ { .driver_data = MT_CLS_DEFAULT,
+ HID_USB_MT_DEVICE(HID_ANY_ID,
+ HID_ANY_ID) },
+
{ }
};
MODULE_DEVICE_TABLE(hid, mt_devices);
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 5b3be43..1e68543 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -62,6 +62,12 @@
#define HID_MAX_DESCRIPTOR_SIZE 4096
+/*
+ * HID identifying tags extracted from reports
+ */
+#define HID_IDTAG_MULTITOUCH 0x0001
+
+
#ifdef __KERNEL__
#include <linux/types.h>
@@ -473,6 +479,7 @@ struct hid_device { /* device report descriptor */
unsigned maxcollection; /* Number of parsed collections */
unsigned maxapplication; /* Number of applications */
__u16 bus; /* BUS ID */
+ __u16 idtags; /* Identifying tags extracted from reports */
__u32 vendor; /* Vendor ID */
__u32 product; /* Product ID */
__u32 version; /* HID version */
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 83ac071..25446f0 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -135,7 +135,7 @@ struct usb_device_id {
struct hid_device_id {
__u16 bus;
- __u16 pad1;
+ __u16 idtags;
__u32 vendor;
__u32 product;
kernel_ulong_t driver_data
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index b89efe6..d0c3a2b 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -336,10 +336,12 @@ static int do_hid_entry(const char *filename,
struct hid_device_id *id, char *alias)
{
id->bus = TO_NATIVE(id->bus);
+ id->idtags = TO_NATIVE(id->idtags);
id->vendor = TO_NATIVE(id->vendor);
id->product = TO_NATIVE(id->product);
sprintf(alias, "hid:b%04X", id->bus);
+ ADD(alias, "i", true, id->idtags);
ADD(alias, "v", id->vendor != HID_ANY_ID, id->vendor);
ADD(alias, "p", id->product != HID_ANY_ID, id->product);
--
1.7.9.5
--
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