Input: wacom - clean up wacom_query_tablet_data

Rewrites this function to be easier to read and understand. The new
function 'wacom_set_device_mode' now handles the grunt work of
assembling the proper feature report, sending it to the device,
and ensuring the setting "sticks".

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 35 insertions, 39 deletions

diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c
index b44bba2a60c2..9edf9806cff9 100644
--- a/drivers/input/tablet/wacom_sys.c
+++ b/drivers/input/tablet/wacom_sys.c
@@ -502,56 +502,52 @@ static int wacom_parse_hid(struct usb_interface *intf,
         return result;
 }
 
-static int wacom_query_tablet_data(struct usb_interface *intf, struct wacom_features *features)
+static int wacom_set_device_mode(struct usb_interface *intf, int report_id, int length, int mode)
 {
         unsigned char *rep_data;
-        int limit = 0, report_id = 2;
-        int error = -ENOMEM;
+        int error = -ENOMEM, limit = 0;
 
-        rep_data = kmalloc(4, GFP_KERNEL);
+        rep_data = kzalloc(length, GFP_KERNEL);
         if (!rep_data)
                 return error;
 
-        /* ask to report Wacom data */
+        rep_data[0] = report_id;
+        rep_data[1] = mode;
+
+        do {
+                error = wacom_set_report(intf, WAC_HID_FEATURE_REPORT,
+                                         report_id, rep_data, length, 1);
+                if (error >= 0)
+                        error = wacom_get_report(intf, WAC_HID_FEATURE_REPORT,
+                                                 report_id, rep_data, length, 1);
+        } while ((error < 0 || rep_data[1] != mode) && limit++ < WAC_MSG_RETRIES);
+
+        kfree(rep_data);
+
+        return error < 0 ? error : 0;
+}
+
+/*
+ * Switch the tablet into its most-capable mode. Wacom tablets are
+ * typically configured to power-up in a mode which sends mouse-like
+ * reports to the OS. To get absolute position, pressure data, etc.
+ * from the tablet, it is necessary to switch the tablet out of this
+ * mode and into one which sends the full range of tablet data.
+ */
+static int wacom_query_tablet_data(struct usb_interface *intf, struct wacom_features *features)
+{
         if (features->device_type == BTN_TOOL_FINGER) {
-                /* if it is an MT Tablet PC touch */
                 if (features->type > TABLETPC) {
-                        do {
-                                rep_data[0] = 3;
-                                rep_data[1] = 4;
-                                rep_data[2] = 0;
-                                rep_data[3] = 0;
-                                report_id = 3;
-                                error = wacom_set_report(intf,
-                                                         WAC_HID_FEATURE_REPORT,
-                                                         report_id,
-                                                         rep_data, 4, 1);
-                                if (error >= 0)
-                                        error = wacom_get_report(intf,
-                                                        WAC_HID_FEATURE_REPORT,
-                                                        report_id,
-                                                        rep_data, 4, 1);
-                        } while ((error < 0 || rep_data[1] != 4) &&
-                                 limit++ < WAC_MSG_RETRIES);
+                        /* MT Tablet PC touch */
+                        return wacom_set_device_mode(intf, 3, 4, 4);
+                }
+        } else if (features->device_type == BTN_TOOL_PEN) {
+                if (features->type <= BAMBOO_PT && features->type != WIRELESS) {
+                        return wacom_set_device_mode(intf, 2, 2, 2);
                 }
-        } else if (features->type <= BAMBOO_PT &&
-                   features->type != WIRELESS &&
-                   features->device_type == BTN_TOOL_PEN) {
-                do {
-                        rep_data[0] = 2;
-                        rep_data[1] = 2;
-                        error = wacom_set_report(intf, WAC_HID_FEATURE_REPORT,
-                                                 report_id, rep_data, 2, 1);
-                        if (error >= 0)
-                                error = wacom_get_report(intf,
-                                                WAC_HID_FEATURE_REPORT,
-                                                report_id, rep_data, 2, 1);
-                } while ((error < 0 || rep_data[1] != 2) && limit++ < WAC_MSG_RETRIES);
         }
 
-        kfree(rep_data);
-
-        return error < 0 ? error : 0;
+        return 0;
 }
 
 static int wacom_retrieve_hid_descriptor(struct usb_interface *intf,