Re: your mail

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Apr 14, 2010 at 01:54:02PM +0100, Alan Cox wrote:
> Subject: [FOR COMMENT] cy8ctmg110 for review
> 
> From: Samuli Konttila <samuli.konttila@aavamobile.com>
> 
> Add support for the cy8ctmg110 capacitive touchscreen used on some embedded
> devices.
> 
> (Some clean up by Alan Cox)
> 
> (No signed off, not yet ready to go in)
> ---
> 
>  drivers/input/touchscreen/Kconfig         |   12 +
>  drivers/input/touchscreen/Makefile        |    3 
>  drivers/input/touchscreen/cy8ctmg110_ts.c |  521 +++++++++++++++++++++++++++++
>  3 files changed, 535 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/input/touchscreen/cy8ctmg110_ts.c
> 
> 
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index b3ba374..89a3eb1 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -591,4 +591,16 @@ config TOUCHSCREEN_TPS6507X
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called tps6507x_ts.
>  
> +config TOUCHSCREEN_CY8CTMG110
> +	tristate "cy8ctmg110 touchscreen"
> +	depends on I2C
> +	help
> +	  Say Y here if you have a cy8ctmg110 touchscreen capacitive
> +	  touchscreen
> +
> +	  If unsure, say N.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called cy8ctmg110_ts.
> +
>  endif
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index dfb7239..c7acb65 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -1,5 +1,5 @@
>  #
> -# Makefile for the touchscreen drivers.
> +# Makefile for the touchscreen drivers.mororor
>  #
>  
>  # Each configuration option enables a list of files.
> @@ -12,6 +12,7 @@ obj-$(CONFIG_TOUCHSCREEN_AD7879)	+= ad7879.o
>  obj-$(CONFIG_TOUCHSCREEN_ADS7846)	+= ads7846.o
>  obj-$(CONFIG_TOUCHSCREEN_ATMEL_TSADCC)	+= atmel_tsadcc.o
>  obj-$(CONFIG_TOUCHSCREEN_BITSY)		+= h3600_ts_input.o
> +obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110)    += cy8ctmg110_ts.o
>  obj-$(CONFIG_TOUCHSCREEN_DYNAPRO)	+= dynapro.o
>  obj-$(CONFIG_TOUCHSCREEN_GUNZE)		+= gunze.o
>  obj-$(CONFIG_TOUCHSCREEN_EETI)		+= eeti_ts.o
> diff --git a/drivers/input/touchscreen/cy8ctmg110_ts.c b/drivers/input/touchscreen/cy8ctmg110_ts.c
> new file mode 100644
> index 0000000..4adbe87
> --- /dev/null
> +++ b/drivers/input/touchscreen/cy8ctmg110_ts.c
> @@ -0,0 +1,521 @@
> +/*
> + * cy8ctmg110_ts.c Driver for cypress touch screen controller
> + * Copyright (c) 2009 Aava Mobile
> + *
> + * 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.
> + *
> + * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/input.h>
> +#include <linux/slab.h>
> +#include <linux/interrupt.h>
> +#include <asm/io.h>
> +#include <linux/i2c.h>
> +#include <linux/timer.h>
> +#include <linux/gpio.h>
> +#include <linux/hrtimer.h>
> +
> +#include <linux/platform_device.h>
> +#include <linux/delay.h>
> +#include <linux/fs.h>
> +#include <asm/ioctl.h>
> +#include <asm/uaccess.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/delay.h>
> +#include <linux/fs.h>
> +#include <asm/ioctl.h>
> +#include <linux/fs.h>
> +#include <linux/init.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +
> +
> +#define CY8CTMG110_DRIVER_NAME      "cy8ctmg110"
> +
> +
> +/*HW definations*/
> +#define CY8CTMG110_RESET_PIN_GPIO   43
> +#define CY8CTMG110_IRQ_PIN_GPIO     59
> +#define CY8CTMG110_I2C_ADDR         0x38
> +#define CY8CTMG110_I2C_ADDR_EXT     0x39
> +#define CY8CTMG110_I2C_ADDR_        0x2	/*i2c address first sample */
> +#define CY8CTMG110_I2C_ADDR__       53	/*i2c address to FW where irq support missing */
> +#define CY8CTMG110_TOUCH_IRQ        21
> +#define CY8CTMG110_TOUCH_LENGHT     9787
> +#define CY8CTMG110_SCREEN_LENGHT    8424
> +
> +
> +/*Touch coordinates*/
> +#define CY8CTMG110_X_MIN        0
> +#define CY8CTMG110_Y_MIN        0
