HID: logitech-dj: allow transfer of HID++ reports from/to the correct dj device

HID++ is a Logitech-specific protocol for communicating with HID
devices. DJ devices implement HID++, and so we can add the HID++
collection in the report descriptor and forward the incoming
reports from the receiver to the appropriate DJ device.

The same can be done in the other way, if someone calls a
.raw_request(), we can forward it to the correct dj device
by overriding the device_index in the HID++ report.

Signed-off-by: Benjamin Tisssoires <benjamin.tissoires@redhat.com>
Tested-by: Andrew de los Reyes <adlr@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 160 insertions, 28 deletions

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 45a7eacdfe98..feddacd87b8b 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -42,6 +42,15 @@
 #define REPORT_ID_DJ_SHORT                      0x20
 #define REPORT_ID_DJ_LONG                       0x21
 
+#define REPORT_ID_HIDPP_SHORT                   0x10
+#define REPORT_ID_HIDPP_LONG                    0x11
+
+#define HIDPP_REPORT_SHORT_LENGTH               7
+#define HIDPP_REPORT_LONG_LENGTH                20
+
+#define HIDPP_RECEIVER_INDEX                    0xff
+
+#define REPORT_TYPE_RFREPORT_FIRST              0x01
 #define REPORT_TYPE_RFREPORT_LAST               0x1F
 
 /* Command Switch to DJ mode */
@@ -242,6 +251,57 @@ static const char media_descriptor[] = {
         0xc0,                   /* EndCollection                       */
 };                              /*                                     */
 
+/* HIDPP descriptor */
+static const char hidpp_descriptor[] = {
+        0x06, 0x00, 0xff,       /* Usage Page (Vendor Defined Page 1)  */
+        0x09, 0x01,             /* Usage (Vendor Usage 1)              */
+        0xa1, 0x01,             /* Collection (Application)            */
+        0x85, 0x10,             /*   Report ID (16)                    */
+        0x75, 0x08,             /*   Report Size (8)                   */
+        0x95, 0x06,             /*   Report Count (6)                  */
+        0x15, 0x00,             /*   Logical Minimum (0)               */
+        0x26, 0xff, 0x00,       /*   Logical Maximum (255)             */
+        0x09, 0x01,             /*   Usage (Vendor Usage 1)            */
+        0x81, 0x00,             /*   Input (Data,Arr,Abs)              */
+        0x09, 0x01,             /*   Usage (Vendor Usage 1)            */
+        0x91, 0x00,             /*   Output (Data,Arr,Abs)             */
+        0xc0,                   /* End Collection                      */
+        0x06, 0x00, 0xff,       /* Usage Page (Vendor Defined Page 1)  */
+        0x09, 0x02,             /* Usage (Vendor Usage 2)              */
+        0xa1, 0x01,             /* Collection (Application)            */
+        0x85, 0x11,             /*   Report ID (17)                    */
+        0x75, 0x08,             /*   Report Size (8)                   */
+        0x95, 0x13,             /*   Report Count (19)                 */
+        0x15, 0x00,             /*   Logical Minimum (0)               */
+        0x26, 0xff, 0x00,       /*   Logical Maximum (255)             */
+        0x09, 0x02,             /*   Usage (Vendor Usage 2)            */
+        0x81, 0x00,             /*   Input (Data,Arr,Abs)              */
+        0x09, 0x02,             /*   Usage (Vendor Usage 2)            */
+        0x91, 0x00,             /*   Output (Data,Arr,Abs)             */
+        0xc0,                   /* End Collection                      */
+        0x06, 0x00, 0xff,       /* Usage Page (Vendor Defined Page 1)  */
+        0x09, 0x04,             /* Usage (Vendor Usage 0x04)           */
+        0xa1, 0x01,             /* Collection (Application)            */
+        0x85, 0x20,             /*   Report ID (32)                    */
+        0x75, 0x08,             /*   Report Size (8)                   */
+        0x95, 0x0e,             /*   Report Count (14)                 */
+        0x15, 0x00,             /*   Logical Minimum (0)               */
+        0x26, 0xff, 0x00,       /*   Logical Maximum (255)             */
+        0x09, 0x41,             /*   Usage (Vendor Usage 0x41)         */
+        0x81, 0x00,             /*   Input (Data,Arr,Abs)              */
+        0x09, 0x41,             /*   Usage (Vendor Usage 0x41)         */
+        0x91, 0x00,             /*   Output (Data,Arr,Abs)             */
+        0x85, 0x21,             /*   Report ID (33)                    */
+        0x95, 0x1f,             /*   Report Count (31)                 */
+        0x15, 0x00,             /*   Logical Minimum (0)               */
+        0x26, 0xff, 0x00,       /*   Logical Maximum (255)             */
+        0x09, 0x42,             /*   Usage (Vendor Usage 0x42)         */
+        0x81, 0x00,             /*   Input (Data,Arr,Abs)              */
+        0x09, 0x42,             /*   Usage (Vendor Usage 0x42)         */
+        0x91, 0x00,             /*   Output (Data,Arr,Abs)             */
+        0xc0,                   /* End Collection                      */
+};
+
 /* Maximum size of all defined hid reports in bytes (including report id) */
 #define MAX_REPORT_SIZE 8
 
