video/backlight/rave-sp-backlight.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002
0003 /*
0004  * LCD Backlight driver for RAVE SP
0005  *
0006  * Copyright (C) 2018 Zodiac Inflight Innovations
0007  *
0008  */
0009
0010 #include <linux/backlight.h>
0011 #include <linux/kernel.h>
0012 #include <linux/module.h>
0013 #include <linux/mfd/rave-sp.h>
0014 #include <linux/platform_device.h>
0015
0016 #define RAVE_SP_BACKLIGHT_LCD_EN    BIT(7)
0017
0018 static int rave_sp_backlight_update_status(struct backlight_device *bd)
0019 {
0020     const struct backlight_properties *p = &bd->props;
0021     const u8 intensity =
0022         (p->power == FB_BLANK_UNBLANK) ? p->brightness : 0;
0023     struct rave_sp *sp = dev_get_drvdata(&bd->dev);
0024     u8 cmd[] = {
0025         [0] = RAVE_SP_CMD_SET_BACKLIGHT,
0026         [1] = 0,
0027         [2] = intensity ? RAVE_SP_BACKLIGHT_LCD_EN | intensity : 0,
0028         [3] = 0,
0029         [4] = 0,
0030     };
0031
0032     return rave_sp_exec(sp, cmd, sizeof(cmd), NULL, 0);
0033 }
0034
0035 static const struct backlight_ops rave_sp_backlight_ops = {
0036     .options    = BL_CORE_SUSPENDRESUME,
0037     .update_status  = rave_sp_backlight_update_status,
0038 };
0039
0040 static struct backlight_properties rave_sp_backlight_props = {
0041     .type       = BACKLIGHT_PLATFORM,
0042     .max_brightness = 100,
0043     .brightness = 50,
0044 };
0045
0046 static int rave_sp_backlight_probe(struct platform_device *pdev)
0047 {
0048     struct device *dev = &pdev->dev;
0049     struct backlight_device *bd;
0050
0051     bd = devm_backlight_device_register(dev, pdev->name, dev,
0052                         dev_get_drvdata(dev->parent),
0053                         &rave_sp_backlight_ops,
0054                         &rave_sp_backlight_props);
0055     if (IS_ERR(bd))
0056         return PTR_ERR(bd);
0057
0058     /*
0059      * If there is a phandle pointing to the device node we can
0060      * assume that another device will manage the status changes.
0061      * If not we make sure the backlight is in a consistent state.
0062      */
0063     if (!dev->of_node->phandle)
0064         backlight_update_status(bd);
0065
0066     return 0;
0067 }
0068
0069 static const struct of_device_id rave_sp_backlight_of_match[] = {
0070     { .compatible = "zii,rave-sp-backlight" },
0071     {}
0072 };
0073
0074 static struct platform_driver rave_sp_backlight_driver = {
0075     .probe = rave_sp_backlight_probe,
0076     .driver = {
0077         .name = KBUILD_MODNAME,
0078         .of_match_table = rave_sp_backlight_of_match,
0079     },
0080 };
0081 module_platform_driver(rave_sp_backlight_driver);
0082
0083 MODULE_DEVICE_TABLE(of, rave_sp_backlight_of_match);
0084 MODULE_LICENSE("GPL");
0085 MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
0086 MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
0087 MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
0088 MODULE_DESCRIPTION("RAVE SP Backlight driver");