Input: add driver for Atmel AT42QT2160 Sensor Chip

This version only supports individual cells (no slide support yet).
The code has been tested on proprietary development ARM board, but
should work fine on other machines.
Signed-off-by: Raphael Derosso Pereira <raphaelpereira@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/keyboard/Kconfig

@@ -114,6 +114,16 @@ config KEYBOARD_ATKBD_RDI_KEYCODES
 	  right-hand column will be interpreted as the key shown in the
 	  left-hand column.
 
+config QT2160
+	tristate "Atmel AT42QT2160 Touch Sensor Chip"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for Atmel AT42QT2160 Touch
+	  Sensor chip as a keyboard input.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called qt2160.
+
 config KEYBOARD_BFIN
 	tristate "Blackfin BF54x keypad support"
 	depends on (BF54x && !BF544)

drivers/input/keyboard/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_KEYBOARD_OMAP)		+= omap-keypad.o
 obj-$(CONFIG_KEYBOARD_OPENCORES)	+= opencores-kbd.o
 obj-$(CONFIG_KEYBOARD_PXA27x)		+= pxa27x_keypad.o
 obj-$(CONFIG_KEYBOARD_PXA930_ROTARY)	+= pxa930_rotary.o
+obj-$(CONFIG_KEYBOARD_QT2160)		+= qt2160.o
 obj-$(CONFIG_KEYBOARD_SH_KEYSC)		+= sh_keysc.o
 obj-$(CONFIG_KEYBOARD_SPITZ)		+= spitzkbd.o
 obj-$(CONFIG_KEYBOARD_STOWAWAY)		+= stowaway.o

