HID: wiimote: add pro-controller analog stick calibration

The analog sticks of the pro-controller might report slightly off values.
To guarantee a uniform setup, we now calibrate analog-stick values during
pro-controller setup.

Unfortunately, the pro-controller fails during normal EEPROM reads and I
couldn't figure out whether there are any calibration values stored on the
device. Therefore, we now use the first values reported by the device (iff
they are not _way_ off, which would indicate movement) to initialize the
calibration values. To allow users to change this calibration data, we
provide a pro_calib sysfs attribute.

We also change the "flat" values so user-space correctly smoothes our
data. It makes slightly off zero-positions less visible while still
guaranteeing highly precise movement reports. Note that the pro controller
reports zero-positions in a quite huge range (at least: -100 to +100).

Reported-by: Rafael Brune <mail@rbrune.de>
Tested-by: Rafael Brune <mail@rbrune.de>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 110 insertions, 9 deletions

diff --git a/drivers/hid/hid-wiimote-modules.c b/drivers/hid/hid-wiimote-modules.c
index e30567af42ed..6b61f01e01e7 100644
--- a/drivers/hid/hid-wiimote-modules.c
+++ b/drivers/hid/hid-wiimote-modules.c
@@ -1655,10 +1655,39 @@ static void wiimod_pro_in_ext(struct wiimote_data *wdata, const __u8 *ext)
         ly = (ext[4] & 0xff) | ((ext[5] & 0x0f) << 8);
         ry = (ext[6] & 0xff) | ((ext[7] & 0x0f) << 8);
 
-        input_report_abs(wdata->extension.input, ABS_X, lx - 0x800);
-        input_report_abs(wdata->extension.input, ABS_Y, 0x800 - ly);
-        input_report_abs(wdata->extension.input, ABS_RX, rx - 0x800);
-        input_report_abs(wdata->extension.input, ABS_RY, 0x800 - ry);
+        /* zero-point offsets */
+        lx -= 0x800;
+        ly = 0x800 - ly;
+        rx -= 0x800;
+        ry = 0x800 - ry;
+
+        /* Trivial automatic calibration. We don't know any calibration data
+         * in the EEPROM so we must use the first report to calibrate the
+         * null-position of the analog sticks. Users can retrigger calibration
+         * via sysfs, or set it explicitly. If data is off more than abs(500),
+         * we skip calibration as the sticks are likely to be moved already. */
+        if (!(wdata->state.flags & WIIPROTO_FLAG_PRO_CALIB_DONE)) {
+                wdata->state.flags |= WIIPROTO_FLAG_PRO_CALIB_DONE;
+                if (abs(lx) < 500)
+                        wdata->state.calib_pro_sticks[0] = -lx;
+                if (abs(ly) < 500)
+                        wdata->state.calib_pro_sticks[1] = -ly;
+                if (abs(rx) < 500)
+                        wdata->state.calib_pro_sticks[2] = -rx;
+                if (abs(ry) < 500)
+                        wdata->state.calib_pro_sticks[3] = -ry;
+        }
+
+        /* apply calibration data */
+        lx += wdata->state.calib_pro_sticks[0];
+        ly += wdata->state.calib_pro_sticks[1];
+        rx += wdata->state.calib_pro_sticks[2];
+        ry += wdata->state.calib_pro_sticks[3];
+
+        input_report_abs(wdata->extension.input, ABS_X, lx);
+        input_report_abs(wdata->extension.input, ABS_Y, ly);
+        input_report_abs(wdata->extension.input, ABS_RX, rx);
+        input_report_abs(wdata->extension.input, ABS_RY, ry);
 
         input_report_key(wdata->extension.input,
                          wiimod_pro_map[WIIMOD_PRO_KEY_RIGHT],
@@ -1766,12 +1795,70 @@ static int wiimod_pro_play(struct input_dev *dev, void *data,
         return 0;
 }
 
+static ssize_t wiimod_pro_calib_show(struct device *dev,
+                                     struct device_attribute *attr,
+                                     char *out)
+{
+        struct wiimote_data *wdata = dev_to_wii(dev);
+        int r;
+
+        r = 0;
+        r += sprintf(&out[r], "%+06hd:", wdata->state.calib_pro_sticks[0]);
+        r += sprintf(&out[r], "%+06hd ", wdata->state.calib_pro_sticks[1]);
+        r += sprintf(&out[r], "%+06hd:", wdata->state.calib_pro_sticks[2]);
+        r += sprintf(&out[r], "%+06hd\n", wdata->state.calib_pro_sticks[3]);
+
+        return r;
+}
+
+static ssize_t wiimod_pro_calib_store(struct device *dev,
+                                      struct device_attribute *attr,
+                                      const char *buf, size_t count)
+{
+        struct wiimote_data *wdata = dev_to_wii(dev);
+        int r;
+        s16 x1, y1, x2, y2;
+
+        if (!strncmp(buf, "scan\n", 5)) {
+                spin_lock_irq(&wdata->state.lock);
+                wdata->state.flags &= ~WIIPROTO_FLAG_PRO_CALIB_DONE;
+                spin_unlock_irq(&wdata->state.lock);
+        } else {
+                r = sscanf(buf, "%hd:%hd %hd:%hd", &x1, &y1, &x2, &y2);
+                if (r != 4)
+                        return -EINVAL;
+
+                spin_lock_irq(&wdata->state.lock);
+                wdata->state.flags |= WIIPROTO_FLAG_PRO_CALIB_DONE;
+                spin_unlock_irq(&wdata->state.lock);
+
+                wdata->state.calib_pro_sticks[0] = x1;
+                wdata->state.calib_pro_sticks[1] = y1;
+                wdata->state.calib_pro_sticks[2] = x2;
+                wdata->state.calib_pro_sticks[3] = y2;
+        }
+
+        return strnlen(buf, PAGE_SIZE);
+}
+
+static DEVICE_ATTR(pro_calib, S_IRUGO|S_IWUSR|S_IWGRP, wiimod_pro_calib_show,
+                   wiimod_pro_calib_store);
+
 static int wiimod_pro_probe(const struct wiimod_ops *ops,
                             struct wiimote_data *wdata)
 {
         int ret, i;
+        unsigned long flags;
 
