Input: hgpk - forced recalibration for the OLPC touchpad

The OLPC XO laptop incorporates a combination touchpad/tablet device
which unfortunately requires frequent recalibration.  The driver will
force this automatically when various suspicious behaviors are
observed, and the user can recalibrate manually (with a special
keyboard sequence). There's currently no way, however, for an external
program to cause recalibration. We can not use the reconnect
capability which is already available in /sys because full reset of
the touchpad takes 1.1 - 1.2 secons which is too long.

This patch creates a new node in /sys which, when written with '1',
will force a touchpad recalibration; no other writes (or reads)
of this node are supported.

Signed-off-by: Paul Fox <pgf@laptop.org>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 52 insertions, 3 deletions

diff --git a/drivers/input/mouse/hgpk.c b/drivers/input/mouse/hgpk.c
index a1ad2f1a7bb3..f5aa035774d9 100644
--- a/drivers/input/mouse/hgpk.c
+++ b/drivers/input/mouse/hgpk.c
@@ -369,12 +369,46 @@ static ssize_t hgpk_set_powered(struct psmouse *psmouse, void *data,
 __PSMOUSE_DEFINE_ATTR(powered, S_IWUSR | S_IRUGO, NULL,
                       hgpk_show_powered, hgpk_set_powered, 0);
 
+static ssize_t hgpk_trigger_recal_show(struct psmouse *psmouse,
+                void *data, char *buf)
+{
+        return -EINVAL;
+}
+
+static ssize_t hgpk_trigger_recal(struct psmouse *psmouse, void *data,
+                                const char *buf, size_t count)
+{
+        struct hgpk_data *priv = psmouse->private;
+        unsigned long value;
+        int err;
+
+        err = strict_strtoul(buf, 10, &value);
+        if (err || value != 1)
+                return -EINVAL;
+
+        /*
+         * We queue work instead of doing recalibration right here
+         * to avoid adding locking to to hgpk_force_recalibrate()
+         * since workqueue provides serialization.
+         */
+        psmouse_queue_work(psmouse, &priv->recalib_wq, 0);
+        return count;
+}
+
+__PSMOUSE_DEFINE_ATTR(recalibrate, S_IWUSR | S_IRUGO, NULL,
+                      hgpk_trigger_recal_show, hgpk_trigger_recal, 0);
+
 static void hgpk_disconnect(struct psmouse *psmouse)
 {
         struct hgpk_data *priv = psmouse->private;
 
         device_remove_file(&psmouse->ps2dev.serio->dev,
                            &psmouse_attr_powered.dattr);
+
+        if (psmouse->model >= HGPK_MODEL_C)
+                device_remove_file(&psmouse->ps2dev.serio->dev,
+                                   &psmouse_attr_recalibrate.dattr);
+
         psmouse_reset(psmouse);
         kfree(priv);
 }
@@ -423,10 +457,25 @@ static int hgpk_register(struct psmouse *psmouse)
 
         err = device_create_file(&psmouse->ps2dev.serio->dev,
                                  &psmouse_attr_powered.dattr);
-        if (err)
-                hgpk_err(psmouse, "Failed to create sysfs attribute\n");
+        if (err) {
+                hgpk_err(psmouse, "Failed creating 'powered' sysfs node\n");
+                return err;
+        }
 
-        return err;
+        /* C-series touchpads added the recalibrate command */
+        if (psmouse->model >= HGPK_MODEL_C) {
+                err = device_create_file(&psmouse->ps2dev.serio->dev,
+                                         &psmouse_attr_recalibrate.dattr);
+                if (err) {
+                        hgpk_err(psmouse,
+                                "Failed creating 'recalibrate' sysfs node\n");
+                        device_remove_file(&psmouse->ps2dev.serio->dev,
+                                        &psmouse_attr_powered.dattr);
+                        return err;
+                }
+        }
+
+        return 0;
 }
 
 int hgpk_init(struct psmouse *psmouse)