aat2870_bl.c (5246B)
1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * linux/drivers/video/backlight/aat2870_bl.c 4 * 5 * Copyright (c) 2011, NVIDIA Corporation. 6 * Author: Jin Park <jinyoungp@nvidia.com> 7 */ 8 9#include <linux/module.h> 10#include <linux/kernel.h> 11#include <linux/init.h> 12#include <linux/platform_device.h> 13#include <linux/mutex.h> 14#include <linux/delay.h> 15#include <linux/fb.h> 16#include <linux/backlight.h> 17#include <linux/mfd/aat2870.h> 18 19struct aat2870_bl_driver_data { 20 struct platform_device *pdev; 21 struct backlight_device *bd; 22 23 int channels; 24 int max_current; 25 int brightness; /* current brightness */ 26}; 27 28static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl, 29 int brightness) 30{ 31 struct backlight_device *bd = aat2870_bl->bd; 32 int val; 33 34 val = brightness * (aat2870_bl->max_current - 1); 35 val /= bd->props.max_brightness; 36 37 return val; 38} 39 40static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl) 41{ 42 struct aat2870_data *aat2870 43 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); 44 45 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 46 (u8)aat2870_bl->channels); 47} 48 49static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl) 50{ 51 struct aat2870_data *aat2870 52 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); 53 54 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0); 55} 56 57static int aat2870_bl_update_status(struct backlight_device *bd) 58{ 59 struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd); 60 struct aat2870_data *aat2870 = 61 dev_get_drvdata(aat2870_bl->pdev->dev.parent); 62 int brightness = bd->props.brightness; 63 int ret; 64 65 if ((brightness < 0) || (bd->props.max_brightness < brightness)) { 66 dev_err(&bd->dev, "invalid brightness, %d\n", brightness); 67 return -EINVAL; 68 } 69 70 dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n", 71 bd->props.brightness, bd->props.power, bd->props.state); 72 73 if ((bd->props.power != FB_BLANK_UNBLANK) || 74 (bd->props.state & BL_CORE_FBBLANK) || 75 (bd->props.state & BL_CORE_SUSPENDED)) 76 brightness = 0; 77 78 ret = aat2870->write(aat2870, AAT2870_BLM, 79 (u8)aat2870_brightness(aat2870_bl, brightness)); 80 if (ret < 0) 81 return ret; 82 83 if (brightness == 0) { 84 ret = aat2870_bl_disable(aat2870_bl); 85 if (ret < 0) 86 return ret; 87 } else if (aat2870_bl->brightness == 0) { 88 ret = aat2870_bl_enable(aat2870_bl); 89 if (ret < 0) 90 return ret; 91 } 92 93 aat2870_bl->brightness = brightness; 94 95 return 0; 96} 97 98static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi) 99{ 100 return 1; 101} 102 103static const struct backlight_ops aat2870_bl_ops = { 104 .options = BL_CORE_SUSPENDRESUME, 105 .update_status = aat2870_bl_update_status, 106 .check_fb = aat2870_bl_check_fb, 107}; 108 109static int aat2870_bl_probe(struct platform_device *pdev) 110{ 111 struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev); 112 struct aat2870_bl_driver_data *aat2870_bl; 113 struct backlight_device *bd; 114 struct backlight_properties props; 115 int ret = 0; 116 117 if (!pdata) { 118 dev_err(&pdev->dev, "No platform data\n"); 119 ret = -ENXIO; 120 goto out; 121 } 122 123 if (pdev->id != AAT2870_ID_BL) { 124 dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id); 125 ret = -EINVAL; 126 goto out; 127 } 128 129 aat2870_bl = devm_kzalloc(&pdev->dev, 130 sizeof(struct aat2870_bl_driver_data), 131 GFP_KERNEL); 132 if (!aat2870_bl) { 133 ret = -ENOMEM; 134 goto out; 135 } 136 137 memset(&props, 0, sizeof(struct backlight_properties)); 138 139 props.type = BACKLIGHT_RAW; 140 bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight", 141 &pdev->dev, aat2870_bl, &aat2870_bl_ops, 142 &props); 143 if (IS_ERR(bd)) { 144 dev_err(&pdev->dev, 145 "Failed allocate memory for backlight device\n"); 146 ret = PTR_ERR(bd); 147 goto out; 148 } 149 150 aat2870_bl->pdev = pdev; 151 platform_set_drvdata(pdev, aat2870_bl); 152 153 aat2870_bl->bd = bd; 154 155 if (pdata->channels > 0) 156 aat2870_bl->channels = pdata->channels; 157 else 158 aat2870_bl->channels = AAT2870_BL_CH_ALL; 159 160 if (pdata->max_current > 0) 161 aat2870_bl->max_current = pdata->max_current; 162 else 163 aat2870_bl->max_current = AAT2870_CURRENT_27_9; 164 165 if (pdata->max_brightness > 0) 166 bd->props.max_brightness = pdata->max_brightness; 167 else 168 bd->props.max_brightness = 255; 169 170 aat2870_bl->brightness = 0; 171 bd->props.power = FB_BLANK_UNBLANK; 172 bd->props.brightness = bd->props.max_brightness; 173 174 ret = aat2870_bl_update_status(bd); 175 if (ret < 0) { 176 dev_err(&pdev->dev, "Failed to initialize\n"); 177 return ret; 178 } 179 180 return 0; 181 182out: 183 return ret; 184} 185 186static int aat2870_bl_remove(struct platform_device *pdev) 187{ 188 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev); 189 struct backlight_device *bd = aat2870_bl->bd; 190 191 bd->props.power = FB_BLANK_POWERDOWN; 192 bd->props.brightness = 0; 193 backlight_update_status(bd); 194 195 return 0; 196} 197 198static struct platform_driver aat2870_bl_driver = { 199 .driver = { 200 .name = "aat2870-backlight", 201 }, 202 .probe = aat2870_bl_probe, 203 .remove = aat2870_bl_remove, 204}; 205 206static int __init aat2870_bl_init(void) 207{ 208 return platform_driver_register(&aat2870_bl_driver); 209} 210subsys_initcall(aat2870_bl_init); 211 212static void __exit aat2870_bl_exit(void) 213{ 214 platform_driver_unregister(&aat2870_bl_driver); 215} 216module_exit(aat2870_bl_exit); 217 218MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight"); 219MODULE_LICENSE("GPL"); 220MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");