Input: add support for Wacom W8001 penabled serial touchscreen

The Wacom W8001 sensor is a sensor device (uses electromagnetic
resonance) and it is interfaced via its serial microcontroller
to the host.

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 339 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 3d1ab8fa9ac..20eb52ed176 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -95,6 +95,19 @@ config TOUCHSCREEN_ELO
           To compile this driver as a module, choose M here: the
           module will be called elo.
 
+config TOUCHSCREEN_WACOM_W8001
+        tristate "Wacom W8001 penabled serial touchscreen"
+        select SERIO
+        help
+          Say Y here if you have an Wacom W8001 penabled serial touchscreen
+          connected to your system.
+
+          If unsure, say N.
+
+          To compile this driver as a module, choose M here: the
+          module will be called wacom_w8001.
+
+
 config TOUCHSCREEN_MTOUCH
         tristate "MicroTouch serial touchscreens"
         select SERIO
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 15cf2907948..3dc84d3846c 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)	+= touchit213.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)    += touchright.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)      += touchwin.o
 obj-$(CONFIG_TOUCHSCREEN_UCB1400)       += ucb1400_ts.o
+obj-$(CONFIG_TOUCHSCREEN_WACOM_W8001)   += wacom_w8001.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX)        += wm97xx-ts.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705)  += wm9705.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712)  += wm9712.o
diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c
new file mode 100644
index 00000000000..2f33a016764
--- /dev/null
+++ b/drivers/input/touchscreen/wacom_w8001.c
@@ -0,0 +1,325 @@
+/*
+ * Wacom W8001 penabled serial touchscreen driver
+ *
+ * Copyright (c) 2008 Jaya Kumar
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ * Layout based on Elo serial touchscreen driver by Vojtech Pavlik
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+
+#define DRIVER_DESC     "Wacom W8001 serial touchscreen driver"
+
+MODULE_AUTHOR("Jaya Kumar <jayakumar.lkml@gmail.com>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Definitions & global arrays.
+ */
+
+#define W8001_MAX_LENGTH        11
+#define W8001_PACKET_LEN        11
+#define W8001_LEAD_MASK 0x80
+#define W8001_LEAD_BYTE 0x80
+#define W8001_TAB_MASK 0x40
+#define W8001_TAB_BYTE 0x40
+
+#define W8001_QUERY_PACKET 0x20
+
+struct w8001_coord {
+        u8 rdy;
+        u8 tsw;
+        u8 f1;
+        u8 f2;
+        u16 x;
+        u16 y;
+        u16 pen_pressure;
+        u8 tilt_x;
+        u8 tilt_y;
+};
+
+/*
+ * Per-touchscreen data.
+ */
+
+struct w8001 {
+        struct input_dev *dev;
+        struct serio *serio;
+        struct mutex cmd_mutex;
+        struct completion cmd_done;
+        int id;
+        int idx;
+        unsigned char expected_packet;
+        unsigned char data[W8001_MAX_LENGTH];
+        unsigned char response[W8001_PACKET_LEN];
+        char phys[32];
+};
+
+static int parse_data(u8 *data, struct w8001_coord *coord)
+{
+        coord->rdy = data[0] & 0x20;
+        coord->tsw = data[0] & 0x01;
+        coord->f1 = data[0] & 0x02;
+        coord->f2 = data[0] & 0x04;
+
+        coord->x = (data[1] & 0x7F) << 9;
+        coord->x |= (data[2] & 0x7F) << 2;
+        coord->x |= (data[6] & 0x60) >> 5;
+
+        coord->y = (data[3] & 0x7F) << 9;
+        coord->y |= (data[4] & 0x7F) << 2;
+        coord->y |= (data[6] & 0x18) >> 3;
+
+        coord->pen_pressure = data[5] & 0x7F;
+        coord->pen_pressure |= (data[6] & 0x07) << 7 ;
+
+        coord->tilt_x = data[7] & 0x7F;
+        coord->tilt_y = data[8] & 0x7F;
+
+        return 0;
+}
+
+static void w8001_process_data(struct w8001 *w8001, unsigned char data)
+{
+        struct input_dev *dev = w8001->dev;
+        u8 tmp;
+        struct w8001_coord coord;
+
+        w8001->data[w8001->idx] = data;
+        switch (w8001->idx++) {
+        case 0:
+                if ((data & W8001_LEAD_MASK) != W8001_LEAD_BYTE) {
+                        pr_debug("w8001: unsynchronized data: 0x%02x\n", data);
+                        w8001->idx = 0;
+                }
+                break;
+        case 8:
+                tmp = w8001->data[0] & W8001_TAB_MASK;
+                if (unlikely(tmp == W8001_TAB_BYTE))
+                        break;
+                w8001->idx = 0;
+                memset(&coord, 0, sizeof(coord));
+                parse_data(w8001->data, &coord);
+                input_report_abs(dev, ABS_X, coord.x);
+                input_report_abs(dev, ABS_Y, coord.y);
+                input_report_abs(dev, ABS_PRESSURE, coord.pen_pressure);
+                input_report_key(dev, BTN_TOUCH, coord.tsw);
+                input_sync(dev);
+                break;
+        case 10:
+                w8001->idx = 0;
+                memcpy(w8001->response, &w8001->data, W8001_PACKET_LEN);
+                w8001->expected_packet = W8001_QUERY_PACKET;
+                complete(&w8001->cmd_done);
+                break;
+        }
+}
+
+
+static irqreturn_t w8001_interrupt(struct serio *serio,
