HID: add ThingM blink(1) USB RGB LED support

The ThingM blink(1) is an open source hardware USB RGB LED. It contains
an internal EEPROM, allowing to configure up to 12 light patterns. A
light pattern is a RGB color plus a fade time. This driver registers a
LED class instance with additional sysfs attributes to support basic
functions such as setting RGB colors, fade and playing. Other functions
are still accessible through the hidraw interface.

At this time, the only documentation for the device is the firmware
source code from ThingM, plus a few schematics. They are available at:

https://github.com/todbot/blink1

This patch is version 3. It updates the name of the source file, the
driver and the led sysfs entry, according to comments from Jiri Kosina
and Simon Wood.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 272 insertions, 0 deletions

diff --git a/drivers/hid/hid-thingm.c b/drivers/hid/hid-thingm.c
new file mode 100644
index 00000000000..2055a52e9a2
--- /dev/null
+++ b/drivers/hid/hid-thingm.c
@@ -0,0 +1,272 @@
+/*
+ * ThingM blink(1) USB RGB LED driver
+ *
+ * Copyright 2013 Savoir-faire Linux Inc.
+ *	Vivien Didelot <vivien.didelot@savoirfairelinux.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, version 2.
+ */
+
+#include <linux/hid.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+#define BLINK1_CMD_SIZE		9
+
+#define blink1_rgb_to_r(rgb)	((rgb & 0xFF0000) >> 16)
+#define blink1_rgb_to_g(rgb)	((rgb & 0x00FF00) >> 8)
+#define blink1_rgb_to_b(rgb)	((rgb & 0x0000FF) >> 0)
+
+/**
+ * struct blink1_data - blink(1) device specific data
+ * @hdev:		HID device.
+ * @led_cdev:		LED class instance.
+ * @rgb:		8-bit per channel RGB notation.
+ * @fade:		fade time in hundredths of a second.
+ * @brightness:		brightness coefficient.
+ * @play:		play/pause in-memory patterns.
+ */
+struct blink1_data {
+	struct hid_device *hdev;
+	struct led_classdev led_cdev;
+	u32 rgb;
+	u16 fade;
+	u8 brightness;
+	bool play;
+};
+
+static int blink1_send_command(struct blink1_data *data,
+		u8 buf[BLINK1_CMD_SIZE])
+{
+	int ret;
+
+	hid_dbg(data->hdev, "command: %d%c%.2x%.2x%.2x%.2x%.2x%.2x%.2x\n",
+			buf[0], buf[1], buf[2], buf[3], buf[4],
+			buf[5], buf[6], buf[7], buf[8]);
+
+	ret = data->hdev->hid_output_raw_report(data->hdev, buf,
+			BLINK1_CMD_SIZE, HID_FEATURE_REPORT);
+
+	return ret < 0 ? ret : 0;
+}
+
+static int blink1_update_color(struct blink1_data *data)
+{
+	u8 buf[BLINK1_CMD_SIZE] = { 1, 'n', 0, 0, 0, 0, 0, 0, 0 };
+
+	if (data->brightness) {
+		unsigned int coef = DIV_ROUND_CLOSEST(255, data->brightness);
+
+		buf[2] = DIV_ROUND_CLOSEST(blink1_rgb_to_r(data->rgb), coef);
+		buf[3] = DIV_ROUND_CLOSEST(blink1_rgb_to_g(data->rgb), coef);
+		buf[4] = DIV_ROUND_CLOSEST(blink1_rgb_to_b(data->rgb), coef);
+	}
+
+	if (data->fade) {
+		buf[1] = 'c';
+		buf[5] = (data->fade & 0xFF00) >> 8;
+		buf[6] = (data->fade & 0x00FF);
+	}
+
+	return blink1_send_command(data, buf);
+}
+
+static void blink1_led_set(struct led_classdev *led_cdev,
+		enum led_brightness brightness)
+{
+	struct blink1_data *data = dev_get_drvdata(led_cdev->dev->parent);
+
+	data->brightness = brightness;
+	if (blink1_update_color(data))
+		hid_err(data->hdev, "failed to update color\n");
+}
+
+static enum led_brightness blink1_led_get(struct led_classdev *led_cdev)
+{
+	struct blink1_data *data = dev_get_drvdata(led_cdev->dev->parent);
+
+	return data->brightness;
+}
+
+static ssize_t blink1_show_rgb(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct blink1_data *data = dev_get_drvdata(dev->parent);
+
+	return sprintf(buf, "%.6X\n", data->rgb);
+}
+
+static ssize_t blink1_store_rgb(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct blink1_data *data = dev_get_drvdata(dev->parent);
+	long unsigned int rgb;
+	int ret;
+
