[PATCH 2/2] input: keyboard: Add D-Link DIR-685 touchpad driver

[Linus Walleij <linus.walleij@linaro.org>]

This adds support for the D-Link DIR-685 touchpad found in the
router with this name.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 MAINTAINERS                                    |   6 +
 drivers/input/keyboard/Kconfig                 |  12 ++
 drivers/input/keyboard/Makefile                |   1 +
 drivers/input/keyboard/dlink-dir685-touchpad.c | 181 +++++++++++++++++++++++++
 4 files changed, 200 insertions(+)
 create mode 100644 drivers/input/keyboard/dlink-dir685-touchpad.c

diff --git a/MAINTAINERS b/MAINTAINERS
index c265a5fe4848..95ef13b4ae71 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3730,6 +3730,12 @@ S:	Supported
 F:	drivers/input/touchscreen/cyttsp*
 F:	include/linux/input/cyttsp.h
 
+D-LINK DIR-685 TOUCHPAD DRIVER
+M:	Linus Walleij <linus.walleij@linaro.org>
+L:	linux-input@vger.kernel.org
+S:	Supported
+F:	drivers/input/dlink-dir685-touchpad.c
+
 DALLAS/MAXIM DS1685-FAMILY REAL TIME CLOCK
 M:	Joshua Kinard <kumba@gentoo.org>
 S:	Maintained
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 97acd6524ad7..06b19aa7cdf5 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -178,6 +178,18 @@ config KEYBOARD_CLPS711X
 	  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 touchpad support"
+	depends on I2C
+	depends on OF
+	default ARCH_GEMINI
+	help
+	  If you say yes here you get support for the D-Link DIR-685
+	  touchpad.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called dlink-dir685-touchpad.
+
 config KEYBOARD_LKKBD
 	tristate "DECstation/VAXstation LK201/LK401 keyboard"
 	select SERIO
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 7d9acff819a7..11c1fb5f2426 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_KEYBOARD_CAP11XX)		+= cap11xx.o
 obj-$(CONFIG_KEYBOARD_CLPS711X)		+= clps711x-keypad.o
 obj-$(CONFIG_KEYBOARD_CROS_EC)		+= cros_ec_keyb.o
 obj-$(CONFIG_KEYBOARD_DAVINCI)		+= davinci_keyscan.o
+obj-$(CONFIG_KEYBOARD_DLINK_DIR685)	+= dlink-dir685-touchpad.o
 obj-$(CONFIG_KEYBOARD_EP93XX)		+= ep93xx_keypad.o
 obj-$(CONFIG_KEYBOARD_GOLDFISH_EVENTS)	+= goldfish_events.o
 obj-$(CONFIG_KEYBOARD_GPIO)		+= gpio_keys.o
diff --git a/drivers/input/keyboard/dlink-dir685-touchpad.c b/drivers/input/keyboard/dlink-dir685-touchpad.c
new file mode 100644
index 000000000000..559e7e9a9340
--- /dev/null
+++ b/drivers/input/keyboard/dlink-dir685-touchpad.c
@@ -0,0 +1,181 @@
+/*
+ * D-Link DIR-685 router I2C-based Touchpad input driver
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * This is a one-off touchpad 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/mutex.h>
+#include <linux/delay.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+
+struct dir685_touchpad {
+	struct device		*dev;
+	struct i2c_client	*client;
+	struct input_dev	*input;
+	unsigned long		cur_key;
+	u16 *codes;
+};
+
+static const u16 dir685_tp_keycodes[] = {
+	KEY_UP,
+	KEY_DOWN,
+	KEY_LEFT,
+	KEY_RIGHT,
+	KEY_ENTER,
+	KEY_W,
+	KEY_O,
+};
+
+static irqreturn_t dir685_tp_irq_thread(int irq, void *data)
+{
+	struct dir685_touchpad *tp = data;
+	u8 buf[6];
+	unsigned long key;
+	int i;
+	int ret;
+
+	memset(buf, 0, sizeof(buf));
+	ret = i2c_master_recv(tp->client, buf, sizeof(buf));
+	if (ret != sizeof(buf)) {
+		dev_err(tp->dev, "short read %d\n", ret);
+		return IRQ_HANDLED;
+	}
+
