HID: elan: Add support for touchpad on the Toshiba Click Mini L9W

The Toshiba Click Mini L9W keyboard dock has a single i2c-hid Elan device
for both the keyboard and the touchpad. Add support for the touchpad to
the hid-elan driver, rather then relying on mouse emulation.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 61 insertions, 5 deletions

diff --git a/drivers/hid/hid-elan.c b/drivers/hid/hid-elan.c
index 4b050d395ecc..07e26c3567eb 100644
--- a/drivers/hid/hid-elan.c
+++ b/drivers/hid/hid-elan.c
@@ -19,10 +19,13 @@
 
 #include "hid-ids.h"
 
+#define ELAN_MT_I2C             0x5d
 #define ELAN_SINGLE_FINGER      0x81
 #define ELAN_MT_FIRST_FINGER    0x82
 #define ELAN_MT_SECOND_FINGER   0x83
 #define ELAN_INPUT_REPORT_SIZE  8
+#define ELAN_I2C_REPORT_SIZE    32
+#define ELAN_FINGER_DATA_LEN    5
 #define ELAN_MAX_FINGERS        5
 #define ELAN_MAX_PRESSURE       255
 #define ELAN_TP_USB_INTF        1
@@ -51,9 +54,14 @@ struct elan_drvdata {
 
 static int is_not_elan_touchpad(struct hid_device *hdev)
 {
-        struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+        if (hdev->bus == BUS_USB) {
+                struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
 
-        return (intf->altsetting->desc.bInterfaceNumber != ELAN_TP_USB_INTF);
+                return (intf->altsetting->desc.bInterfaceNumber !=
+                        ELAN_TP_USB_INTF);
+        }
+
+        return 0;
 }
 
 static int elan_input_mapping(struct hid_device *hdev, struct hid_input *hi,
@@ -65,7 +73,8 @@ static int elan_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 
         if (field->report->id == ELAN_SINGLE_FINGER ||
             field->report->id == ELAN_MT_FIRST_FINGER ||
-            field->report->id == ELAN_MT_SECOND_FINGER)
+            field->report->id == ELAN_MT_SECOND_FINGER ||
+            field->report->id == ELAN_MT_I2C)
                 return -1;
 
         return 0;
@@ -224,7 +233,7 @@ static void elan_report_mt_slot(struct elan_drvdata *drvdata, u8 *data,
         }
 }
 
-static void elan_report_input(struct elan_drvdata *drvdata, u8 *data)
+static void elan_usb_report_input(struct elan_drvdata *drvdata, u8 *data)
 {
         int i;
         struct input_dev *input = drvdata->input;
@@ -311,6 +320,46 @@ static void elan_report_input(struct elan_drvdata *drvdata, u8 *data)
         input_sync(input);
 }
 
+static void elan_i2c_report_input(struct elan_drvdata *drvdata, u8 *data)
+{
+        struct input_dev *input = drvdata->input;
+        u8 *finger_data;
+        int i;
+
+        /*
+         * Elan MT touchpads in i2c mode send finger data in the same format
+         * as in USB mode, but then with all fingers in a single packet.
+         *
+         * packet structure for ELAN_MT_I2C:
+         *
+         * byte     1: 1   0   0   1   1   1   0   1   // 0x5d
+         * byte     2: f5  f4  f3  f2  f1  0   0   L
+         * byte     3: x12 x11 x10 x9  0?  y11 y10 y9
+         * byte     4: x8  x7  x6  x5  x4  x3  x2  x1
+         * byte     5: y8  y7  y6  y5  y4  y3  y2  y1
+         * byte     6: sy4 sy3 sy2 sy1 sx4 sx3 sx2 sx1
+         * byte     7: p8  p7  p6  p5  p4  p3  p2  p1
+         * byte  8-12: Same as byte 3-7 for second finger down
+         * byte 13-17: Same as byte 3-7 for third finger down
+         * byte 18-22: Same as byte 3-7 for fourth finger down
+         * byte 23-27: Same as byte 3-7 for fifth finger down
+         */
+
+        finger_data = data + 2;
+        for (i = 0; i < ELAN_MAX_FINGERS; i++) {
+                if (data[1] & BIT(i + 3)) {
+                        elan_report_mt_slot(drvdata, finger_data, i);
+                        finger_data += ELAN_FINGER_DATA_LEN;
+                } else {
+                        elan_report_mt_slot(drvdata, NULL, i);
+                }
+        }
+
+        input_report_key(input, BTN_LEFT, data[1] & 0x01);
+        input_mt_sync_frame(input);
+        input_sync(input);
+}
+
 static int elan_raw_event(struct hid_device *hdev,
                           struct hid_report *report, u8 *data, int size)
 {
@@ -323,11 +372,16 @@ static int elan_raw_event(struct hid_device *hdev,
             data[0] == ELAN_MT_FIRST_FINGER ||
             data[0] == ELAN_MT_SECOND_FINGER) {
                 if (size == ELAN_INPUT_REPORT_SIZE) {
-                        elan_report_input(drvdata, data);
+                        elan_usb_report_input(drvdata, data);
                         return 1;
                 }
         }
 
+        if (data[0] == ELAN_MT_I2C && size == ELAN_I2C_REPORT_SIZE) {
+                elan_i2c_report_input(drvdata, data);
+                return 1;
+        }
+
         return 0;
 }
 
@@ -474,6 +528,7 @@ static const struct hid_device_id elan_devices[] = {
           .driver_data = ELAN_HAS_LED },
         { HID_USB_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_HP_X2_10_COVER),
           .driver_data = ELAN_HAS_LED },
+        { HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_TOSHIBA_CLICK_L9W) },
         { }
 };
 MODULE_DEVICE_TABLE(hid, elan_devices);
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 28f96de2a84e..aa57e70e54db 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -369,6 +369,7 @@
 #define USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_A001       0xa001
 
 #define USB_VENDOR_ID_ELAN              0x04f3
+#define USB_DEVICE_ID_TOSHIBA_CLICK_L9W 0x0401
 #define USB_DEVICE_ID_HP_X2             0x074d
 #define USB_DEVICE_ID_HP_X2_10_COVER    0x0755