[PATCH 1/1] Input/Joystick Driver: add support AD7142 joystick driver (v2)

[PATCH 1/1] Input/Joystick Driver: add support AD7142 joystick driver (v2)

[Bryan Wu]

v1-v2:
 - Remove depends on Blackfin
 - Add module information to Kconfig
 - Fixup duplicated Signed-off-by

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
---
 drivers/input/joystick/Kconfig  |    9 +
 drivers/input/joystick/Makefile |    1 +
 drivers/input/joystick/ad7142.c |  447 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 457 insertions(+), 0 deletions(-)
 create mode 100644 drivers/input/joystick/ad7142.c

diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
index 7c662ee..b107e60 100644
--- a/drivers/input/joystick/Kconfig
+++ b/drivers/input/joystick/Kconfig
@@ -282,4 +282,13 @@ config JOYSTICK_XPAD_LEDS
 	  This option enables support for the LED which surrounds the Big X on
 	  XBox 360 controller.
 
+config JOYSTICK_AD7142
+	tristate "Analog Devices AD7142 Joystick support"
+	depends on I2C
+	---help---
+	  Say Y here if you want to support an AD7142 joystick
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad7142.
+
 endif
diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
index e855abb..8df388f 100644
--- a/drivers/input/joystick/Makefile
+++ b/drivers/input/joystick/Makefile
@@ -5,6 +5,7 @@
 # Each configuration option enables a list of files.
 
