Input: add a driver for TSC-40 serial touchscreen

This patch adds the TSC-40 serial touchscreen driver and should be
compatible with TSC-10 and TSC-25.

The driver was written by Linutronix on behalf of Bachmann electronic GmbH.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 197 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index cabd9e54863f..3488ffe1fa0a 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -651,6 +651,18 @@ config TOUCHSCREEN_TOUCHIT213
           To compile this driver as a module, choose M here: the
           module will be called touchit213.
 
+config TOUCHSCREEN_TSC_SERIO
+        tristate "TSC-10/25/40 serial touchscreen support"
+        select SERIO
+        help
+          Say Y here if you have a TSC-10, 25 or 40 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 tsc40.
+
 config TOUCHSCREEN_TSC2005
         tristate "TSC2005 based touchscreens"
         depends on SPI_MASTER && GENERIC_HARDIRQS
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 282d6f76ae26..f957676035a4 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_TOUCHSCREEN_TNETV107X)	+= tnetv107x-ts.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)    += touchit213.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)    += touchright.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)      += touchwin.o
+obj-$(CONFIG_TOUCHSCREEN_TSC_SERIO)     += tsc40.o
 obj-$(CONFIG_TOUCHSCREEN_TSC2005)       += tsc2005.o
 obj-$(CONFIG_TOUCHSCREEN_TSC2007)       += tsc2007.o
 obj-$(CONFIG_TOUCHSCREEN_UCB1400)       += ucb1400_ts.o
diff --git a/drivers/input/touchscreen/tsc40.c b/drivers/input/touchscreen/tsc40.c
new file mode 100644
index 000000000000..29d5ed4dd31c
--- /dev/null
+++ b/drivers/input/touchscreen/tsc40.c
@@ -0,0 +1,184 @@
+/*
+ * TSC-40 serial touchscreen driver. It should be compatible with
+ * TSC-10 and 25.
+ *
+ * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+ * License: GPLv2 as published by the FSF.
+ */
+
+#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 PACKET_LENGTH  5
+struct tsc_ser {
+        struct input_dev *dev;
+        struct serio *serio;
+        u32 idx;
+        unsigned char data[PACKET_LENGTH];
+        char phys[32];
+};
+
+static void tsc_process_data(struct tsc_ser *ptsc)
+{
+        struct input_dev *dev = ptsc->dev;
+        u8 *data = ptsc->data;
+        u32 x;
+        u32 y;
+
+        x = ((data[1] & 0x03) << 8) | data[2];
+        y = ((data[3] & 0x03) << 8) | data[4];
+
+        input_report_abs(dev, ABS_X, x);
+        input_report_abs(dev, ABS_Y, y);
+        input_report_key(dev, BTN_TOUCH, 1);
+
+        input_sync(dev);
+}
+
+static irqreturn_t tsc_interrupt(struct serio *serio,
+                unsigned char data, unsigned int flags)
+{
+        struct tsc_ser *ptsc = serio_get_drvdata(serio);
+        struct input_dev *dev = ptsc->dev;
+
+        ptsc->data[ptsc->idx] = data;
+        switch (ptsc->idx++) {
+        case 0:
+                if (unlikely((data & 0x3e) != 0x10)) {
+                        dev_dbg(&serio->dev,
+                                "unsynchronized packet start (0x%02x)\n", data);
+                        ptsc->idx = 0;
+                } else if (!(data & 0x01)) {
+                        input_report_key(dev, BTN_TOUCH, 0);
+                        input_sync(dev);
+                        ptsc->idx = 0;
+                }
+                break;
+
+        case 1:
+        case 3:
+                if (unlikely(data & 0xfc)) {
+                        dev_dbg(&serio->dev,
+                                "unsynchronized data 0x%02x at offset %d\n",
+                                data, ptsc->idx - 1);
+                        ptsc->idx = 0;
+                }
+                break;
+
+        case 4:
+                tsc_process_data(ptsc);
+                ptsc->idx = 0;
+                break;
+        }
+
+        return IRQ_HANDLED;
+}
+
+static int tsc_connect(struct serio *serio, struct serio_driver *drv)
+{
+        struct tsc_ser *ptsc;
+        struct input_dev *input_dev;
+        int error;
+
+        ptsc = kzalloc(sizeof(struct tsc_ser), GFP_KERNEL);
+        input_dev = input_allocate_device();
+        if (!ptsc || !input_dev) {
+                error = -ENOMEM;
+                goto fail1;
+        }
+
+        ptsc->serio = serio;
+        ptsc->dev = input_dev;
+        snprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys);
+
+        input_dev->name = "TSC-10/25/40 Serial TouchScreen";
+        input_dev->phys = ptsc->phys;
+        input_dev->id.bustype = BUS_RS232;
+        input_dev->id.vendor = SERIO_TSC40;
+        input_dev->id.product = 40;
+        input_dev->id.version = 0x0001;
+        input_dev->dev.parent = &serio->dev;
+
+        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+        __set_bit(BTN_TOUCH, input_dev->keybit);
+        input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0);
+        input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0);
+        input_set_abs_params(ptsc->dev, ABS_PRESSURE, 0, 0, 0, 0);
+
+        serio_set_drvdata(serio, ptsc);
+
+        error = serio_open(serio, drv);
+        if (error)
+                goto fail2;
+
+        error = input_register_device(ptsc->dev);
+        if (error)
+                goto fail3;
+
+        return 0;
+
+fail3:
+        serio_close(serio);
+fail2:
+        serio_set_drvdata(serio, NULL);
+fail1:
+        input_free_device(input_dev);
+        kfree(ptsc);
+        return error;
+}
+
+static void tsc_disconnect(struct serio *serio)
+{
+        struct tsc_ser *ptsc = serio_get_drvdata(serio);
+
+        serio_close(serio);
+
+        input_unregister_device(ptsc->dev);
+        kfree(ptsc);
+
+        serio_set_drvdata(serio, NULL);
+}
+
+static struct serio_device_id tsc_serio_ids[] = {
+        {
+                .type   = SERIO_RS232,
+                .proto  = SERIO_TSC40,
+                .id     = SERIO_ANY,
+                .extra  = SERIO_ANY,
+        },
+        { 0 }
+};
+MODULE_DEVICE_TABLE(serio, tsc_serio_ids);
+
+#define DRIVER_DESC    "TSC-10/25/40 serial touchscreen driver"
+
+static struct serio_driver tsc_drv = {
+        .driver = {
+                .name   = "tsc40",
+        },
+        .description    = DRIVER_DESC,
+        .id_table       = tsc_serio_ids,
+        .interrupt      = tsc_interrupt,
+        .connect        = tsc_connect,
+        .disconnect     = tsc_disconnect,
+};
+
+static int __init tsc_ser_init(void)
+{
+        return serio_register_driver(&tsc_drv);
+}
+module_init(tsc_ser_init);
+
+static void __exit tsc_exit(void)
+{
+        serio_unregister_driver(&tsc_drv);
+}
+module_exit(tsc_exit);
+
+MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL v2");