Input: add support for touchscreen on W90P910 ARM platform

The touchscreen works in two modes, wait trigger mode and auto-semi
mode. The device starts in wait trigger mode and waits until pressure
is detected, then device sets WT_INT bit and raises an interrupt.
The driver should put the device into auto-semi mode and prepare for
reading first X and then Y coordinates. When coordinate data is ready
the driver sets ADC_INT bit and raises interrupt again.

[dtor@mail.ru: various cleanups]
Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 359 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 1b4a1675cbc8..72e2712c7e2a 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -490,4 +490,12 @@ config TOUCHSCREEN_TSC2007
 	  To compile this driver as a module, choose M here: the
 	  module will be called tsc2007.
 
+config TOUCHSCREEN_W90X900
+	tristate "W90P910 touchscreen driver"
+	help
+	  Say Y here if you have a W90P910 based touchscreen.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called w90p910_ts.
+
 endif
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 10e0be6cea43..3e1c5e0b952f 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -39,3 +39,4 @@ wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713)	+= wm9713.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_ATMEL)	+= atmel-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE)	+= zylonite-wm97xx.o
+obj-$(CONFIG_TOUCHSCREEN_W90X900)	+= w90p910_ts.o
diff --git a/drivers/input/touchscreen/w90p910_ts.c b/drivers/input/touchscreen/w90p910_ts.c
new file mode 100644
index 000000000000..6071f5882572
--- /dev/null
+++ b/drivers/input/touchscreen/w90p910_ts.c
@@ -0,0 +1,350 @@
+/*
+ * Copyright (c) 2008 Nuvoton technology corporation.
+ *
+ * Wan ZongShun <mcuos.com@gmail.com>
+ *
+ * This program 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;version 2 of the License.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+
+/* ADC controller bit defines */
+#define ADC_DELAY	0xf00
+#define ADC_DOWN	0x01
+#define ADC_TSC_Y	(0x01 << 8)
+#define ADC_TSC_X	(0x00 << 8)
+#define TSC_FOURWIRE	(~(0x03 << 1))
+#define ADC_CLK_EN	(0x01 << 28)	/* ADC clock enable */
+#define ADC_READ_CON	(0x01 << 12)
+#define ADC_CONV	(0x01 << 13)
+#define ADC_SEMIAUTO	(0x01 << 14)
+#define ADC_WAITTRIG	(0x03 << 14)
+#define ADC_RST1	(0x01 << 16)
+#define ADC_RST0	(0x00 << 16)
+#define ADC_EN		(0x01 << 17)
+#define ADC_INT		(0x01 << 18)
+#define WT_INT		(0x01 << 20)
+#define ADC_INT_EN	(0x01 << 21)
+#define LVD_INT_EN	(0x01 << 22)
+#define WT_INT_EN	(0x01 << 23)
+#define ADC_DIV		(0x04 << 1)	/* div = 6 */
+
+enum ts_state {
+	TS_WAIT_NEW_PACKET,	/* We are waiting next touch report */
+	TS_WAIT_X_COORD,	/* We are waiting for ADC to report X coord */
+	TS_WAIT_Y_COORD,	/* We are waiting for ADC to report Y coord */
+	TS_IDLE,		/* Input device is closed, don't do anything */
+};
+
+struct w90p910_ts {
+	struct input_dev *input;
+	struct timer_list timer;
+	int irq_num;
+	void __iomem *clocken;
+	void __iomem *ts_reg;
+	spinlock_t lock;
+	enum ts_state state;
+};
+
+static void w90p910_report_event(struct w90p910_ts *w90p910_ts, bool down)
+{
+	struct input_dev *dev = w90p910_ts->input;
+
+	if (down) {
+		input_report_abs(dev, ABS_X,
+				 __raw_readl(w90p910_ts->ts_reg + 0x0c));
+		input_report_abs(dev, ABS_Y,
+				 __raw_readl(w90p910_ts->ts_reg + 0x10));
+	}
+
+	input_report_key(dev, BTN_TOUCH, down);
+	input_sync(dev);
+}
+
+static void w90p910_prepare_x_reading(struct w90p910_ts *w90p910_ts)
