cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pcf50633-backlight.c (3974B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
      4 *      PCF50633 backlight device driver
      5 */
      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#include <linux/fb.h>
     14
     15#include <linux/mfd/pcf50633/core.h>
     16#include <linux/mfd/pcf50633/backlight.h>
     17
     18struct pcf50633_bl {
     19	struct pcf50633 *pcf;
     20	struct backlight_device *bl;
     21
     22	unsigned int brightness;
     23	unsigned int brightness_limit;
     24};
     25
     26/*
     27 * pcf50633_bl_set_brightness_limit
     28 *
     29 * Update the brightness limit for the pc50633 backlight. The actual brightness
     30 * will not go above the limit. This is useful to limit power drain for example
     31 * on low battery.
     32 *
     33 * @dev: Pointer to a pcf50633 device
     34 * @limit: The brightness limit. Valid values are 0-63
     35 */
     36int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)
     37{
     38	struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);
     39
     40	if (!pcf_bl)
     41		return -ENODEV;
     42
     43	pcf_bl->brightness_limit = limit & 0x3f;
     44	backlight_update_status(pcf_bl->bl);
     45
     46	return 0;
     47}
     48
     49static int pcf50633_bl_update_status(struct backlight_device *bl)
     50{
     51	struct pcf50633_bl *pcf_bl = bl_get_data(bl);
     52	unsigned int new_brightness;
     53
     54
     55	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) ||
     56		bl->props.power != FB_BLANK_UNBLANK)
     57		new_brightness = 0;
     58	else if (bl->props.brightness < pcf_bl->brightness_limit)
     59		new_brightness = bl->props.brightness;
     60	else
     61		new_brightness = pcf_bl->brightness_limit;
     62
     63
     64	if (pcf_bl->brightness == new_brightness)
     65		return 0;
     66
     67	if (new_brightness) {
     68		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,
     69					new_brightness);
     70		if (!pcf_bl->brightness)
     71			pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);
     72	} else {
     73		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);
     74	}
     75
     76	pcf_bl->brightness = new_brightness;
     77
     78	return 0;
     79}
     80
     81static int pcf50633_bl_get_brightness(struct backlight_device *bl)
     82{
     83	struct pcf50633_bl *pcf_bl = bl_get_data(bl);
     84
     85	return pcf_bl->brightness;
     86}
     87
     88static const struct backlight_ops pcf50633_bl_ops = {
     89	.get_brightness = pcf50633_bl_get_brightness,
     90	.update_status	= pcf50633_bl_update_status,
     91	.options	= BL_CORE_SUSPENDRESUME,
     92};
     93
     94static int pcf50633_bl_probe(struct platform_device *pdev)
     95{
     96	struct pcf50633_bl *pcf_bl;
     97	struct device *parent = pdev->dev.parent;
     98	struct pcf50633_platform_data *pcf50633_data = dev_get_platdata(parent);
     99	struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
    100	struct backlight_properties bl_props;
    101
    102	pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);
    103	if (!pcf_bl)
    104		return -ENOMEM;
    105
    106	memset(&bl_props, 0, sizeof(bl_props));
    107	bl_props.type = BACKLIGHT_RAW;
    108	bl_props.max_brightness = 0x3f;
    109	bl_props.power = FB_BLANK_UNBLANK;
    110
    111	if (pdata) {
    112		bl_props.brightness = pdata->default_brightness;
    113		pcf_bl->brightness_limit = pdata->default_brightness_limit;
    114	} else {
    115		bl_props.brightness = 0x3f;
    116		pcf_bl->brightness_limit = 0x3f;
    117	}
    118
    119	pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);
    120
    121	pcf_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
    122						&pdev->dev, pcf_bl,
    123						&pcf50633_bl_ops, &bl_props);
    124
    125	if (IS_ERR(pcf_bl->bl))
    126		return PTR_ERR(pcf_bl->bl);
    127
    128	platform_set_drvdata(pdev, pcf_bl);
    129
    130	pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
    131
    132	/*
    133	 * Should be different from bl_props.brightness, so we do not exit
    134	 * update_status early the first time it's called
    135	 */
    136	pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;
    137
    138	backlight_update_status(pcf_bl->bl);
    139
    140	return 0;
    141}
    142
    143static struct platform_driver pcf50633_bl_driver = {
    144	.probe =	pcf50633_bl_probe,
    145	.driver = {
    146		.name = "pcf50633-backlight",
    147	},
    148};
    149
    150module_platform_driver(pcf50633_bl_driver);
    151
    152MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
    153MODULE_DESCRIPTION("PCF50633 backlight driver");
    154MODULE_LICENSE("GPL");
    155MODULE_ALIAS("platform:pcf50633-backlight");