drivers/input/keyboard/qt2160.c

+/*
+ *  qt2160.c - Atmel AT42QT2160 Touch Sense Controller
+ *
+ *  Copyright (C) 2009 Raphael Derosso Pereira <raphaelpereira@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+
+#define QT2160_VALID_CHIPID  0x11
+
+#define QT2160_CMD_CHIPID     0
+#define QT2160_CMD_CODEVER    1
+#define QT2160_CMD_GSTAT      2
+#define QT2160_CMD_KEYS3      3
+#define QT2160_CMD_KEYS4      4
+#define QT2160_CMD_SLIDE      5
+#define QT2160_CMD_GPIOS      6
+#define QT2160_CMD_SUBVER     7
+#define QT2160_CMD_CALIBRATE  10
+
+#define QT2160_CYCLE_INTERVAL	(2*HZ)
+
+static unsigned char qt2160_key2code[] = {
+	KEY_0, KEY_1, KEY_2, KEY_3,
+	KEY_4, KEY_5, KEY_6, KEY_7,
+	KEY_8, KEY_9, KEY_A, KEY_B,
+	KEY_C, KEY_D, KEY_E, KEY_F,
+};
+
+struct qt2160_data {
+	struct i2c_client *client;
+	struct input_dev *input;
+	struct delayed_work dwork;
+	spinlock_t lock;        /* Protects canceling/rescheduling of dwork */
+	unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
+	u16 key_matrix;
+};
+
+static int qt2160_read_block(struct i2c_client *client,
+			     u8 inireg, u8 *buffer, unsigned int count)
+{
+	int error, idx = 0;
+
+	/*
+	 * Can't use SMBus block data read. Check for I2C functionality to speed
+	 * things up whenever possible. Otherwise we will be forced to read
+	 * sequentially.
+	 */
+	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))	{
+
+		error = i2c_smbus_write_byte(client, inireg + idx);
+		if (error) {
+			dev_err(&client->dev,
+				"couldn't send request. Returned %d\n", error);
+			return error;
+		}
+
+		error = i2c_master_recv(client, buffer, count);
+		if (error != count) {
+			dev_err(&client->dev,
+				"couldn't read registers. Returned %d bytes\n", error);
+			return error;
+		}
+	} else {
+
+		while (count--) {
+			int data;
+
+			error = i2c_smbus_write_byte(client, inireg + idx);
+			if (error) {
+				dev_err(&client->dev,
+					"couldn't send request. Returned %d\n", error);
+				return error;
+			}
+
+			data = i2c_smbus_read_byte(client);
+			if (data < 0) {
+				dev_err(&client->dev,
+					"couldn't read register. Returned %d\n", data);
+				return data;
+			}
+
+			buffer[idx++] = data;
+		}
+	}
+
+	return 0;
+}
+
+static int qt2160_get_key_matrix(struct qt2160_data *qt2160)
+{
+	struct i2c_client *client = qt2160->client;
+	struct input_dev *input = qt2160->input;
+	u8 regs[6];
+	u16 old_matrix, new_matrix;
+	int ret, i, mask;
+
+	dev_dbg(&client->dev, "requesting keys...\n");
+
+	/*
+	 * Read all registers from General Status Register
+	 * to GPIOs register
+	 */
+	ret = qt2160_read_block(client, QT2160_CMD_GSTAT, regs, 6);
+	if (ret) {
+		dev_err(&client->dev,
+			"could not perform chip read.\n");
+		return ret;
+	}
+
+	old_matrix = qt2160->key_matrix;
+	qt2160->key_matrix = new_matrix = (regs[2] << 8) | regs[1];
+
+	mask = 0x01;
+	for (i = 0; i < 16; ++i, mask <<= 1) {
+		int keyval = new_matrix & mask;
+
+		if ((old_matrix & mask) != keyval) {
+			input_report_key(input, qt2160->keycodes[i], keyval);
+			dev_dbg(&client->dev, "key %d %s\n",
+				i, keyval ? "pressed" : "released");
+		}
+	}
+
+	input_sync(input);
+
+	return 0;
+}
+
+static irqreturn_t qt2160_irq(int irq, void *_qt2160)
+{
+	struct qt2160_data *qt2160 = _qt2160;
+	unsigned long flags;
+
+	spin_lock_irqsave(&qt2160->lock, flags);
+
+	__cancel_delayed_work(&qt2160->dwork);
+	schedule_delayed_work(&qt2160->dwork, 0);
+
+	spin_unlock_irqrestore(&qt2160->lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static void qt2160_schedule_read(struct qt2160_data *qt2160)
+{
+	spin_lock_irq(&qt2160->lock);
+	schedule_delayed_work(&qt2160->dwork, QT2160_CYCLE_INTERVAL);
+	spin_unlock_irq(&qt2160->lock);
+}
+
+static void qt2160_worker(struct work_struct *work)
+{
+	struct qt2160_data *qt2160 =
+		container_of(work, struct qt2160_data, dwork.work);
+
+	dev_dbg(&qt2160->client->dev, "worker\n");
+
+	qt2160_get_key_matrix(qt2160);
+
+	/* Avoid device lock up by checking every so often */
+	qt2160_schedule_read(qt2160);
+}
+
+static int __devinit qt2160_read(struct i2c_client *client, u8 reg)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte(client, reg);
+	if (ret) {
+		dev_err(&client->dev,
+			"couldn't send request. Returned %d\n", ret);
+		return ret;
+	}
+
+	ret = i2c_smbus_read_byte(client);
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"couldn't read register. Returned %d\n", ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int __devinit qt2160_write(struct i2c_client *client, u8 reg, u8 data)
