root/drivers/hid/hid-picolcd_leds.c
// SPDX-License-Identifier: GPL-2.0-only
/***************************************************************************
 *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
 *                                                                         *
 *   Based on Logitech G13 driver (v0.4)                                   *
 *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
 *                                                                         *
 ***************************************************************************/

#include <linux/hid.h>
#include <linux/hid-debug.h>
#include <linux/input.h>
#include "hid-ids.h"

#include <linux/fb.h>
#include <linux/vmalloc.h>
#include <linux/backlight.h>
#include <linux/lcd.h>

#include <linux/leds.h>

#include <linux/seq_file.h>
#include <linux/debugfs.h>

#include <linux/completion.h>
#include <linux/uaccess.h>
#include <linux/module.h>

#include "hid-picolcd.h"


void picolcd_leds_set(struct picolcd_data *data)
{
        struct hid_report *report;
        unsigned long flags;

        if (!data->led[0])
                return;
        report = picolcd_out_report(REPORT_LED_STATE, data->hdev);
        if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
                return;

        spin_lock_irqsave(&data->lock, flags);
        hid_set_field(report->field[0], 0, data->led_state);
        if (!(data->status & PICOLCD_FAILED))
                hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
        spin_unlock_irqrestore(&data->lock, flags);
}

static void picolcd_led_set_brightness(struct led_classdev *led_cdev,
                        enum led_brightness value)
{
        struct device *dev;
        struct hid_device *hdev;
        struct picolcd_data *data;
        int i, state = 0;

        dev  = led_cdev->dev->parent;
        hdev = to_hid_device(dev);
        data = hid_get_drvdata(hdev);
        if (!data)
                return;
        for (i = 0; i < 8; i++) {
                if (led_cdev != data->led[i])
                        continue;
                state = (data->led_state >> i) & 1;
                if (value == LED_OFF && state) {
                        data->led_state &= ~(1 << i);
                        picolcd_leds_set(data);
                } else if (value != LED_OFF && !state) {
                        data->led_state |= 1 << i;
                        picolcd_leds_set(data);
                }
                break;
        }
}

static enum led_brightness picolcd_led_get_brightness(struct led_classdev *led_cdev)
{
        struct device *dev;
        struct hid_device *hdev;
        struct picolcd_data *data;
        int i, value = 0;

        dev  = led_cdev->dev->parent;
        hdev = to_hid_device(dev);
        data = hid_get_drvdata(hdev);
        for (i = 0; i < 8; i++)
                if (led_cdev == data->led[i]) {
                        value = (data->led_state >> i) & 1;
                        break;
                }
        return value ? LED_FULL : LED_OFF;
}

int picolcd_init_leds(struct picolcd_data *data, struct hid_report *report)
{
        struct device *dev = &data->hdev->dev;
        struct led_classdev *led;
        size_t name_sz = strlen(dev_name(dev)) + 8;
        char *name;
        int i, ret = 0;

        if (!report)
                return -ENODEV;
        if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
                        report->field[0]->report_size != 8) {
                dev_err(dev, "unsupported LED_STATE report");
                return -EINVAL;
        }

        for (i = 0; i < 8; i++) {
                led = kzalloc(sizeof(struct led_classdev)+name_sz, GFP_KERNEL);
                if (!led) {
                        dev_err(dev, "can't allocate memory for LED %d\n", i);
                        ret = -ENOMEM;
                        goto err;
                }
                name = (void *)(&led[1]);
                snprintf(name, name_sz, "%s::GPO%d", dev_name(dev), i);
                led->name = name;
                led->brightness = 0;
                led->max_brightness = 1;
                led->brightness_get = picolcd_led_get_brightness;
                led->brightness_set = picolcd_led_set_brightness;

                data->led[i] = led;
                ret = led_classdev_register(dev, data->led[i]);
                if (ret) {
                        data->led[i] = NULL;
                        kfree(led);
                        dev_err(dev, "can't register LED %d\n", i);
                        goto err;
                }
        }
        return 0;
err:
        for (i = 0; i < 8; i++)
                if (data->led[i]) {
                        led = data->led[i];
                        data->led[i] = NULL;
                        led_classdev_unregister(led);
                        kfree(led);
                }
        return ret;
}

void picolcd_exit_leds(struct picolcd_data *data)
{
        struct led_classdev *led;
        int i;

        for (i = 0; i < 8; i++) {
                led = data->led[i];
                data->led[i] = NULL;
                if (!led)
                        continue;
                led_classdev_unregister(led);
                kfree(led);
        }
}