[MFD] Add code UCB1200/UCB1300 touchscreen support

Add support for Philips UCB1200 and UCB1300 touchscreen
interfaces found on ARM devices.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 430 insertions, 0 deletions

diff --git a/drivers/mfd/ucb1x00-ts.c b/drivers/mfd/ucb1x00-ts.c
new file mode 100644
index 000000000000..52e0699eeb8b
--- /dev/null
+++ b/drivers/mfd/ucb1x00-ts.c
@@ -0,0 +1,430 @@
+/*
+ *  linux/drivers/mfd/ucb1x00-ts.c
+ *
+ *  Copyright (C) 2001 Russell King, All Rights Reserved.
+ *
+ * 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.
+ *
+ * 21-Jan-2002 <jco@ict.es> :
+ *
+ * Added support for synchronous A/D mode. This mode is useful to
+ * avoid noise induced in the touchpanel by the LCD, provided that
+ * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
+ * It is important to note that the signal connected to the ADCSYNC
+ * pin should provide pulses even when the LCD is blanked, otherwise
+ * a pen touch needed to unblank the LCD will never be read.
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/string.h>
+#include <linux/input.h>
+#include <linux/device.h>
+#include <linux/suspend.h>
+#include <linux/slab.h>
+
+#include <asm/dma.h>
+#include <asm/semaphore.h>
+
+#include "ucb1x00.h"
+
+
+struct ucb1x00_ts {
+        struct input_dev        idev;
+        struct ucb1x00          *ucb;
+
+        wait_queue_head_t       irq_wait;
+        struct semaphore        sem;
+        struct completion       init_exit;
+        struct task_struct      *rtask;
+        int                     use_count;
+        u16                     x_res;
+        u16                     y_res;
+
+        int                     restart:1;
+        int                     adcsync:1;
+};
+
+static int adcsync;
+
+static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
+{
+        input_report_abs(&ts->idev, ABS_X, x);
+        input_report_abs(&ts->idev, ABS_Y, y);
+        input_report_abs(&ts->idev, ABS_PRESSURE, pressure);
+        input_sync(&ts->idev);
+}
+
+static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
+{
+        input_report_abs(&ts->idev, ABS_PRESSURE, 0);
+        input_sync(&ts->idev);
+}
+
+/*
+ * Switch to interrupt mode.
+ */
+static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
+{
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
+                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
+                        UCB_TS_CR_MODE_INT);
+}
+
+/*
+ * Switch to pressure mode, and read pressure.  We don't need to wait
+ * here, since both plates are being driven.
+ */
+static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
+{
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
+                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+
+        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
+}
+
+/*
+ * Switch to X position mode and measure Y plate.  We switch the plate
+ * configuration in pressure mode, then switch to position mode.  This
+ * gives a faster response time.  Even so, we need to wait about 55us
+ * for things to stabilise.
+ */
+static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
+{
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
+                        UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
+
+        udelay(55);
+
+        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
+}
+
+/*
+ * Switch to Y position mode and measure X plate.  We switch the plate
+ * configuration in pressure mode, then switch to position mode.  This
+ * gives a faster response time.  Even so, we need to wait about 55us
+ * for things to stabilise.
+ */
+static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
+{
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
+                        UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
+
+        udelay(55);
+
+        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
+}
+
+/*
+ * Switch to X plate resistance mode.  Set MX to ground, PX to
+ * supply.  Measure current.
+ */
+static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
+{
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+        return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
+}
+
+/*
+ * Switch to Y plate resistance mode.  Set MY to ground, PY to
+ * supply.  Measure current.
+ */
+static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
+{
+        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
+                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
+                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+        return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
+}
+
+/*
+ * This is a RT kernel thread that handles the ADC accesses
+ * (mainly so we can use semaphores in the UCB1200 core code
+ * to serialise accesses to the ADC).
+ */
+static int ucb1x00_thread(void *_ts)
+{
+        struct ucb1x00_ts *ts = _ts;
+        struct task_struct *tsk = current;
+        DECLARE_WAITQUEUE(wait, tsk);
+        int valid;
+
+        ts->rtask = tsk;
+
+        daemonize("ktsd");
+        /* only want to receive SIGKILL */
+        allow_signal(SIGKILL);
+
+        /*
+         * We could run as a real-time thread.  However, thus far
+         * this doesn't seem to be necessary.
+         */
+//      tsk->policy = SCHED_FIFO;
+//      tsk->rt_priority = 1;
+
+        complete(&ts->init_exit);
+
+        valid = 0;
+
+        add_wait_queue(&ts->irq_wait, &wait);
+        for (;;) {
+                unsigned int x, y, p, val;
+                signed long timeout;
+
+                ts->restart = 0;
+
+                ucb1x00_adc_enable(ts->ucb);
+
+                x = ucb1x00_ts_read_xpos(ts);
+                y = ucb1x00_ts_read_ypos(ts);
+                p = ucb1x00_ts_read_pressure(ts);
+
+                /*
+                 * Switch back to interrupt mode.
+                 */
+                ucb1x00_ts_mode_int(ts);
+                ucb1x00_adc_disable(ts->ucb);
+
+                set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+                schedule_timeout(HZ / 100);
+                if (signal_pending(tsk))
+                        break;
+
+                ucb1x00_enable(ts->ucb);
+                val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
+
+                if (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW)) {
+                        set_task_state(tsk, TASK_INTERRUPTIBLE);
+
+                        ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
+                        ucb1x00_disable(ts->ucb);
+
+                        /*
+                         * If we spat out a valid sample set last time,
+                         * spit out a "pen off" sample here.