 obj-$(CONFIG_JOYSTICK_A3D)		+= a3d.o
+obj-$(CONFIG_JOYSTICK_AD7142)		+= ad7142.o
 obj-$(CONFIG_JOYSTICK_ADI)		+= adi.o
 obj-$(CONFIG_JOYSTICK_AMIGA)		+= amijoy.o
 obj-$(CONFIG_JOYSTICK_ANALOG)		+= analog.o
diff --git a/drivers/input/joystick/ad7142.c b/drivers/input/joystick/ad7142.c
new file mode 100644
index 0000000..900affd
--- /dev/null
+++ b/drivers/input/joystick/ad7142.c
@@ -0,0 +1,447 @@
+/*
+ * I2C Based AD7142 Joystick Input Device Driver
+ *
+ * Copyright 2005-2008 Analog Devices Inc.
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+
+MODULE_AUTHOR("Bryan Wu <cooloney@kernel.org>");
+MODULE_DESCRIPTION("Driver for AD7142 Joysticks");
+MODULE_LICENSE("GPL");
+
+#define AD7142_I2C_ID		0xE622
+
+/*
+ * Ram map - these registers are defined as we go along
+ */
+/* RW   Power & conversion control */
+#define PWRCONVCTL		0x00
+
+/* RW   Ambient compensation control register 0 - 3 */
+#define AMBCOMPCTL_REG0		0x01
+#define AMBCOMPCTL_REG1		0x02
+#define AMBCOMPCTL_REG2		0x03
+#define AMBCOMPCTL_REG3		0x04
+
+/* RW   Interrupt enable register 0 - 2 */
+#define INTEN_REG0		0x05
+#define INTEN_REG1		0x06
+#define INTEN_REG2		0x07
+
+/* R    Low limit interrupt status register 0 */
+#define INTSTAT_REG0		0x08
+/* R    High limit interrupt status register 1 */
+#define INTSTAT_REG1		0x09
+/* R    Interrupt status register 2 */
+#define INTSTAT_REG2		0x0A
+
+/* R    ADC stage 0 - 11 result (uncompensated) actually located in SRAM */
+#define ADCRESULT_S0		0x0B
+#define ADCRESULT_S1		0x0C
+#define ADCRESULT_S2		0x0D
+#define ADCRESULT_S3		0x0E
+#define ADCRESULT_S4		0x0F
+#define ADCRESULT_S5		0x10
+#define ADCRESULT_S6		0x11
+#define ADCRESULT_S7		0x12
+#define ADCRESULT_S8		0x13
+#define ADCRESULT_S9		0x14
+#define ADCRESULT_S10		0x15
+#define ADCRESULT_S11		0x16
+
+/* R    I.D. Register */
+#define DEVID			0x17
+
+/* R    Current threshold status register 0, 1 */
+#define THRES_STAT_REG0		0x40
+#define THRES_STAT_REG1		0x41
+/* R    Current proximity status register 2 */
+#define PROX_STAT_REG		0x42
+
+#define STAGE0_CONNECTION	0x80
+#define STAGE1_CONNECTION	0x88
+#define STAGE2_CONNECTION	0x90
+#define STAGE3_CONNECTION	0x98
+#define STAGE4_CONNECTION	0xA0
+#define STAGE5_CONNECTION	0xA8
+#define STAGE6_CONNECTION	0xB0
+#define STAGE7_CONNECTION	0xB8
+#define STAGE8_CONNECTION	0xC0
+#define STAGE9_CONNECTION	0xC8
+#define STAGE10_CONNECTION	0xD0
+#define STAGE11_CONNECTION	0xD8
+
+/*
+ *	STAGE0: Button1   <----> CIN6(+)	Button2    <----> CIN5(-)
+ *	STAGE1: Button3   <----> CIN4(-)	Button4    <----> CIN3(+)
+ *	STAGE2: Axes.Left <----> CIN11(-)	Axes.Right <----> CIN13(+)
+ *	STAGE3: Axes.Up   <----> CIN12(-)	Axes.Down  <----> CIN10(+)
+ */
+static const unsigned short stage[5][8] = {
+	{0xE7FF, 0x3FFF, 0x0005, 0x2626, 0x01F4, 0x01F4, 0x028A, 0x028A},
+	{0xFDBF, 0x3FFF, 0x0001, 0x2626, 0x01F4, 0x01F4, 0x028A, 0x028A},
+	{0xFFFF, 0x2DFF, 0x0001, 0x2626, 0x01F4, 0x01F4, 0x028A, 0x028A},
+	{0xFFFF, 0x37BF, 0x0001, 0x2626, 0x01F4, 0x01F4, 0x028A, 0x028A},
+	{0xFFFF, 0x3FFF, 0x0000, 0x0606, 0x01F4, 0x01F4, 0x0320, 0x0320},
+};
+
+struct ad7142_data {
+	struct input_dev *input;
+	struct i2c_client *client;
+
+	struct work_struct work;
+	int is_open;
+
+	unsigned short old_status_low;
+	unsigned short old_status_high;
+};
+
+static irqreturn_t ad7142_interrupt(int irq, void *_data)
+{
+	struct ad7142_data *data = _data;
+
+	disable_irq_nosync(irq);
+	if (data->is_open)
+		schedule_work(&data->work);
+
+	return IRQ_HANDLED;
+}
+
+static int ad7142_i2c_write(struct i2c_client *client, unsigned short offset,
+			const unsigned short *data, unsigned int len)
+{
+	int ret = -1;
+	int i;
+	u8 block_data[34];
+
+	if (len < 1 || len > 16) {
+		dev_err(&client->dev, "Write data length error\n");
+		return ret;
+	}
+
+	/* Do raw I2C, not smbus compatible */
+	block_data[0] = (offset & 0xFF00) >> 8;
