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Re: [PATCH] ili210x: Add support for Ilitek ILI210x based touchscreens

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Hi Henrik,

On Mon, Mar 05, 2012 at 05:48:38PM +0100, Henrik Rydberg wrote:
> Hi Olivier,
> 
> > The driver supports chipsets ILI2102, ILI2102s, ILI2103, ILI2103s and
> > ILI2105.
> > 
> > Reviewed-by: Jan Paesmans <jan.paesmans@xxxxxxxxx>
> > Signed-off-by: Olivier Sobrie <olivier@xxxxxxxxx>
> > ---
> 
> Thanks for the driver, looking pretty good overall. Please find
> comments inline.
> 
> >  drivers/input/touchscreen/Kconfig   |   13 +
> >  drivers/input/touchscreen/Makefile  |    1 +
> >  drivers/input/touchscreen/ili210x.c |  442 +++++++++++++++++++++++++++++++++++
> >  include/linux/input/ili210x.h       |    9 +
> >  4 files changed, 465 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/input/touchscreen/ili210x.c
> >  create mode 100644 include/linux/input/ili210x.h
> > 
> > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > index fc087b3..37b052f 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -243,6 +243,19 @@ config TOUCHSCREEN_FUJITSU
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called fujitsu-ts.
> >  
> > +config TOUCHSCREEN_ILI210X
> > +	tristate "Ilitek ILI210X based touchscreen"
> > +	depends on I2C
> > +	help
> > +	  Say Y here if you have a ILI210X based touchscreen
> > +	  controller. This driver supports models ILI2102,
> > +	  ILI2102s, ILI2103, ILI2103s and ILI2105.
> > +
> > +	  If unsure, say N.
> > +
> > +	  To compile this driver as a module, choose M here: the
> > +	  module will be called ili210x.
> > +
> 
> If any of these are found in the Kindles, saying so here might help a bit.
I use it for an industrial application, driver console of public
transports...
Google doesn't say a lot about ILI210x. It's possible that you can find it
on some Android tablet but I cannot say on which one.

> >  config TOUCHSCREEN_S3C2410
> >  	tristate "Samsung S3C2410/generic touchscreen input driver"
> >  	depends on ARCH_S3C2410 || SAMSUNG_DEV_TS
> > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> > index e748fb8..3d5cf8c 100644
> > --- a/drivers/input/touchscreen/Makefile
> > +++ b/drivers/input/touchscreen/Makefile
> > @@ -29,6 +29,7 @@ obj-$(CONFIG_TOUCHSCREEN_EETI)		+= eeti_ts.o
> >  obj-$(CONFIG_TOUCHSCREEN_ELO)		+= elo.o
> >  obj-$(CONFIG_TOUCHSCREEN_EGALAX)	+= egalax_ts.o
> >  obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
> > +obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o
> >  obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
> >  obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o
> >  obj-$(CONFIG_TOUCHSCREEN_LPC32XX)	+= lpc32xx_ts.o
> > diff --git a/drivers/input/touchscreen/ili210x.c b/drivers/input/touchscreen/ili210x.c
> > new file mode 100644
> > index 0000000..131e1b1
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/ili210x.c
> > @@ -0,0 +1,442 @@
> > +#include <linux/module.h>
> > +#include <linux/i2c.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/slab.h>
> > +#include <linux/input.h>
> > +#include <linux/input/mt.h>
> > +#include <linux/delay.h>
> > +#include <linux/timer.h>
> > +#include <linux/input/ili210x.h>
> > +
> > +#define MAX_TOUCHES		2
> > +#define TS_PEN_UP_TIMEOUT	msecs_to_jiffies(50)
> > +
> > +/* Touchscreen commands */
> > +#define REG_TOUCHDATA		0x10
> > +#define REG_PANEL_INFO		0x20
> > +#define REG_FIRMWARE_VERSION	0x40
> > +#define REG_CALIBRATE		0xcc
> > +
> > +struct finger {
> > +	u8 x_low;
> > +	u8 x_high;
> > +	u8 y_low;
> > +	u8 y_high;
> > +} __packed;
> > +
> > +struct touchdata {
> > +	u8 status;
> > +	struct finger finger[MAX_TOUCHES];
> > +} __packed;
> > +
> > +struct panel_info {
> > +	struct finger finger_max;
> > +	u8 xchannel_num;
> > +	u8 ychannel_num;
> > +} __packed;
> > +
> > +struct firmware_version {
> > +	u8 id;
> > +	u8 major;
> > +	u8 minor;
> > +} __packed;
> > +
> > +struct ili210x {
> > +	struct i2c_client *client;
> > +	struct input_dev *input;
> > +	bool stopped;
> > +	int (*get_pendown_state)(void);
> > +	spinlock_t lock;
> > +	struct timer_list timer;
> > +};
> > +
> > +static int ili210x_read_reg(struct i2c_client *client, u8 reg, void *buf,
> > +			    size_t len)
> > +{
> > +	struct i2c_msg msg[2];
> > +
> > +	msg[0].addr = client->addr;
> > +	msg[0].flags = 0;
> > +	msg[0].len = 1;
> > +	msg[0].buf = &reg;
> > +
> > +	msg[1].addr = client->addr;
> > +	msg[1].flags = I2C_M_RD;
> > +	msg[1].len = len;
> > +	msg[1].buf = buf;
> > +
> > +	if (i2c_transfer(client->adapter, msg, 2) != 2) {
> > +		dev_err(&client->dev, "i2c transfer failed\n");
> > +		return -EIO;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void ili210x_report_events(struct input_dev *input,
> > +				  struct touchdata *touchdata)
> 
> Why not const struct touchdata here?
Because my keyboard forgot it ;-)

