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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>4 * PCF50633 backlight device driver5 */6 7#include <linux/kernel.h>8#include <linux/module.h>9#include <linux/slab.h>10#include <linux/platform_device.h>11 12#include <linux/backlight.h>13 14#include <linux/mfd/pcf50633/core.h>15#include <linux/mfd/pcf50633/backlight.h>16 17struct pcf50633_bl {18 struct pcf50633 *pcf;19 struct backlight_device *bl;20 21 unsigned int brightness;22 unsigned int brightness_limit;23};24 25/*26 * pcf50633_bl_set_brightness_limit27 *28 * Update the brightness limit for the pc50633 backlight. The actual brightness29 * will not go above the limit. This is useful to limit power drain for example30 * on low battery.31 *32 * @dev: Pointer to a pcf50633 device33 * @limit: The brightness limit. Valid values are 0-6334 */35int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)36{37 struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);38 39 if (!pcf_bl)40 return -ENODEV;41 42 pcf_bl->brightness_limit = limit & 0x3f;43 backlight_update_status(pcf_bl->bl);44 45 return 0;46}47 48static int pcf50633_bl_update_status(struct backlight_device *bl)49{50 struct pcf50633_bl *pcf_bl = bl_get_data(bl);51 unsigned int new_brightness;52 53 54 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) ||55 bl->props.power != BACKLIGHT_POWER_ON)56 new_brightness = 0;57 else if (bl->props.brightness < pcf_bl->brightness_limit)58 new_brightness = bl->props.brightness;59 else60 new_brightness = pcf_bl->brightness_limit;61 62 63 if (pcf_bl->brightness == new_brightness)64 return 0;65 66 if (new_brightness) {67 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,68 new_brightness);69 if (!pcf_bl->brightness)70 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);71 } else {72 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);73 }74 75 pcf_bl->brightness = new_brightness;76 77 return 0;78}79 80static int pcf50633_bl_get_brightness(struct backlight_device *bl)81{82 struct pcf50633_bl *pcf_bl = bl_get_data(bl);83 84 return pcf_bl->brightness;85}86 87static const struct backlight_ops pcf50633_bl_ops = {88 .get_brightness = pcf50633_bl_get_brightness,89 .update_status = pcf50633_bl_update_status,90 .options = BL_CORE_SUSPENDRESUME,91};92 93static int pcf50633_bl_probe(struct platform_device *pdev)94{95 struct pcf50633_bl *pcf_bl;96 struct device *parent = pdev->dev.parent;97 struct pcf50633_platform_data *pcf50633_data = dev_get_platdata(parent);98 struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;99 struct backlight_properties bl_props;100 101 pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);102 if (!pcf_bl)103 return -ENOMEM;104 105 memset(&bl_props, 0, sizeof(bl_props));106 bl_props.type = BACKLIGHT_RAW;107 bl_props.max_brightness = 0x3f;108 bl_props.power = BACKLIGHT_POWER_ON;109 110 if (pdata) {111 bl_props.brightness = pdata->default_brightness;112 pcf_bl->brightness_limit = pdata->default_brightness_limit;113 } else {114 bl_props.brightness = 0x3f;115 pcf_bl->brightness_limit = 0x3f;116 }117 118 pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);119 120 pcf_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,121 &pdev->dev, pcf_bl,122 &pcf50633_bl_ops, &bl_props);123 124 if (IS_ERR(pcf_bl->bl))125 return PTR_ERR(pcf_bl->bl);126 127 platform_set_drvdata(pdev, pcf_bl);128 129 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);130 131 /*132 * Should be different from bl_props.brightness, so we do not exit133 * update_status early the first time it's called134 */135 pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;136 137 backlight_update_status(pcf_bl->bl);138 139 return 0;140}141 142static struct platform_driver pcf50633_bl_driver = {143 .probe = pcf50633_bl_probe,144 .driver = {145 .name = "pcf50633-backlight",146 },147};148 149module_platform_driver(pcf50633_bl_driver);150 151MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");152MODULE_DESCRIPTION("PCF50633 backlight driver");153MODULE_LICENSE("GPL");154MODULE_ALIAS("platform:pcf50633-backlight");155