Input: add S3C24XX touchscreen driver

S3C24XX touchscreen driver, originally written by Arnaud Patard and
other contributors. The driver has had substantial testing as well as
a number of tidying up passes done by Ben Dooks, as noted:

- added kernel-doc comments to most of the routines
- removed old code from pre adc framework days
- updated device probe code to use platform id list matching
- cleaned up debug, since printk() now has timestamp feature
- ensure code uses dev_() reporting macros where necessary
- remove ABS_PRESSURE reporting, tslib can be fixed
- ensure timer is removed on driver exit
- move to using dev_pmops for power management

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/Kconfig

@@ -145,6 +145,18 @@ config TOUCHSCREEN_FUJITSU
 	  To compile this driver as a module, choose M here: the
 	  module will be called fujitsu-ts.
 
+config TOUCHSCREEN_S3C2410
+	tristate "Samsung S3C2410 touchscreen input driver"
+	depends on ARCH_S3C2410
+	select S3C24XX_ADC
+	help
+	  Say Y here if you have the s3c2410 touchscreen.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called s3c2410_ts.
+
 config TOUCHSCREEN_GUNZE
 	tristate "Gunze AHL-51S touchscreen"
 	select SERIO

drivers/input/touchscreen/Makefile

@@ -26,7 +26,9 @@ obj-$(CONFIG_TOUCHSCREEN_HP600)		+= hp680_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_HP7XX)		+= jornada720_ts.o
 obj-$(CONFIG_TOUCHSCREEN_HTCPEN)	+= htcpen.o
 obj-$(CONFIG_TOUCHSCREEN_USB_COMPOSITE)	+= usbtouchscreen.o
+obj-$(CONFIG_TOUCHSCREEN_PCAP)		+= pcap_ts.o
 obj-$(CONFIG_TOUCHSCREEN_PENMOUNT)	+= penmount.o
+obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)	+= touchit213.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)	+= touchright.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)	+= touchwin.o
@@ -42,4 +44,3 @@ 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
-obj-$(CONFIG_TOUCHSCREEN_PCAP)		+= pcap_ts.o

