[PATCH 04/15] Input - wacom: use HID core to actually fetch the report descriptor

From: Benjamin Tissoires
Date: Mon Jun 30 2014 - 17:31:15 EST


HID core already retrieves the report descritor. There is no need
to ask ourself for one.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
drivers/input/tablet/wacom_sys.c | 70 ++++++----------------------------------
1 file changed, 10 insertions(+), 60 deletions(-)

diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c
index eb39314..cd3d936 100644
--- a/drivers/input/tablet/wacom_sys.c
+++ b/drivers/input/tablet/wacom_sys.c
@@ -15,9 +15,6 @@
#include "wacom.h"
#include <linux/hid.h>

-/* defines to get HID report descriptor */
-#define HID_DEVICET_HID (USB_TYPE_CLASS | 0x01)
-#define HID_DEVICET_REPORT (USB_TYPE_CLASS | 0x02)
#define HID_HDESC_USAGE_UNDEFINED 0x00
#define HID_HDESC_USAGE_PAGE 0x05
#define HID_HDESC_USAGE 0x09
@@ -25,15 +22,6 @@
#define HID_HDESC_COLLECTION_LOGICAL 0x02
#define HID_HDESC_COLLECTION_END 0xc0

-struct wac_hid_descriptor {
- struct usb_descriptor_header header;
- __le16 bcdHID;
- u8 bCountryCode;
- u8 bNumDescriptors;
- u8 bDescriptorType;
- __le16 wDescriptorLength;
-} __attribute__ ((packed));
-
#define WAC_MSG_RETRIES 5

#define WAC_CMD_LED_CONTROL 0x20
@@ -230,39 +218,14 @@ static void wacom_retrieve_report_data(struct hid_device *hdev,
* this after returning from this function.
*/
static int wacom_parse_hid(struct hid_device *hdev,
- struct wac_hid_descriptor *hid_desc,
struct wacom_features *features)
{
- struct wacom *wacom = hid_get_drvdata(hdev);
- struct usb_interface *intf = wacom->intf;
- struct usb_device *dev = interface_to_usbdev(intf);
- char limit = 0;
/* result has to be defined as int for some devices */
int result = 0, touch_max = 0;
int i = 0, page = 0, finger = 0, pen = 0;
- unsigned char *report;
+ unsigned char *report = hdev->rdesc;

- report = kzalloc(hid_desc->wDescriptorLength, GFP_KERNEL);
- if (!report)
- return -ENOMEM;
-
- /* retrive report descriptors */
- do {
- result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
- USB_REQ_GET_DESCRIPTOR,
- USB_RECIP_INTERFACE | USB_DIR_IN,
- HID_DEVICET_REPORT << 8,
- intf->altsetting[0].desc.bInterfaceNumber, /* interface */
- report,
- hid_desc->wDescriptorLength,
- 5000); /* 5 secs */
- } while (result < 0 && limit++ < WAC_MSG_RETRIES);
-
- /* No need to parse the Descriptor. It isn't an error though */
- if (result < 0)
- goto out;
-
- for (i = 0; i < hid_desc->wDescriptorLength; i++) {
+ for (i = 0; i < hdev->rsize; i++) {

switch (report[i]) {
case HID_HDESC_USAGE_PAGE:
@@ -452,11 +415,9 @@ static int wacom_parse_hid(struct hid_device *hdev,
}
}

- out:
if (!features->touch_max && touch_max)
features->touch_max = touch_max;
result = 0;
- kfree(report);
return result;
}

@@ -519,8 +480,6 @@ static int wacom_retrieve_hid_descriptor(struct hid_device *hdev,
int error = 0;
struct wacom *wacom = hid_get_drvdata(hdev);
struct usb_interface *intf = wacom->intf;
- struct usb_host_interface *interface = intf->cur_altsetting;
- struct wac_hid_descriptor *hid_desc;

/* default features */
features->device_type = BTN_TOOL_PEN;
@@ -549,17 +508,7 @@ static int wacom_retrieve_hid_descriptor(struct hid_device *hdev,
goto out;
}

- error = usb_get_extra_descriptor(interface, HID_DEVICET_HID, &hid_desc);
- if (error) {
- error = usb_get_extra_descriptor(&interface->endpoint[0],
- HID_DEVICET_REPORT, &hid_desc);
- if (error) {
- hid_err(hdev,
- "can not retrieve extra class descriptor\n");
- goto out;
- }
- }
- error = wacom_parse_hid(hdev, hid_desc, features);
+ error = wacom_parse_hid(hdev, features);

out:
return error;
@@ -1299,6 +1248,13 @@ static int wacom_probe(struct hid_device *hdev,
hid_set_drvdata(hdev, wacom);
wacom->hdev = hdev;

+ /* ask for the report descriptor to be loaded by HID */
+ error = hid_parse(hdev);
+ if (error) {
+ hid_err(hdev, "parse failed\n");
+ goto fail1;
+ }
+
wacom_wac = &wacom->wacom_wac;
wacom_wac->features = *((struct wacom_features *)id->driver_data);
features = &wacom_wac->features;
@@ -1392,12 +1348,6 @@ static int wacom_probe(struct hid_device *hdev,
wacom_query_tablet_data(hdev, features);

/* Regular HID work starts now */
- error = hid_parse(hdev);
- if (error) {
- hid_err(hdev, "parse failed\n");
- goto fail4;
- }
-
error = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
if (error) {
hid_err(hdev, "hw start failed\n");
--
2.0.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/