[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>

drivers/mfd/Kconfig

@@ -18,4 +18,8 @@ config MCP_UCB1200
 	tristate "Support for UCB1200 / UCB1300"
 	depends on MCP
 
+config MCP_UCB1200_TS
+	tristate "Touchscreen interface support"
+	depends on MCP_UCB1200 && INPUT
+
 endmenu

drivers/mfd/Makefile

@@ -5,3 +5,4 @@
 obj-$(CONFIG_MCP)		+= mcp-core.o
 obj-$(CONFIG_MCP_SA11X0)	+= mcp-sa11x0.o
 obj-$(CONFIG_MCP_UCB1200)	+= ucb1x00-core.o
+obj-$(CONFIG_MCP_UCB1200_TS)	+= ucb1x00-ts.o

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");