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");