HID: migrate USB LED driver from usb misc to hid

This patch migrates the USB LED driver to the HID subsystem.
Supported are Dream Cheeky Webmail Notifier / Friends Alert
and Riso Kagaku Webmail Notifier.

Benefits:
- Avoid using USB low-level calls and use the HID subsystem instead
  (as this device provides a USB HID interface)
- Use standard LED subsystem instead of proprietary sysfs entries,
  this allows e.g. to use the device with features like triggers

Successfully tested with a Dream Cheeky Webmail Notifier and a
Riso Kagaku Webmail Notifier compatible device.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 288 insertions, 0 deletions

diff --git a/drivers/hid/hid-led.c b/drivers/hid/hid-led.c
new file mode 100644
index 000000000000..43fb089a8cd5
--- /dev/null
+++ b/drivers/hid/hid-led.c
@@ -0,0 +1,288 @@
+/*
+ * Simple USB RGB LED driver
+ *
+ * Copyright 2016 Heiner Kallweit <hkallweit1@gmail.com>
+ * Based on drivers/hid/hid-thingm.c and
+ * drivers/usb/misc/usbled.c
+ *
+ * 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, version 2.
+ */
+
+#include <linux/hid.h>
+#include <linux/hidraw.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+#include "hid-ids.h"
+
+enum hidled_report_type {
+	RAW_REQUEST,
+	OUTPUT_REPORT
+};
+
+enum hidled_type {
+	RISO_KAGAKU,
+	DREAM_CHEEKY,
+};
+
+static unsigned const char riso_kagaku_tbl[] = {
+/* R+2G+4B -> riso kagaku color index */
+	[0] = 0, /* black   */
+	[1] = 2, /* red     */
+	[2] = 1, /* green   */
+	[3] = 5, /* yellow  */
+	[4] = 3, /* blue    */
+	[5] = 6, /* magenta */
+	[6] = 4, /* cyan    */
+	[7] = 7  /* white   */
+};
+
+#define RISO_KAGAKU_IX(r, g, b) riso_kagaku_tbl[((r)?1:0)+((g)?2:0)+((b)?4:0)]
+
+struct hidled_device;
+
+struct hidled_config {
+	enum hidled_type	type;
+	const char		*name;
+	const char		*short_name;
+	enum led_brightness	max_brightness;
+	size_t			report_size;
+	enum hidled_report_type	report_type;
+	u8			report_id;
+	int (*init)(struct hidled_device *ldev);
+	int (*write)(struct led_classdev *cdev, enum led_brightness br);
+};
+
+struct hidled_led {
+	struct led_classdev	cdev;
+	struct hidled_device	*ldev;
+	char			name[32];
+};
+
+struct hidled_device {
+	const struct hidled_config *config;
+	struct hidled_led	red;
+	struct hidled_led	green;
+	struct hidled_led	blue;
+	struct hid_device       *hdev;
+	struct mutex		lock;
+};
+
+#define MAX_REPORT_SIZE		16
+
+#define to_hidled_led(arg) container_of(arg, struct hidled_led, cdev)
+
+static bool riso_kagaku_switch_green_blue;
+module_param(riso_kagaku_switch_green_blue, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(riso_kagaku_switch_green_blue,
+	"switch green and blue RGB component for Riso Kagaku devices");
+
+static int hidled_send(struct hidled_device *ldev, __u8 *buf)
+{
+	int ret;
+
+	buf[0] = ldev->config->report_id;
+
+	mutex_lock(&ldev->lock);
+
+	if (ldev->config->report_type == RAW_REQUEST)
+		ret = hid_hw_raw_request(ldev->hdev, buf[0], buf,
+					 ldev->config->report_size,
+					 HID_FEATURE_REPORT,
+					 HID_REQ_SET_REPORT);
+	else if (ldev->config->report_type == OUTPUT_REPORT)
+		ret = hid_hw_output_report(ldev->hdev, buf,
+					   ldev->config->report_size);
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&ldev->lock);
+
+	if (ret < 0)
+		return ret;
+
+	return ret == ldev->config->report_size ? 0 : -EMSGSIZE;
+}
+
+static u8 riso_kagaku_index(struct hidled_device *ldev)
+{
+	enum led_brightness r, g, b;
+
+	r = ldev->red.cdev.brightness;
+	g = ldev->green.cdev.brightness;
+	b = ldev->blue.cdev.brightness;
+
+	if (riso_kagaku_switch_green_blue)
+		return RISO_KAGAKU_IX(r, b, g);
+	else
+		return RISO_KAGAKU_IX(r, g, b);
+}
+
+static int riso_kagaku_write(struct led_classdev *cdev, enum led_brightness br)
+{
+	struct hidled_led *led = to_hidled_led(cdev);
+	struct hidled_device *ldev = led->ldev;
+	__u8 buf[MAX_REPORT_SIZE] = {};
+
+	buf[1] = riso_kagaku_index(ldev);
+