> +#define CY8CTMG110_X_MAX        864
> +#define CY8CTMG110_Y_MAX        480
> +
> +
> +/*cy8ctmg110 registers defination*/
> +#define CY8CTMG110_TOUCH_WAKEUP_TIME   0
> +#define CY8CTMG110_TOUCH_SLEEP_TIME    2
> +#define CY8CTMG110_TOUCH_X1            3
> +#define CY8CTMG110_TOUCH_Y1            5
> +#define CY8CTMG110_TOUCH_X2            7
> +#define CY8CTMG110_TOUCH_Y2            9
> +#define CY8CTMG110_FINGERS             11
> +#define CY8CTMG110_GESTURE             12
> +#define CY8CTMG110_REG_MAX             13
> +
> +#define CY8CTMG110_POLL_TIMER_DELAY  1000*1000*100
> +#define TOUCH_MAX_I2C_FAILS          50
> +
> +/* Scale factors for coordinates */
> +#define X_SCALE_FACTOR 9387/8424
> +#define Y_SCALE_FACTOR 97/100
> +
> +/* For tracing */
> +static int g_y_trace_coord = 0;
> +module_param(g_y_trace_coord, int, 0600);
> +
> +/* Polling mode */
> +static int polling = 0;
> +module_param(polling, int, 0);
> +MODULE_PARM_DESC(polling, "Set to enabling polling of the touchscreen");
> +
> +
> +/*
> + * The touch position structure.
> + */
> +struct ts_event {
> +	int x1;
> +	int y1;
> +	int x2;
> +	int y2;
> +	bool event_sended;
> +};
> +
> +/*
> + * The touch driver structure.
> + */
> +struct cy8ctmg110 {
> +	struct input_dev *input;
> +	char phys[32];
> +	struct ts_event tc;
> +	struct i2c_client *client;
> +	bool pending;
> +	spinlock_t lock;
> +	bool initController;
> +	bool sleepmode;
> +	int i2c_fail_count;
> +	struct hrtimer timer;
> +};
> +
> +/*
> + * cy8ctmg110_poweroff is the routine that is called when touch hardware 
> + * will powered off
> + */
> +static void cy8ctmg110_power(bool poweron)
> +{
> +	if (poweron)
> +		gpio_direction_output(CY8CTMG110_RESET_PIN_GPIO, 0);
> +	else
> +		gpio_direction_output(CY8CTMG110_RESET_PIN_GPIO, 1);
> +}
> +
> +/*
> + * cy8ctmg110_write_req write regs to the i2c devices
> + * 
> + */
> +static int cy8ctmg110_write_req(struct cy8ctmg110 *tsc, unsigned char reg,
> +		unsigned char len, unsigned char *value)
> +{
> +	struct i2c_client *client = tsc->client;
> +	unsigned int ret;
> +	unsigned char i2c_data[] = { 0, 0, 0, 0, 0, 0 };
> +	struct i2c_msg msg[] = {
> +			{client->addr, 0, len + 1, i2c_data},
> +			};
> +
> +	i2c_data[0] = reg;
> +	memcpy(i2c_data + 1, value, len);
> +
> +	ret = i2c_transfer(client->adapter, msg, 1);
> +	if (ret != 1) {
> +		printk("cy8ctmg110 touch : i2c write data cmd failed \n");
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +/*
> + * cy8ctmg110_read_req read regs from i2c devise
> + * 
> + */
> +
> +static int cy8ctmg110_read_req(struct cy8ctmg110 *tsc,
> +		unsigned char *i2c_data, unsigned char len, unsigned char cmd)
> +{
> +	struct i2c_client *client = tsc->client;
> +	unsigned int ret;
> +	unsigned char regs_cmd[2] = { 0, 0 };
> +	struct i2c_msg msg1[] = {
> +		{client->addr, 0, 1, regs_cmd},
> +	};
> +	struct i2c_msg msg2[] = {
> +		{client->addr, I2C_M_RD, len, i2c_data},
> +	};
> +
> +	regs_cmd[0] = cmd;
> +
> +	/* first write slave position to i2c devices */
> +	ret = i2c_transfer(client->adapter, msg1, 1);
> +	if (ret != 1) {
> +		tsc->i2c_fail_count++;
> +		return ret;
> +	}
> +
> +	/* Second read data from position */
> +	ret = i2c_transfer(client->adapter, msg2, 1);
> +	if (ret != 1) {
> +		tsc->i2c_fail_count++;
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +/*
> + * cy8ctmg110_send_event delevery touch event to the userpace
> + * function use normal input interface
> + */
> +static void cy8ctmg110_send_event(void *tsc)
> +{
> +	struct cy8ctmg110 *ts = tsc;
> +	struct input_dev *input = ts->input;
> +	u16 x, y;
> +	u16 x2, y2;
> +
> +	x = ts->tc.x1;
> +	y = ts->tc.y1;
> +
> +	if (ts->tc.event_sended == false) {

