hid-picolcd_lcd.c

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/***************************************************************************
 *   Copyright (C) 2010-2012 by Bruno Prémont <[email protected]>  *
 *                                                                         *
 *   Based on Logitech G13 driver (v0.4)                                   *
 *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <[email protected]>   *
 *                                                                         *
 *   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 of the License.               *
 *                                                                         *
 *   This driver is distributed in the hope that it will be useful, but    *
 *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
 *   General Public License for more details.                              *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this software. If not see <http://www.gnu.org/licenses/>.  *
 ***************************************************************************/

#include <linux/hid.h>
#include "usbhid/usbhid.h"
#include <linux/usb.h>

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

#include "hid-picolcd.h"

/*
 * lcd class device
 */
static int picolcd_get_contrast(struct lcd_device *ldev)
{
    struct picolcd_data *data = lcd_get_data(ldev);
    return data->lcd_contrast;
}

static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
{
    struct picolcd_data *data = lcd_get_data(ldev);
    struct hid_report *report = picolcd_out_report(REPORT_CONTRAST, data->hdev);
    unsigned long flags;

    if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
        return -ENODEV;

    data->lcd_contrast = contrast & 0x0ff;
    spin_lock_irqsave(&data->lock, flags);
    hid_set_field(report->field[0], 0, data->lcd_contrast);
    if (!(data->status & PICOLCD_FAILED))
        usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
    spin_unlock_irqrestore(&data->lock, flags);
    return 0;
}

static int picolcd_check_lcd_fb(struct lcd_device *ldev, struct fb_info *fb)
{
    return fb && fb == picolcd_fbinfo((struct picolcd_data *)lcd_get_data(ldev));
}

static struct lcd_ops picolcd_lcdops = {
    .get_contrast   = picolcd_get_contrast,
    .set_contrast   = picolcd_set_contrast,
    .check_fb       = picolcd_check_lcd_fb,
};

int picolcd_init_lcd(struct picolcd_data *data, struct hid_report *report)
{
    struct device *dev = &data->hdev->dev;
    struct lcd_device *ldev;

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

    ldev = lcd_device_register(dev_name(dev), dev, data, &picolcd_lcdops);
    if (IS_ERR(ldev)) {
        dev_err(dev, "failed to register LCD\n");
        return PTR_ERR(ldev);
    }
    ldev->props.max_contrast = 0x0ff;
    data->lcd_contrast = 0xe5;
    data->lcd = ldev;
    picolcd_set_contrast(ldev, 0xe5);
    return 0;
}

void picolcd_exit_lcd(struct picolcd_data *data)
{
    struct lcd_device *ldev = data->lcd;

    data->lcd = NULL;
    if (ldev)
        lcd_device_unregister(ldev);
}

int picolcd_resume_lcd(struct picolcd_data *data)
{
    if (!data->lcd)
        return 0;
    return picolcd_set_contrast(data->lcd, data->lcd_contrast);
}