         INIT_WORK(&wdata->rumble_worker, wiimod_rumble_worker);
+        wdata->state.calib_pro_sticks[0] = 0;
+        wdata->state.calib_pro_sticks[1] = 0;
+        wdata->state.calib_pro_sticks[2] = 0;
+        wdata->state.calib_pro_sticks[3] = 0;
+
+        spin_lock_irqsave(&wdata->state.lock, flags);
+        wdata->state.flags &= ~WIIPROTO_FLAG_PRO_CALIB_DONE;
+        spin_unlock_irqrestore(&wdata->state.lock, flags);
 
         wdata->extension.input = input_allocate_device();
         if (!wdata->extension.input)
@@ -1786,6 +1873,13 @@ static int wiimod_pro_probe(const struct wiimod_ops *ops,
                 goto err_free;
         }
 
+        ret = device_create_file(&wdata->hdev->dev,
+                                 &dev_attr_pro_calib);
+        if (ret) {
+                hid_err(wdata->hdev, "cannot create sysfs attribute\n");
+                goto err_free;
+        }
+
         wdata->extension.input->open = wiimod_pro_open;
         wdata->extension.input->close = wiimod_pro_close;
         wdata->extension.input->dev.parent = &wdata->hdev->dev;
@@ -1806,20 +1900,23 @@ static int wiimod_pro_probe(const struct wiimod_ops *ops,
         set_bit(ABS_RX, wdata->extension.input->absbit);
         set_bit(ABS_RY, wdata->extension.input->absbit);
         input_set_abs_params(wdata->extension.input,
-                             ABS_X, -0x800, 0x800, 2, 4);
+                             ABS_X, -0x400, 0x400, 4, 100);
         input_set_abs_params(wdata->extension.input,
-                             ABS_Y, -0x800, 0x800, 2, 4);
+                             ABS_Y, -0x400, 0x400, 4, 100);
         input_set_abs_params(wdata->extension.input,
-                             ABS_RX, -0x800, 0x800, 2, 4);
+                             ABS_RX, -0x400, 0x400, 4, 100);
         input_set_abs_params(wdata->extension.input,
-                             ABS_RY, -0x800, 0x800, 2, 4);
+                             ABS_RY, -0x400, 0x400, 4, 100);
 
         ret = input_register_device(wdata->extension.input);
         if (ret)
-                goto err_free;
+                goto err_file;
 
         return 0;
 
+err_file:
+        device_remove_file(&wdata->hdev->dev,
+                           &dev_attr_pro_calib);
 err_free:
         input_free_device(wdata->extension.input);
         wdata->extension.input = NULL;
@@ -1837,6 +1934,8 @@ static void wiimod_pro_remove(const struct wiimod_ops *ops,
         input_unregister_device(wdata->extension.input);
         wdata->extension.input = NULL;
         cancel_work_sync(&wdata->rumble_worker);
+        device_remove_file(&wdata->hdev->dev,
+                           &dev_attr_pro_calib);
 
         spin_lock_irqsave(&wdata->state.lock, flags);
         wiiproto_req_rumble(wdata, 0);
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h
index 75db0c400037..03065f1917fc 100644
--- a/drivers/hid/hid-wiimote.h
+++ b/drivers/hid/hid-wiimote.h
@@ -46,6 +46,7 @@
 #define WIIPROTO_FLAG_DRM_LOCKED        0x8000
 #define WIIPROTO_FLAG_BUILTIN_MP        0x010000
 #define WIIPROTO_FLAG_NO_MP             0x020000
+#define WIIPROTO_FLAG_PRO_CALIB_DONE    0x040000
 
 #define WIIPROTO_FLAGS_LEDS (WIIPROTO_FLAG_LED1 | WIIPROTO_FLAG_LED2 | \
                                         WIIPROTO_FLAG_LED3 | WIIPROTO_FLAG_LED4)
@@ -135,6 +136,7 @@ struct wiimote_state {
 
         /* calibration/cache data */
         __u16 calib_bboard[4][3];
+        __s16 calib_pro_sticks[4];
         __u8 cache_rumble;
 };