Input: add driver for hampshire serial touchscreens

Adds support for Hampshire TSHARC serial touchscreens.  Implements
Hampshire's 4-byte communication protocol.

Signed-off-by: Adam Bennett <abennett72@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 218 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 3d1ade2e5196..cc471983ac0e 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -119,6 +119,18 @@ config TOUCHSCREEN_DYNAPRO
           To compile this driver as a module, choose M here: the
           module will be called dynapro.
 
+config TOUCHSCREEN_HAMPSHIRE
+        tristate "Hampshire serial touchscreen"
+        select SERIO
+        help
+          Say Y here if you have a Hampshire 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 hampshire.
+
 config TOUCHSCREEN_EETI
         tristate "EETI touchscreen panel support"
         depends on I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 41145d074dec..8ad36eef90a2 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_TOUCHSCREEN_ADS7846)	+= ads7846.o
 obj-$(CONFIG_TOUCHSCREEN_ATMEL_TSADCC)  += atmel_tsadcc.o
 obj-$(CONFIG_TOUCHSCREEN_BITSY)         += h3600_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_DYNAPRO)       += dynapro.o
+obj-$(CONFIG_TOUCHSCREEN_HAMPSHIRE)     += hampshire.o
 obj-$(CONFIG_TOUCHSCREEN_GUNZE)         += gunze.o
 obj-$(CONFIG_TOUCHSCREEN_EETI)          += eeti_ts.o
 obj-$(CONFIG_TOUCHSCREEN_ELO)           += elo.o
diff --git a/drivers/input/touchscreen/hampshire.c b/drivers/input/touchscreen/hampshire.c
new file mode 100644
index 000000000000..2da6cc31bb21
--- /dev/null
+++ b/drivers/input/touchscreen/hampshire.c
@@ -0,0 +1,205 @@
+/*
+ * Hampshire serial touchscreen driver
+ *
+ * Copyright (c) 2010 Adam Bennett
+ * Based on the dynapro driver (c) Tias Guns
+ *
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+/*
+ * 2010/04/08 Adam Bennett <abennett72@gmail.com>
+ *   Copied dynapro.c and edited for Hampshire 4-byte protocol
+ */
+
+#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>
+
+#define DRIVER_DESC     "Hampshire serial touchscreen driver"
+
+MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Definitions & global arrays.
+ */
+
+#define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
+#define HAMPSHIRE_FORMAT_LENGTH 4
+#define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
+
+#define HAMPSHIRE_MIN_XC 0
+#define HAMPSHIRE_MAX_XC 0x1000
+#define HAMPSHIRE_MIN_YC 0
+#define HAMPSHIRE_MAX_YC 0x1000
+
+#define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
+#define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
+#define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
+
+/*
+ * Per-touchscreen data.
+ */
+
+struct hampshire {
+        struct input_dev *dev;
+        struct serio *serio;
+        int idx;
+        unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
+        char phys[32];
+};
+
+static void hampshire_process_data(struct hampshire *phampshire)
+{
+        struct input_dev *dev = phampshire->dev;
+
+        if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
+                input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
+                input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
+                input_report_key(dev, BTN_TOUCH,
+                                 HAMPSHIRE_GET_TOUCHED(phampshire->data));
+                input_sync(dev);
+
+                phampshire->idx = 0;
+        }
+}
+
+static irqreturn_t hampshire_interrupt(struct serio *serio,
+                unsigned char data, unsigned int flags)
+{
+        struct hampshire *phampshire = serio_get_drvdata(serio);
+
+        phampshire->data[phampshire->idx] = data;
+
+        if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
+                hampshire_process_data(phampshire);
+        else
+                dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
+                        phampshire->data[0]);
+
+        return IRQ_HANDLED;
+}
+
+static void hampshire_disconnect(struct serio *serio)
+{
+        struct hampshire *phampshire = serio_get_drvdata(serio);
+
+        input_get_device(phampshire->dev);
+        input_unregister_device(phampshire->dev);
+        serio_close(serio);
+        serio_set_drvdata(serio, NULL);
+        input_put_device(phampshire->dev);
+        kfree(phampshire);
+}
+
+/*
+ * hampshire_connect() is the routine that is called when someone adds a
+ * new serio device that supports hampshire protocol and registers it as
+ * an input device. This is usually accomplished using inputattach.
+ */
+
+static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
+{
+        struct hampshire *phampshire;
+        struct input_dev *input_dev;
+        int err;
+
+        phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
+        input_dev = input_allocate_device();
+        if (!phampshire || !input_dev) {
+                err = -ENOMEM;
+                goto fail1;
+        }
+
+        phampshire->serio = serio;
+        phampshire->dev = input_dev;
+        snprintf(phampshire->phys, sizeof(phampshire->phys),
+                 "%s/input0", serio->phys);
+
+        input_dev->name = "Hampshire Serial TouchScreen";
+        input_dev->phys = phampshire->phys;
+        input_dev->id.bustype = BUS_RS232;
+        input_dev->id.vendor = SERIO_HAMPSHIRE;
+        input_dev->id.product = 0;
+        input_dev->id.version = 0x0001;
+        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);
+        input_set_abs_params(phampshire->dev, ABS_X,
+                             HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
+        input_set_abs_params(phampshire->dev, ABS_Y,
+                             HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
+
+        serio_set_drvdata(serio, phampshire);
+
+        err = serio_open(serio, drv);
+        if (err)
+                goto fail2;
+
+        err = input_register_device(phampshire->dev);
+        if (err)
+                goto fail3;
+
+        return 0;
+
+ fail3: serio_close(serio);
+ fail2: serio_set_drvdata(serio, NULL);
+ fail1: input_free_device(input_dev);
+        kfree(phampshire);
+        return err;
+}
+
+/*
+ * The serio driver structure.
+ */
+
+static struct serio_device_id hampshire_serio_ids[] = {
+        {
+                .type   = SERIO_RS232,
+                .proto  = SERIO_HAMPSHIRE,
+                .id     = SERIO_ANY,
+                .extra  = SERIO_ANY,
+        },
+        { 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
+
+static struct serio_driver hampshire_drv = {
+        .driver         = {
+                .name   = "hampshire",
+        },
+        .description    = DRIVER_DESC,
+        .id_table       = hampshire_serio_ids,
+        .interrupt      = hampshire_interrupt,
+        .connect        = hampshire_connect,
+        .disconnect     = hampshire_disconnect,
+};
+
+/*
+ * The functions for inserting/removing us as a module.
+ */
+
+static int __init hampshire_init(void)
+{
+        return serio_register_driver(&hampshire_drv);
+}
+
+static void __exit hampshire_exit(void)
+{
+        serio_unregister_driver(&hampshire_drv);
+}
+
+module_init(hampshire_init);
+module_exit(hampshire_exit);