+	block_data[1] = (offset & 0x00FF);
+
+	for (i = 0; i < len; i++) {
+		block_data[2 * i + 2] = (*data & 0xFF00) >> 8;
+		block_data[2 * i + 3] = *data++ & 0x00FF;
+	}
+
+	ret = i2c_master_send(client, block_data, (len * 2 + 2));
+	if (ret < 0) {
+		dev_err(&client->dev, "I2C write error\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+static int ad7142_i2c_read(struct i2c_client *client, unsigned short offset,
+		unsigned short *data, unsigned int len)
+{
+	int ret = -1;
+	int i;
+	u8 block_data[32];
+
+	if (len < 1 || len > 16) {
+		dev_err(&client->dev, "read data length error\n");
+		return ret;
+	}
+
+	/* Do raw I2C, not smbus compatible */
+	block_data[0] = (offset & 0xFF00) >> 8;
+	block_data[1] = (offset & 0x00FF);
+
+	ret = i2c_master_send(client, block_data, 2);
+	if (ret < 0) {
+		dev_err(&client->dev, "I2C read error\n");
+		return ret;
+	}
+
+	ret = i2c_master_recv(client, block_data, len * 2);
+	if (ret < 0) {
+		dev_err(&client->dev, "I2C transfer error\n");
+		return ret;
+	}
+
+	for (i = 0; i < len; i++) {
+		unsigned short temp;
+		temp = block_data[2 * i];
+		temp = (temp << 8) & 0xFF00;
+		*data++ = temp | block_data[2 * i + 1];
+	}
+
+	return ret;
+}
+
+static void ad7142_work(struct work_struct *work)
+{
+	struct ad7142_data *data = container_of(work,
+						struct ad7142_data,
+						work);
+	struct i2c_client *client = data->client;
+	struct input_dev *input = data->input;
+	unsigned short irqno_low, irqno_high;
+	unsigned short temp;
+
+	ad7142_i2c_read(client, INTSTAT_REG0, &irqno_low, 1);
+	temp = irqno_low ^ data->old_status_low;
+	switch (temp) {
+	case 0x0001:
+		input_report_key(input, BTN_BASE, (irqno_low & 0x0001));
+		break;
+	case 0x0002:
+		input_report_key(input, BTN_BASE4,
+					((irqno_low & 0x0002) >> 1));
+		break;
+	case 0x0004:
+		input_report_key(input, KEY_UP,
+					((irqno_low & 0x0004) >> 2));
+		break;
+	case 0x0008:
+		input_report_key(input, KEY_RIGHT,
+					((irqno_low & 0x0008) >> 3));
+		break;
+	}
+	data->old_status_low = irqno_low;
+
+	ad7142_i2c_read(client, INTSTAT_REG1, &irqno_high, 1);
+	temp = irqno_high ^ data->old_status_high;
+	switch (temp) {
+	case 0x0001:
+		input_report_key(input, BTN_BASE2, irqno_high & 0x0001);
+		break;
+	case 0x0002:
+		input_report_key(input, BTN_BASE3,
+					((irqno_high & 0x0002) >> 1));
+		break;
+	case 0x0004:
+		input_report_key(input, KEY_DOWN,
+					((irqno_high & 0x0004) >> 2));
+		break;
+	case 0x0008:
+		input_report_key(input, KEY_LEFT,
+					((irqno_high & 0x0008) >> 3));
+		break;
+	}
+	data->old_status_high = irqno_high;
+
+	input_sync(input);
+
+	enable_irq(client->irq);
+}
+
+static int ad7142_open(struct input_dev *dev)
+{
+	struct ad7142_data *data = input_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned short id, value;
+
+	ad7142_i2c_read(client, DEVID, &id, 1);
+	if (id != AD7142_I2C_ID) {
+		dev_err(&client->dev, "Open AD7142 error\n");
+		return -ENODEV;
+	}
+
+	ad7142_i2c_write(client, STAGE0_CONNECTION, stage[0], 8);
+	ad7142_i2c_write(client, STAGE1_CONNECTION, stage[1], 8);
+	ad7142_i2c_write(client, STAGE2_CONNECTION, stage[2], 8);
+	ad7142_i2c_write(client, STAGE3_CONNECTION, stage[3], 8);
+	ad7142_i2c_write(client, STAGE4_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE5_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE6_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE7_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE8_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE9_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE10_CONNECTION, stage[4], 8);
+	ad7142_i2c_write(client, STAGE11_CONNECTION, stage[4], 8);
+
+	/* In full power mode */
+	value = 0x00B0;
+	ad7142_i2c_write(client, PWRCONVCTL, &value, 1);
+
+	value = 0x0690;
+	ad7142_i2c_write(client, AMBCOMPCTL_REG1, &value, 1);
+
+	value = 0x0664;
+	ad7142_i2c_write(client, AMBCOMPCTL_REG2, &value, 1);