> > +{
> > +	int i, count = 0;
> > +	bool touch;
> > +	unsigned int x, y;
> > +	struct finger *finger;
> > +
> > +	for (i = 0; i < MAX_TOUCHES; i++) {
> > +		input_mt_slot(input, i);
> > +
> > +		finger = &touchdata->finger[i];
> > +
> > +		touch = touchdata->status & (1 << i);
> > +		input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
> > +		if (touch) {
> > +			x = finger->x_low | (finger->x_high << 8);
> > +			y = finger->y_low | (finger->y_high << 8);
> > +
> > +			input_report_abs(input, ABS_MT_POSITION_X, x);
> > +			input_report_abs(input, ABS_MT_POSITION_Y, y);
> > +
> > +			if (!count) {
> > +				input_report_abs(input, ABS_X, x);
> > +				input_report_abs(input, ABS_Y, y);
> > +			}
> 
> No need to handle ABS_X/Y explicitly; please use
> input_mt_report_pointer_emulation() instead.
Ok I'll change that. Thanks.

> > +
> > +			count++;
> > +		}
> > +	}
> > +
> > +	if (count > 0) {
> > +		input_report_key(input, BTN_TOUCH, count > 0);
> > +		input_sync(input);
> > +	}
> 
> This one is also handled by input_mt_report_pointer_emulation().
Ok.

> > +}
> > +
> > +static int get_pendown_state(struct ili210x *priv)
> 
> Why not const struct here?
Once again I forgot it. Thanks.

> > +{
> > +	int state = 0;
> > +
> > +	if (priv->get_pendown_state)
> > +		state = priv->get_pendown_state();
> > +
> > +	return state;
> > +}
> > +
> > +static void ili210x_timer(unsigned long handle)
> > +{
> > +	struct ili210x *priv = (void *)handle;
> > +	unsigned long flags;
> > +
> > +	spin_lock_irqsave(&priv->lock, flags);
> > +
> > +	input_report_key(priv->input, BTN_TOUCH, 0);
> > +	input_sync(priv->input);
> > +
> > +	spin_unlock_irqrestore(&priv->lock, flags);
> > +}
> 
> Why is the timer necessary, won't the hardware flag zero touches any other way?
The touchscreen works with level triggered interrupts. When it detects a
finger on the screen, it pulls down the interrupt linei and it stays low
until the finger left the screen.
If working with an irq handler that is level triggered, we must be sure to
report the zero touches, meaning that the irq handler should be called
after the finger(s) left the touchscreen to read the zero touches.
The timer is here to be sure that the zero touches will be called after the
finger left the sensor surface.