drivers/input/touchscreen/s3c2410_ts.c

@@ -0,0 +1,457 @@
+/*
+ * Samsung S3C24XX touchscreen driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the term of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Copyright 2004 Arnaud Patard <arnaud.patard@rtp-net.org>
+ * Copyright 2008 Ben Dooks <ben-linux@fluff.org>
+ * Copyright 2009 Simtec Electronics <linux@simtec.co.uk>
+ *
+ * Additional work by Herbert Pötzl <herbert@13thfloor.at> and
+ * Harald Welte <laforge@openmoko.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/input.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <plat/adc.h>
+#include <plat/regs-adc.h>
+
+#include <mach/regs-gpio.h>
+#include <mach/ts.h>
+
+#define TSC_SLEEP  (S3C2410_ADCTSC_PULL_UP_DISABLE | S3C2410_ADCTSC_XY_PST(0))
+
+#define INT_DOWN	(0)
+#define INT_UP		(1 << 8)
+
+#define WAIT4INT	(S3C2410_ADCTSC_YM_SEN | \
+			 S3C2410_ADCTSC_YP_SEN | \
+			 S3C2410_ADCTSC_XP_SEN | \
+			 S3C2410_ADCTSC_XY_PST(3))
+
+#define AUTOPST		(S3C2410_ADCTSC_YM_SEN | \
+			 S3C2410_ADCTSC_YP_SEN | \
+			 S3C2410_ADCTSC_XP_SEN | \
+			 S3C2410_ADCTSC_AUTO_PST | \
+			 S3C2410_ADCTSC_XY_PST(0))
+
+/* Per-touchscreen data. */
+
+/**
+ * struct s3c2410ts - driver touchscreen state.
+ * @client: The ADC client we registered with the core driver.
+ * @dev: The device we are bound to.
+ * @input: The input device we registered with the input subsystem.
+ * @clock: The clock for the adc.
+ * @io: Pointer to the IO base.
+ * @xp: The accumulated X position data.
+ * @yp: The accumulated Y position data.
+ * @irq_tc: The interrupt number for pen up/down interrupt
+ * @count: The number of samples collected.
+ * @shift: The log2 of the maximum count to read in one go.
+ */
+struct s3c2410ts {
+	struct s3c_adc_client *client;
+	struct device *dev;
+	struct input_dev *input;
+	struct clk *clock;
+	void __iomem *io;
+	unsigned long xp;
+	unsigned long yp;
+	int irq_tc;
+	int count;
+	int shift;
+};
+
+static struct s3c2410ts ts;
+
+/**
+ * s3c2410_ts_connect - configure gpio for s3c2410 systems
+ *
+ * Configure the GPIO for the S3C2410 system, where we have external FETs
+ * connected to the device (later systems such as the S3C2440 integrate
+ * these into the device).
+*/
+static inline void s3c2410_ts_connect(void)
+{
+	s3c2410_gpio_cfgpin(S3C2410_GPG(12), S3C2410_GPG12_XMON);
+	s3c2410_gpio_cfgpin(S3C2410_GPG(13), S3C2410_GPG13_nXPON);
+	s3c2410_gpio_cfgpin(S3C2410_GPG(14), S3C2410_GPG14_YMON);
+	s3c2410_gpio_cfgpin(S3C2410_GPG(15), S3C2410_GPG15_nYPON);
+}
+
+/**
+ * get_down - return the down state of the pen
+ * @data0: The data read from ADCDAT0 register.
+ * @data1: The data read from ADCDAT1 register.
+ *
+ * Return non-zero if both readings show that the pen is down.
+ */
+static inline bool get_down(unsigned long data0, unsigned long data1)
+{
+	/* returns true if both data values show stylus down */
+	return (!(data0 & S3C2410_ADCDAT0_UPDOWN) &&
+		!(data1 & S3C2410_ADCDAT0_UPDOWN));
+}
+
+static void touch_timer_fire(unsigned long data)
+{
+	unsigned long data0;
+	unsigned long data1;
+	bool down;
+
+	data0 = readl(ts.io + S3C2410_ADCDAT0);
+	data1 = readl(ts.io + S3C2410_ADCDAT1);
+
+	down = get_down(data0, data1);
+
+	if (ts.count == (1 << ts.shift)) {
+		ts.xp >>= ts.shift;
+		ts.yp >>= ts.shift;
+
+		dev_dbg(ts.dev, "%s: X=%lu, Y=%lu, count=%d\n",
+			__func__, ts.xp, ts.yp, ts.count);
+
+		input_report_abs(ts.input, ABS_X, ts.xp);
+		input_report_abs(ts.input, ABS_Y, ts.yp);
+
+		input_report_key(ts.input, BTN_TOUCH, 1);
+		input_sync(ts.input);
+
+		ts.xp = 0;
+		ts.yp = 0;
+		ts.count = 0;
+	}
+
+	if (down) {
+		s3c_adc_start(ts.client, 0, 1 << ts.shift);
+	} else {
+		ts.count = 0;
+
+		input_report_key(ts.input, BTN_TOUCH, 0);
+		input_sync(ts.input);
+
