[PATCH v2 1/1] HID: Logitech K290: Add driver for the Logitech K290 USB keyboard

[Florent Flament <contact@florentflament.com>]

With the generic HID driver, K290 keyboards' F1 to F12 keys send
multimedia events by default, and standard keycodes when the function
key is pressed. This driver allows to configure K290 keyboards, so
that F1 to F12 have a standard behavior and send multimedia events
when the function key is pressed. The keyboard mode is set through the
fn_mode module parameter: when set to 1 (default setting) the keyboard
behaves as with the generic HID driver, when set to 0 the keyboard is
configured to work as standard keyboards.

Signed-off-by: Florent Flament <contact@florentflament.com>
---
 drivers/hid/Kconfig             |  18 ++++++++
 drivers/hid/Makefile            |   1 +
 drivers/hid/hid-ids.h           |   1 +
 drivers/hid/hid-logitech-k290.c | 100 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 120 insertions(+)
 create mode 100644 drivers/hid/hid-logitech-k290.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 19c499f5623d..6686da8daac6 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -488,6 +488,24 @@ config HID_LOGITECH_HIDPP
 	T651, TK820), some mice (Zone Touch mouse), or even keyboards (Solar
 	Keyboard).
 
+config HID_LOGITECH_K290
+	tristate "Logitech K290 Keyboard support"
+	depends on USB_HID
+	---help---
+	This enhances support of Logitech K290 keyboards.
+
+	With the generic HID driver, K290 keyboards' F1 to F12 keys
+	send multimedia events by default, and standard keycodes when
+	the function key is pressed. This driver allows to configure
+	K290 keyboards, so that F1 to F12 have a standard behavior and
+	send multimedia events when the function key is pressed. The
+	keyboard mode is set through the fn_mode module parameter:
+	when set to 1 (default setting) the keyboard behaves as with
+	the generic HID driver, when set to 0 the keyboard is
+	configured to work as standard keyboards.
+
+	Say Y if you have a Logitech K290 keyboard.
+
 config LOGITECH_FF
 	bool "Logitech force feedback support"
 	depends on HID_LOGITECH
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index eb13b9e92d85..78079d3a5d58 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_HID_LENOVO)	+= hid-lenovo.o
 obj-$(CONFIG_HID_LOGITECH)	+= hid-logitech.o
 obj-$(CONFIG_HID_LOGITECH_DJ)	+= hid-logitech-dj.o
 obj-$(CONFIG_HID_LOGITECH_HIDPP)	+= hid-logitech-hidpp.o
+obj-$(CONFIG_HID_LOGITECH_K290)	+= hid-logitech-k290.o
 obj-$(CONFIG_HID_MAGICMOUSE)	+= hid-magicmouse.o
 obj-$(CONFIG_HID_MAYFLASH)	+= hid-mf.o
 obj-$(CONFIG_HID_MICROSOFT)	+= hid-microsoft.o
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 9454ac134ce2..68caba7e666c 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -693,6 +693,7 @@
 #define USB_DEVICE_ID_LOGITECH_HARMONY_LAST 0xc14f
 #define USB_DEVICE_ID_LOGITECH_HARMONY_PS3 0x0306
 #define USB_DEVICE_ID_LOGITECH_KEYBOARD_G710_PLUS 0xc24d
+#define USB_DEVICE_ID_LOGITECH_KEYBOARD_K290	0xc31f
 #define USB_DEVICE_ID_LOGITECH_MOUSE_C01A	0xc01a
 #define USB_DEVICE_ID_LOGITECH_MOUSE_C05A	0xc05a
 #define USB_DEVICE_ID_LOGITECH_MOUSE_C06A	0xc06a
diff --git a/drivers/hid/hid-logitech-k290.c b/drivers/hid/hid-logitech-k290.c
new file mode 100644
index 000000000000..36fdb5838842
--- /dev/null
+++ b/drivers/hid/hid-logitech-k290.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * HID driver for Logitech K290 keyboard
+ *
+ * Copyright (c) 2018 Florent Flament
+ *
+ * This drivers allows to configure the K290 keyboard's function key
+ * behaviour (whether function mode is activated or not by default).
+ *
+ * Logitech custom commands taken from Marcus Ilgner k290-fnkeyctl
+ * (https://github.com/milgner/k290-fnkeyctl):
+ * K290_SET_FUNCTION_CMD
+ * K290_SET_FUNCTION_VAL
+ * K290_SET_FUNCTION_OFF
+ * K290_SET_FUNCTION_ON
+ *
+ * Based on hid-accutouch.c and hid-elo.c
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/stat.h>
+#include <linux/types.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+#include "usbhid/usbhid.h"
+
+// Logitech K290 custom USB command and value to setup function key
+#define K290_SET_FUNCTION_CMD 0x02
+#define K290_SET_FUNCTION_VAL 0x001a
+
+// Have function mode turned off (as with standard keyboards)
+#define K290_SET_FUNCTION_OFF 0x0001
+// Have function mode turned on (default k290 behavior)
+#define K290_SET_FUNCTION_ON  0x0000
+
+// Function key default mode is set at module load time for every K290
+// keyboards plugged on the machine. By default fn_mode = 1, i.e
+// sending K290_SET_FUNCTION_ON (default K290 behavior).
+static bool fn_mode = 1;
+module_param(fn_mode, bool, 0444);
+MODULE_PARM_DESC(fn_mode, "Logitech K290 function key mode (default = 1)");
+
+static void k290_set_function(struct usb_device *dev, uint16_t function_mode)
+{
+	int ret;
+
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      K290_SET_FUNCTION_CMD,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      K290_SET_FUNCTION_VAL,
+			      function_mode, 0, 0, USB_CTRL_SET_TIMEOUT);
+
+	if (ret < 0)
+		dev_err(&dev->dev,
+			"Failed to setup K290 function key, error %d\n", ret);
+}
+
+static int k290_set_function_hid_device(struct hid_device *hid)
+{
+	struct usb_device *usb_dev = hid_to_usb_dev(hid);
+
+	k290_set_function(usb_dev,
+			fn_mode ? K290_SET_FUNCTION_ON : K290_SET_FUNCTION_OFF);
+	return 0;
+}
+
+static int k290_input_configured(struct hid_device *hid,
+				 struct hid_input *hidinput)
+{
+	return k290_set_function_hid_device(hid);
+}
+
+static int k290_resume(struct hid_device *hid)
+{
+	return k290_set_function_hid_device(hid);
+}
+
+static const struct hid_device_id k290_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
+			 USB_DEVICE_ID_LOGITECH_KEYBOARD_K290) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, k290_devices);
+
+static struct hid_driver k290_driver = {
+	.name = "hid-logitech-k290",
+	.id_table = k290_devices,
+	.input_configured = k290_input_configured,
+	.resume = k290_resume,
+	.reset_resume = k290_resume,
+};
+
+module_hid_driver(k290_driver);
+
+MODULE_AUTHOR("Florent Flament <contact@florentflament.com>");
+MODULE_DESCRIPTION("Logitech K290 keyboard driver");
+MODULE_LICENSE("GPL v2");
-- 
2.14.3