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