We set "event_sended" to false immediately before calling
cy8ctmg110_send_event() so I do not see the point of this flag.

> +		input_report_key(input, BTN_TOUCH, 1);
> +		ts->pending = true;
> +		x2 = (u16) (y * X_SCALE_FACTOR);
> +		y2 = (u16) (x * Y_SCALE_FACTOR);
> +		input_report_abs(input, ABS_X, x2);
> +		input_report_abs(input, ABS_Y, y2);
> +		input_sync(input);
> +		if (g_y_trace_coord)
> +			printk("cy8ctmg110 touch position X:%d (was = %d) Y:%d (was = %d)\n", x2, y, y2, x);

Do we really need this? Seems to be early development diagnostic.

> +	}
> +
> +}
> +
> +/*
> + * cy8ctmg110_touch_pos check touch position from i2c devices
> + * 
> + */
> +static int cy8ctmg110_touch_pos(struct cy8ctmg110 *tsc)
> +{
> +	unsigned char reg_p[CY8CTMG110_REG_MAX];
> +	int x, y;
> +
> +	memset(reg_p, 0, CY8CTMG110_REG_MAX);
> +
> +	/*Reading coordinates */
> +	if (cy8ctmg110_read_req(tsc, reg_p, 9, CY8CTMG110_TOUCH_X1) != 0)
> +		return -EIO;
> +		
> +	y = reg_p[2] << 8 | reg_p[3];
> +	x = reg_p[0] << 8 | reg_p[1];
> +		/*number of touch */
> +	if (reg_p[8] == 0) {
> +		if (tsc->pending == true) {
> +			struct input_dev *input = tsc->input;
> +
> +			input_report_key(input, BTN_TOUCH, 0);
> +			tsc->tc.event_sended = true;
> +			tsc->pending = false;
> +		}

Just do input_report_key(input, BTN_TOUCH, 0); and let input core take
care of filtering duplicates. This will allow you get rid of bunch of
flags. Also input_sync() is missing here.

> +	} else if (tsc->tc.x1 != x || tsc->tc.y1 != y) {
> +		tsc->tc.y1 = y;
> +		tsc->tc.x1 = x;
> +		tsc->tc.event_sended = false;
> +		cy8ctmg110_send_event(tsc);
> +	}
> +	return 0;
> +}
> +
> +/*
> + * if interrupt isn't in use the touch positions can reads by polling
> + * 
> + */
> +static enum hrtimer_restart cy8ctmg110_timer(struct hrtimer *handle)
> +{
> +	struct cy8ctmg110 *ts = container_of(handle, struct cy8ctmg110, timer);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&ts->lock, flags);
> +
> +	cy8ctmg110_touch_pos(ts);
> +	if (ts->i2c_fail_count < TOUCH_MAX_I2C_FAILS)
> +		hrtimer_start(&ts->timer, ktime_set(0, CY8CTMG110_POLL_TIMER_DELAY), HRTIMER_MODE_REL);
> +

So device simply dies after so many errors?

> +	spin_unlock_irqrestore(&ts->lock, flags);

The timer handler is the only user for the spinlock, what is the point?

