SPI: TSC2046 touchscreen support

This is a rework of the tsc2046 driver from TI's tree, based
on the tsc2301 driver and using the new SPI framework.
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/input/touchscreen/Kconfig

@@ -165,4 +165,10 @@ config TOUCHSCREEN_TSC2301
 	help
 	  Say Y here for if you are using the touchscreen features of TSC2301.
 
+config TOUCHSCREEN_TSC2046
+	tristate "TSC2046 touchscreen support"
+	default MACH_OMAP2430SDP
+	  help
+	  Say Y here for if you are using the touchscreen features of TSC2046
+
 endif

drivers/input/touchscreen/Makefile

@@ -19,3 +19,4 @@ obj-$(CONFIG_TOUCHSCREEN_UCB1400)	+= ucb1400_ts.o
 obj-$(CONFIG_TOUCHSCREEN_TSC2102)	+= tsc2102_ts.o
 obj-$(CONFIG_TOUCHSCREEN_OMAP)	+= omap/
 obj-$(CONFIG_TOUCHSCREEN_TSC2301)	+= tsc2301_ts.o
+obj-$(CONFIG_TOUCHSCREEN_TSC2046)	+= tsc2046_ts.o

drivers/input/touchscreen/tsc2046_ts.c

+/*
+ * TSC2046 Touchscreen driver
+ *
+ * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
+ *
+ * Communication details from original TI driver
+ * Copyright (C) 2004-2005 Texas Instruments, Inc.
+ *
+ * Structure based heavily on TSC2301 driver
+ * Copyright (C) 2005-2006 Nokia Corporation
+ *
+ * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+
+#ifdef CONFIG_ARCH_OMAP
+#include <asm/arch/gpio.h>
+#endif
+
+#include <linux/spi/tsc2046.h>
+
+/* TSC2046 commands */
+#define START_BYTE		0x8000
+#define	X_CMDWD			0xd300
+#define Y_CMDWD			0x9300
+#define Z1_CMDWD		0xb300
+#define Z2_CMDWD		0xc300
+
+#define TSC2046_TS_SCAN_TIME	1
+#define MAX_12BIT		((1 << 12) - 1)
+
+struct tsc2046_ts {
+	struct input_dev	*idev;
+	char			phys[32];
+	struct timer_list	timer;
+	spinlock_t		lock;
+
+	struct spi_transfer	read_xfer[3];
+	struct spi_message	read_msg;
+	struct spi_message	enable_msg;
+	u16                     data[5];
+
+	u16			x;
+	u16			y;
+	u16			p;
+	int			sample_cnt;
+
+	int			ignore_last : 1;
+	u16			x_plate_ohm;
+	int			max_pressure;
+	int			touch_pressure;
+	int			pressure_limit;
+
+	u16			irq_enabled:1;
+	u16			pen_down:1;
+	u16			disabled:1;
+	u16			pending:1;
+
+	s16			dav_gpio;
+	int			irq;
+};
+
+static const u16 tsc2046_ts_cmd_data[] = {
+	START_BYTE, X_CMDWD, Y_CMDWD, Z1_CMDWD, Z2_CMDWD,
+};
+
+static int device_suspended(struct device *dev)
+{
+	struct tsc2046 *tsc = dev_get_drvdata(dev);
+	return dev->power.power_state.event != PM_EVENT_ON || tsc->ts->disabled;
+}
+
+static void update_pen_state(struct tsc2046 *tsc, int x, int y, int pressure)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+	int sync = 0;
+
+	if (pressure) {
+		input_report_abs(ts->idev, ABS_X, x);
+		input_report_abs(ts->idev, ABS_Y, y);
+		input_report_abs(ts->idev, ABS_PRESSURE, pressure);
+		if (!ts->pen_down)
+			input_report_key(ts->idev, BTN_TOUCH, 1);
+		sync = 1;
+	} else if (ts->pen_down) {
+		input_report_abs(ts->idev, ABS_PRESSURE, 0);
+		input_report_key(ts->idev, BTN_TOUCH, 0);
+		sync = 1;
+	}
+
+	if (sync)
+		input_sync(ts->idev);
+
+	ts->pen_down = pressure ? 1 : 0;
+
+#ifdef VERBOSE
+	dev_dbg(&tsc->spi->dev, "x %4d y %4d p %4d\n", x, y, pressure);
+#endif
+}
+
+#define CONV_DATA(d1, d2) \
+  (((d1 & 0x7f) << 5) | ((d2 >> 11) & 0x1f))
+
+/*
+ * This procedure is called by the SPI framework after the coordinates
+ * have been read from TSC2046
+ */
+static void tsc2046_ts_rx(void *arg)
+{
+	struct tsc2046 *tsc = arg;
+	struct tsc2046_ts *ts = tsc->ts;