@@ -251,7 +311,8 @@ static const char media_descriptor[] = {
          sizeof(mse_descriptor) +               \
          sizeof(consumer_descriptor) +          \
          sizeof(syscontrol_descriptor) +        \
-         sizeof(media_descriptor))
+         sizeof(media_descriptor) +     \
+         sizeof(hidpp_descriptor))
 
 /* Number of possible hid report types that can be created by this driver.
  *
@@ -512,6 +573,13 @@ static void logi_dj_recv_forward_report(struct dj_receiver_dev *djrcv_dev,
         }
 }
 
+static void logi_dj_recv_forward_hidpp(struct dj_device *dj_dev, u8 *data,
+                                       int size)
+{
+        /* We are called from atomic context (tasklet && djrcv->lock held) */
+        if (hid_input_report(dj_dev->hdev, HID_INPUT_REPORT, data, size, 1))
+                dbg_hid("hid_input_report error\n");
+}
 
 static int logi_dj_recv_send_report(struct dj_receiver_dev *djrcv_dev,
                                     struct dj_report *dj_report)
@@ -609,6 +677,16 @@ static int logi_dj_ll_raw_request(struct hid_device *hid,
         u8 *out_buf;
         int ret;
 
+        if ((buf[0] == REPORT_ID_HIDPP_SHORT) ||
+            (buf[0] == REPORT_ID_HIDPP_LONG)) {
+                if (count < 2)
+                        return -EINVAL;
+
+                buf[1] = djdev->device_index;
+                return hid_hw_raw_request(djrcv_dev->hdev, reportnum, buf,
+                                count, report_type, reqtype);
+        }
+
         if (buf[0] != REPORT_TYPE_LEDS)
                 return -EINVAL;
 
@@ -687,6 +765,8 @@ static int logi_dj_ll_parse(struct hid_device *hid)
                         __func__, djdev->reports_supported);
         }
 
+        rdcat(rdesc, &rsize, hidpp_descriptor, sizeof(hidpp_descriptor));
+
         retval = hid_parse_report(hid, rdesc, rsize);
         kfree(rdesc);
 
@@ -714,8 +794,7 @@ static struct hid_ll_driver logi_dj_ll_driver = {
         .raw_request = logi_dj_ll_raw_request,
 };
 
-
-static int logi_dj_raw_event(struct hid_device *hdev,
+static int logi_dj_dj_event(struct hid_device *hdev,
                              struct hid_report *report, u8 *data,
                              int size)
 {
@@ -723,36 +802,24 @@ static int logi_dj_raw_event(struct hid_device *hdev,
         struct dj_report *dj_report = (struct dj_report *) data;
         unsigned long flags;
 