+	return hidled_send(ldev, buf);
+}
+
+static int dream_cheeky_write(struct led_classdev *cdev, enum led_brightness br)
+{
+	struct hidled_led *led = to_hidled_led(cdev);
+	struct hidled_device *ldev = led->ldev;
+	__u8 buf[MAX_REPORT_SIZE] = {};
+
+	buf[1] = ldev->red.cdev.brightness;
+	buf[2] = ldev->green.cdev.brightness;
+	buf[3] = ldev->blue.cdev.brightness;
+	buf[7] = 0x1a;
+	buf[8] = 0x05;
+
+	return hidled_send(ldev, buf);
+}
+
+static int dream_cheeky_init(struct hidled_device *ldev)
+{
+	__u8 buf[MAX_REPORT_SIZE] = {};
+
+	/* Dream Cheeky magic */
+	buf[1] = 0x1f;
+	buf[2] = 0x02;
+	buf[4] = 0x5f;
+	buf[7] = 0x1a;
+	buf[8] = 0x03;
+
+	return hidled_send(ldev, buf);
+}
+
+static const struct hidled_config hidled_configs[] = {
+	{
+		.type = RISO_KAGAKU,
+		.name = "Riso Kagaku Webmail Notifier",
+		.short_name = "riso_kagaku",
+		.max_brightness = 1,
+		.report_size = 6,
+		.report_type = OUTPUT_REPORT,
+		.report_id = 0,
+		.write = riso_kagaku_write,
+	},
+	{
+		.type = DREAM_CHEEKY,
+		.name = "Dream Cheeky Webmail Notifier",
+		.short_name = "dream_cheeky",
+		.max_brightness = 31,
+		.report_size = 9,
+		.report_type = RAW_REQUEST,
+		.report_id = 0,
+		.init = dream_cheeky_init,
+		.write = dream_cheeky_write,
+	},
+};
+
+static int hidled_init_led(struct hidled_led *led, const char *color_name,
+			   struct hidled_device *ldev, unsigned int minor)
+{
+	snprintf(led->name, sizeof(led->name), "%s%u:%s",
+		 ldev->config->short_name, minor, color_name);
+	led->cdev.name = led->name;
+	led->cdev.max_brightness = ldev->config->max_brightness;
+	led->cdev.brightness_set_blocking = ldev->config->write;
+	led->cdev.flags = LED_HW_PLUGGABLE;
+	led->ldev = ldev;
+
+	return devm_led_classdev_register(&ldev->hdev->dev, &led->cdev);
+}
+
+static int hidled_init_rgb(struct hidled_device *ldev, unsigned int minor)
+{
+	int ret;
+
+	/* Register the red diode */
+	ret = hidled_init_led(&ldev->red, "red", ldev, minor);
+	if (ret)
+		return ret;
+
+	/* Register the green diode */
+	ret = hidled_init_led(&ldev->green, "green", ldev, minor);
+	if (ret)
+		return ret;
+
+	/* Register the blue diode */
+	return hidled_init_led(&ldev->blue, "blue", ldev, minor);
+}
+
+static int hidled_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct hidled_device *ldev;
+	unsigned int minor;
+	int ret, i;
+
+	ldev = devm_kzalloc(&hdev->dev, sizeof(*ldev), GFP_KERNEL);
+	if (!ldev)
+		return -ENOMEM;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	ldev->hdev = hdev;
+	mutex_init(&ldev->lock);
+
+	for (i = 0; !ldev->config && i < ARRAY_SIZE(hidled_configs); i++)
+		if (hidled_configs[i].type == id->driver_data)
+			ldev->config = &hidled_configs[i];
+
+	if (!ldev->config)
+		return -EINVAL;
+
+	if (ldev->config->init) {
+		ret = ldev->config->init(ldev);
+		if (ret)
+			return ret;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		return ret;
+
+	minor = ((struct hidraw *) hdev->hidraw)->minor;
+
+	ret = hidled_init_rgb(ldev, minor);
+	if (ret) {
+		hid_hw_stop(hdev);
+		return ret;
+	}
+
+	hid_info(hdev, "%s initialized\n", ldev->config->name);
+
+	return 0;
+}
+
+static const struct hid_device_id hidled_table[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_RISO_KAGAKU,
+	  USB_DEVICE_ID_RI_KA_WEBMAIL), .driver_data = RISO_KAGAKU },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DREAM_CHEEKY,
+	  USB_DEVICE_ID_DREAM_CHEEKY_WN), .driver_data = DREAM_CHEEKY },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DREAM_CHEEKY,
+	  USB_DEVICE_ID_DREAM_CHEEKY_FA), .driver_data = DREAM_CHEEKY },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, hidled_table);
+
+static struct hid_driver hidled_driver = {
+	.name = "hid-led",
+	.probe = hidled_probe,
+	.id_table = hidled_table,
+};
+
+module_hid_driver(hidled_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Heiner Kallweit <hkallweit1@gmail.com>");
+MODULE_DESCRIPTION("Simple USB RGB LED driver");