+	unsigned int x, y, z1, z2, pressure;
+
+	x  = CONV_DATA(ts->data[2], ts->data[3]);
+	y  = CONV_DATA(ts->data[1], ts->data[2]);
+	z1 = CONV_DATA(ts->data[3], ts->data[4]);
+	z2 = CONV_DATA(ts->data[4], 0);
+
+	if (z1) {
+		pressure = ts->x_plate_ohm * x;
+		pressure /= 4096;
+		pressure *= z2 - z1;
+		pressure /= z1;
+	} else
+		pressure = 0;
+
+	/* If pressure value is above a preset limit (pen is barely
+	 * touching the screen) we can't trust the coordinate values.
+	 */
+	if (pressure < ts->pressure_limit && x < MAX_12BIT && y < MAX_12BIT) {
+		ts->pressure_limit = ts->max_pressure;
+		if (ts->ignore_last) {
+			if (ts->sample_cnt)
+				update_pen_state(tsc, ts->x, ts->y, ts->p);
+			ts->x = x;
+			ts->y = y;
+			ts->p = pressure;
+		} else
+			update_pen_state(tsc, x, y, pressure);
+		ts->sample_cnt++;
+	}
+
+	mod_timer(&ts->timer,
+		  jiffies + msecs_to_jiffies(TSC2046_TS_SCAN_TIME));
+}
+
+static int is_pen_down(struct tsc2046_ts *ts)
+{
+	return ts->pen_down;
+}
+
+/*
+ * Timer is called every TSC2046_TS_SCAN_TIME when the pen is down
+ */
+static void tsc2046_ts_timer(unsigned long arg)
+{
+	struct tsc2046 *tsc = (void *) arg;
+	struct tsc2046_ts *ts = tsc->ts;
+	unsigned long flags;
+	int ndav;
+	int r;
+
+	spin_lock_irqsave(&ts->lock, flags);
+	ndav = omap_get_gpio_datain(ts->dav_gpio);
+	if (ndav || device_suspended(&tsc->spi->dev)) {
+		/* Pen has been lifted */
+		if (!device_suspended(&tsc->spi->dev) &&
+		    !ts->irq_enabled) {
+			ts->irq_enabled = 1;
+			enable_irq(ts->irq);
+		}
+		update_pen_state(tsc, 0, 0, 0);
+		ts->pending = 0;
+		spin_unlock_irqrestore(&ts->lock, flags);
+
+	} else {
+		ts->pen_down = 1;
+		spin_unlock_irqrestore(&ts->lock, flags);
+
+		r = spi_async(tsc->spi, &ts->read_msg);
+		if (r)
+			dev_err(&tsc->spi->dev, "ts: spi_async() failed");
+	}
+}
+
+/*
+ * This interrupt is called when pen is down and first coordinates are
+ * available. That is indicated by a falling edge on DEV line.  IRQ is
+ * disabled here because while the pen is down the coordinates are
+ * read by a timer.
+ */
+static irqreturn_t tsc2046_ts_irq_handler(int irq, void *dev_id)
+{
+	struct tsc2046 *tsc = dev_id;
+	struct tsc2046_ts *ts = tsc->ts;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ts->lock, flags);
+	if (ts->irq_enabled) {
+		ts->irq_enabled = 0;
+		disable_irq(ts->irq);
+		ts->pending = 1;
+		ts->pressure_limit = ts->touch_pressure;
+		ts->sample_cnt = 0;
+		mod_timer(&ts->timer,
+			  jiffies + msecs_to_jiffies(TSC2046_TS_SCAN_TIME));
+	}
+	spin_unlock_irqrestore(&ts->lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+/* Must be called with ts->lock held */
+static void tsc2046_ts_disable(struct tsc2046 *tsc)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+
+	if (ts->disabled)
+		return;
+
+	ts->disabled = 1;
+	if (!ts->pending) {
+		ts->irq_enabled = 0;
+		disable_irq(ts->irq);
+	} else {
+		while (ts->pending) {
+			spin_unlock_irq(&ts->lock);
+			msleep(1);
+			spin_lock_irq(&ts->lock);
+		}
+	}
+}
+
+static void tsc2046_ts_enable(struct tsc2046 *tsc)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+
+	if (!ts->disabled)
+		return;
+
+	ts->disabled = 0;
+	ts->irq_enabled = 1;
+	enable_irq(ts->irq);
+}
+
+#ifdef CONFIG_PM
+int tsc2046_ts_suspend(struct tsc2046 *tsc)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+
+	spin_lock_irq(&ts->lock);
+	tsc2046_ts_disable(tsc);
