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");