+
+	value = 0x290F;
+	ad7142_i2c_write(client, AMBCOMPCTL_REG3, &value, 1);
+
+	value = 0x000F;
+	ad7142_i2c_write(client, INTEN_REG0, &value, 1);
+	ad7142_i2c_write(client, INTEN_REG1, &value, 1);
+
+	value = 0x0000;
+	ad7142_i2c_write(client, INTEN_REG2, &value, 1);
+
+	ad7142_i2c_read(client, AMBCOMPCTL_REG1, &value, 1);
+
+	value = 0x000F;
+	ad7142_i2c_write(client, AMBCOMPCTL_REG0, &value, 1);
+
+	data->is_open = 1;
+	enable_irq(client->irq);
+	return 0;
+}
+
+static void ad7142_close(struct input_dev *dev)
+{
+	struct ad7142_data *data = input_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned short value;
+
+	disable_irq(client->irq);
+	data->is_open = 0;
+
+	flush_scheduled_work();
+
+	/*
+	 * Turn AD7142 to full shutdown mode
+	 * No CDC conversions
+	 */
+	value = 0x0001;
+	ad7142_i2c_write(client, PWRCONVCTL, &value, 1);
+}
+
+static int ad7142_probe(struct i2c_client *client)
+{
+	struct ad7142_data *data;
+	struct input_dev *input;
+	int rc;
+
+	/*
+	 * The ADV7142 has an autoincrement function,
+	 * use it if the adapter understands raw I2C
+	 */
+	rc = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);
+	if (!rc) {
+		dev_err(&client->dev,
+			"This bus doesn't support raw I2C operation\n");
+		return -EINVAL;
+	}
+
+	data = kzalloc(sizeof(struct ad7142_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->client = client;
+
+	i2c_set_clientdata(client, data);
+
+	/* Start workqueue for defer message transfer */
+	INIT_WORK(&data->work, ad7142_work);
+
+	if (client->irq > 0) {
+		rc = request_irq(client->irq, ad7142_interrupt,
+				IRQF_TRIGGER_LOW, "ad7142_joystick", data);
+		if (rc) {
+			dev_err(&client->dev, "Can't allocate irq %d\n",
+				client->irq);
+			goto fail_irq;
+		}
+	} else
+		dev_warn(&client->dev, "IRQ not configured!\n");
+
+	dev_info(&client->dev, "is attached at 0x%02x\n", client->addr);
+
+	/* Allocate and register AD7142 input device */
+	data->input = input_allocate_device();
+	if (!data->input) {
+		dev_err(&client->dev, "Can't allocate input device\n");
+		rc = -ENOMEM;
+		goto fail_allocate;
+	}
+
+	input = data->input;
+	input->open = ad7142_open;
+	input->close = ad7142_close;
+	input->evbit[0] = BIT_MASK(EV_KEY);
+	input->keybit[BIT_WORD(BTN_BASE)] = BIT_MASK(BTN_BASE) |
+						BIT_MASK(BTN_BASE2) |
+						BIT_MASK(BTN_BASE3) |
+						BIT_MASK(BTN_BASE4);
+	input->keybit[BIT_WORD(KEY_UP)] |=  BIT_MASK(KEY_UP) |
+						BIT_MASK(KEY_DOWN) |
+						BIT_MASK(KEY_LEFT) |
+						BIT_MASK(KEY_RIGHT);
+
+	input->name = "ad7142 joystick";
+	input->phys = "ad7142/input0";
+	input->id.bustype = BUS_I2C;
+	input->id.vendor = 0x0001;
+	input->id.product = 0x0001;
+	input->id.version = 0x0100;
+
+	input_set_drvdata(input, data);
+
+	rc = input_register_device(input);
+	if (rc) {
+		dev_err(&client->dev,
+			"Failed to register AD7142 input device!\n");
+		goto fail_register;
+	}
+
+	return 0;
+
+fail_register:
+	input_set_drvdata(input, NULL);
+	input_free_device(input);
+fail_allocate:
+	free_irq(client->irq, data);
+fail_irq:
+	i2c_set_clientdata(client, NULL);
+	kfree(data);
+	return rc;
+}
+
+static int __exit ad7142_remove(struct i2c_client *client)
+{
+	struct ad7142_data *data = i2c_get_clientdata(client);
+
+	if (client->irq > 0)
+		free_irq(client->irq, data);
+
+	flush_scheduled_work();
+
+	input_set_drvdata(data->input, NULL);
+	input_unregister_device(data->input);
+
+	kfree(data);
+
+	i2c_set_clientdata(client, NULL);
+	return 0;
+}
+
+static struct i2c_driver ad7142_driver = {
+	.driver = {
+		.name = "ad7142_joystick",
+	},
+	.probe = ad7142_probe,
+	.remove = __exit_p(ad7142_remove),
+};
+
+static int __init ad7142_init(void)
+{
+	return i2c_add_driver(&ad7142_driver);
+}
+
+static void __exit ad7142_exit(void)
+{
+	i2c_del_driver(&ad7142_driver);
+}
+
+module_init(ad7142_init);
+module_exit(ad7142_exit);
+
-- 
1.5.4.3

