Hi Richard,

This adds proper single-touch support for BYD touchpads to the psmouse input
driver.

I posted a driver for the same touchpad a few weeks ago, which has been merged
into linux-next. There's some stuff in this patch which is missing in my driver
though, so we should definitely try and include that, and I'm very curious
about the pseudo-absolute mode.

This patch is against commit b82dde0230439215b55e545880e90337ee16f51a (Merge tag
'please-pull-copy_file_range' of
git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux ) of Linus' kernel
branch.

Can you rebase against
'git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input'?

+/* BYD commands reverse engineered from windows driver */
+
+/*
+ * swipe gesture from off-pad to on-pad
+ *  0 : disable
+ *  1 : enable
+ */
+#define BYD_CMD_SET_OFFSCREEN_SWIPE             0xcc
+/*
+ * tap and drag delay time
+ *  0 : disable
+ *  1 - 8 : least to most delay
+ */
+#define BYD_CMD_SET_TAP_DRAG_DELAY_TIME         0xcf
+/*
+ * physical buttons function mapping
+ *  0 : enable
+ *  4 : normal
+ *  5 : left button custom command
+ *  6 : right button custom command
+ *  8 : disable
+ */
+#define BYD_CMD_SET_PHYSICAL_BUTTONS            0xd0
+/*
+ * absolute mode (1 byte X/Y resolution)
+ *  0 : disable
+ *  2 : enable
+ */
+#define BYD_CMD_SET_ABSOLUTE_MODE               0xd1
+/*
+ * two finger scrolling
+ *  1 : vertical
+ *  2 : horizontal
+ *  3 : vertical + horizontal
+ *  4 : disable
+ */
+#define BYD_CMD_SET_TWO_FINGER_SCROLL           0xd2
+/*
+ * handedness
+ *  1 : right handed
+ *  2 : left handed
+ */
+#define BYD_CMD_SET_HANDEDNESS                  0xd3
+/*
+ * tap to click
+ *  1 : enable
+ *  2 : disable
+ */
+#define BYD_CMD_SET_TAP                         0xd4
+/*
+ * tap and drag
+ *  1 : tap and hold to drag
+ *  2 : tap and hold to drag + lock
+ *  3 : disable
+ */
+#define BYD_CMD_SET_TAP_DRAG                    0xd5
+/*
+ * touch sensitivity
+ *  1 - 7 : least to most sensitive
+ */
+#define BYD_CMD_SET_TOUCH_SENSITIVITY           0xd6
+/*
+ * one finger scrolling
+ *  1 : vertical
+ *  2 : horizontal
+ *  3 : vertical + horizontal
+ *  4 : disable
+ */
+#define BYD_CMD_SET_ONE_FINGER_SCROLL           0xd7
+/*
+ * one finger scrolling function
+ *  1 : free scrolling
+ *  2 : edge motion
+ *  3 : free scrolling + edge motion
+ *  4 : disable
+ */
+#define BYD_CMD_SET_ONE_FINGER_SCROLL_FUNC      0xd8
+/*
+ * sliding speed
+ *  1 - 5 : slowest to fastest
+ */
+#define BYD_CMD_SET_SLIDING_SPEED               0xda
+/*
+ * edge motion
+ *  1 : disable
+ *  2 : enable when dragging
+ *  3 : enable when dragging and pointing
+ */
+#define BYD_CMD_SET_EDGE_MOTION                 0xdb
+/*
+ * left edge region size
+ *  0 - 7 : smallest to largest width
+ */
+#define BYD_CMD_SET_LEFT_EDGE_REGION            0xdc
+/*
+ * top edge region size
+ *  0 - 9 : smallest to largest height
+ */
+#define BYD_CMD_SET_TOP_EDGE_REGION             0xdd
+/*
+ * disregard palm press as clicks
+ *  1 - 6 : smallest to largest
+ */
+#define BYD_CMD_SET_PALM_CHECK                  0xde
+/* right edge region size
+ *  0 - 7 : smallest to largest width
+ */
+#define BYD_CMD_SET_RIGHT_EDGE_REGION           0xdf
+/*
+ * bottom edge region size
+ *  0 - 9 : smallest to largest height
+ */
+#define BYD_CMD_SET_BOTTOM_EDGE_REGION          0xe1
+/*
+ * multitouch gestures
+ *  1 : enable
+ *  2 : disable
+ */
+#define BYD_CMD_SET_MULTITOUCH                  0xe3
+/*
+ * edge motion speed
+ *  0 : control with finger pressure
+ *  1 - 9 : slowest to fastest
+ */
+#define BYD_CMD_SET_EDGE_MOTION_SPEED           0xe4
+/*
+ * two finger scolling function
+ *  0 : free scrolling
+ *  1 : free scrolling (with momentum)
+ *  2 : edge motion
+ *  3 : free scrolling (with momentum) + edge motion
+ *  4 : disable
+ */
+#define BYD_CMD_SET_TWO_FINGER_SCROLL_FUNC      0xe5

