HID: huion: Switch to generating report descriptor
authorNikolai Kondrashov <spbnick@gmail.com>
Wed, 23 Jul 2014 16:31:56 +0000 (19:31 +0300)
committerJiri Kosina <jkosina@suse.cz>
Tue, 29 Jul 2014 09:21:25 +0000 (11:21 +0200)
Switch to generating tablet pen report descriptor from a template and
parameters retrieved from string descriptor 0x64.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
drivers/hid/hid-huion.c

index 46c425bf4f0def5b13f884c9a7fa5706176e8ccc..6c811c1fbf55dd08342e9172c5cf35c6c7440f0b 100644 (file)
 #include <linux/hid.h>
 #include <linux/module.h>
 #include <linux/usb.h>
+#include <asm/unaligned.h>
 #include "usbhid/usbhid.h"
 
 #include "hid-ids.h"
 
-/* Original tablet report descriptor size */
-#define HUION_TABLET_RDESC_ORIG_SIZE   177
-
-/* Fixed tablet report descriptor */
-static __u8 huion_tablet_rdesc_fixed[] = {
-       0x05, 0x0D,         /*  Usage Page (Digitizer),             */
-       0x09, 0x02,         /*  Usage (Pen),                        */
-       0xA1, 0x01,         /*  Collection (Application),           */
-       0x85, 0x07,         /*      Report ID (7),                  */
-       0x09, 0x20,         /*      Usage (Stylus),                 */
-       0xA0,               /*      Collection (Physical),          */
-       0x14,               /*          Logical Minimum (0),        */
-       0x25, 0x01,         /*          Logical Maximum (1),        */
-       0x75, 0x01,         /*          Report Size (1),            */
-       0x09, 0x42,         /*          Usage (Tip Switch),         */
-       0x09, 0x44,         /*          Usage (Barrel Switch),      */
-       0x09, 0x46,         /*          Usage (Tablet Pick),        */
-       0x95, 0x03,         /*          Report Count (3),           */
-       0x81, 0x02,         /*          Input (Variable),           */
-       0x95, 0x03,         /*          Report Count (3),           */
-       0x81, 0x03,         /*          Input (Constant, Variable), */
-       0x09, 0x32,         /*          Usage (In Range),           */
-       0x95, 0x01,         /*          Report Count (1),           */
-       0x81, 0x02,         /*          Input (Variable),           */
-       0x95, 0x01,         /*          Report Count (1),           */
-       0x81, 0x03,         /*          Input (Constant, Variable), */
-       0x75, 0x10,         /*          Report Size (16),           */
-       0x95, 0x01,         /*          Report Count (1),           */
-       0xA4,               /*          Push,                       */
-       0x05, 0x01,         /*          Usage Page (Desktop),       */
-       0x65, 0x13,         /*          Unit (Inch),                */
-       0x55, 0xFD,         /*          Unit Exponent (-3),         */
-       0x34,               /*          Physical Minimum (0),       */
-       0x09, 0x30,         /*          Usage (X),                  */
-       0x46, 0x40, 0x1F,   /*          Physical Maximum (8000),    */
-       0x26, 0x00, 0x7D,   /*          Logical Maximum (32000),    */
-       0x81, 0x02,         /*          Input (Variable),           */
-       0x09, 0x31,         /*          Usage (Y),                  */
-       0x46, 0x88, 0x13,   /*          Physical Maximum (5000),    */
-       0x26, 0x20, 0x4E,   /*          Logical Maximum (20000),    */
-       0x81, 0x02,         /*          Input (Variable),           */
-       0xB4,               /*          Pop,                        */
-       0x09, 0x30,         /*          Usage (Tip Pressure),       */
-       0x26, 0xFF, 0x07,   /*          Logical Maximum (2047),     */
-       0x81, 0x02,         /*          Input (Variable),           */
-       0xC0,               /*      End Collection,                 */
-       0xC0                /*  End Collection                      */
+/* Report descriptor template placeholder head */
+#define HUION_PH_HEAD  0xFE, 0xED, 0x1D
+
+/* Report descriptor template placeholder IDs */
+enum huion_ph_id {
+       HUION_PH_ID_X_LM,
+       HUION_PH_ID_X_PM,
+       HUION_PH_ID_Y_LM,
+       HUION_PH_ID_Y_PM,
+       HUION_PH_ID_PRESSURE_LM,
+       HUION_PH_ID_NUM
+};
+
+/* Report descriptor template placeholder */
+#define HUION_PH(_ID) HUION_PH_HEAD, HUION_PH_ID_##_ID
+
+/* Fixed report descriptor template */
+static const __u8 huion_tablet_rdesc_template[] = {
+       0x05, 0x0D,             /*  Usage Page (Digitizer),                 */
+       0x09, 0x02,             /*  Usage (Pen),                            */
+       0xA1, 0x01,             /*  Collection (Application),               */
+       0x85, 0x07,             /*      Report ID (7),                      */
+       0x09, 0x20,             /*      Usage (Stylus),                     */
+       0xA0,                   /*      Collection (Physical),              */
+       0x14,                   /*          Logical Minimum (0),            */
+       0x25, 0x01,             /*          Logical Maximum (1),            */
+       0x75, 0x01,             /*          Report Size (1),                */
+       0x09, 0x42,             /*          Usage (Tip Switch),             */
+       0x09, 0x44,             /*          Usage (Barrel Switch),          */
+       0x09, 0x46,             /*          Usage (Tablet Pick),            */
+       0x95, 0x03,             /*          Report Count (3),               */
+       0x81, 0x02,             /*          Input (Variable),               */
+       0x95, 0x03,             /*          Report Count (3),               */
+       0x81, 0x03,             /*          Input (Constant, Variable),     */
+       0x09, 0x32,             /*          Usage (In Range),               */
+       0x95, 0x01,             /*          Report Count (1),               */
+       0x81, 0x02,             /*          Input (Variable),               */
+       0x95, 0x01,             /*          Report Count (1),               */
+       0x81, 0x03,             /*          Input (Constant, Variable),     */
+       0x75, 0x10,             /*          Report Size (16),               */
+       0x95, 0x01,             /*          Report Count (1),               */
+       0xA4,                   /*          Push,                           */
+       0x05, 0x01,             /*          Usage Page (Desktop),           */
+       0x65, 0x13,             /*          Unit (Inch),                    */
+       0x55, 0xFD,             /*          Unit Exponent (-3),             */
+       0x34,                   /*          Physical Minimum (0),           */
+       0x09, 0x30,             /*          Usage (X),                      */
+       0x27, HUION_PH(X_LM),   /*          Logical Maximum (PLACEHOLDER),  */
+       0x47, HUION_PH(X_PM),   /*          Physical Maximum (PLACEHOLDER), */
+       0x81, 0x02,             /*          Input (Variable),               */
+       0x09, 0x31,             /*          Usage (Y),                      */
+       0x27, HUION_PH(Y_LM),   /*          Logical Maximum (PLACEHOLDER),  */
+       0x47, HUION_PH(Y_PM),   /*          Physical Maximum (PLACEHOLDER), */
+       0x81, 0x02,             /*          Input (Variable),               */
+       0xB4,                   /*          Pop,                            */
+       0x09, 0x30,             /*          Usage (Tip Pressure),           */
+       0x27,
+       HUION_PH(PRESSURE_LM),  /*          Logical Maximum (PLACEHOLDER),  */
+       0x81, 0x02,             /*          Input (Variable),               */
+       0xC0,                   /*      End Collection,                     */
+       0xC0                    /*  End Collection                          */
+};
+
+/* Driver data */
+struct huion_drvdata {
+       __u8 *rdesc;
+       unsigned int rsize;
 };
 
