[patch 1/1] TOUCHSCREEN: S3C24XX touchscreen driver from Arnaud Patard.

[Dmitry Torokhov]

Hi Ben,

On Wed, Nov 18, 2009 at 11:29:40PM +0000, Ben Dooks wrote:
> From: Arnaud Patard <arnaud.patard at rtp-net.org>
> 
> S3C24XX touchscreen driver, originally written by Arnaud Patard and
> other contributors. This driver is the version from the Simtec Electronics
> tree, and as such is the best place to start and thus proposed to be
> merged into the linux input system.
> 

Thank you for the patch. First thing first - do we have an agreement
from all Samsung folks and other interested parties that _this_ is the
driver? Because it's like 3rd implementation that came across...

> 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
> 
> Signed-off-by: Arnaud Patard <arnaud.patard at rtp-net.org>
> Signed-off-by: Simtec Linux Team <linux at simtec.co.uk>
> Signed-off-by: Ben Dooks <ben at simtec.co.uk>
> 
> ---
>  drivers/input/touchscreen/Kconfig      |   18 +
>  drivers/input/touchscreen/Makefile     |    1 
>  drivers/input/touchscreen/s3c2410_ts.c |  464 +++++++++++++++++++++++++++++++++
>  3 files changed, 483 insertions(+)
> 
> 
> Index: b/drivers/input/touchscreen/Kconfig
> ===================================================================
> --- a/drivers/input/touchscreen/Kconfig	2009-11-09 22:28:23.000000000 +0000
> +++ b/drivers/input/touchscreen/Kconfig	2009-11-10 10:38:44.000000000 +0000
> @@ -133,6 +133,24 @@ 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 && INPUT && INPUT_TOUCHSCREEN

INPUT && INPUT_TOUCHSCREEN are superfluous.

> +	select SERIO

I don't think you need SERIO

> +	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_S3C2410_DEBUG
> +	boolean "Samsung S3C2410 touchscreen debug messages"
> +	depends on TOUCHSCREEN_S3C2410
> +	help
> +	  Select this if you want debug messages

Where is this used?

> +
>  config TOUCHSCREEN_GUNZE
>  	tristate "Gunze AHL-51S touchscreen"
>  	select SERIO
> Index: b/drivers/input/touchscreen/Makefile
> ===================================================================
> --- a/drivers/input/touchscreen/Makefile	2009-11-09 22:28:23.000000000 +0000
> +++ b/drivers/input/touchscreen/Makefile	2009-11-10 10:38:44.000000000 +0000
> @@ -26,6 +26,7 @@ obj-$(CONFIG_TOUCHSCREEN_HP7XX)		+= jorn
>  obj-$(CONFIG_TOUCHSCREEN_HTCPEN)	+= htcpen.o
>  obj-$(CONFIG_TOUCHSCREEN_USB_COMPOSITE)	+= usbtouchscreen.o
>  obj-$(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
> Index: b/drivers/input/touchscreen/s3c2410_ts.c
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ b/drivers/input/touchscreen/s3c2410_ts.c	2009-11-10 10:47:38.000000000 +0000
> @@ -0,0 +1,464 @@
> +/* drivers/input/touchscreen/s3c2410_ts.c
> + *
> + * 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 at rtp-net.org>
> + * Copyright 2008 Ben Dooks <ben-linux at fluff.org>
> + * Copyright 2009 Simtec Electronics <linux at simtec.co.uk>
> + *
> + * Additional work by Herbert Pötzl <herbert at 13thfloor.at> and
> + * Harald Welte <laforge at 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/serio.h>

No serio in sight.

> +#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>
> +
> +/* For ts.dev.id.version */
> +#define S3C2410TSVERSION	0x0101
> +
> +#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))
> +
> +#define DEBUG_LVL    KERN_DEBUG

Don't seem to be used.

> +
> +static char *s3c2410ts_name = "s3c2410 TouchScreen";
> +
> +/* 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.
> + */

These sructures are driver-internal and so don't need to be kernel-doc-ed.
Same goes for the driver-private functions.