Re: [PATCH 1/1] Input/Joystick Driver: add support AD7142 joystick driver (v2)

[Dmitry Torokhov]

Hi Bryan,

On Thu, Mar 27, 2008 at 11:38:30AM -0700, Bryan Wu wrote:
> +	input->keybit[BIT_WORD(BTN_BASE)] = BIT_MASK(BTN_BASE) |
> +						BIT_MASK(BTN_BASE2) |
> +						BIT_MASK(BTN_BASE3) |
> +						BIT_MASK(BTN_BASE4);
> +	input->keybit[BIT_WORD(KEY_UP)] |=  BIT_MASK(KEY_UP) |
> +						BIT_MASK(KEY_DOWN) |
> +						BIT_MASK(KEY_LEFT) |
> +						BIT_MASK(KEY_RIGHT);
> +

Why don't you use REL_X/REL_Y to report directional movement? Using
buttons for that is pretty unusual.

-- 
Dmitry

Re: [PATCH 1/1] Input/Joystick Driver: add support AD7142 joystick driver (v2)

[Bryan Wu]

On Sat, Apr 19, 2008 at 1:15 AM, Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
> Hi Bryan,
>
>
>  On Thu, Mar 27, 2008 at 11:38:30AM -0700, Bryan Wu wrote:
>  > +     input->keybit[BIT_WORD(BTN_BASE)] = BIT_MASK(BTN_BASE) |
>  > +                                             BIT_MASK(BTN_BASE2) |
>  > +                                             BIT_MASK(BTN_BASE3) |
>  > +                                             BIT_MASK(BTN_BASE4);
>  > +     input->keybit[BIT_WORD(KEY_UP)] |=  BIT_MASK(KEY_UP) |
>  > +                                             BIT_MASK(KEY_DOWN) |
>  > +                                             BIT_MASK(KEY_LEFT) |
>  > +                                             BIT_MASK(KEY_RIGHT);
>  > +
>
>  Why don't you use REL_X/REL_Y to report directional movement? Using
>  buttons for that is pretty unusual.
>

In our development board, it includes UP/DOWN/LEFT/RIGHT 4 buttons. So
this driver matches this.
Please found some information about the hardware as below:
http://docs.blackfin.uclinux.org/doku.php?id=capacitance_touch_sensors&s[]=ad7142

Thanks
-Bryan

Re: [PATCH 1/1] Input/Joystick Driver: add support AD7142 joystick driver (v2)

[Dmitry Torokhov]

On Fri, Apr 25, 2008 at 06:09:52PM +0800, Bryan Wu wrote:
> On Sat, Apr 19, 2008 at 1:15 AM, Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> > Hi Bryan,
> >
> >
> >  On Thu, Mar 27, 2008 at 11:38:30AM -0700, Bryan Wu wrote:
> >  > +     input->keybit[BIT_WORD(BTN_BASE)] = BIT_MASK(BTN_BASE) |
> >  > +                                             BIT_MASK(BTN_BASE2) |
> >  > +                                             BIT_MASK(BTN_BASE3) |
> >  > +                                             BIT_MASK(BTN_BASE4);
> >  > +     input->keybit[BIT_WORD(KEY_UP)] |=  BIT_MASK(KEY_UP) |
> >  > +                                             BIT_MASK(KEY_DOWN) |
> >  > +                                             BIT_MASK(KEY_LEFT) |
> >  > +                                             BIT_MASK(KEY_RIGHT);
> >  > +
> >
> >  Why don't you use REL_X/REL_Y to report directional movement? Using
> >  buttons for that is pretty unusual.
> >
> 
> In our development board, it includes UP/DOWN/LEFT/RIGHT 4 buttons. So
> this driver matches this.
> Please found some information about the hardware as below:
> http://docs.blackfin.uclinux.org/doku.php?id=capacitance_touch_sensors&s[]=ad7142

What is the expected behaviur when a person touches one of these
buttons? Is it generatig a left/rigth mouse button clocks or moving a
pointer in some direction? Judging by the category of the devices you
are placing it in (joystick) it seems that latter is what you want,
therefore it should generate REL_X and REL_Y events. Otherwise it
should probably be called a button driver and live either in
drivers/input/keyboard or driver/input/misc. Do you agree?

Thanks.