 static __u8 *huion_report_fixup(struct hid_device *hdev, __u8 *rdesc,
                unsigned int *rsize)
 {
+       struct huion_drvdata *drvdata = hid_get_drvdata(hdev);
        switch (hdev->product) {
        case USB_DEVICE_ID_HUION_TABLET:
-               if (*rsize == HUION_TABLET_RDESC_ORIG_SIZE) {
-                       rdesc = huion_tablet_rdesc_fixed;
-                       *rsize = sizeof(huion_tablet_rdesc_fixed);
+               if (drvdata->rdesc != NULL) {
+                       rdesc = drvdata->rdesc;
+                       *rsize = drvdata->rsize;
                }
                break;
        }
@@ -84,57 +106,124 @@ static __u8 *huion_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 }
 
 /**
- * Enable fully-functional tablet mode by reading special string
- * descriptor.
+ * Enable fully-functional tablet mode and determine device parameters.
  *
  * @hdev:      HID device
- *
- * The specific string descriptor and data were discovered by sniffing
- * the Windows driver traffic.
  */
 static int huion_tablet_enable(struct hid_device *hdev)
 {
        int rc;
-       char buf[22];
+       struct usb_device *usb_dev = hid_to_usb_dev(hdev);
+       struct huion_drvdata *drvdata = hid_get_drvdata(hdev);
+       u16 buf[6];
 