+	spin_unlock_irq(&ts->lock);
+
+	return 0;
+}
+
+void tsc2046_ts_resume(struct tsc2046 *tsc)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+
+	spin_lock_irq(&ts->lock);
+	tsc2046_ts_enable(tsc);
+	spin_unlock_irq(&ts->lock);
+}
+#endif
+
+static void tsc2046_ts_setup_spi_xfer(struct tsc2046 *tsc)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+	struct spi_message *m = &ts->read_msg;
+	struct spi_transfer *x = &ts->read_xfer[1];
+
+	spi_message_init(m);
+
+	/* read and write data in one transaction */
+	x->tx_buf = &tsc2046_ts_cmd_data;
+	x->rx_buf = &ts->data;
+	x->len    = 10;
+	spi_message_add_tail(x, m);
+
+	/* send another START_BYTE to (re)enable pen interrupts */
+	x++;
+	x->tx_buf = &tsc2046_ts_cmd_data[0];
+	x->len = 2;
+	spi_message_add_tail(x, m);
+
+	m->complete = tsc2046_ts_rx;
+	m->context = tsc;
+}
+
+static ssize_t tsc2046_ts_pen_down_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct tsc2046 *tsc = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", is_pen_down(tsc->ts));
+}
+
+static DEVICE_ATTR(pen_down, S_IRUGO, tsc2046_ts_pen_down_show, NULL);
+
+static ssize_t tsc2046_ts_disable_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct tsc2046		*tsc = dev_get_drvdata(dev);
+	struct tsc2046_ts	*ts = tsc->ts;
+
+	return sprintf(buf, "%u\n", ts->disabled);
+}
+
+static ssize_t tsc2046_ts_disable_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct tsc2046		*tsc = dev_get_drvdata(dev);
+	struct tsc2046_ts	*ts = tsc->ts;
+	char *endp;
+	int i;
+
+	i = simple_strtoul(buf, &endp, 10);
+	spin_lock_irq(&ts->lock);
+
+	if (i)
+		tsc2046_ts_disable(tsc);
+	else
+		tsc2046_ts_enable(tsc);
+
+	spin_unlock_irq(&ts->lock);
+
+	return count;
+}
+
+static DEVICE_ATTR(disable_ts, 0664, tsc2046_ts_disable_show,
+		   tsc2046_ts_disable_store);
+
+int __devinit tsc2046_ts_init(struct tsc2046 *tsc,
+			      struct tsc2046_platform_data *pdata)
+{
+	struct tsc2046_ts *ts;
+	struct input_dev *idev;
+	int dav_gpio, r;
+
+	if (pdata->dav_gpio < 0) {
+		dev_err(&tsc->spi->dev, "need DAV GPIO");
+		return -EINVAL;
+	}
+	dav_gpio = pdata->dav_gpio;
+
+	ts = kzalloc(sizeof(*ts), GFP_KERNEL);
+	if (ts == NULL)
+		return -ENOMEM;
+	tsc->ts = ts;
+
+	ts->dav_gpio = dav_gpio;
+#ifdef CONFIG_ARCH_OMAP
+	r = omap_request_gpio(dav_gpio);
+	if (r < 0) {
+		dev_err(&tsc->spi->dev, "unable to get DAV GPIO");
+		goto err1;
+	}
+	omap_set_gpio_direction(dav_gpio, 1);
+	if (pdata->gpio_debounce) {
+		omap_set_gpio_debounce(tsc->gpio, 1);
+		omap_set_gpio_debounce_time(tsc->gpio, pdata->gpio_debounce);
+	}
+
+	ts->irq = OMAP_GPIO_IRQ(dav_gpio);
+#endif
+	init_timer(&ts->timer);
+	ts->timer.data = (unsigned long) tsc;
+	ts->timer.function = tsc2046_ts_timer;
+
+	spin_lock_init(&ts->lock);
+
+	ts->x_plate_ohm	= pdata->ts_x_plate_ohm ? : 280;
+	ts->max_pressure= pdata->ts_max_pressure ? : MAX_12BIT;
+	ts->touch_pressure = pdata->ts_touch_pressure ? : ts->max_pressure;
+	ts->ignore_last	= pdata->ts_ignore_last;
+
+	idev = input_allocate_device();
+	if (idev == NULL) {
+		r = -ENOMEM;
+		goto err2;
+	}
+	idev->name = "TSC2046 touchscreen";
+	snprintf(ts->phys, sizeof(ts->phys),
+		 "%s/input-ts", tsc->spi->dev.bus_id);
+	idev->phys = ts->phys;
+
+	idev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
+	idev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE);
+	ts->idev = idev;
+
+	tsc2046_ts_setup_spi_xfer(tsc);
+