-- 
Dmitry

Re: [PATCH 1/1] Input/Joystick Driver: add support AD7142 joystickdriver (v2)

[Robin Getz]

On Fri 25 Apr 2008 11:39, Dmitry Torokhov pondered:
> On Fri, Apr 25, 2008 at 06:09:52PM +0800, Bryan Wu wrote:
> > On Sat, Apr 19, 2008 at 1:15 AM, Dmitry Torokhov
> > <dmitry.torokhov@gmail.com> wrote:
> > > Hi Bryan,
> > >
> > >  Why don't you use REL_X/REL_Y to report directional movement? Using
> > >  buttons for that is pretty unusual.
> > >
> > 
> > In our development board, it includes UP/DOWN/LEFT/RIGHT 4 buttons. So
> > this driver matches this.
> > Please found some information about the hardware as below:
> >
> http://docs.blackfin.uclinux.org/doku.php?id=capacitance_touch_sensors&s
> []=ad7142
> 
> What is the expected behaviur when a person touches one of these
> buttons?

It depends on the design of the button on the target hardware. They can be 
pretty much any number of different shapes and sizes. Buttons, wheels, 
scroll-bar, joypad, and touchpad shapes can be laid out as traces on the 
sensor PCB. While we tested/wrote something for what we had hardware to 
verify, it is not restricted to this.

As Bryan indicated - have a look at:
http://docs.blackfin.uclinux.org/doku.php?id=capacitance_touch_sensors#overview

for a variety of options.

> Is it generatig a left/rigth mouse button clocks or moving a 
> pointer in some direction? Judging by the category of the devices you
> are placing it in (joystick) it seems that latter is what you want,
> therefore it should generate REL_X and REL_Y events. Otherwise it
> should probably be called a button driver and live either in
> drivers/input/keyboard or driver/input/misc. Do you agree?

If someone makes a joypad, it is a joypad. If someone makes a button, it is a 
button. The specific ad7142_work function will need to be modified to match 
the hardware design.

So, I am not sure where it should live - maybe driver/input/misc since it can 
be so many different things. The issue (in my mind) is how it gets exposed to 
userspace. If someone makes a joypad - they want it to show up as a joystick, 
so they don't have to modify any standard userspace applications to use it.

-Robin

Re: [PATCH 1/1] Input/Joystick Driver: add support AD7142 joystick driver (v2)

[Bryan Wu]

On Fri, Apr 25, 2008 at 11:39 PM, Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> On Fri, Apr 25, 2008 at 06:09:52PM +0800, Bryan Wu wrote:
>  > On Sat, Apr 19, 2008 at 1:15 AM, Dmitry Torokhov
>  > <dmitry.torokhov@gmail.com> wrote:
>  > > Hi Bryan,
>  > >
>  > >
>  > >  On Thu, Mar 27, 2008 at 11:38:30AM -0700, Bryan Wu wrote:
>  > >  > +     input->keybit[BIT_WORD(BTN_BASE)] = BIT_MASK(BTN_BASE) |
>  > >  > +                                             BIT_MASK(BTN_BASE2) |
>  > >  > +                                             BIT_MASK(BTN_BASE3) |
>  > >  > +                                             BIT_MASK(BTN_BASE4);
>  > >  > +     input->keybit[BIT_WORD(KEY_UP)] |=  BIT_MASK(KEY_UP) |
>  > >  > +                                             BIT_MASK(KEY_DOWN) |
>  > >  > +                                             BIT_MASK(KEY_LEFT) |
>  > >  > +                                             BIT_MASK(KEY_RIGHT);
>  > >  > +
>  > >
>  > >  Why don't you use REL_X/REL_Y to report directional movement? Using
>  > >  buttons for that is pretty unusual.
>  > >
>  >
>  > In our development board, it includes UP/DOWN/LEFT/RIGHT 4 buttons. So
>  > this driver matches this.
>  > Please found some information about the hardware as below:
>  > http://docs.blackfin.uclinux.org/doku.php?id=capacitance_touch_sensors&s[]=ad7142
>
>  What is the expected behaviur when a person touches one of these
>  buttons? Is it generatig a left/rigth mouse button clocks or moving a
>  pointer in some direction? Judging by the category of the devices you
>  are placing it in (joystick) it seems that latter is what you want,
>  therefore it should generate REL_X and REL_Y events. Otherwise it
>  should probably be called a button driver and live either in
>  drivers/input/keyboard or driver/input/misc. Do you agree?
>

AD7142 is a chip for input devices over i2c interface. So it can be a
joystick, joypad or other input devices.
And this driver is an example for real product driver developers.

Maybe drivers/input/misc is OK for this driver.

Thanks
-Bryan