These are definitely worth merging into the existing driver - I never got the
time to figure out all of the different settings.

+
+struct byd_data {
+ struct timer_list timer;
+ int32_t abs_x;
+ int32_t abs_y;
+ uint32_t last_touch_time;
+ uint32_t button_left      : 1;
+ uint32_t button_right     : 1;
+ uint32_t touch            : 1;
+};
+

It looks like whatever email client you used has broken the formatting - when
you resend, can you use something which will preserve whitespace properly? See
'Documentation/email-clients.txt'.

+static void byd_report_input(struct psmouse *psmouse)
+{
+ struct byd_data *priv = (struct byd_data *)psmouse->private;
+ struct input_dev *dev = psmouse->dev;
+
+ input_report_abs(dev, ABS_X, priv->abs_x);
+ input_report_abs(dev, ABS_Y, priv->abs_y);
+ input_report_key(dev, BTN_LEFT, priv->button_left);
+ input_report_key(dev, BTN_RIGHT, priv->button_right);
+ input_report_key(dev, BTN_TOUCH, priv->touch);
+ input_report_key(dev, BTN_TOOL_FINGER, priv->touch);
+
+ input_sync(dev);
+}

Could you explain generally why you're reporting in absolute mode? What
advantage does it have over using relative reporting and turning off the
absolute packets in the touchpad init sequence?

+
+static void byd_clear_touch(unsigned long data)
+{
+ struct psmouse *psmouse = (struct psmouse *)data;
+ struct byd_data *priv = psmouse->private;
+
+ serio_pause_rx(psmouse->ps2dev.serio);
+
+ priv->touch = 0;
+ /*
+ * move cursor back to center of pad when we lose touch
+ * this specifically improves user experiencce when moving
+ * cursor with one finger, and pressing butoton with other
+ */
+ priv->abs_x = BYD_CONST_PAD_WIDTH / 2;
+ priv->abs_y = BYD_CONST_PAD_HEIGHT / 2;
+
+ byd_report_input(psmouse);

serio_pause_rx() takes a spinlock - might be worth checking that
byd_report_input() doesn't do anything that might sleep.

+ switch (packet[3]) {
+ case BYD_PKT_ABSOLUTE:
+ /* on first touch, use the absolute packet to determine our start location */
+ if (priv->touch == 0) {
+ priv->abs_x = packet[1] * (BYD_CONST_PAD_WIDTH / 256);
+ priv->abs_y = (255 - packet[2]) * (BYD_CONST_PAD_HEIGHT / 256);
+
+ /* needed to detect tap */
+ if (now_msecs - priv->last_touch_time > 64) {
+ priv->touch = 1;
+ }
+ }
+ break;
+ case BYD_PKT_RELATIVE:
+ {
+ int32_t rel_x, rel_y;
+
+ /* same as regular PS/2 psmouse protocoal */
+ rel_x = packet[1] ? (int) packet[1] - (int) ((packet[0] << 4) & 0x100) : 0;
+ rel_y = packet[2] ? (int) ((packet[0] << 3) & 0x100) - (int) packet[2] : 0;
+
+ /*
+ * experiments show relative mouse packets come in increments of
+ * 1 unit / 11 msecs (regardless of time delta between relative packets)
+ */
+ priv->abs_x += rel_x * 11;
+ priv->abs_y += rel_y * 11;
+
+ priv->touch = 1;
+ }

So can this not handle gestures/multitouch?

Cheers!
Chris