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Subject[PATCH] HID: google: add google hammer HID driver
Date
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.

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

Changes since v4:
- HID quirk is actually not necessary, as recent kernel always prefers
binding specialized drivers over hid-generic.
- Rework backlight detection, relying only on HID report descriptor. We
also make the test a little more specific, to make sure the output
descriptor is actually a backlight control.

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-google-hammer.c | 124 ++++++++++++++++++++++++++++++++
drivers/hid/hid-ids.h | 3 +
4 files changed, 134 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-google-hammer.c b/drivers/hid/hid-google-hammer.c
new file mode 100644
index 000000000000..6486469ce0f6
--- /dev/null
+++ b/drivers/hid/hid-google-hammer.c
@@ -0,0 +1,124 @@
+// 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 "hid-ids.h"
+
+#define MAX_BRIGHTNESS 100
+
+/* HID usage for keyboard backlight (Alphanumeric display brightness) */
+#define HID_AD_BRIGHTNESS 0x00140046
+
+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 list_head *report_list =
+ &hdev->report_enum[HID_OUTPUT_REPORT].report_list;
+ struct hid_report *report;
+
+ if (list_empty(report_list))
+ return 0;
+
+ report = list_first_entry(report_list, struct hid_report, list);
+
+ if (report->maxfield == 1 &&
+ report->field[0]->application == HID_GD_KEYBOARD &&
+ report->field[0]->maxusage == 1 &&
+ report->field[0]->usage[0].hid == HID_AD_BRIGHTNESS) {
+ 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,
+ USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
+ { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
+ USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
+ { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
+ 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
--
2.16.2.804.g6dcf76e118-goog
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