+{
+	unsigned long ctlreg;
+
+	__raw_writel(ADC_TSC_X, w90p910_ts->ts_reg + 0x04);
+	ctlreg = __raw_readl(w90p910_ts->ts_reg);
+	ctlreg &= ~(ADC_WAITTRIG | WT_INT | WT_INT_EN);
+	ctlreg |= ADC_SEMIAUTO | ADC_INT_EN | ADC_CONV;
+	__raw_writel(ctlreg, w90p910_ts->ts_reg);
+
+	w90p910_ts->state = TS_WAIT_X_COORD;
+}
+
+static void w90p910_prepare_y_reading(struct w90p910_ts *w90p910_ts)
+{
+	unsigned long ctlreg;
+
+	__raw_writel(ADC_TSC_Y, w90p910_ts->ts_reg + 0x04);
+	ctlreg = __raw_readl(w90p910_ts->ts_reg);
+	ctlreg &= ~(ADC_WAITTRIG | ADC_INT | WT_INT_EN);
+	ctlreg |= ADC_SEMIAUTO | ADC_INT_EN | ADC_CONV;
+	__raw_writel(ctlreg, w90p910_ts->ts_reg);
+
+	w90p910_ts->state = TS_WAIT_Y_COORD;
+}
+
+static void w90p910_prepare_next_packet(struct w90p910_ts *w90p910_ts)
+{
+	unsigned long ctlreg;
+
+	ctlreg = __raw_readl(w90p910_ts->ts_reg);
+	ctlreg &= ~(ADC_INT | ADC_INT_EN | ADC_SEMIAUTO | ADC_CONV);
+	ctlreg |= ADC_WAITTRIG | WT_INT_EN;
+	__raw_writel(ctlreg, w90p910_ts->ts_reg);
+
+	w90p910_ts->state = TS_WAIT_NEW_PACKET;
+}
+
+static irqreturn_t w90p910_ts_interrupt(int irq, void *dev_id)
+{
+	struct w90p910_ts *w90p910_ts = dev_id;
+	unsigned long flags;
+
+	spin_lock_irqsave(&w90p910_ts->lock, flags);
+
+	switch (w90p910_ts->state) {
+	case TS_WAIT_NEW_PACKET:
+		/*
+		 * The controller only generates interrupts when pen
+		 * is down.
+		 */
+		del_timer(&w90p910_ts->timer);
+		w90p910_prepare_x_reading(w90p910_ts);
+		break;
+
+
+	case TS_WAIT_X_COORD:
+		w90p910_prepare_y_reading(w90p910_ts);
+		break;
+
+	case TS_WAIT_Y_COORD:
+		w90p910_report_event(w90p910_ts, true);
+		w90p910_prepare_next_packet(w90p910_ts);
+		mod_timer(&w90p910_ts->timer, jiffies + msecs_to_jiffies(100));
+		break;
+
+	case TS_IDLE:
+		break;
+	}
+
+	spin_unlock_irqrestore(&w90p910_ts->lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static void w90p910_check_pen_up(unsigned long data)
+{
+	struct w90p910_ts *w90p910_ts = (struct w90p910_ts *) data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&w90p910_ts->lock, flags);
+
+	if (w90p910_ts->state == TS_WAIT_NEW_PACKET &&
+	    !(__raw_readl(w90p910_ts->ts_reg + 0x04) & ADC_DOWN)) {
+
+		w90p910_report_event(w90p910_ts, false);
+	}
+
+	spin_unlock_irqrestore(&w90p910_ts->lock, flags);
+}
+
+static int w90p910_open(struct input_dev *dev)
+{
+	struct w90p910_ts *w90p910_ts = input_get_drvdata(dev);
+	unsigned long val;
+
+	/* enable the ADC clock */
+	val = __raw_readl(w90p910_ts->clocken);
+	__raw_writel(val | ADC_CLK_EN, w90p910_ts->clocken);
+
+	__raw_writel(ADC_RST1, w90p910_ts->ts_reg);
+	msleep(1);
+	__raw_writel(ADC_RST0, w90p910_ts->ts_reg);
+	msleep(1);
+
+	/* set delay and screen type */
+	val = __raw_readl(w90p910_ts->ts_reg + 0x04);
+	__raw_writel(val & TSC_FOURWIRE, w90p910_ts->ts_reg + 0x04);
+	__raw_writel(ADC_DELAY, w90p910_ts->ts_reg + 0x08);
+
+	w90p910_ts->state = TS_WAIT_NEW_PACKET;
+	wmb();
+
+	/* set trigger mode */
+	val = __raw_readl(w90p910_ts->ts_reg);
+	val |= ADC_WAITTRIG | ADC_DIV | ADC_EN | WT_INT_EN;
+	__raw_writel(val, w90p910_ts->ts_reg);
+
+	return 0;
+}
+
+static void w90p910_close(struct input_dev *dev)
+{
+	struct w90p910_ts *w90p910_ts = input_get_drvdata(dev);
+	unsigned long val;
+
+	/* disable trigger mode */
+
+	spin_lock_irq(&w90p910_ts->lock);
+
+	w90p910_ts->state = TS_IDLE;
+
+	val = __raw_readl(w90p910_ts->ts_reg);
+	val &= ~(ADC_WAITTRIG | ADC_DIV | ADC_EN | WT_INT_EN | ADC_INT_EN);
+	__raw_writel(val, w90p910_ts->ts_reg);
+