> > +
> > +static irqreturn_t ili210x_hardirq(int irq, void *irq_data)
> > +{
> > +	struct ili210x *priv = irq_data;
> > +
> > +	if (!priv->get_pendown_state)
> > +		return IRQ_WAKE_THREAD;
> > +
> > +	return get_pendown_state(priv) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
> > +}
> > +
> > +static irqreturn_t ili210x_irq(int irq, void *irq_data)
> > +{
> > +	struct ili210x *priv = irq_data;
> > +	struct i2c_client *client = priv->client;
> > +	struct input_dev *input = priv->input;
> > +	struct device *dev = &client->dev;
> > +	struct touchdata touchdata;
> > +	int rc;
> > +
> > +	do {
> > +		rc = ili210x_read_reg(client, REG_TOUCHDATA, &touchdata,
> > +				      sizeof(touchdata));
> > +		if (rc < 0) {
> > +			dev_err(dev, "Unable to get touchdata, err = %d\n",
> > +				rc);
> > +			goto end;
> > +		}
> > +
> > +		ili210x_report_events(input, &touchdata);
> > +
> > +		usleep_range(100, 1000);
> > +		mod_timer(&priv->timer, jiffies + TS_PEN_UP_TIMEOUT);
> > +	} while (get_pendown_state(priv) && !priv->stopped);
> 
> It looks odd to loop in an irq handler, even if it is threaded. What
> is the pdata->get_pendown_state() doing?
I agree. The reason of the loop is for edge triggered interrupt.

On my hardware I don't have support for level triggered irq. I'm working
with edge triggered interrupts.
In the pdata structure I give to the driver it set irq_flags to
IRQF_TRIGGER_FALLING and the get_pendown_state function implemented is the
following:
	static int get_pendown_state(void)
	{
		return gpio_get_value(GPIO_TOUCHSCREEN_IRQ) ? 0 : 1;
	}
The get_pendown_state() function will look at the irq line to see if it's
still low meaning there is a finger on the screen.
If it is the case, we loop, otherwise we exit from the thread and the timer
will fire after TS_PEN_UP_TIMEOUT.

On the contrary if working with a level triggered interrupt, i.e. with
irqflags set to IRQF_TRIGGER_LOW, there is no need to add the
get_pendown_state function and the thread will exit after each touch read.
In this case the usleep_range() is even not needed...

I agree it's maybe not the best solution... Do I've to use something else
like a workqueue or something else?

> > +
> > +end:
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static ssize_t ili210x_calibrate(struct device *dev,
> > +				 struct device_attribute *attr,
> > +				 const char *buf, size_t count)
> > +{
> > +	struct ili210x *priv = dev_get_drvdata(dev);
> > +	unsigned long calibrate;
> > +	int rc;
> > +	u8 cmd = REG_CALIBRATE;
> > +
> > +	if (kstrtoul(buf, 10, &calibrate))
> > +		return -EINVAL;
> > +
> > +	if (calibrate != 1)
> > +		return -EINVAL;
> 
> Maybe allowing zero as a NOP would help userland here?
Ok I'll change it.

> > +
> > +	rc = i2c_master_send(priv->client, &cmd, sizeof(cmd));
> > +	if (rc != sizeof(cmd))
> > +		return -EIO;
> > +
> > +	return count;
> > +}
> > +static DEVICE_ATTR(calibrate, 0644, NULL, ili210x_calibrate);
> > +
> > +static ssize_t ili210x_readtouch(struct device *dev,
> > +				 struct device_attribute *attr,
> > +				 char *buf)
> > +{
> > +	struct ili210x *priv = dev_get_drvdata(dev);
> > +	struct touchdata touchdata;
> > +	struct finger *finger;
> > +	ssize_t count = 0;
> > +	int i, rc;
> > +	int x, y;
> > +	bool touch;
> > +
> > +	rc = ili210x_read_reg(priv->client, REG_TOUCHDATA, &touchdata,
> > +			      sizeof(touchdata));
> > +	if (rc < 0) {
> > +		dev_err(dev, "Unable to get touchdata, err = %d\n",
> > +			rc);
> > +		return rc;
> > +	}
> > +
> > +	for (i = 0; i < MAX_TOUCHES; i++) {
> > +		finger = &touchdata.finger[i];
> > +		touch = touchdata.status & (1 << i);
> > +		if (touch) {
> > +			x = finger->x_low | (finger->x_high << 8);
> > +			y = finger->y_low | (finger->y_high << 8);
> > +			count += sprintf(&buf[count], "%d: %d,%d\n", i, x,
> > +					 y);
> > +		}
> > +	}
> > +
> > +	return count;
> > +}
> > +static DEVICE_ATTR(readtouch, 0x644, ili210x_readtouch, NULL);
> 
> I do not think adding this sysfs node is a good idea; you will not be
> able to change it easily to accomodate more data. Better move to
> debugfs or simply remove completely.
I used it at the beginning of the development, I'll remove this useless
sysfs entry.

