Input: add D-Link DIR-685 touchkeys driver

* D-Link DIR-685 Touchkeys

This is a I2C one-off touchkey controller based on the Cypress Semiconductor

CY8C214 MCU with some firmware in its internal 8KB flash. The circuit

board inside the router is named E119921.

The touchkey device node should be placed inside an I2C bus node.

Required properties:

- compatible: must be "dlink,dir685-touchkeys"

- reg: the I2C address of the touchkeys

- interrupts: reference to the interrupt number

Example:

touchkeys@26 {

	compatible = "dlink,dir685-touchkeys";

	reg = <0x26>;

	interrupt-parent = <&gpio0>;

	interrupts = <17 IRQ_TYPE_EDGE_FALLING>;

};

F:	drivers/input/touchscreen/cyttsp*

F:	include/linux/input/cyttsp.h

D-LINK DIR-685 TOUCHKEYS DRIVER

M:	Linus Walleij <linus.walleij@linaro.org>

L:	linux-input@vger.kernel.org

S:	Supported

F:	drivers/input/dlink-dir685-touchkeys.c

DALLAS/MAXIM DS1685-FAMILY REAL TIME CLOCK

M:	Joshua Kinard <kumba@gentoo.org>

S:	Maintained

	  To compile this driver as a module, choose M here: the

	  module will be called clps711x-keypad.

config KEYBOARD_DLINK_DIR685

	tristate "D-Link DIR-685 touchkeys support"

	depends on I2C

	default ARCH_GEMINI

	help

	  If you say yes here you get support for the D-Link DIR-685

	  touchkeys.

	  To compile this driver as a module, choose M here: the

	  module will be called dlink-dir685-touchkeys.

config KEYBOARD_LKKBD

	tristate "DECstation/VAXstation LK201/LK401 keyboard"

	select SERIO

obj-$(CONFIG_KEYBOARD_CLPS711X)		+= clps711x-keypad.o

obj-$(CONFIG_KEYBOARD_CROS_EC)		+= cros_ec_keyb.o

obj-$(CONFIG_KEYBOARD_DAVINCI)		+= davinci_keyscan.o

obj-$(CONFIG_KEYBOARD_DLINK_DIR685)	+= dlink-dir685-touchkeys.o

obj-$(CONFIG_KEYBOARD_EP93XX)		+= ep93xx_keypad.o

obj-$(CONFIG_KEYBOARD_GOLDFISH_EVENTS)	+= goldfish_events.o

obj-$(CONFIG_KEYBOARD_GPIO)		+= gpio_keys.o

/*

 * D-Link DIR-685 router I2C-based Touchkeys input driver

 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>

 *

 * This is a one-off touchkey controller based on the Cypress Semiconductor

 * CY8C214 MCU with some firmware in its internal 8KB flash. The circuit

 * board inside the router is named E119921

 */

#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/interrupt.h>

#include <linux/delay.h>

#include <linux/input.h>

#include <linux/slab.h>

#include <linux/bitops.h>

struct dir685_touchkeys {

	struct device		*dev;

	struct i2c_client	*client;

	struct input_dev	*input;

	unsigned long		cur_key;

	u16			codes[7];

};

static irqreturn_t dir685_tk_irq_thread(int irq, void *data)

{

	struct dir685_touchkeys *tk = data;

	const int num_bits = min_t(int, ARRAY_SIZE(tk->codes), 16);

	unsigned long changed;

	u8 buf[6];

	unsigned long key;

	int i;

	int err;

	memset(buf, 0, sizeof(buf));

	err = i2c_master_recv(tk->client, buf, sizeof(buf));

	if (err != sizeof(buf)) {

		dev_err(tk->dev, "short read %d\n", err);

		return IRQ_HANDLED;

	}

	dev_dbg(tk->dev, "IN: %*ph\n", (int)sizeof(buf), buf);

	key = be16_to_cpup((__be16 *) &buf[4]);

	/* Figure out if any bits went high or low since last message */

	changed = tk->cur_key ^ key;

	for_each_set_bit(i, &changed, num_bits) {

		dev_dbg(tk->dev, "key %d is %s\n", i,

			test_bit(i, &key) ? "down" : "up");

		input_report_key(tk->input, tk->codes[i], test_bit(i, &key));

	}

	/* Store currently down keys */

	tk->cur_key = key;

	input_sync(tk->input);

	return IRQ_HANDLED;

}

static int dir685_tk_probe(struct i2c_client *client,

			   const struct i2c_device_id *id)

{

	struct dir685_touchkeys *tk;

	struct device *dev = &client->dev;

	u8 bl_data[] = { 0xa7, 0x40 };

	int err;

	int i;

	tk = devm_kzalloc(&client->dev, sizeof(*tk), GFP_KERNEL);

	if (!tk)

		return -ENOMEM;

	tk->input = devm_input_allocate_device(dev);

	if (!tk->input)

		return -ENOMEM;

	tk->client = client;

	tk->dev = dev;

	tk->input->keycodesize = sizeof(u16);

	tk->input->keycodemax = ARRAY_SIZE(tk->codes);

	tk->input->keycode = tk->codes;

	tk->codes[0] = KEY_UP;

	tk->codes[1] = KEY_DOWN;

	tk->codes[2] = KEY_LEFT;

	tk->codes[3] = KEY_RIGHT;

	tk->codes[4] = KEY_ENTER;

	tk->codes[5] = KEY_WPS_BUTTON;

	/*

	 * This key appears in the vendor driver, but I have

	 * not been able to activate it.

	 */

	tk->codes[6] = KEY_RESERVED;

	__set_bit(EV_KEY, tk->input->evbit);

	for (i = 0; i < ARRAY_SIZE(tk->codes); i++)

		__set_bit(tk->codes[i], tk->input->keybit);

	__clear_bit(KEY_RESERVED, tk->input->keybit);

	tk->input->name = "D-Link DIR-685 touchkeys";

	tk->input->id.bustype = BUS_I2C;

	err = input_register_device(tk->input);

	if (err)

		return err;

	/* Set the brightness to max level */

	err = i2c_master_send(client, bl_data, sizeof(bl_data));

	if (err != sizeof(bl_data))

		dev_warn(tk->dev, "error setting brightness level\n");

	if (!client->irq) {

		dev_err(dev, "no IRQ on the I2C device\n");

		return -ENODEV;

	}

	err = devm_request_threaded_irq(dev, client->irq,

					NULL, dir685_tk_irq_thread,

					IRQF_ONESHOT,

					"dir685-tk", tk);

	if (err) {

		dev_err(dev, "can't request IRQ\n");

		return err;

	}

	return 0;

}

static const struct i2c_device_id dir685_tk_id[] = {

	{ "dir685tk", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, dir685_tk_id);

#ifdef CONFIG_OF

static const struct of_device_id dir685_tk_of_match[] = {

	{ .compatible = "dlink,dir685-touchkeys" },

	{},

};

MODULE_DEVICE_TABLE(of, dir685_tk_of_match);

#endif

static struct i2c_driver dir685_tk_i2c_driver = {

	.driver = {

		.name	= "dlin-dir685-touchkeys",

		.of_match_table = of_match_ptr(dir685_tk_of_match),

	},

	.probe		= dir685_tk_probe,

	.id_table	= dir685_tk_id,

};

module_i2c_driver(dir685_tk_i2c_driver);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");

MODULE_DESCRIPTION("D-Link DIR-685 touchkeys driver");

MODULE_LICENSE("GPL");