+		writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
+	}
+}
+
+static DEFINE_TIMER(touch_timer, touch_timer_fire, 0, 0);
+
+/**
+ * stylus_irq - touchscreen stylus event interrupt
+ * @irq: The interrupt number
+ * @dev_id: The device ID.
+ *
+ * Called when the IRQ_TC is fired for a pen up or down event.
+ */
+static irqreturn_t stylus_irq(int irq, void *dev_id)
+{
+	unsigned long data0;
+	unsigned long data1;
+	bool down;
+
+	data0 = readl(ts.io + S3C2410_ADCDAT0);
+	data1 = readl(ts.io + S3C2410_ADCDAT1);
+
+	down = get_down(data0, data1);
+
+	/* TODO we should never get an interrupt with down set while
+	 * the timer is running, but maybe we ought to verify that the
+	 * timer isn't running anyways. */
+
+	if (down)
+		s3c_adc_start(ts.client, 0, 1 << ts.shift);
+	else
+		dev_info(ts.dev, "%s: count=%d\n", __func__, ts.count);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * s3c24xx_ts_conversion - ADC conversion callback
+ * @client: The client that was registered with the ADC core.
+ * @data0: The reading from ADCDAT0.
+ * @data1: The reading from ADCDAT1.
+ * @left: The number of samples left.
+ *
+ * Called when a conversion has finished.
+ */
+static void s3c24xx_ts_conversion(struct s3c_adc_client *client,
+				  unsigned data0, unsigned data1,
+				  unsigned *left)
+{
+	dev_dbg(ts.dev, "%s: %d,%d\n", __func__, data0, data1);
+
+	ts.xp += data0;
+	ts.yp += data1;
+
+	ts.count++;
+
+	/* From tests, it seems that it is unlikely to get a pen-up
+	 * event during the conversion process which means we can
+	 * ignore any pen-up events with less than the requisite
+	 * count done.
+	 *
+	 * In several thousand conversions, no pen-ups where detected
+	 * before count completed.
+	 */
+}
+
+/**
+ * s3c24xx_ts_select - ADC selection callback.
+ * @client: The client that was registered with the ADC core.
+ * @select: The reason for select.
+ *
+ * Called when the ADC core selects (or deslects) us as a client.
+ */
+static void s3c24xx_ts_select(struct s3c_adc_client *client, unsigned select)
+{
+	if (select) {
+		writel(S3C2410_ADCTSC_PULL_UP_DISABLE | AUTOPST,
+		       ts.io + S3C2410_ADCTSC);
+	} else {
+		mod_timer(&touch_timer, jiffies+1);
+		writel(WAIT4INT | INT_UP, ts.io + S3C2410_ADCTSC);
+	}
+}
+
+/**
+ * s3c2410ts_probe - device core probe entry point
+ * @pdev: The device we are being bound to.
+ *
+ * Initialise, find and allocate any resources we need to run and then
+ * register with the ADC and input systems.
+ */
+static int __devinit s3c2410ts_probe(struct platform_device *pdev)
+{
+	struct s3c2410_ts_mach_info *info;
+	struct device *dev = &pdev->dev;
+	struct input_dev *input_dev;
+	struct resource *res;
+	int ret = -EINVAL;
+
+	/* Initialise input stuff */
+	memset(&ts, 0, sizeof(struct s3c2410ts));
+
+	ts.dev = dev;
+
+	info = pdev->dev.platform_data;
+	if (!info) {
+		dev_err(dev, "no platform data, cannot attach\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(dev, "initialising touchscreen\n");
+
+	ts.clock = clk_get(dev, "adc");
+	if (IS_ERR(ts.clock)) {
+		dev_err(dev, "cannot get adc clock source\n");
+		return -ENOENT;
+	}
+
+	clk_enable(ts.clock);
+	dev_dbg(dev, "got and enabled clocks\n");
+
+	ts.irq_tc = ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "no resource for interrupt\n");
+		goto err_clk;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "no resource for registers\n");
+		ret = -ENOENT;
+		goto err_clk;
+	}
+
+	ts.io = ioremap(res->start, resource_size(res));
+	if (ts.io == NULL) {
+		dev_err(dev, "cannot map registers\n");
+		ret = -ENOMEM;
+		goto err_clk;
+	}
+
+	/* Configure the touchscreen external FETs on the S3C2410 */
+	if (!platform_get_device_id(pdev)->driver_data)
+		s3c2410_ts_connect();
+