+                unsigned char data, unsigned int flags)
+{
+        struct w8001 *w8001 = serio_get_drvdata(serio);
+
+        w8001_process_data(w8001, data);
+
+        return IRQ_HANDLED;
+}
+
+static int w8001_async_command(struct w8001 *w8001, unsigned char *packet,
+                                        int len)
+{
+        int rc = -1;
+        int i;
+
+        mutex_lock(&w8001->cmd_mutex);
+
+        for (i = 0; i < len; i++) {
+                if (serio_write(w8001->serio, packet[i]))
+                        goto out;
+        }
+        rc = 0;
+
+out:
+        mutex_unlock(&w8001->cmd_mutex);
+        return rc;
+}
+
+static int w8001_command(struct w8001 *w8001, unsigned char *packet, int len)
+{
+        int rc = -1;
+        int i;
+
+        mutex_lock(&w8001->cmd_mutex);
+
+        serio_pause_rx(w8001->serio);
+        init_completion(&w8001->cmd_done);
+        serio_continue_rx(w8001->serio);
+
+        for (i = 0; i < len; i++) {
+                if (serio_write(w8001->serio, packet[i]))
+                        goto out;
+        }
+
+        wait_for_completion_timeout(&w8001->cmd_done, HZ);
+
+        if (w8001->expected_packet == W8001_QUERY_PACKET) {
+                /* We are back in reporting mode, the query was ACKed */
+                memcpy(packet, w8001->response, W8001_PACKET_LEN);
+                rc = 0;
+        }
+
+out:
+        mutex_unlock(&w8001->cmd_mutex);
+        return rc;
+}
+
+static int w8001_setup(struct w8001 *w8001)
+{
+        struct w8001_coord coord;
+        struct input_dev *dev = w8001->dev;
+        unsigned char start[1] = { '1' };
+        unsigned char query[11] = { '*' };
+
+        if (w8001_command(w8001, query, 1))
+                return -1;
+
+        memset(&coord, 0, sizeof(coord));
+        parse_data(query, &coord);
+
+        input_set_abs_params(dev, ABS_X, 0, coord.x, 0, 0);
+        input_set_abs_params(dev, ABS_Y, 0, coord.y, 0, 0);
+        input_set_abs_params(dev, ABS_PRESSURE, 0, coord.pen_pressure, 0, 0);
+        input_set_abs_params(dev, ABS_TILT_X, 0, coord.tilt_x, 0, 0);
+        input_set_abs_params(dev, ABS_TILT_Y, 0, coord.tilt_y, 0, 0);
+
+        if (w8001_async_command(w8001, start, 1))
+                return -1;
+
+        return 0;
+}
+
+/*
+ * w8001_disconnect() is the opposite of w8001_connect()
+ */
+
+static void w8001_disconnect(struct serio *serio)
+{
+        struct w8001 *w8001 = serio_get_drvdata(serio);
+
+        input_get_device(w8001->dev);
+        input_unregister_device(w8001->dev);
+        serio_close(serio);
+        serio_set_drvdata(serio, NULL);
+        input_put_device(w8001->dev);
+        kfree(w8001);
+}
+
+/*
+ * w8001_connect() is the routine that is called when someone adds a
+ * new serio device that supports the w8001 protocol and registers it as
+ * an input device.
+ */
+
+static int w8001_connect(struct serio *serio, struct serio_driver *drv)
+{
+        struct w8001 *w8001;
+        struct input_dev *input_dev;
+        int err;
+
+        w8001 = kzalloc(sizeof(struct w8001), GFP_KERNEL);
+        input_dev = input_allocate_device();
+        if (!w8001 || !input_dev) {
+                err = -ENOMEM;
+                goto fail1;
+        }
+
+        w8001->serio = serio;
+        w8001->id = serio->id.id;
+        w8001->dev = input_dev;
+        mutex_init(&w8001->cmd_mutex);
+        init_completion(&w8001->cmd_done);
+        snprintf(w8001->phys, sizeof(w8001->phys), "%s/input0", serio->phys);
+
+        input_dev->name = "Wacom W8001 Penabled Serial TouchScreen";
+        input_dev->phys = w8001->phys;
+        input_dev->id.bustype = BUS_RS232;
+        input_dev->id.vendor = SERIO_W8001;
+        input_dev->id.product = w8001->id;
+        input_dev->id.version = 0x0100;
+        input_dev->dev.parent = &serio->dev;
+
+        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+
+        serio_set_drvdata(serio, w8001);
+        err = serio_open(serio, drv);
+        if (err)
+                goto fail2;
+
+        if (w8001_setup(w8001))
+                goto fail3;
+
+        err = input_register_device(w8001->dev);
+        if (err)
+                goto fail3;
+
+        return 0;
+
+fail3:
+        serio_close(serio);
+fail2:
+        serio_set_drvdata(serio, NULL);
+fail1:
+        input_free_device(input_dev);
+        kfree(w8001);
+        return err;
+}
+
+static struct serio_device_id w8001_serio_ids[] = {
+        {
+                .type   = SERIO_RS232,
+                .proto  = SERIO_W8001,
+                .id     = SERIO_ANY,
+                .extra  = SERIO_ANY,
+        },
+        { 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, w8001_serio_ids);
+
+static struct serio_driver w8001_drv = {
+        .driver         = {
+                .name   = "w8001",
+        },
+        .description    = DRIVER_DESC,
+        .id_table       = w8001_serio_ids,
+        .interrupt      = w8001_interrupt,
+        .connect        = w8001_connect,
+        .disconnect     = w8001_disconnect,
+};
+
+static int __init w8001_init(void)
+{
+        return serio_register_driver(&w8001_drv);
+}
+
+static void __exit w8001_exit(void)
+{
+        serio_unregister_driver(&w8001_drv);
+}
+
+module_init(w8001_init);
+module_exit(w8001_exit);