> +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);

No gpiolib? Also, should it be in the driver or maybe in the platform
code?

> +}
> +
> +/**
> + * 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 int get_down(unsigned long data0, unsigned long data1)

bool?

> +{
> +	/* 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;
> +	int down;

bool?

> +
> +	data0 = readl(ts.io + S3C2410_ADCDAT0);
> +	data1 = readl(ts.io + S3C2410_ADCDAT1);
> +
> +	down = get_down(data0, data1);
> +
> +	if (ts.count == (1<<ts.shift)) {

Syyle: x << y

> +		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_report_abs(ts.input, ABS_PRESSURE, 1);

No fake pressure events please, BTN_TOUCH should be enough.

> +		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_report_abs(ts.input, ABS_PRESSURE, 0);
> +		input_sync(ts.input);
> +
> +		writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
> +	}
> +}
> +
> +static struct timer_list touch_timer = TIMER_INITIALIZER(touch_timer_fire, 0, 0);

static DEFINE_TIMER(...);

> +
> +/**
> + * 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;
> +	int 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 __init s3c2410ts_probe(struct platform_device *pdev)

__devinit or switch to platform_driver_probe().

> +{
> +	struct s3c2410_ts_mach_info *info;
> +	struct device *dev = &pdev->dev;
> +	struct input_dev *input_dev;
> +	struct resource *res;
> +	int ret = -EINVAL;

Can we call it "error" (since that's what you use it for).
> +
> +	/* 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;
> +	}
> +

request_mem_region() here?

> +	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_SYN) | BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

No need setting EV_SYN explicitely.

> +	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);
> +	input_set_abs_params(ts.input, ABS_PRESSURE, 0, 1, 0, 0);

Drop ABS_PRESSURE.

> +
> +	ts.input->name = s3c2410ts_name;
> +	ts.input->id.bustype = BUS_HOST;
> +	ts.input->id.vendor = 0xDEAD;
> +	ts.input->id.product = 0xBEEF;
> +	ts.input->id.version = S3C2410TSVERSION;
> +
> +	ts.shift = info->oversampling_shift;
> +
> +	if (request_irq(ts.irq_tc, stylus_irq, IRQF_DISABLED,
> +			"s3c2410_ts_pen", ts.input)) {
> +		dev_err(dev, "cannot get TC interrupt\n");
> +		ret = -EIO;

Don't mangle what request_irq returned.

> +		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);

del_timer_sync().

> + err_inputdev:
> +	input_unregister_device(ts.input);
> + err_iomap:
> +	iounmap(ts.io);
> + err_clk:
> +	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 s3c2410ts_remove(struct platform_device *pdev)
> +{
> +	free_irq(ts.irq_tc, ts.input);

del_timer_sync().

> +
> +	clk_disable(ts.clock);
> +	clk_put(ts.clock);
> +
> +	input_unregister_device(ts.input);
> +	iounmap(ts.io);

release_mem_region()

> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int s3c2410ts_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> +	writel(TSC_SLEEP, ts.io + S3C2410_ADCTSC);
> +	disable_irq(ts.irq_tc);
> +	clk_disable(ts.clock);
> +
> +	return 0;
> +}
> +
> +static int s3c2410ts_resume(struct platform_device *pdev)
> +{
> +	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;
> +}
> +
> +#else
> +#define s3c2410ts_suspend NULL
> +#define s3c2410ts_resume  NULL
> +#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,
> +	},
> +	.id_table	= s3cts_driver_ids,
> +	.probe		= s3c2410ts_probe,
> +	.remove		= s3c2410ts_remove,

__devexit_p()

> +	.suspend	= s3c2410ts_suspend,
> +	.resume		= s3c2410ts_resume,

Switch to pm_ops.

> +};
> +
> +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 at rtp-net.org>, "
> +	      "Ben Dooks <ben at simtec.co.uk>, "
> +	      "Simtec Electronics <linux at simtec.co.uk>");
> +MODULE_DESCRIPTION("S3C24XX Touchscreen driver");
> +MODULE_LICENSE("GPL v2");
> 

Thanks!

-- 
Dmitry