+	ts.client = s3c_adc_register(pdev, s3c24xx_ts_select,
+				     s3c24xx_ts_conversion, 1);
+	if (IS_ERR(ts.client)) {
+		dev_err(dev, "failed to register adc client\n");
+		ret = PTR_ERR(ts.client);
+		goto err_iomap;
+	}
+
+	/* Initialise registers */
+	if ((info->delay & 0xffff) > 0)
+		writel(info->delay & 0xffff, ts.io + S3C2410_ADCDLY);
+
+	writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
+
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(dev, "Unable to allocate the input device !!\n");
+		ret = -ENOMEM;
+		goto err_iomap;
+	}
+
+	ts.input = input_dev;
+	ts.input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	ts.input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	input_set_abs_params(ts.input, ABS_X, 0, 0x3FF, 0, 0);
+	input_set_abs_params(ts.input, ABS_Y, 0, 0x3FF, 0, 0);
+
+	ts.input->name = "S3C24XX TouchScreen";
+	ts.input->id.bustype = BUS_HOST;
+	ts.input->id.vendor = 0xDEAD;
+	ts.input->id.product = 0xBEEF;
+	ts.input->id.version = 0x0102;
+
+	ts.shift = info->oversampling_shift;
+
+	ret = request_irq(ts.irq_tc, stylus_irq, IRQF_DISABLED,
+			  "s3c2410_ts_pen", ts.input);
+	if (ret) {
+		dev_err(dev, "cannot get TC interrupt\n");
+		goto err_inputdev;
+	}
+
+	dev_info(dev, "driver attached, registering input device\n");
+
+	/* All went ok, so register to the input system */
+	ret = input_register_device(ts.input);
+	if (ret < 0) {
+		dev_err(dev, "failed to register input device\n");
+		ret = -EIO;
+		goto err_tcirq;
+	}
+
+	return 0;
+
+ err_tcirq:
+	free_irq(ts.irq_tc, ts.input);
+ err_inputdev:
+	input_unregister_device(ts.input);
+ err_iomap:
+	iounmap(ts.io);
+ err_clk:
+	del_timer_sync(&touch_timer);
+	clk_put(ts.clock);
+	return ret;
+}
+
+/**
+ * s3c2410ts_remove - device core removal entry point
+ * @pdev: The device we are being removed from.
+ *
+ * Free up our state ready to be removed.
+ */
+static int __devexit s3c2410ts_remove(struct platform_device *pdev)
+{
+	free_irq(ts.irq_tc, ts.input);
+	del_timer_sync(&touch_timer);
+
+	clk_disable(ts.clock);
+	clk_put(ts.clock);
+
+	input_unregister_device(ts.input);
+	iounmap(ts.io);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int s3c2410ts_suspend(struct device *dev)
+{
+	writel(TSC_SLEEP, ts.io + S3C2410_ADCTSC);
+	disable_irq(ts.irq_tc);
+	clk_disable(ts.clock);
+
+	return 0;
+}
+
+static int s3c2410ts_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct s3c2410_ts_mach_info *info = pdev->dev.platform_data;
+
+	clk_enable(ts.clock);
+
+	/* Initialise registers */
+	if ((info->delay & 0xffff) > 0)
+		writel(info->delay & 0xffff, ts.io + S3C2410_ADCDLY);
+
+	writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
+
+	return 0;
+}
+
+static struct dev_pm_ops s3c_ts_pmops = {
+	.suspend	= s3c2410ts_suspend,
+	.resume		= s3c2410ts_resume,
+};
+#endif
+
+static struct platform_device_id s3cts_driver_ids[] = {
+	{ "s3c2410-ts", 0 },
+	{ "s3c2440-ts", 1 },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, s3cts_driver_ids);
+
+static struct platform_driver s3c_ts_driver = {
+	.driver         = {
+		.name   = "s3c24xx-ts",
+		.owner  = THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm	= &s3c_ts_pmops,
+#endif
+	},
+	.id_table	= s3cts_driver_ids,
+	.probe		= s3c2410ts_probe,
+	.remove		= __devexit_p(s3c2410ts_remove),
+};
+
+static int __init s3c2410ts_init(void)
+{
+	return platform_driver_register(&s3c_ts_driver);
+}
+
+static void __exit s3c2410ts_exit(void)
+{
+	platform_driver_unregister(&s3c_ts_driver);
+}
+
+module_init(s3c2410ts_init);
+module_exit(s3c2410ts_exit);
+
+MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>, "
+	      "Ben Dooks <ben@simtec.co.uk>, "
+	      "Simtec Electronics <linux@simtec.co.uk>");
+MODULE_DESCRIPTION("S3C24XX Touchscreen driver");
+MODULE_LICENSE("GPL v2");