+	spin_unlock_irq(&w90p910_ts->lock);
+
+	/* Now that interrupts are shut off we can safely delete timer */
+	del_timer_sync(&w90p910_ts->timer);
+
+	/* stop the ADC clock */
+	val = __raw_readl(w90p910_ts->clocken);
+	__raw_writel(val & ~ADC_CLK_EN, w90p910_ts->clocken);
+}
+
+static int __devinit w90x900ts_probe(struct platform_device *pdev)
+{
+	struct w90p910_ts *w90p910_ts;
+	struct input_dev *input_dev;
+	struct resource *res;
+	int err;
+
+	w90p910_ts = kzalloc(sizeof(struct w90p910_ts), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!w90p910_ts || !input_dev) {
+		err = -ENOMEM;
+		goto fail1;
+	}
+
+	w90p910_ts->input = input_dev;
+	w90p910_ts->state = TS_IDLE;
+	spin_lock_init(&w90p910_ts->lock);
+	setup_timer(&w90p910_ts->timer, w90p910_check_pen_up,
+		    (unsigned long)&w90p910_ts);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		err = -ENXIO;
+		goto fail1;
+	}
+
+	if (!request_mem_region(res->start, res->end - res->start + 1,
+				pdev->name)) {
+		err = -EBUSY;
+		goto fail1;
+	}
+
+	w90p910_ts->ts_reg = ioremap(res->start, res->end - res->start + 1);
+	if (!w90p910_ts->ts_reg) {
+		err = -ENOMEM;
+		goto fail2;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res) {
+		err = -ENXIO;
+		goto fail3;
+	}
+
+	w90p910_ts->clocken = (void __iomem *)res->start;
+
+	input_dev->name = "W90P910 TouchScreen";
+	input_dev->phys = "w90p910ts/event0";
+	input_dev->id.bustype = BUS_HOST;
+	input_dev->id.vendor  = 0x0005;
+	input_dev->id.product = 0x0001;
+	input_dev->id.version = 0x0100;
+	input_dev->dev.parent = &pdev->dev;
+	input_dev->open = w90p910_open;
+	input_dev->close = w90p910_close;
+
+	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(input_dev, ABS_X, 0, 0x400, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, 0x400, 0, 0);
+
+	input_set_drvdata(input_dev, w90p910_ts);
+
+	w90p910_ts->irq_num = platform_get_irq(pdev, 0);
+	if (request_irq(w90p910_ts->irq_num, w90p910_ts_interrupt,
+			IRQF_DISABLED, "w90p910ts", w90p910_ts)) {
+		err = -EBUSY;
+		goto fail3;
+	}
+
+	err = input_register_device(w90p910_ts->input);
+	if (err)
+		goto fail4;
+
+	platform_set_drvdata(pdev, w90p910_ts);
+
+	return 0;
+
+fail4:	free_irq(w90p910_ts->irq_num, w90p910_ts);
+fail3:	iounmap(w90p910_ts->ts_reg);
+fail2:	release_mem_region(res->start, res->end - res->start + 1);
+fail1:	input_free_device(input_dev);
+	kfree(w90p910_ts);
+	return err;
+}
+
+static int __devexit w90x900ts_remove(struct platform_device *pdev)
+{
+	struct w90p910_ts *w90p910_ts = platform_get_drvdata(pdev);
+	struct resource *res;
+
+	free_irq(w90p910_ts->irq_num, w90p910_ts);
+	del_timer_sync(&w90p910_ts->timer);
+	iounmap(w90p910_ts->ts_reg);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(res->start, res->end - res->start + 1);
+
+	input_unregister_device(w90p910_ts->input);
+	kfree(w90p910_ts);
+
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver w90x900ts_driver = {
+	.probe		= w90x900ts_probe,
+	.remove		= __devexit_p(w90x900ts_remove),
+	.driver		= {
+		.name	= "w90x900-ts",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init w90x900ts_init(void)
+{
+	return platform_driver_register(&w90x900ts_driver);
+}
+
+static void __exit w90x900ts_exit(void)
+{
+	platform_driver_unregister(&w90x900ts_driver);
+}
+
+module_init(w90x900ts_init);
+module_exit(w90x900ts_exit);
+
+MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
+MODULE_DESCRIPTION("w90p910 touch screen driver!");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:w90p910-ts");