Input: add D-Link DIR-685 touchkeys driver

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

The vendor code calles this a "touchpad" but we are registering
it here under its real name.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

5 files changed, 194 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/dlink,dir685-touchkeys.txt b/Documentation/devicetree/bindings/input/dlink,dir685-touchkeys.txt
new file mode 100644
index 000000000000..10dec1c57abf
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/dlink,dir685-touchkeys.txt
@@ -0,0 +1,21 @@
+* 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>;
+};
diff --git a/MAINTAINERS b/MAINTAINERS
index 053c3bdd1fe5..98861181fb2a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3786,6 +3786,12 @@ S:	Supported
 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
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 97acd6524ad7..4c4ab1ced235 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -178,6 +178,17 @@ 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 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
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 7d9acff819a7..d2338bacdad1 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-$(CONFIG_KEYBOARD_DLINK_DIR685)     += dlink-dir685-touchkeys.o
 obj-$(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-touchkeys.c b/drivers/input/keyboard/dlink-dir685-touchkeys.c
new file mode 100644
index 000000000000..88e321b76397
--- /dev/null
+++ b/drivers/input/keyboard/dlink-dir685-touchkeys.c
@@ -0,0 +1,155 @@
+/*
+ * 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");