SPI: TSC2102 Touchscreen

This a driver for touchscreens connected to the TSC2102 chip. It uses
the normal input events framework and can be accessed through
/dev/input/eventX.
Signed-off-by: Andrzej Zaborowski <balrog@zabor.org>

drivers/input/touchscreen/Kconfig

@@ -111,6 +111,21 @@ config TOUCHSCREEN_HP600
 	  To compile this driver as a module, choose M here: the
 	  module will be called hp680_ts_input.
 
+config TOUCHSCREEN_TSC2102
+	tristate "TSC 2102 based touchscreens"
+	depends on SPI_MASTER
+	select TSC2102
+	help
+	  Say Y here if you have a touchscreen interface using the
+	  TI TSC 2102 controller, and your board-specific initialization
+	  code includes that in its table of SPI devices.  Also make
+	  sure the proper SPI controller is selected.
+
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called tsc2102_ts.
+
 endif
 config TOUCHSCREEN_OMAP
 	tristate "OMAP touchscreen input driver"

drivers/input/touchscreen/Makefile

@@ -12,4 +12,5 @@ obj-$(CONFIG_TOUCHSCREEN_ELO)	+= elo.o
 obj-$(CONFIG_TOUCHSCREEN_MTOUCH) += mtouch.o
 obj-$(CONFIG_TOUCHSCREEN_MK712)	+= mk712.o
 obj-$(CONFIG_TOUCHSCREEN_HP600)	+= hp680_ts_input.o
+obj-$(CONFIG_TOUCHSCREEN_TSC2102)	+= tsc2102_ts.o
 obj-$(CONFIG_TOUCHSCREEN_OMAP)	+= omap/

drivers/input/touchscreen/tsc2102_ts.c

+/*
+ * input/touchscreen/tsc2102_ts.c
+ *
+ * Touchscreen input device driver for the TSC 2102 chip.
+ *
+ * Copyright (c) 2006 Andrzej Zaborowski  <balrog@zabor.org>
+ *
+ * This package is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This package is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this package; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+
+#include <linux/spi/tsc2102.h>
+
+struct input_dev *dev;
+
+static void tsc2102_touch(int touching)
+{
+	if (!touching) {
+		input_report_abs(dev, ABS_X, 0);
+		input_report_abs(dev, ABS_Y, 0);
+		input_report_abs(dev, ABS_PRESSURE, 0);
+		input_sync(dev);
+	}
+
+	input_report_key(dev, BTN_TOUCH, touching);
+}
+
+static void tsc2102_coords(int x, int y, int z1, int z2)
+{
+	int p;
+
+	/* Calculate the touch resistance a la equation #1 */
+	if (z1 != 0)
+		p = x * (z2 - z1) / (z1 << 4);
+	else
+		p = 1;
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, y);
+	input_report_abs(dev, ABS_PRESSURE, p);
+	input_sync(dev);
+}
+
+static int tsc2102_ts_probe(struct platform_device *pdev)
+{
+	int status;
+
+	dev = input_allocate_device();
+	if (!dev)
+		return -ENOMEM;
+
+	status = tsc2102_touch_cb(tsc2102_touch);
+	if (status) {
+		input_free_device(dev);
+		return status;
+	}
+
+	status = tsc2102_coords_cb(tsc2102_coords);
+	if (status) {
+		tsc2102_touch_cb(0);
+		input_free_device(dev);
+		return status;
+	}
+
+	dev->name = "TSC2102 Touchscreen";
+	dev->dev = &pdev->dev;
+	dev->cdev.dev = &pdev->dev;
+	dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
+	dev->keybit[LONG(BTN_TOUCH)] |= BIT(BTN_TOUCH);
+	dev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE);
+	dev->phys = "tsc2102/input0";
+	dev->id.bustype = BUS_HOST;
+	dev->id.vendor = 0x0001;
+	dev->id.product = 0x2102;
+	dev->id.version = 0x0001;
+
+	status = input_register_device(dev);
+	if (status) {
+		tsc2102_coords_cb(0);
+		tsc2102_touch_cb(0);
+		input_free_device(dev);
+		return status;
+	}
+
+	printk(KERN_INFO "TSC2102 touchscreen driver initialized\n");
+	return 0;
+}
+
+static int tsc2102_ts_remove(struct platform_device *pdev)
+{
+	tsc2102_touch_cb(0);
+	tsc2102_coords_cb(0);
+	input_unregister_device(dev);
+	input_free_device(dev);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int
+tsc2102_ts_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	return 0;
+}
+
+static int tsc2102_ts_resume(struct platform_device *pdev)
+{
+	return 0;
+}
+#else
+#define tsc2102_ts_suspend	NULL
+#define tsc2102_ts_resume	NULL
+#endif
+
+static struct platform_driver tsc2102_ts_driver = {
+	.probe 		= tsc2102_ts_probe,
+	.remove 	= tsc2102_ts_remove,
+	.suspend 	= tsc2102_ts_suspend,
+	.resume 	= tsc2102_ts_resume,
+	.driver		= {
+		.name	= "tsc2102-ts",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init tsc2102_ts_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&tsc2102_ts_driver);
+	if (ret)
+		return -ENODEV;
+
+	return 0;
+}
+
+static void __exit tsc2102_ts_exit(void)
+{
+	platform_driver_unregister(&tsc2102_ts_driver);
+}
+
+module_init(tsc2102_ts_init);
+module_exit(tsc2102_ts_exit);
+
+MODULE_AUTHOR("Andrzej Zaborowski");
+MODULE_DESCRIPTION("Touchscreen input driver for TI TSC2102.");
+MODULE_LICENSE("GPL");