Input: add driver for Fujitsu serial touchscreens

These serial touchscreens are found on some Fujitsu lifebook
P-series laptops, and the B6210. Using this requires a new
version of inputattach and doing:

 inputattach -fjt /dev/ttyS0

Big thanks to Stephen Hemminger for testing it and making it
work on his B6210 laptop.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 189 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/fujitsu_ts.c b/drivers/input/touchscreen/fujitsu_ts.c
new file mode 100644
index 000000000000..daf7a4afc935
--- /dev/null
+++ b/drivers/input/touchscreen/fujitsu_ts.c
@@ -0,0 +1,189 @@
+/*
+ * Fujitsu serial touchscreen driver
+ *
+ * Copyright (c) Dmitry Torokhov <dtor@mail.ru>
+ */
+
+/*
+ * 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.
+ */
+
+#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     "Fujitsu serial touchscreen driver"
+
+MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+#define FUJITSU_LENGTH 5
+
+/*
+ * Per-touchscreen data.
+ */
+struct fujitsu {
+        struct input_dev *dev;
+        struct serio *serio;
+        int idx;
+        unsigned char data[FUJITSU_LENGTH];
+        char phys[32];
+};
+
+/*
+ * Decode serial data (5 bytes per packet)
+ * First byte
+ * 1 C 0 0 R S S S
+ * Where C is 1 while in calibration mode (which we don't use)
+ * R is 1 when no coordinate corection was done.
+ * S are button state
+ */
+static irqreturn_t fujitsu_interrupt(struct serio *serio,
+                                     unsigned char data, unsigned int flags)
+{
+        struct fujitsu *fujitsu = serio_get_drvdata(serio);
+        struct input_dev *dev = fujitsu->dev;
+
+        if (fujitsu->idx == 0) {
+                /* resync skip until start of frame */
+                if ((data & 0xf0) != 0x80)
+                        return IRQ_HANDLED;
+        } else {
+                /* resync skip garbage */
+                if (data & 0x80) {
+                        fujitsu->idx = 0;
+                        return IRQ_HANDLED;
+                }
+        }
+
+        fujitsu->data[fujitsu->idx++] = data;
+        if (fujitsu->idx == FUJITSU_LENGTH) {
+                input_report_abs(dev, ABS_X,
+                                 (fujitsu->data[2] << 7) | fujitsu->data[1]);
+                input_report_abs(dev, ABS_Y,
+                                 (fujitsu->data[4] << 7) | fujitsu->data[3]);
+                input_report_key(dev, BTN_TOUCH,
+                                 (fujitsu->data[0] & 0x03) != 2);
+                input_sync(dev);
+                fujitsu->idx = 0;
+        }
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * fujitsu_disconnect() is the opposite of fujitsu_connect()
+ */
+static void fujitsu_disconnect(struct serio *serio)
+{
+        struct fujitsu *fujitsu = serio_get_drvdata(serio);
+
+        input_get_device(fujitsu->dev);
+        input_unregister_device(fujitsu->dev);
+        serio_close(serio);
+        serio_set_drvdata(serio, NULL);
+        input_put_device(fujitsu->dev);
+        kfree(fujitsu);
+}
+
+/*
+ * fujitsu_connect() is the routine that is called when someone adds a
+ * new serio device that supports the Fujitsu protocol and registers it
+ * as input device.
+ */
+static int fujitsu_connect(struct serio *serio, struct serio_driver *drv)
+{
+        struct fujitsu *fujitsu;
+        struct input_dev *input_dev;
+        int err;
+
+        fujitsu = kzalloc(sizeof(struct fujitsu), GFP_KERNEL);
+        input_dev = input_allocate_device();
+        if (!fujitsu || !input_dev) {
+                err = -ENOMEM;
+                goto fail1;
+        }
+
+        fujitsu->serio = serio;
+        fujitsu->dev = input_dev;
+        snprintf(fujitsu->phys, sizeof(fujitsu->phys),
+                 "%s/input0", serio->phys);
+
+        input_dev->name = "Fujitsu Serial Touchscreen";
+        input_dev->phys = fujitsu->phys;
+        input_dev->id.bustype = BUS_RS232;
+        input_dev->id.vendor = SERIO_FUJITSU;
+        input_dev->id.product = 0;
+        input_dev->id.version = 0x0100;
+        input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
+        input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
+
+        input_set_abs_params(input_dev, ABS_X, 0, 4096, 0, 0);
+        input_set_abs_params(input_dev, ABS_Y, 0, 4096, 0, 0);
+        serio_set_drvdata(serio, fujitsu);
+
+        err = serio_open(serio, drv);
+        if (err)
+                goto fail2;
+
+        err = input_register_device(fujitsu->dev);
+        if (err)
+                goto fail3;
+
+        return 0;
+
+ fail3:
+        serio_close(serio);
+ fail2:
+        serio_set_drvdata(serio, NULL);
+ fail1:
+        input_free_device(input_dev);
+        kfree(fujitsu);
+        return err;
+}
+
+/*
+ * The serio driver structure.
+ */
+static struct serio_device_id fujitsu_serio_ids[] = {
+        {
+                .type   = SERIO_RS232,
+                .proto  = SERIO_FUJITSU,
+                .id     = SERIO_ANY,
+                .extra  = SERIO_ANY,
+        },
+        { 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, fujitsu_serio_ids);
+
+static struct serio_driver fujitsu_drv = {
+        .driver         = {
+                .name   = "fujitsu_ts",
+        },
+        .description    = DRIVER_DESC,
+        .id_table       = fujitsu_serio_ids,
+        .interrupt      = fujitsu_interrupt,
+        .connect        = fujitsu_connect,
+        .disconnect     = fujitsu_disconnect,
+};
+
+static int __init fujitsu_init(void)
+{
+        return serio_register_driver(&fujitsu_drv);
+}
+
+static void __exit fujitsu_exit(void)
+{
+        serio_unregister_driver(&fujitsu_drv);
+}
+
+module_init(fujitsu_init);
+module_exit(fujitsu_exit);