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From:   Nicolas Boichat <drinkcat@chromium.org>
To:     Jiri Kosina <jikos@kernel.org>
Cc:     Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        groeck@chromium.org, dtor@chromium.org
Subject: [PATCH v4] HID: google: add google hammer HID driver
Date:   Wed, 14 Mar 2018 13:22:19 +0800
Message-Id: <20180314052219.224622-1-drinkcat@chromium.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Wei-Ning Huang <wnhuang@chromium.org>

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

We add a new HID quirk, that allows us to have the keyboard interface
to bind to google-hammer driver, while the touchpad interface can
bind to the multitouch driver.

Signed-off-by: Wei-Ning Huang <wnhuang@google.com>
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
---

Changes since v3:
 - Rebase on latest linux-next/master, which moved the quirk list from
   hid-core.c to hid-quirks.c. Also, completely rework the logic to make
   it possible to bind google-hammer driver to keyboard interface, and
   generic multitouch driver to touchpad interface, as it is much simpler
   to do now that quirks are read early in hid_add_device.
 - Add dynamic backlight detection support (only such devices have an
   output HID descriptor).
 - Add support for wand (one more USB product ID).
 - Add SPDX-License-Identifier, fix one minor formatting issue.

 drivers/hid/Kconfig             |   6 ++
 drivers/hid/Makefile            |   1 +
 drivers/hid/hid-core.c          |   4 ++
 drivers/hid/hid-google-hammer.c | 116 ++++++++++++++++++++++++++++++++
 drivers/hid/hid-ids.h           |   3 +
 drivers/hid/hid-quirks.c        |   5 ++
 include/linux/hid.h             |   2 +
 7 files changed, 137 insertions(+)
 create mode 100644 drivers/hid/hid-google-hammer.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 1fce4c94e5ac..60252fd796f6 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -339,6 +339,12 @@ 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 713601c7bfa6..17a8bd97da9d 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -45,6 +45,7 @@ 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 36af26c2565b..61c7d135d680 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2116,6 +2116,10 @@ int hid_add_device(struct hid_device *hdev)
 		ret = hid_scan_report(hdev);
 		if (ret)
 			hid_warn(hdev, "bad device descriptor (%d)\n", ret);
+
+		if (hdev->quirks & HID_QUIRK_NO_GENERIC &&
+				hdev->group == HID_GROUP_GENERIC)
+			hdev->group = HID_GROUP_GENERIC_OVERRIDE;
 	}
 
 	/* XXX hack, any other cleaner solution after the driver core
diff --git a/drivers/hid/hid-google-hammer.c b/drivers/hid/hid-google-hammer.c
new file mode 100644
index 000000000000..e7ad042a8464
--- /dev/null
+++ b/drivers/hid/hid-google-hammer.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  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);
+
+	struct list_head *report_list =
+		&hdev->report_enum[HID_OUTPUT_REPORT].report_list;
+
+	if (intf->cur_altsetting->desc.bInterfaceProtocol ==
+	    USB_INTERFACE_PROTOCOL_KEYBOARD && !list_empty(report_list)) {
+		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) },
+	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC_OVERRIDE,
+		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
+	{ }
+};
+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 41f227a841fb..5a3a7ead3012 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -448,7 +448,10 @@
 #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_DEVICE_ID_GOOGLE_WAND	0x502d
 
 #define USB_VENDOR_ID_GOTOP		0x08f2
 #define USB_DEVICE_ID_SUPER_Q2		0x007f
diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
index 587e2681a53f..d112a14da200 100644
--- a/drivers/hid/hid-quirks.c
+++ b/drivers/hid/hid-quirks.c
@@ -84,6 +84,11 @@ static const struct hid_device_id hid_quirks[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_FREESCALE, USB_DEVICE_ID_FREESCALE_MX28), HID_QUIRK_NOGET },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_FUTABA, USB_DEVICE_ID_LED_DISPLAY), HID_QUIRK_NO_INIT_REPORTS },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, USB_DEVICE_ID_GREENASIA_DUAL_USB_JOYPAD), HID_QUIRK_MULTI_INPUT },
+#if IS_ENABLED(CONFIG_HID_GOOGLE_HAMMER)
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER), HID_QUIRK_NO_GENERIC },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF), HID_QUIRK_NO_GENERIC },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND), HID_QUIRK_NO_GENERIC },
+#endif
 	{ HID_USB_DEVICE(USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_DRIVING), HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_FIGHTING), HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_FLYING), HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },
diff --git a/include/linux/hid.h b/include/linux/hid.h
index dfea5a656a1a..f2655265f8b5 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -340,6 +340,7 @@ struct hid_item {
 #define HID_QUIRK_NO_EMPTY_INPUT		0x00000100
 /* 0x00000200 reserved for backward compatibility, was NO_INIT_INPUT_REPORTS */
 #define HID_QUIRK_ALWAYS_POLL			0x00000400
+#define HID_QUIRK_NO_GENERIC			0x00000800
 #define HID_QUIRK_SKIP_OUTPUT_REPORTS		0x00010000
 #define HID_QUIRK_SKIP_OUTPUT_REPORT_ID		0x00020000
 #define HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP	0x00040000
@@ -359,6 +360,7 @@ 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
-- 
2.16.2.804.g6dcf76e118-goog