-       rc = usb_string(hid_to_usb_dev(hdev), 0x64, buf, sizeof(buf));
-       if (rc < 0)
-               return rc;
+       /*
+        * Read string descriptor containing tablet parameters. The specific
+        * string descriptor and data were discovered by sniffing the Windows
+        * driver traffic.
+        * NOTE: This enables fully-functional tablet mode.
+        */
+       rc = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
+                               USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
+                               (USB_DT_STRING << 8) + 0x64,
+                               0x0409, buf, sizeof(buf),
+                               USB_CTRL_GET_TIMEOUT);
+       if (rc == -EPIPE)
+               hid_warn(hdev, "device parameters not found\n");
+       else if (rc < 0)
+               hid_warn(hdev, "failed to get device parameters: %d\n", rc);
+       else if (rc != sizeof(buf))
+               hid_warn(hdev, "invalid device parameters\n");
+       else {
+               s32 params[HUION_PH_ID_NUM];
+               s32 resolution;
+               __u8 *p;
+               s32 v;
+
+               /* Extract device parameters */
+               params[HUION_PH_ID_X_LM] = le16_to_cpu(buf[1]);
+               params[HUION_PH_ID_Y_LM] = le16_to_cpu(buf[2]);
+               params[HUION_PH_ID_PRESSURE_LM] = le16_to_cpu(buf[4]);
+               resolution = le16_to_cpu(buf[5]);
+               if (resolution == 0) {
+                       params[HUION_PH_ID_X_PM] = 0;
+                       params[HUION_PH_ID_Y_PM] = 0;
+               } else {
+                       params[HUION_PH_ID_X_PM] = params[HUION_PH_ID_X_LM] *
+                                                       1000 / resolution;
+                       params[HUION_PH_ID_Y_PM] = params[HUION_PH_ID_Y_LM] *
+                                                       1000 / resolution;
+               }
+
+               /* Allocate fixed report descriptor */
+               drvdata->rdesc = devm_kmalloc(&hdev->dev,
+                                       sizeof(huion_tablet_rdesc_template),
+                                       GFP_KERNEL);
+               if (drvdata->rdesc == NULL) {
+                       hid_err(hdev, "failed to allocate fixed rdesc\n");
+                       return -ENOMEM;
+               }
+               drvdata->rsize = sizeof(huion_tablet_rdesc_template);
+
+               /* Format fixed report descriptor */
+               memcpy(drvdata->rdesc, huion_tablet_rdesc_template,
+                       drvdata->rsize);
+               for (p = drvdata->rdesc;
+                    p <= drvdata->rdesc + drvdata->rsize - 4;) {
+                       if (p[0] == 0xFE && p[1] == 0xED && p[2] == 0x1D &&
+                           p[3] < sizeof(params)) {
+                               v = params[p[3]];
+                               put_unaligned(cpu_to_le32(v), (s32 *)p);
+                               p += 4;
+                       } else {
+                               p++;
+                       }
+               }
+       }
 
        return 0;
 }
 
 static int huion_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
-       int ret;
-
-       ret = hid_parse(hdev);
-       if (ret) {
-               hid_err(hdev, "parse failed\n");
-               goto err;
-       }
+       int rc;
+       struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+       struct huion_drvdata *drvdata;
 
-       ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
-       if (ret) {
-               hid_err(hdev, "hw start failed\n");
-               goto err;
+       /* Allocate and assign driver data */
+       drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+       if (drvdata == NULL) {
+               hid_err(hdev, "failed to allocate driver data\n");
+               return -ENOMEM;
        }
+       hid_set_drvdata(hdev, drvdata);
 
        switch (id->product) {
        case USB_DEVICE_ID_HUION_TABLET:
-               ret = huion_tablet_enable(hdev);
-               if (ret) {
-                       hid_err(hdev, "tablet enabling failed\n");
-                       goto enabling_err;
+               /* If this is the pen interface */
+               if (intf->cur_altsetting->desc.bInterfaceNumber == 0) {
+                       rc = huion_tablet_enable(hdev);
+                       if (rc) {
+                               hid_err(hdev, "tablet enabling failed\n");
+                               return rc;
+                       }
                }
                break;
        }
 
+       rc = hid_parse(hdev);
+       if (rc) {
+               hid_err(hdev, "parse failed\n");
+               return rc;
+       }
+
+       rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+       if (rc) {
+               hid_err(hdev, "hw start failed\n");
+               return rc;
+       }
+
        return 0;
-enabling_err:
-       hid_hw_stop(hdev);
-err:
-       return ret;
 }
 
 static int huion_raw_event(struct hid_device *hdev, struct hid_report *report,