-        dbg_hid("%s, size:%d\n", __func__, size);
-
-        /* Here we receive all data coming from iface 2, there are 4 cases:
-         *
-         * 1) Data should continue its normal processing i.e. data does not
-         * come from the DJ collection, in which case we do nothing and
-         * return 0, so hid-core can continue normal processing (will forward
-         * to associated hidraw device)
+        /*
+         * Here we receive all data coming from iface 2, there are 3 cases:
          *
-         * 2) Data is from DJ collection, and is intended for this driver i. e.
-         * data contains arrival, departure, etc notifications, in which case
-         * we queue them for delayed processing by the work queue. We return 1
-         * to hid-core as no further processing is required from it.
+         * 1) Data is intended for this driver i. e. data contains arrival,
+         * departure, etc notifications, in which case we queue them for delayed
+         * processing by the work queue. We return 1 to hid-core as no further
+         * processing is required from it.
          *
-         * 3) Data is from DJ collection, and informs a connection change,
-         * if the change means rf link loss, then we must send a null report
-         * to the upper layer to discard potentially pressed keys that may be
-         * repeated forever by the input layer. Return 1 to hid-core as no
-         * further processing is required.
+         * 2) Data informs a connection change, if the change means rf link
+         * loss, then we must send a null report to the upper layer to discard
+         * potentially pressed keys that may be repeated forever by the input
+         * layer. Return 1 to hid-core as no further processing is required.
          *
-         * 4) Data is from DJ collection and is an actual input event from
-         * a paired DJ device in which case we forward it to the correct hid
-         * device (via hid_input_report() ) and return 1 so hid-core does not do
-         * anything else with it.
+         * 3) Data is an actual input event from a paired DJ device in which
+         * case we forward it to the correct hid device (via hid_input_report()
+         * ) and return 1 so hid-core does not anything else with it.
          */
 
-        /* case 1) */
-        if (data[0] != REPORT_ID_DJ_SHORT)
-                return false;
-
         if ((dj_report->device_index < DJ_DEVICE_INDEX_MIN) ||
             (dj_report->device_index > DJ_DEVICE_INDEX_MAX)) {
                 /*
@@ -797,6 +864,71 @@ out:
         return true;
 }
 
+static int logi_dj_hidpp_event(struct hid_device *hdev,
+                             struct hid_report *report, u8 *data,
+                             int size)
+{
+        struct dj_receiver_dev *djrcv_dev = hid_get_drvdata(hdev);
+        struct dj_report *dj_report = (struct dj_report *) data;
+        unsigned long flags;
+        u8 device_index = dj_report->device_index;
+
+        if (device_index == HIDPP_RECEIVER_INDEX)
+                return false;
+
+        /*
+         * Data is from the HID++ collection, in this case, we forward the
+         * data to the corresponding child dj device and return 0 to hid-core
+         * so he data also goes to the hidraw device of the receiver. This
+         * allows a user space application to implement the full HID++ routing
+         * via the receiver.
+         */
+
+        if ((device_index < DJ_DEVICE_INDEX_MIN) ||
+            (device_index > DJ_DEVICE_INDEX_MAX)) {
+                /*
+                 * Device index is wrong, bail out.
+                 * This driver can ignore safely the receiver notifications,
+                 * so ignore those reports too.
+                 */
+                dev_err(&hdev->dev, "%s: invalid device index:%d\n",
+                                __func__, dj_report->device_index);
+                return false;
+        }
+
+        spin_lock_irqsave(&djrcv_dev->lock, flags);
+
+        if (!djrcv_dev->paired_dj_devices[device_index])
+                /* received an event for an unknown device, bail out */
+                goto out;
+
+        logi_dj_recv_forward_hidpp(djrcv_dev->paired_dj_devices[device_index],
+                                   data, size);
+
+out:
+        spin_unlock_irqrestore(&djrcv_dev->lock, flags);
+
+        return false;
+}
+
+static int logi_dj_raw_event(struct hid_device *hdev,
+                             struct hid_report *report, u8 *data,
+                             int size)
+{
+        dbg_hid("%s, size:%d\n", __func__, size);
+
+        switch (data[0]) {
+        case REPORT_ID_DJ_SHORT:
+                return logi_dj_dj_event(hdev, report, data, size);
+        case REPORT_ID_HIDPP_SHORT:
+                /* intentional fallthrough */
+        case REPORT_ID_HIDPP_LONG:
+                return logi_dj_hidpp_event(hdev, report, data, size);
+        }
+
+        return false;
+}
+
 static int logi_dj_probe(struct hid_device *hdev,
                          const struct hid_device_id *id)
 {