+                         */
+                        if (valid) {
+                                ucb1x00_ts_event_release(ts);
+                                valid = 0;
+                        }
+
+                        timeout = MAX_SCHEDULE_TIMEOUT;
+                } else {
+                        ucb1x00_disable(ts->ucb);
+
+                        /*
+                         * Filtering is policy.  Policy belongs in user
+                         * space.  We therefore leave it to user space
+                         * to do any filtering they please.
+                         */
+                        if (!ts->restart) {
+                                ucb1x00_ts_evt_add(ts, p, x, y);
+                                valid = 1;
+                        }
+
+                        set_task_state(tsk, TASK_INTERRUPTIBLE);
+                        timeout = HZ / 100;
+                }
+
+                try_to_freeze();
+
+                schedule_timeout(timeout);
+                if (signal_pending(tsk))
+                        break;
+        }
+
+        remove_wait_queue(&ts->irq_wait, &wait);
+
+        ts->rtask = NULL;
+        complete_and_exit(&ts->init_exit, 0);
+}
+
+/*
+ * We only detect touch screen _touches_ with this interrupt
+ * handler, and even then we just schedule our task.
+ */
+static void ucb1x00_ts_irq(int idx, void *id)
+{
+        struct ucb1x00_ts *ts = id;
+        ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
+        wake_up(&ts->irq_wait);
+}
+
+static int ucb1x00_ts_open(struct input_dev *idev)
+{
+        struct ucb1x00_ts *ts = (struct ucb1x00_ts *)idev;
+        int ret = 0;
+
+        if (down_interruptible(&ts->sem))
+                return -EINTR;
+
+        if (ts->use_count++ != 0)
+                goto out;
+
+        if (ts->rtask)
+                panic("ucb1x00: rtask running?");
+
+        init_waitqueue_head(&ts->irq_wait);
+        ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
+        if (ret < 0)
+                goto out;
+
+        /*
+         * If we do this at all, we should allow the user to
+         * measure and read the X and Y resistance at any time.
+         */
+        ucb1x00_adc_enable(ts->ucb);
+        ts->x_res = ucb1x00_ts_read_xres(ts);
+        ts->y_res = ucb1x00_ts_read_yres(ts);
+        ucb1x00_adc_disable(ts->ucb);
+
+        init_completion(&ts->init_exit);
+        ret = kernel_thread(ucb1x00_thread, ts, CLONE_KERNEL);
+        if (ret >= 0) {
+                wait_for_completion(&ts->init_exit);
+                ret = 0;
+        } else {
+                ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
+        }
+
+ out:
+        if (ret)
+                ts->use_count--;
+        up(&ts->sem);
+        return ret;
+}
+
+/*
+ * Release touchscreen resources.  Disable IRQs.
+ */
+static void ucb1x00_ts_close(struct input_dev *idev)
+{
+        struct ucb1x00_ts *ts = (struct ucb1x00_ts *)idev;
+
+        down(&ts->sem);
+        if (--ts->use_count == 0) {
+                if (ts->rtask) {
+                        send_sig(SIGKILL, ts->rtask, 1);
+                        wait_for_completion(&ts->init_exit);
+                }
+
+                ucb1x00_enable(ts->ucb);
+                ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
+                ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
+                ucb1x00_disable(ts->ucb);
+        }
+        up(&ts->sem);
+}
+
+#ifdef CONFIG_PM
+static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
+{
+        struct ucb1x00_ts *ts = dev->priv;
+
+        if (ts->rtask != NULL) {
+                /*
+                 * Restart the TS thread to ensure the
+                 * TS interrupt mode is set up again
+                 * after sleep.
+                 */
+                ts->restart = 1;
+                wake_up(&ts->irq_wait);
+        }
+        return 0;
+}
+#else
+#define ucb1x00_ts_resume NULL
+#endif
+
+
+/*
+ * Initialisation.
+ */
+static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
+{
+        struct ucb1x00_ts *ts;
+
+        ts = kmalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
+        if (!ts)
+                return -ENOMEM;
+
+        memset(ts, 0, sizeof(struct ucb1x00_ts));
+
+        ts->ucb = dev->ucb;
+        ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
+        init_MUTEX(&ts->sem);
+
+        ts->idev.name       = "Touchscreen panel";
+        ts->idev.id.product = ts->ucb->id;
+        ts->idev.open       = ucb1x00_ts_open;
+        ts->idev.close      = ucb1x00_ts_close;
+
+        __set_bit(EV_ABS, ts->idev.evbit);
+        __set_bit(ABS_X, ts->idev.absbit);
+        __set_bit(ABS_Y, ts->idev.absbit);
+        __set_bit(ABS_PRESSURE, ts->idev.absbit);
+
+        input_register_device(&ts->idev);
+
+        dev->priv = ts;
+
+        return 0;
+}
+
+static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
+{
+        struct ucb1x00_ts *ts = dev->priv;
+        input_unregister_device(&ts->idev);
+        kfree(ts);
+}
+
+static struct ucb1x00_driver ucb1x00_ts_driver = {
+        .add            = ucb1x00_ts_add,
+        .remove         = ucb1x00_ts_remove,
+        .resume         = ucb1x00_ts_resume,
+};
+
+static int __init ucb1x00_ts_init(void)
+{
+        return ucb1x00_register_driver(&ucb1x00_ts_driver);
+}
+
+static void __exit ucb1x00_ts_exit(void)
+{
+        ucb1x00_unregister_driver(&ucb1x00_ts_driver);
+}
+
+module_param(adcsync, int, 0444);
+module_init(ucb1x00_ts_init);
+module_exit(ucb1x00_ts_exit);
+
+MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
+MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
+MODULE_LICENSE("GPL");