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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Backlight driver for Maxim MAX89254 *5 * Copyright (C) 2009 Marvell International Ltd.6 * Haojian Zhuang <haojian.zhuang@marvell.com>7 */8 9#include <linux/init.h>10#include <linux/kernel.h>11#include <linux/platform_device.h>12#include <linux/fb.h>13#include <linux/i2c.h>14#include <linux/backlight.h>15#include <linux/mfd/max8925.h>16#include <linux/slab.h>17#include <linux/module.h>18 19#define MAX_BRIGHTNESS (0xff)20#define MIN_BRIGHTNESS (0)21 22#define LWX_FREQ(x) (((x - 601) / 100) & 0x7)23 24struct max8925_backlight_data {25 struct max8925_chip *chip;26 27 int current_brightness;28 int reg_mode_cntl;29 int reg_cntl;30};31 32static int max8925_backlight_set(struct backlight_device *bl, int brightness)33{34 struct max8925_backlight_data *data = bl_get_data(bl);35 struct max8925_chip *chip = data->chip;36 unsigned char value;37 int ret;38 39 if (brightness > MAX_BRIGHTNESS)40 value = MAX_BRIGHTNESS;41 else42 value = brightness;43 44 ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);45 if (ret < 0)46 goto out;47 48 if (!data->current_brightness && brightness)49 /* enable WLED output */50 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);51 else if (!brightness)52 /* disable WLED output */53 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);54 if (ret < 0)55 goto out;56 dev_dbg(chip->dev, "set brightness %d\n", value);57 data->current_brightness = value;58 return 0;59out:60 dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",61 value, ret);62 return ret;63}64 65static int max8925_backlight_update_status(struct backlight_device *bl)66{67 return max8925_backlight_set(bl, backlight_get_brightness(bl));68}69 70static int max8925_backlight_get_brightness(struct backlight_device *bl)71{72 struct max8925_backlight_data *data = bl_get_data(bl);73 struct max8925_chip *chip = data->chip;74 int ret;75 76 ret = max8925_reg_read(chip->i2c, data->reg_cntl);77 if (ret < 0)78 return -EINVAL;79 data->current_brightness = ret;80 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);81 return ret;82}83 84static const struct backlight_ops max8925_backlight_ops = {85 .options = BL_CORE_SUSPENDRESUME,86 .update_status = max8925_backlight_update_status,87 .get_brightness = max8925_backlight_get_brightness,88};89 90static void max8925_backlight_dt_init(struct platform_device *pdev)91{92 struct device_node *nproot = pdev->dev.parent->of_node, *np;93 struct max8925_backlight_pdata *pdata;94 u32 val;95 96 if (!nproot || !IS_ENABLED(CONFIG_OF))97 return;98 99 pdata = devm_kzalloc(&pdev->dev,100 sizeof(struct max8925_backlight_pdata),101 GFP_KERNEL);102 if (!pdata)103 return;104 105 np = of_get_child_by_name(nproot, "backlight");106 if (!np) {107 dev_err(&pdev->dev, "failed to find backlight node\n");108 return;109 }110 111 if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))112 pdata->dual_string = val;113 114 of_node_put(np);115 116 pdev->dev.platform_data = pdata;117}118 119static int max8925_backlight_probe(struct platform_device *pdev)120{121 struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);122 struct max8925_backlight_pdata *pdata;123 struct max8925_backlight_data *data;124 struct backlight_device *bl;125 struct backlight_properties props;126 struct resource *res;127 unsigned char value;128 int ret = 0;129 130 data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),131 GFP_KERNEL);132 if (data == NULL)133 return -ENOMEM;134 135 res = platform_get_resource(pdev, IORESOURCE_REG, 0);136 if (!res) {137 dev_err(&pdev->dev, "No REG resource for mode control!\n");138 return -ENXIO;139 }140 data->reg_mode_cntl = res->start;141 res = platform_get_resource(pdev, IORESOURCE_REG, 1);142 if (!res) {143 dev_err(&pdev->dev, "No REG resource for control!\n");144 return -ENXIO;145 }146 data->reg_cntl = res->start;147 148 data->chip = chip;149 data->current_brightness = 0;150 151 memset(&props, 0, sizeof(struct backlight_properties));152 props.type = BACKLIGHT_RAW;153 props.max_brightness = MAX_BRIGHTNESS;154 bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight",155 &pdev->dev, data,156 &max8925_backlight_ops, &props);157 if (IS_ERR(bl)) {158 dev_err(&pdev->dev, "failed to register backlight\n");159 return PTR_ERR(bl);160 }161 bl->props.brightness = MAX_BRIGHTNESS;162 163 platform_set_drvdata(pdev, bl);164 165 value = 0;166 if (!pdev->dev.platform_data)167 max8925_backlight_dt_init(pdev);168 169 pdata = pdev->dev.platform_data;170 if (pdata) {171 if (pdata->lxw_scl)172 value |= (1 << 7);173 if (pdata->lxw_freq)174 value |= (LWX_FREQ(pdata->lxw_freq) << 4);175 if (pdata->dual_string)176 value |= (1 << 1);177 }178 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);179 if (ret < 0)180 return ret;181 backlight_update_status(bl);182 return 0;183}184 185static struct platform_driver max8925_backlight_driver = {186 .driver = {187 .name = "max8925-backlight",188 },189 .probe = max8925_backlight_probe,190};191 192module_platform_driver(max8925_backlight_driver);193 194MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");195MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");196MODULE_LICENSE("GPL");197MODULE_ALIAS("platform:max8925-backlight");198