+{
+	int error;
+
+	error = i2c_smbus_write_byte(client, reg);
+	if (error) {
+		dev_err(&client->dev,
+			"couldn't send request. Returned %d\n", error);
+		return error;
+	}
+
+	error = i2c_smbus_write_byte(client, data);
+	if (error) {
+		dev_err(&client->dev,
+			"couldn't write data. Returned %d\n", error);
+		return error;
+	}
+
+	return error;
+}
+
+
+static bool __devinit qt2160_identify(struct i2c_client *client)
+{
+	int id, ver, rev;
+
+	/* Read Chid ID to check if chip is valid */
+	id = qt2160_read(client, QT2160_CMD_CHIPID);
+	if (id != QT2160_VALID_CHIPID) {
+		dev_err(&client->dev, "ID %d not supported\n", id);
+		return false;
+	}
+
+	/* Read chip firmware version */
+	ver = qt2160_read(client, QT2160_CMD_CODEVER);
+	if (ver < 0) {
+		dev_err(&client->dev, "could not get firmware version\n");
+		return false;
+	}
+
+	/* Read chip firmware revision */
+	rev = qt2160_read(client, QT2160_CMD_SUBVER);
+	if (rev < 0) {
+		dev_err(&client->dev, "could not get firmware revision\n");
+		return false;
+	}
+
+	dev_info(&client->dev, "AT42QT2160 firmware version %d.%d.%d\n",
+			ver >> 4, ver & 0xf, rev);
+
+	return true;
+}
+
+static int __devinit qt2160_probe(struct i2c_client *client,
+				  const struct i2c_device_id *id)
+{
+	struct qt2160_data *qt2160;
+	struct input_dev *input;
+	int i;
+	int error;
+
+	/* Check functionality */
+	error = i2c_check_functionality(client->adapter,
+			I2C_FUNC_SMBUS_BYTE);
+	if (!error) {
+		dev_err(&client->dev, "%s adapter not supported\n",
+				dev_driver_string(&client->adapter->dev));
+		return -ENODEV;
+	}
+
+	if (!qt2160_identify(client))
+		return -ENODEV;
+
+	/* Chip is valid and active. Allocate structure */
+	qt2160 = kzalloc(sizeof(struct qt2160_data), GFP_KERNEL);
+	input = input_allocate_device();
+	if (!qt2160 || !input) {
+		dev_err(&client->dev, "insufficient memory\n");
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	qt2160->client = client;
+	qt2160->input = input;
+	INIT_DELAYED_WORK(&qt2160->dwork, qt2160_worker);
+	spin_lock_init(&qt2160->lock);
+
+	input->name = "AT42QT2160 Touch Sense Keyboard";
+	input->id.bustype = BUS_I2C;
+
+	input->keycode = qt2160->keycodes;
+	input->keycodesize = sizeof(qt2160->keycodes[0]);
+	input->keycodemax = ARRAY_SIZE(qt2160_key2code);
+
+	__set_bit(EV_KEY, input->evbit);
+	__clear_bit(EV_REP, input->evbit);
+	for (i = 0; i < ARRAY_SIZE(qt2160_key2code); i++) {
+		qt2160->keycodes[i] = qt2160_key2code[i];
+		__set_bit(qt2160_key2code[i], input->keybit);
+	}
+	__clear_bit(KEY_RESERVED, input->keybit);
+
+	/* Calibrate device */
+	error = qt2160_write(client, QT2160_CMD_CALIBRATE, 1);
+	if (error) {
+		dev_err(&client->dev, "failed to calibrate device\n");
+		goto err_free_mem;
+	}
+
+	if (client->irq) {
+		error = request_irq(client->irq, qt2160_irq,
+				    IRQF_TRIGGER_FALLING, "qt2160", qt2160);
+		if (error) {
+			dev_err(&client->dev,
+				"failed to allocate irq %d\n", client->irq);
+			goto err_free_mem;
+		}
+	}
+
+	error = input_register_device(qt2160->input);
+	if (error) {
+		dev_err(&client->dev,
+			"Failed to register input device\n");
+		goto err_free_irq;
+	}
+
+	i2c_set_clientdata(client, qt2160);
+	qt2160_schedule_read(qt2160);
+
+	return 0;
+
+err_free_irq:
+	if (client->irq)
+		free_irq(client->irq, qt2160);
+err_free_mem:
+	input_free_device(input);
+	kfree(qt2160);
+	return error;
+}
+
+static int __devexit qt2160_remove(struct i2c_client *client)
+{
+	struct qt2160_data *qt2160 = i2c_get_clientdata(client);
+
+	/* Release IRQ so no queue will be scheduled */
+	if (client->irq)
+		free_irq(client->irq, qt2160);
+
+	cancel_delayed_work_sync(&qt2160->dwork);
+
+	input_unregister_device(qt2160->input);
+	kfree(qt2160);
+
+	i2c_set_clientdata(client, NULL);
+	return 0;
+}
+
+static struct i2c_device_id qt2160_idtable[] = {
+	{ "qt2160", 0, },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, qt2160_idtable);
+
+static struct i2c_driver qt2160_driver = {
+	.driver = {
+		.name	= "qt2160",
+		.owner  = THIS_MODULE,
+	},
+
+	.id_table	= qt2160_idtable,
+	.probe		= qt2160_probe,
+	.remove		= __devexit_p(qt2160_remove),
+};
+
+static int __init qt2160_init(void)
+{
+	return i2c_add_driver(&qt2160_driver);
+}
+module_init(qt2160_init);
+
+static void __exit qt2160_cleanup(void)
+{
+	i2c_del_driver(&qt2160_driver);
+}
+module_exit(qt2160_cleanup);
+
+MODULE_AUTHOR("Raphael Derosso Pereira <raphaelpereira@gmail.com>");
+MODULE_DESCRIPTION("Driver for AT42QT2160 Touch Sensor");
+MODULE_LICENSE("GPL");