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 = pdev->dev.platform_data; 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 dev_err(&pdev->dev, 153 "Failed to allocate memory for aat2870 backlight\n"); 154 ret = -ENOMEM; 155 goto out; 156 } 157 158 memset(&props, 0, sizeof(struct backlight_properties)); 159 160 props.type = BACKLIGHT_RAW; 161 bd = backlight_device_register("aat2870-backlight", &pdev->dev, 162 aat2870_bl, &aat2870_bl_ops, &props); 163 if (IS_ERR(bd)) { 164 dev_err(&pdev->dev, 165 "Failed allocate memory for backlight device\n"); 166 ret = PTR_ERR(bd); 167 goto out; 168 } 169 170 aat2870_bl->pdev = pdev; 171 platform_set_drvdata(pdev, aat2870_bl); 172 173 aat2870_bl->bd = bd; 174 175 if (pdata->channels > 0) 176 aat2870_bl->channels = pdata->channels; 177 else 178 aat2870_bl->channels = AAT2870_BL_CH_ALL; 179 180 if (pdata->max_current > 0) 181 aat2870_bl->max_current = pdata->max_current; 182 else 183 aat2870_bl->max_current = AAT2870_CURRENT_27_9; 184 185 if (pdata->max_brightness > 0) 186 bd->props.max_brightness = pdata->max_brightness; 187 else 188 bd->props.max_brightness = 255; 189 190 aat2870_bl->brightness = 0; 191 bd->props.power = FB_BLANK_UNBLANK; 192 bd->props.brightness = bd->props.max_brightness; 193 194 ret = aat2870_bl_update_status(bd); 195 if (ret < 0) { 196 dev_err(&pdev->dev, "Failed to initialize\n"); 197 goto out_bl_dev_unregister; 198 } 199 200 return 0; 201 202 out_bl_dev_unregister: 203 backlight_device_unregister(bd); 204 out: 205 return ret; 206 } 207 208 static int aat2870_bl_remove(struct platform_device *pdev) 209 { 210 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev); 211 struct backlight_device *bd = aat2870_bl->bd; 212 213 bd->props.power = FB_BLANK_POWERDOWN; 214 bd->props.brightness = 0; 215 backlight_update_status(bd); 216 217 backlight_device_unregister(bd); 218 219 return 0; 220 } 221 222 static struct platform_driver aat2870_bl_driver = { 223 .driver = { 224 .name = "aat2870-backlight", 225 .owner = THIS_MODULE, 226 }, 227 .probe = aat2870_bl_probe, 228 .remove = aat2870_bl_remove, 229 }; 230 231 static int __init aat2870_bl_init(void) 232 { 233 return platform_driver_register(&aat2870_bl_driver); 234 } 235 subsys_initcall(aat2870_bl_init); 236 237 static void __exit aat2870_bl_exit(void) 238 { 239 platform_driver_unregister(&aat2870_bl_driver); 240 } 241 module_exit(aat2870_bl_exit); 242 243 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight"); 244 MODULE_LICENSE("GPL"); 245 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>"); 246