+	/* These parameters should perhaps be configurable? */
+	input_set_abs_params(idev, ABS_X, 0, 4096, 0, 0);
+	input_set_abs_params(idev, ABS_Y, 0, 4096, 0, 0);
+	input_set_abs_params(idev, ABS_PRESSURE, 0, 1024, 0, 0);
+
+	ts->irq_enabled = 1;
+	r = request_irq(ts->irq, tsc2046_ts_irq_handler,
+			SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
+			"tsc2046-ts", tsc);
+	if (r < 0) {
+		dev_err(&tsc->spi->dev, "unable to get DAV IRQ");
+		goto err3;
+	}
+	set_irq_wake(ts->irq, 1);
+
+	if (device_create_file(&tsc->spi->dev, &dev_attr_pen_down) < 0)
+		goto err4;
+	if (device_create_file(&tsc->spi->dev, &dev_attr_disable_ts) < 0)
+		goto err5;
+
+	r = input_register_device(idev);
+	if (r < 0) {
+		dev_err(&tsc->spi->dev, "can't register touchscreen device\n");
+		goto err6;
+	}
+
+	/* kick off a transaction to enable pen interrupts */
+	spi_async(tsc->spi, &ts->read_msg);
+
+	return 0;
+err6:
+	device_remove_file(&tsc->spi->dev, &dev_attr_disable_ts);
+err5:
+	device_remove_file(&tsc->spi->dev, &dev_attr_pen_down);
+err4:
+	free_irq(ts->irq, tsc);
+err3:
+	input_free_device(idev);
+err2:
+#ifdef CONFIG_ARCH_OMAP
+	omap_free_gpio(dav_gpio);
+#endif
+ err1:
+	kfree(ts);
+	return r;
+}
+EXPORT_SYMBOL(tsc2046_ts_init);
+
+void __devexit tsc2046_ts_exit(struct tsc2046 *tsc)
+{
+	struct tsc2046_ts *ts = tsc->ts;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ts->lock, flags);
+	tsc2046_ts_disable(tsc);
+	spin_unlock_irqrestore(&ts->lock, flags);
+
+	device_remove_file(&tsc->spi->dev, &dev_attr_disable_ts);
+	device_remove_file(&tsc->spi->dev, &dev_attr_pen_down);
+
+	free_irq(ts->irq, tsc);
+	input_unregister_device(ts->idev);
+
+#ifdef CONFIG_ARCH_OMAP
+	omap_free_gpio(ts->dav_gpio);
+#endif
+	kfree(ts);
+}
+EXPORT_SYMBOL(tsc2046_ts_exit);
+
+
+static int __devinit tsc2046_probe(struct spi_device *spi)
+{
+	struct tsc2046			*tsc;
+	struct tsc2046_platform_data	*pdata = spi->dev.platform_data;
+	int r = -ENODEV;
+
+	dev_dbg(&spi->dev, "%s\n", __FUNCTION__);
+
+	if (!pdata) {
+		dev_dbg(&spi->dev, "no platform data?\n");
+		return -ENODEV;
+	}
+
+	tsc = kzalloc(sizeof(*tsc), GFP_KERNEL);
+	if (tsc == NULL)
+		return -ENOMEM;
+
+	dev_set_drvdata(&spi->dev, tsc);
+	tsc->spi = spi;
+	spi->dev.power.power_state = PMSG_ON;
+
+	spi->mode = SPI_MODE_1;
+	spi->bits_per_word = 16;
+
+	/* The max speed might've been defined by the board-specific
+	 * struct */
+	if (!spi->max_speed_hz)
+		spi->max_speed_hz = TSC2046_HZ;
+	spi_setup(spi);
+
+	r = tsc2046_ts_init(tsc, pdata);
+	if (r)
+		goto err1;
+
+	return 0;
+ err1:
+	kfree(tsc);
+	return r;
+}
+
+static int __devexit tsc2046_remove(struct spi_device *spi)
+{
+	struct tsc2046 *tsc = dev_get_drvdata(&spi->dev);
+
+	dev_dbg(&tsc->spi->dev, "%s\n", __FUNCTION__);
+
+        tsc2046_ts_exit(tsc);
+	kfree(tsc);
+
+	return 0;
+}
+
+static struct spi_driver tsc2046_driver = {
+	.driver = {
+		   .name = "tsc2046",
+		   .bus = &spi_bus_type,
+		   .owner = THIS_MODULE,
+	},
+	.probe = tsc2046_probe,
+	.remove = __devexit_p(tsc2046_remove),
+};
+
+static int __init tsc2046_init(void)
+{
+	printk("TSC2046 driver initializing\n");
+
+	return spi_register_driver(&tsc2046_driver);
+}
+module_init(tsc2046_init);
+
+static void __exit tsc2046_exit(void)
+{
+	spi_unregister_driver(&tsc2046_driver);
+}
+module_exit(tsc2046_exit);
+
+MODULE_AUTHOR("Kevin Hilman <khilman@mvista.com>");
+MODULE_LICENSE("GPL");