> > +
> > +static struct attribute *ili210x_attributes[] = {
> > +	&dev_attr_calibrate.attr,
> > +	&dev_attr_readtouch.attr,
> > +	NULL,
> > +};
> > +
> > +static const struct attribute_group ili210x_attr_group = {
> > +	.attrs = ili210x_attributes,
> > +};
> > +
> > +static int __devinit ili210x_i2c_probe(struct i2c_client *client,
> > +				       const struct i2c_device_id *id)
> > +{
> > +	struct ili210x *priv;
> > +	struct input_dev *input;
> > +	struct device *dev = &client->dev;
> > +	struct ili210x_platform_data *pdata = dev->platform_data;
> > +	struct panel_info panel;
> > +	struct firmware_version firmware;
> > +	int xmax, ymax;
> > +	int rc;
> > +
> > +	dev_dbg(dev, "Probing for ILI210X I2C Touschreen driver");
> > +
> > +	if (!pdata) {
> > +		dev_err(dev, "No platform data!\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	if (client->irq <= 0) {
> > +		dev_err(dev, "No IRQ!\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > +	if (!priv) {
> > +		dev_err(dev, "Failed to allocate driver data!\n");
> > +		rc = -ENOMEM;
> > +		goto fail;
> > +	}
> > +
> > +	dev_set_drvdata(dev, priv);
> > +
> > +	input = input_allocate_device();
> > +	if (!input) {
> > +		dev_err(dev, "Failed to allocate input device\n");
> > +		rc = -ENOMEM;
> > +		goto fail;
> > +	}
> > +
> > +	/* Get firmware version */
> > +	rc = ili210x_read_reg(client, REG_FIRMWARE_VERSION, &firmware,
> > +			      sizeof(firmware));
> > +	if (rc < 0) {
> > +		dev_err(dev, "Failed to get firmware version, err: %d\n",
> > +			rc);
> > +		goto fail_probe;
> > +	}
> > +
> > +	/* get panel info */
> > +	rc = ili210x_read_reg(client, REG_PANEL_INFO, &panel,
> > +			      sizeof(panel));
> > +	if (rc < 0) {
> > +		dev_err(dev, "Failed to get panel informations, err: %d\n",
> > +			rc);
> > +		goto fail_probe;
> > +	}
> > +
> > +	xmax = panel.finger_max.x_low | (panel.finger_max.x_high << 8);
> > +	ymax = panel.finger_max.y_low | (panel.finger_max.y_high << 8);
> > +
> > +	/* Setup input device */
> > +	__set_bit(EV_SYN, input->evbit);
> > +	__set_bit(EV_KEY, input->evbit);
> > +	__set_bit(EV_ABS, input->evbit);
> > +	__set_bit(BTN_TOUCH, input->keybit);
> > +
> > +	/* Single touch */
> > +	input_set_abs_params(input, ABS_X, 0, xmax, 0, 0);
> > +	input_set_abs_params(input, ABS_Y, 0, ymax, 0, 0);
> > +
> > +	/* Multi touch */
> > +	input_mt_init_slots(input, MAX_TOUCHES);
> > +	input_set_abs_params(input, ABS_MT_POSITION_X, 0, xmax, 0, 0);
> > +	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, ymax, 0, 0);
> > +
> > +	input->name = "ILI210x Touchscreen";
> > +	input->id.bustype = BUS_I2C;
> > +	input->dev.parent = dev;
> > +
> > +	input_set_drvdata(input, priv);
> > +
> > +	setup_timer(&priv->timer, ili210x_timer, (unsigned long) priv);
> > +	spin_lock_init(&priv->lock);
> > +	priv->get_pendown_state = pdata->get_pendown_state;
> > +	rc = request_threaded_irq(client->irq, ili210x_hardirq, ili210x_irq,
> > +				  pdata->irq_flags, client->name,
> > +				  priv);
> > +	if (rc) {
> > +		dev_err(dev, "Unable to request touchscreen IRQ, err: %d\n",
> > +			rc);
> > +		goto fail_probe;
> > +	}
> > +
> > +	rc = sysfs_create_group(&dev->kobj, &ili210x_attr_group);
> > +	if (rc) {
> > +		dev_err(dev, "Unable to create sysfs attributes, err: %d\n",
> > +			rc);
