HID: google: add google hammer HID driver

From: Wei-Ning Huang <[email protected]>

Add Google hammer HID driver. This driver allow us to control hammer keyboard backlights and support future features. Since current hid-core logic does not allow us to specify different USB interface for binding different driver, some code are added in HID core to allow us to bind the touchpad to multitouch driver, and bind keyboard to the hammer driver and the same time.

Signed-off-by Wei-Ning Huang <[email protected]>

Reviewed-by Dmitry Torokhov <[email protected]>

---

 drivers/hid/Kconfig             |   6 +++
 drivers/hid/Makefile            |   1 +
 drivers/hid/hid-core.c          |  33 ++++++++++--
 drivers/hid/hid-google-hammer.c | 110 ++++++++++++++++++++++++++++++++++++++++
 drivers/hid/hid-ids.h           |   2 +
 include/linux/hid.h             |   1 +
 6 files changed, 148 insertions(+), 5 deletions(-)
 create mode 100644 drivers/hid/hid-google-hammer.c

drivers/hid/Kconfig +6 -0

index 0a3117cc29e7..5373887f056e 100644
@@ -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

drivers/hid/Makefile +1 -0

index 8659d7e633a5..b5d3039286e3 100644
@@ -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

drivers/hid/hid-core.c +0 -0

index 9bc91160819b..78d2dbc74cce 100644

drivers/hid/hid-core.c +26 -5

+ * that some of the interfaces on the bus should not use the generic hid driver.
+ */
+#define QUIRK_NO_HID_GENERIC BIT(0)
+
 int hid_debug = 0;
 module_param_named(debug, hid_debug, int, 0600);
 MODULE_PARM_DESC(debug, "toggle HID debugging messages");

@@ -2053,6 +2059,12 @@ static const struct hid_device_id hid_have_special_driver[] = {
 #if IS_ENABLED(CONFIG_HID_GREENASIA)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, 0x0012) },
 #endif
+#if IS_ENABLED(CONFIG_HID_GOOGLE_HAMMER)
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER),
+	  .driver_data = QUIRK_NO_HID_GENERIC },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF),
+	  .driver_data = QUIRK_NO_HID_GENERIC },
+#endif
 #if IS_ENABLED(CONFIG_HID_GT683R)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_MSI, USB_DEVICE_ID_MSI_GT683R_LED_PANEL) },
 #endif

@@ -2952,11 +2964,22 @@ int hid_add_device(struct hid_device *hdev)
 	 */
 	if (hid_ignore_special_drivers) {
 		hdev->group = HID_GROUP_GENERIC;
-	} else if (!hdev->group &&
-		   !hid_match_id(hdev, hid_have_special_driver)) {
-		ret = hid_scan_report(hdev);
-		if (ret)
-			hid_warn(hdev, "bad device descriptor (%d)\n", ret);
+	} else if (!hdev->group) {
+		const struct hid_device_id *matched_id = hid_match_id(
+			hdev, hid_have_special_driver);
+
+		if (!matched_id ||
+		    matched_id->driver_data & QUIRK_NO_HID_GENERIC) {
+			ret = hid_scan_report(hdev);
+			if (ret)
+				hid_warn(hdev, "bad device descriptor (%d)\n",
+					 ret);
+
+			if (matched_id &&
+			    matched_id->driver_data & QUIRK_NO_HID_GENERIC &&
+			    hdev->group == HID_GROUP_GENERIC)
+				hdev->group = HID_GROUP_GENERIC_OVERRIDE;
+		}
 	}
 
 	/* XXX hack, any other cleaner solution after the driver core

drivers/hid/hid-google-hammer.c new file +110 -0

new file mode 100644
index 000000000000..4d301e1a6707
@@ -0,0 +1,110 @@
+/*
+ *  HID driver for Google Hammer device.
+ *
+ *  Copyright (c) 2017 Google Inc.
+ *  Author: Wei-Ning Huang <[email protected]>
+ */
+
+/*
+ * 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_DEVICE(BUS_USB, HID_GROUP_GENERIC_OVERRIDE,
+		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
+	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC_OVERRIDE,
+		     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");

drivers/hid/hid-ids.h +2 -0

index b397a14ab970..112ae4053321 100644
@@ -436,7 +436,9 @@
 #define USB_DEVICE_ID_GOODTOUCH_000f	0x000f
 
 #define USB_VENDOR_ID_GOOGLE		0x18d1
+#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

include/linux/hid.h +1 -0

index ab05a86269dc..e34430cfc8b8 100644
@@ -356,6 +356,7 @@ struct hid_item {
 #define HID_GROUP_MULTITOUCH			0x0002
 #define HID_GROUP_SENSOR_HUB			0x0003
 #define HID_GROUP_MULTITOUCH_WIN_8		0x0004
+#define HID_GROUP_GENERIC_OVERRIDE		0x0005
 
 /*
  * Vendor specific HID device groups