+	ret = kstrtoul(buf, 16, &rgb);
+	if (ret)
+		return ret;
+
+	/* RGB triplet notation is 24-bit hexadecimal */
+	if (rgb > 0xFFFFFF)
+		return -EINVAL;
+
+	data->rgb = rgb;
+	ret = blink1_update_color(data);
+
+	return ret ? ret : count;
+}
+
+static DEVICE_ATTR(rgb, S_IRUGO | S_IWUSR, blink1_show_rgb, blink1_store_rgb);
+
+static ssize_t blink1_show_fade(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct blink1_data *data = dev_get_drvdata(dev->parent);
+
+	return sprintf(buf, "%d\n", data->fade * 10);
+}
+
+static ssize_t blink1_store_fade(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct blink1_data *data = dev_get_drvdata(dev->parent);
+	long unsigned int fade;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &fade);
+	if (ret)
+		return ret;
+
+	/* blink(1) accepts 16-bit fade time, number of 10ms ticks */
+	fade = DIV_ROUND_CLOSEST(fade, 10);
+	if (fade > 65535)
+		return -EINVAL;
+
+	data->fade = fade;
+
+	return count;
+}
+
+static DEVICE_ATTR(fade, S_IRUGO | S_IWUSR,
+		blink1_show_fade, blink1_store_fade);
+
+static ssize_t blink1_show_play(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct blink1_data *data = dev_get_drvdata(dev->parent);
+
+	return sprintf(buf, "%d\n", data->play);
+}
+
+static ssize_t blink1_store_play(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct blink1_data *data = dev_get_drvdata(dev->parent);
+	u8 cmd[BLINK1_CMD_SIZE] = { 1, 'p', 0, 0, 0, 0, 0, 0, 0 };
+	long unsigned int play;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &play);
+	if (ret)
+		return ret;
+
+	data->play = !!play;
+	cmd[2] = data->play;
+	ret = blink1_send_command(data, cmd);
+
+	return ret ? ret : count;
+}
+
+static DEVICE_ATTR(play, S_IRUGO | S_IWUSR,
+		blink1_show_play, blink1_store_play);
+
+static const struct attribute_group blink1_sysfs_group = {
+	.attrs = (struct attribute *[]) {
+		&dev_attr_rgb.attr,
+		&dev_attr_fade.attr,
+		&dev_attr_play.attr,
+		NULL
+	},
+};
+
+static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct blink1_data *data;
+	struct led_classdev *led;
+	char led_name[13];
+	int ret;
+
+	data = devm_kzalloc(&hdev->dev, sizeof(struct blink1_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	hid_set_drvdata(hdev, data);
+	data->hdev = hdev;
+	data->rgb = 0xFFFFFF; /* set a default white color */
+
+	ret = hid_parse(hdev);
+	if (ret)
+		goto error;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		goto error;
+
+	/* blink(1) serial numbers range is 0x1A001000 to 0x1A002FFF */
+	led = &data->led_cdev;
+	snprintf(led_name, sizeof(led_name), "blink1::%s", hdev->uniq + 4);
+	led->name = led_name;
+	led->brightness_set = blink1_led_set;
+	led->brightness_get = blink1_led_get;
+	ret = led_classdev_register(&hdev->dev, led);
+	if (ret)
+		goto stop;
+
+	ret = sysfs_create_group(&led->dev->kobj, &blink1_sysfs_group);
+	if (ret)
+		goto remove_led;
+
+	return 0;
+
+remove_led:
+	led_classdev_unregister(led);
+stop:
+	hid_hw_stop(hdev);
+error:
+	return ret;
+}
+
+static void thingm_remove(struct hid_device *hdev)
+{
+	struct blink1_data *data = hid_get_drvdata(hdev);
+	struct led_classdev *led = &data->led_cdev;
+
+	sysfs_remove_group(&led->dev->kobj, &blink1_sysfs_group);
+	led_classdev_unregister(led);
+	hid_hw_stop(hdev);
+}
+
+static const struct hid_device_id thingm_table[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_THINGM, USB_DEVICE_ID_BLINK1) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, thingm_table);
+
+static struct hid_driver thingm_driver = {
+	.name = "thingm",
+	.probe = thingm_probe,
+	.remove = thingm_remove,
+	.id_table = thingm_table,
+};
+
+module_hid_driver(thingm_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Vivien Didelot <vivien.didelot@savoirfairelinux.com>");
+MODULE_DESCRIPTION("ThingM blink(1) USB RGB LED driver");