> +	return HRTIMER_NORESTART;
> +}
> +
> +/*
> + * 
> + */
> +static bool cy8ctmg110_set_sleepmode(struct cy8ctmg110 *ts)
> +{
> +	unsigned char reg_p[3];
> +
> +	if (ts->sleepmode == true) {
> +		reg_p[0] = 0x00;
> +		reg_p[1] = 0xff;
> +		reg_p[2] = 5;
> +	} else {
> +		reg_p[0] = 0x10;
> +		reg_p[1] = 0xff;
> +		reg_p[2] = 0;
> +	}
> +
> +	if (cy8ctmg110_write_req(ts, CY8CTMG110_TOUCH_WAKEUP_TIME, 3, reg_p))
> +		return false;
> +
> +	ts->initController = true;
> +	return true;
> +}
> +
> +/*
> + * cy8ctmg110_irq_handler irq handling function
> + * 
> + */
> +
> +static irqreturn_t cy8ctmg110_irq_handler(int irq, void *dev_id)
> +{
> +	struct cy8ctmg110 *tsc = (struct cy8ctmg110 *) dev_id;
> +
> +	if (tsc->initController == false) {
> +		if (cy8ctmg110_set_sleepmode(tsc) == true)
> +			tsc->initController = true;
> +	} else
> +		cy8ctmg110_touch_pos(tsc);

Initalizing device from interrupt handler is quite novel concept...

> +
> +	/* if interrupt supported in the touch controller
> +	   timer polling need to stop */
> +	tsc->i2c_fail_count = TOUCH_MAX_I2C_FAILS;
> +	return IRQ_HANDLED;
> +}
> +
> +
> +static int cy8ctmg110_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> +	struct cy8ctmg110 *ts;
> +	struct input_dev *input_dev;
> +	int err;
> +	client->irq = CY8CTMG110_TOUCH_IRQ;
> +
> +	if (!i2c_check_functionality(client->adapter,
> +					I2C_FUNC_SMBUS_READ_WORD_DATA))
> +		return -EIO;
> +
> +	ts = kzalloc(sizeof(struct cy8ctmg110), GFP_KERNEL);
> +	input_dev = input_allocate_device();
> +
> +	if (!ts || !input_dev) {
> +		err = -ENOMEM;
> +		goto err_free_mem;
> +	}
> +
> +	ts->client = client;
> +	i2c_set_clientdata(client, ts);
> +
> +	ts->input = input_dev;
> +	ts->pending = false;
> +	ts->sleepmode = false;
> +
> +	snprintf(ts->phys, sizeof(ts->phys), "%s/input0",
> +						dev_name(&client->dev));
> +
> +	input_dev->name = CY8CTMG110_DRIVER_NAME " Touchscreen";
> +	input_dev->phys = ts->phys;
> +	input_dev->id.bustype = BUS_I2C;
> +
> +	spin_lock_init(&ts->lock);
> +
> +	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP) |

You usually do not set up autorepeat for pointingt devices.

> +					BIT_MASK(EV_REL) | BIT_MASK(EV_ABS);

The device does not emit relative events.

> +	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> +
> +	input_set_capability(input_dev, EV_KEY, KEY_F);

KEY_F?

> +
> +	input_set_abs_params(input_dev, ABS_X, CY8CTMG110_X_MIN, CY8CTMG110_X_MAX, 0, 0);
> +	input_set_abs_params(input_dev, ABS_Y, CY8CTMG110_Y_MIN, CY8CTMG110_Y_MAX, 0, 0);
> +
> +	err = gpio_request(CY8CTMG110_RESET_PIN_GPIO, NULL);
> +
> +	if (err) {
> +		dev_err(&client->dev, "cy8ctmg110_ts: Unable to request GPIO pin %d.\n",
> +						CY8CTMG110_RESET_PIN_GPIO);
> +		goto err_free_irq;
> +	}
> +	cy8ctmg110_power(true);
> +
> +	ts->initController = false;
> +	ts->i2c_fail_count = 0;
> +
> +	hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> +	ts->timer.function = cy8ctmg110_timer;
> +
> +	if (polling)
> +		hrtimer_start(&ts->timer, ktime_set(10, 0), HRTIMER_MODE_REL);
> +

Polling mode shoudl be controlled by platform data, not kernel module I think.