> > +		goto fail_sysfs;
> > +	}
> > +
> > +	rc = input_register_device(input);
> > +	if (rc) {
> > +		dev_err(dev, "Cannot regiser input device, err: %d\n", rc);
> > +		goto fail_input;
> > +	}
> > +
> > +	priv->client = client;
> > +	priv->input = input;
> > +
> > +	device_init_wakeup(&client->dev, 1);
> > +
> > +	dev_info(dev,
> > +		 "ILI210x initialized (IRQ: %d), firmware version %d.%d.%d",
> > +		 client->irq, firmware.id, firmware.major, firmware.minor);
> > +
> > +	return 0;
> > +
> > +fail_input:
> > +	sysfs_remove_group(&dev->kobj, &ili210x_attr_group);
> > +fail_sysfs:
> > +	free_irq(client->irq, priv);
> > +fail_probe:
> > +	input_free_device(input);
> > +fail:
> > +	kfree(priv);
> > +	return rc;
> > +}
> > +
> > +static int __devexit ili210x_i2c_remove(struct i2c_client *client)
> > +{
> > +	struct ili210x *priv = dev_get_drvdata(&client->dev);
> > +	struct device *dev = &priv->client->dev;
> > +
> > +	sysfs_remove_group(&dev->kobj, &ili210x_attr_group);
> > +	del_timer_sync(&priv->timer);
> > +	priv->stopped = true;
> > +	free_irq(priv->client->irq, priv);
> > +	input_unregister_device(priv->input);
> > +	kfree(priv);
> > +
> > +	return 0;
> > +}
> > +
> > +#ifdef CONFIG_PM_SLEEP
> > +static int ili210x_i2c_suspend(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +
> > +	if (device_may_wakeup(&client->dev))
> > +		enable_irq_wake(client->irq);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ili210x_i2c_resume(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +
> > +	if (device_may_wakeup(&client->dev))
> > +		disable_irq_wake(client->irq);
> > +
> > +	return 0;
> > +}
> > +#endif
> > +
> > +static SIMPLE_DEV_PM_OPS(ili210x_i2c_pm, ili210x_i2c_suspend,
> > +			 ili210x_i2c_resume);
> > +
> > +static const struct i2c_device_id ili210x_i2c_id[] = {
> > +	{ "ili210x", 0 },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, ili210x_i2c_id);
> > +
> > +static struct i2c_driver ili210x_ts_driver = {
> > +	.driver = {
> > +		.name = "ili210x_i2c",
> > +		.owner = THIS_MODULE,
> > +		.pm = &ili210x_i2c_pm,
> > +	},
> > +	.id_table = ili210x_i2c_id,
> > +	.probe = ili210x_i2c_probe,
> > +	.remove = ili210x_i2c_remove,
> > +};
> > +
> > +static int __init ili210x_ts_init(void)
> > +{
> > +	return i2c_add_driver(&ili210x_ts_driver);
> > +}
> > +module_init(ili210x_ts_init);
> > +
> > +static void __exit ili210x_ts_exit(void)
> > +{
> > +	i2c_del_driver(&ili210x_ts_driver);
> > +}
> > +module_exit(ili210x_ts_exit);
> > +
> > +MODULE_AUTHOR("Olivier Sobrie <olivier@xxxxxxxxx>");
> > +MODULE_DESCRIPTION("ILI210X I2C Touchscreen Driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/input/ili210x.h b/include/linux/input/ili210x.h
> > new file mode 100644
> > index 0000000..710b3dd2
> > --- /dev/null
> > +++ b/include/linux/input/ili210x.h
> > @@ -0,0 +1,9 @@
> > +#ifndef _ILI210X_H
> > +#define _ILI210X_H
> > +
> > +struct ili210x_platform_data {
> > +	unsigned long irq_flags;
> > +	int (*get_pendown_state)(void);
> > +};
> > +
> > +#endif
> > -- 
> > 1.7.5.4
> > 
> 
> Thanks,
> Henrik

Thanks for the review!
I'm looking forward for your comments and suggestions for the irq handler.
After that I send you an update of the patch.

Cheers,

-- 
Olivier Sobrie
--
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