[PATCH] HID: google: add google hammer HID driver

[Wei-Ning Huang <wnhuang@chromium.org>]

Add Google hammer HID driver. This driver allow us to control hammer
keyboard backlights and support future features.

Signed-off-by: Wei-Ning Huang <wnhuang@google.com>
---
 drivers/hid/Kconfig             |   6 +++
 drivers/hid/Makefile            |   1 +
 drivers/hid/hid-core.c          |   4 ++
 drivers/hid/hid-google-hammer.c | 108 ++++++++++++++++++++++++++++++++++++++++
 drivers/hid/hid-ids.h           |   3 ++
 5 files changed, 122 insertions(+)
 create mode 100644 drivers/hid/hid-google-hammer.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 3cd60f460b61..efc71acbcf5b 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -329,6 +329,12 @@ config HOLTEK_FF
 	  Say Y here if you have a Holtek On Line Grip based game controller
 	  and want to have force feedback support for it.
 
+config HID_GOOGLE_HAMMER
+	tristate "Google Hammer Keyboard"
+	depends on USB_HID && LEDS_CLASS
+	---help---
+	Say Y here if you have a Google Hammer device.
+
 config HID_GT683R
 	tristate "MSI GT68xR LED support"
 	depends on LEDS_CLASS && USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 8659d7e633a5..b5d3039286e3 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_HID_ELO)		+= hid-elo.o
 obj-$(CONFIG_HID_EZKEY)		+= hid-ezkey.o
 obj-$(CONFIG_HID_GEMBIRD)	+= hid-gembird.o
 obj-$(CONFIG_HID_GFRM)		+= hid-gfrm.o
+obj-$(CONFIG_HID_GOOGLE_HAMMER)	+= hid-google-hammer.o
 obj-$(CONFIG_HID_GT683R)	+= hid-gt683r.o
 obj-$(CONFIG_HID_GYRATION)	+= hid-gyration.o
 obj-$(CONFIG_HID_HOLTEK)	+= hid-holtek-kbd.o
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 9017dcc14502..3894e31a0c95 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2213,6 +2213,10 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_17) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_18) },
 #endif
+#if IS_ENABLED(CONFIG_HID_GOOGLE_HAMMER)
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
+#endif
 #if IS_ENABLED(CONFIG_HID_ORTEK)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_PKB1700) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_WKB2000) },
diff --git a/drivers/hid/hid-google-hammer.c b/drivers/hid/hid-google-hammer.c
new file mode 100644
index 000000000000..b6955f01c656
--- /dev/null
+++ b/drivers/hid/hid-google-hammer.c
@@ -0,0 +1,108 @@
+/*
+ *  HID driver for Google Hammer device.
+ *
+ *  Copyright (c) 2017 Google Inc.
+ *  Author: Wei-Ning Huang <wnhuang@google.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.
+ */
+
+#include <linux/hid.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+#define MAX_BRIGHTNESS 100
+
+struct hammer_kbd_leds {
+	struct led_classdev cdev;
+	struct hid_device *hdev;
+	u8 buf[2] ____cacheline_aligned;
+};
+
+static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
+		enum led_brightness br)
+{
+	struct hammer_kbd_leds *led = container_of(cdev,
+						   struct hammer_kbd_leds,
+						   cdev);
+	int ret;
+
+	led->buf[0] = 0;
+	led->buf[1] = br;
+
+	ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
+	if (ret == -ENOSYS)
+		ret = hid_hw_raw_request(led->hdev, 0, led->buf,
+					 sizeof(led->buf),
+					 HID_OUTPUT_REPORT,
+					 HID_REQ_SET_REPORT);
+	if (ret < 0)
+		hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
+			ret);
+	return ret;
+}
+
+static int hammer_register_leds(struct hid_device *hdev)
+{
+	struct hammer_kbd_leds *kbd_backlight;
+
+	kbd_backlight = devm_kzalloc(&hdev->dev,
+				     sizeof(*kbd_backlight),
+				     GFP_KERNEL);
+	if (!kbd_backlight)
+		return -ENOMEM;
+
+	kbd_backlight->hdev = hdev;
+	kbd_backlight->cdev.name = "hammer::kbd_backlight";
+	kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
+	kbd_backlight->cdev.brightness_set_blocking =
+		hammer_kbd_brightness_set_blocking;
+	kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
+
+	/* Set backlight to 0% initially. */
+	hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
+
+	return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
+}
+
+static int hammer_input_configured(struct hid_device *hdev,
+				   struct hid_input *hi)
+{
+	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+
+	if (intf->cur_altsetting->desc.bInterfaceProtocol ==
+	    USB_INTERFACE_PROTOCOL_KEYBOARD) {
+		int err = hammer_register_leds(hdev);
+
+		if (err)
+			hid_warn(hdev,
+				 "Failed to register keyboard backlight: %d\n",
+				 err);
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id hammer_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, hammer_devices);
+
+static struct hid_driver hammer_driver = {
+	.name = "hammer",
+	.id_table = hammer_devices,
+	.input_configured = hammer_input_configured,
+};
+module_hid_driver(hammer_driver);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index c9ba4c6db74c..193959700df8 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -434,7 +434,10 @@
 #define USB_DEVICE_ID_GOODTOUCH_000f	0x000f
 
 #define USB_VENDOR_ID_GOOGLE		0x18d1
+#define USB_DEVICE_ID_GOOGLE_QUICKSTEP	0x0477
+#define USB_DEVICE_ID_GOOGLE_HAMMER	0x5022
 #define USB_DEVICE_ID_GOOGLE_TOUCH_ROSE	0x5028
+#define USB_DEVICE_ID_GOOGLE_STAFF	0x502b
 
 #define USB_VENDOR_ID_GOTOP		0x08f2
 #define USB_DEVICE_ID_SUPER_Q2		0x007f
-- 
2.12.2