1 /* 2 * linux/drivers/video/backlight/aat2870_bl.c 3 * 4 * Copyright (c) 2011, NVIDIA Corporation. 5 * Author: Jin Park <jinyoungp@nvidia.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * version 2 as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 19 * 02110-1301 USA 20 */ 21 22 #include <linux/module.h> 23 #include <linux/kernel.h> 24 #include <linux/init.h> 25 #include <linux/platform_device.h> 26 #include <linux/mutex.h> 27 #include <linux/delay.h> 28 #include <linux/fb.h> 29 #include <linux/backlight.h> 30 #include <linux/mfd/aat2870.h> 31 32 struct aat2870_bl_driver_data { 33 struct platform_device *pdev; 34 struct backlight_device *bd; 35 36 int channels; 37 int max_current; 38 int brightness; /* current brightness */ 39 }; 40 41 static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl, 42 int brightness) 43 { 44 struct backlight_device *bd = aat2870_bl->bd; 45 int val; 46 47 val = brightness * (aat2870_bl->max_current - 1); 48 val /= bd->props.max_brightness; 49 50 return val; 51 } 52 53 static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl) 54 { 55 struct aat2870_data *aat2870 56 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); 57 58 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 59 (u8)aat2870_bl->channels); 60 } 61 62 static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl) 63 { 64 struct aat2870_data *aat2870 65 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); 66 67 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0); 68 } 69 70 static int aat2870_bl_get_brightness(struct backlight_device *bd) 71 { 72 return bd->props.brightness; 73 } 74 75 static int aat2870_bl_update_status(struct backlight_device *bd) 76 { 77 struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd); 78 struct aat2870_data *aat2870 = 79 dev_get_drvdata(aat2870_bl->pdev->dev.parent); 80 int brightness = bd->props.brightness; 81 int ret; 82 83 if ((brightness < 0) || (bd->props.max_brightness < brightness)) { 84 dev_err(&bd->dev, "invalid brightness, %d\n", brightness); 85 return -EINVAL; 86 } 87 88 dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n", 89 bd->props.brightness, bd->props.power, bd->props.state); 90 91 if ((bd->props.power != FB_BLANK_UNBLANK) || 92 (bd->props.state & BL_CORE_FBBLANK) || 93 (bd->props.state & BL_CORE_SUSPENDED)) 94 brightness = 0; 95 96 ret = aat2870->write(aat2870, AAT2870_BLM, 97 (u8)aat2870_brightness(aat2870_bl, brightness)); 98 if (ret < 0) 99 return ret; 100 101 if (brightness == 0) { 102 ret = aat2870_bl_disable(aat2870_bl); 103 if (ret < 0) 104 return ret; 105 } else if (aat2870_bl->brightness == 0) { 106 ret = aat2870_bl_enable(aat2870_bl); 107 if (ret < 0) 108 return ret; 109 } 110 111 aat2870_bl->brightness = brightness; 112 113 return 0; 114 } 115 116 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi) 117 { 118 return 1; 119 } 120 121 static const struct backlight_ops aat2870_bl_ops = { 122 .options = BL_CORE_SUSPENDRESUME, 123 .get_brightness = aat2870_bl_get_brightness, 124 .update_status = aat2870_bl_update_status, 125 .check_fb = aat2870_bl_check_fb, 126 }; 127 128 static int aat2870_bl_probe(struct platform_device *pdev) 129 { 130 struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev); 131 struct aat2870_bl_driver_data *aat2870_bl; 132 struct backlight_device *bd; 133 struct backlight_properties props; 134 int ret = 0; 135 136 if (!pdata) { 137 dev_err(&pdev->dev, "No platform data\n"); 138 ret = -ENXIO; 139 goto out; 140 } 141 142 if (pdev->id != AAT2870_ID_BL) { 143 dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id); 144 ret = -EINVAL; 145 goto out; 146 } 147 148 aat2870_bl = devm_kzalloc(&pdev->dev, 149 sizeof(struct aat2870_bl_driver_data), 150 GFP_KERNEL); 151 if (!aat2870_bl) { 152 ret = -ENOMEM; 153 goto out; 154 } 155 156 memset(&props, 0, sizeof(struct backlight_properties)); 157 158 props.type = BACKLIGHT_RAW; 159 bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight", 160 &pdev->dev, aat2870_bl, &aat2870_bl_ops, 161 &props); 162 if (IS_ERR(bd)) { 163 dev_err(&pdev->dev, 164 "Failed allocate memory for backlight device\n"); 165 ret = PTR_ERR(bd); 166 goto out; 167 } 168 169 aat2870_bl->pdev = pdev; 170 platform_set_drvdata(pdev, aat2870_bl); 171 172 aat2870_bl->bd = bd; 173 174 if (pdata->channels > 0) 175 aat2870_bl->channels = pdata->channels; 176 else 177 aat2870_bl->channels = AAT2870_BL_CH_ALL; 178 179 if (pdata->max_current > 0) 180 aat2870_bl->max_current = pdata->max_current; 181 else 182 aat2870_bl->max_current = AAT2870_CURRENT_27_9; 183 184 if (pdata->max_brightness > 0) 185 bd->props.max_brightness = pdata->max_brightness; 186 else 187 bd->props.max_brightness = 255; 188 189 aat2870_bl->brightness = 0; 190 bd->props.power = FB_BLANK_UNBLANK; 191 bd->props.brightness = bd->props.max_brightness; 192 193 ret = aat2870_bl_update_status(bd); 194 if (ret < 0) { 195 dev_err(&pdev->dev, "Failed to initialize\n"); 196 return ret; 197 } 198 199 return 0; 200 201 out: 202 return ret; 203 } 204 205 static int aat2870_bl_remove(struct platform_device *pdev) 206 { 207 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev); 208 struct backlight_device *bd = aat2870_bl->bd; 209 210 bd->props.power = FB_BLANK_POWERDOWN; 211 bd->props.brightness = 0; 212 backlight_update_status(bd); 213 214 return 0; 215 } 216 217 static struct platform_driver aat2870_bl_driver = { 218 .driver = { 219 .name = "aat2870-backlight", 220 .owner = THIS_MODULE, 221 }, 222 .probe = aat2870_bl_probe, 223 .remove = aat2870_bl_remove, 224 }; 225 226 static int __init aat2870_bl_init(void) 227 { 228 return platform_driver_register(&aat2870_bl_driver); 229 } 230 subsys_initcall(aat2870_bl_init); 231 232 static void __exit aat2870_bl_exit(void) 233 { 234 platform_driver_unregister(&aat2870_bl_driver); 235 } 236 module_exit(aat2870_bl_exit); 237 238 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight"); 239 MODULE_LICENSE("GPL"); 240 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>"); 241