include/linux/spi/tsc2046.h

+#ifndef _LINUX_SPI_TSC2046_H
+#define _LINUX_SPI_TSC2046_H
+
+#include <linux/types.h>
+#include <linux/timer.h>
+
+struct tsc2046_platform_data {
+	s16	dav_gpio;
+	s16	gpio_debounce;
+	u16	ts_x_plate_ohm;
+	u32	ts_max_pressure;  /* Samples with bigger pressure value will
+				     be ignored, since the corresponding X, Y
+				     values are unreliable */
+	u32	ts_touch_pressure;/* Pressure limit until we report a
+				     touch event. After that we switch
+				     to ts_max_pressure. */
+	unsigned ts_ignore_last : 1;
+
+};
+
+struct tsc2046_ts;
+
+struct tsc2046 {
+	struct spi_device	*spi;
+	int                     gpio;
+
+	struct tsc2046_ts	*ts;
+};
+
+/* The TSC2046 operates at a maximum speed of 2MHz */
+#define TSC2046_HZ	2000000
+
+#define TSC2046_DECL_MOD(module)					\
+extern int  tsc2046_##module##_init(struct tsc2046 *tsc,		\
+			   struct tsc2046_platform_data *pdata);	\
+extern void tsc2046_##module##_exit(struct tsc2046 *tsc);		\
+extern int  tsc2046_##module##_suspend(struct tsc2046 *tsc);		\
+extern void tsc2046_##module##_resume(struct tsc2046 *tsc);
+
+#define TSC2046_DECL_EMPTY_MOD(module)					\
+static inline int tsc2046_##module##_init(struct tsc2046 *tsc,		\
+			   struct tsc2046_platform_data *pdata)		\
+{									\
+	return 0;							\
+}									\
+static inline void tsc2046_##module##_exit(struct tsc2046 *tsc) {}	\
+static inline int  tsc2046_##module##_suspend(struct tsc2046 *tsc)	\
+{									\
+	return 0;							\
+}									\
+static inline void tsc2046_##module##_resume(struct tsc2046 *tsc) {}
+
+#if defined(CONFIG_TOUCHSCREEN_TSC2046) || \
+    defined(CONFIG_TOUCHSCREEN_TSC2046_MODULE)
+TSC2046_DECL_MOD(ts)
+#else
+TSC2046_DECL_EMPTY_MOD(ts)
+#endif
+
+#endif