> +	/* Can we fall back to polling if these bits fail - something to look
> +	   at for robustness */
> +
> +	err = gpio_request(CY8CTMG110_IRQ_PIN_GPIO, "touch_irq_key");
> +	if (err < 0) {
> +		dev_err(&client->dev,
> +			"cy8ctmg110_ts: failed to request GPIO %d, error %d\n",
> +						CY8CTMG110_IRQ_PIN_GPIO, err);
> +		goto err_free_timer;
> +	}
> +
> +	err = gpio_direction_input(CY8CTMG110_IRQ_PIN_GPIO);
> +
> +	if (err < 0) {
> +		dev_err(&client->dev,
> +			"cy8ctmg110_ts: failed to configure input direction for GPIO %d, error %d\n",
> +						CY8CTMG110_IRQ_PIN_GPIO, err);
> +		goto err_free_gpio;
> +	}
> +	client->irq = gpio_to_irq(CY8CTMG110_IRQ_PIN_GPIO);
> +
> +	if (client->irq < 0) {
> +		err = client->irq;
> +		dev_err(&client->dev,
> +	"cy8ctmg110_ts: Unable to get irq number" " for GPIO %d, error %d\n",
> +						CY8CTMG110_IRQ_PIN_GPIO, err);
> +		goto err_free_gpio;
> +	}
> +	err = request_irq(client->irq, cy8ctmg110_irq_handler, IRQF_TRIGGER_RISING | IRQF_SHARED, "touch_reset_key", ts);
> +	if (err < 0) {
> +		dev_err(&client->dev,
> +			"cy8ctmg110 irq %d busy? error %d\n",
> +				client->irq, err);
> +		goto err_free_gpio;
> +	}
> +
> +	err = input_register_device(input_dev);
> +	if (!err)
> +		return 0;
> +err_free_gpio:
> +	gpio_free(CY8CTMG110_IRQ_PIN_GPIO);
> +err_free_timer:
> +	if (polling)
> +		hrtimer_cancel(&ts->timer);
> +err_free_irq:
> +	free_irq(client->irq, ts);
> +err_free_mem:
> +	input_free_device(input_dev);
> +	kfree(ts);
> +	return err;
> +}
> +
> +/*
> + * cy8ctmg110_suspend
> + * 
> + */
> +
> +static int cy8ctmg110_suspend(struct i2c_client *client, pm_message_t mesg)
> +{

Stop timer here? Also power down the device?

> +	if (device_may_wakeup(&client->dev))
> +		enable_irq_wake(client->irq);
> +
> +	return 0;
> +}
> +
> +/*
> + * cy8ctmg110_resume 
> + * 
> + */
> +
> +static int cy8ctmg110_resume(struct i2c_client *client)
> +{
> +	if (device_may_wakeup(&client->dev))
> +		disable_irq_wake(client->irq);
> +
> +	return 0;
> +}
> +
> +/*
> + * cy8ctmg110_remove
> + * 
> + */
> +
> +static int cy8ctmg110_remove(struct i2c_client *client)
> +{
> +	struct cy8ctmg110 *ts = i2c_get_clientdata(client);
> +
> +	cy8ctmg110_power(false);
> +
> +	if (polling)
> +		hrtimer_cancel(&ts->timer);

Implement close() method and move the code above there? Also do open().

> +	free_irq(client->irq, ts);
> +	input_unregister_device(ts->input);
> +	/* FIXME: Do we need to free the GPIO ? */
> +	kfree(ts);
> +	return 0;
> +}
> +
> +static struct i2c_device_id cy8ctmg110_idtable[] = {
> +	{CY8CTMG110_DRIVER_NAME, 1},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, cy8ctmg110_idtable);
> +
> +static struct i2c_driver cy8ctmg110_driver = {
> +	.driver = {
> +		   .owner = THIS_MODULE,
> +		   .name = CY8CTMG110_DRIVER_NAME,
> +		   .bus = &i2c_bus_type,
> +		   },
> +	.id_table = cy8ctmg110_idtable,
> +	.probe = cy8ctmg110_probe,
> +	.remove = cy8ctmg110_remove,
> +	.suspend = cy8ctmg110_suspend,
> +	.resume = cy8ctmg110_resume,
> +};
> +
> +static int __init cy8ctmg110_init(void)
> +{
> +	return i2c_add_driver(&cy8ctmg110_driver);
> +}
> +
> +static void __exit cy8ctmg110_exit(void)
> +{
> +	i2c_del_driver(&cy8ctmg110_driver);
> +}
> +
> +module_init(cy8ctmg110_init);
> +module_exit(cy8ctmg110_exit);
> +
> +MODULE_AUTHOR("Samuli Konttila <samuli.konttila@aavamobile.com>");
> +MODULE_DESCRIPTION("cy8ctmg110 TouchScreen Driver");
> +MODULE_LICENSE("GPL v2");
> 
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-- 
Dmitry