+	dev_dbg(tp->dev, "IN: %02x, %02x, %02x, %02x, %02x, %02x\n",
+		buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
+	key  = buf[4] << 8 | buf[5];
+
+	/* Figure out if any bits went high since last message */
+	for_each_set_bit(i, &key, 16) {
+		if (!(tp->cur_key & BIT(i))) {
+			dev_dbg(tp->dev, "key %d down\n", i);
+			if (i < ARRAY_SIZE(dir685_tp_keycodes)) {
+				input_report_key(tp->input,
+						 tp->codes[i], 1);
+			}
+		}
+	}
+	/* Figure out if any bits went low since last message */
+	for_each_set_bit(i, &tp->cur_key, 16) {
+		if (!(key & BIT(i))) {
+			dev_dbg(tp->dev, "key %d up\n", i);
+			if (i < ARRAY_SIZE(dir685_tp_keycodes)) {
+				input_report_key(tp->input,
+						 tp->codes[i], 0);
+			}
+		}
+	}
+
+	/* Store currently down keys */
+	tp->cur_key = key;
+	input_sync(tp->input);
+
+	return IRQ_HANDLED;
+}
+
+static int dir685_tp_probe(struct i2c_client *client,
+				 const struct i2c_device_id *id)
+{
+	struct dir685_touchpad *tp;
+	struct device *dev = &client->dev;
+	u8 bl_data[] = { 0xa7, 0x40 };
+	int ret;
+	int i;
+
+	tp = devm_kzalloc(&client->dev, sizeof(*tp), GFP_KERNEL);
+	if (!tp)
+		return -ENOMEM;
+
+	tp->input = devm_input_allocate_device(dev);
+	if (!tp->input)
+		return -ENOMEM;
+
+	tp->client = client;
+	tp->dev = dev;
+
+	tp->input->keycodesize = sizeof(dir685_tp_keycodes[0]);
+	tp->input->keycodemax = ARRAY_SIZE(dir685_tp_keycodes);
+	tp->codes = devm_kmemdup(dev, dir685_tp_keycodes,
+			   tp->input->keycodesize * tp->input->keycodemax,
+			   GFP_KERNEL);
+	tp->input->keycode = tp->codes;
+
+	__set_bit(EV_KEY, tp->input->evbit);
+	for (i = 0; i < ARRAY_SIZE(dir685_tp_keycodes); i++)
+		__set_bit(dir685_tp_keycodes[i], tp->input->keybit);
+
+	tp->input->name = "D-Link DIR-685 touchpad";
+	input_set_drvdata(tp->input, tp);
+
+	ret = input_register_device(tp->input);
+	if (ret)
+		return ret;
+
+	/* Set up the brightness to max level */
+	ret = i2c_master_send(client, bl_data, sizeof(bl_data));
+	if (ret != sizeof(bl_data))
+		dev_err(tp->dev, "error setting up brightness level\n");
+
+	if (!client->irq) {
+		dev_err(dev, "no IRQ on the I2C device\n");
+		return -ENODEV;
+	}
+	ret = request_threaded_irq(client->irq, NULL,
+				   dir685_tp_irq_thread,
+				   IRQF_ONESHOT,
+				   "dir685-tp",
+				   tp);
+	if (ret) {
+		dev_err(dev, "can't request IRQ\n");
+		return ret;
+	}
+
+	i2c_set_clientdata(client, tp);
+
+	dev_info(tp->dev, "registered D-Link DIR-685 touchpad\n");
+	return 0;
+}
+
+static int dir685_tp_remove(struct i2c_client *client)
+{
+	struct dir685_touchpad *tp = i2c_get_clientdata(client);
+
+	input_unregister_device(tp->input);
+
+	return 0;
+}
+
+static const struct i2c_device_id dir685_tp_id[] = {
+	{ "dir685tp", 0 },
+	{ }
+};
+
+static const struct of_device_id dir685_tp_of_match[] = {
+	{ .compatible = "dlink,dir685-touchpad" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dir685_tp_of_match);
+
+static struct i2c_driver dir685_tp_i2c_driver = {
+	.driver = {
+		.name	= "dlin-dir685-touchpad",
+		.of_match_table = of_match_ptr(dir685_tp_of_match),
+	},
+	.probe		= dir685_tp_probe,
+	.remove		= dir685_tp_remove,
+	.id_table	= dir685_tp_id,
+};
+MODULE_DEVICE_TABLE(i2c, dir685_tp_id);
+
+module_i2c_driver(dir685_tp_i2c_driver);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("D-Link DIR-685 touchpad driver");
+MODULE_LICENSE("GPL");
-- 
2.9.3