1 /* 2 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de> 3 * PCF50633 backlight device driver 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License as published by the 7 * Free Software Foundation; either version 2 of the License, or (at your 8 * option) any later version. 9 * 10 * You should have received a copy of the GNU General Public License along 11 * with this program; if not, write to the Free Software Foundation, Inc., 12 * 675 Mass Ave, Cambridge, MA 02139, USA. 13 * 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/slab.h> 19 #include <linux/platform_device.h> 20 21 #include <linux/backlight.h> 22 #include <linux/fb.h> 23 24 #include <linux/mfd/pcf50633/core.h> 25 #include <linux/mfd/pcf50633/backlight.h> 26 27 struct pcf50633_bl { 28 struct pcf50633 *pcf; 29 struct backlight_device *bl; 30 31 unsigned int brightness; 32 unsigned int brightness_limit; 33 }; 34 35 /* 36 * pcf50633_bl_set_brightness_limit 37 * 38 * Update the brightness limit for the pc50633 backlight. The actual brightness 39 * will not go above the limit. This is useful to limit power drain for example 40 * on low battery. 41 * 42 * @dev: Pointer to a pcf50633 device 43 * @limit: The brightness limit. Valid values are 0-63 44 */ 45 int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit) 46 { 47 struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev); 48 49 if (!pcf_bl) 50 return -ENODEV; 51 52 pcf_bl->brightness_limit = limit & 0x3f; 53 backlight_update_status(pcf_bl->bl); 54 55 return 0; 56 } 57 58 static int pcf50633_bl_update_status(struct backlight_device *bl) 59 { 60 struct pcf50633_bl *pcf_bl = bl_get_data(bl); 61 unsigned int new_brightness; 62 63 64 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) || 65 bl->props.power != FB_BLANK_UNBLANK) 66 new_brightness = 0; 67 else if (bl->props.brightness < pcf_bl->brightness_limit) 68 new_brightness = bl->props.brightness; 69 else 70 new_brightness = pcf_bl->brightness_limit; 71 72 73 if (pcf_bl->brightness == new_brightness) 74 return 0; 75 76 if (new_brightness) { 77 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT, 78 new_brightness); 79 if (!pcf_bl->brightness) 80 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1); 81 } else { 82 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0); 83 } 84 85 pcf_bl->brightness = new_brightness; 86 87 return 0; 88 } 89 90 static int pcf50633_bl_get_brightness(struct backlight_device *bl) 91 { 92 struct pcf50633_bl *pcf_bl = bl_get_data(bl); 93 return pcf_bl->brightness; 94 } 95 96 static const struct backlight_ops pcf50633_bl_ops = { 97 .get_brightness = pcf50633_bl_get_brightness, 98 .update_status = pcf50633_bl_update_status, 99 .options = BL_CORE_SUSPENDRESUME, 100 }; 101 102 static int __devinit pcf50633_bl_probe(struct platform_device *pdev) 103 { 104 int ret; 105 struct pcf50633_bl *pcf_bl; 106 struct device *parent = pdev->dev.parent; 107 struct pcf50633_platform_data *pcf50633_data = parent->platform_data; 108 struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data; 109 struct backlight_properties bl_props; 110 111 pcf_bl = kzalloc(sizeof(*pcf_bl), GFP_KERNEL); 112 if (!pcf_bl) 113 return -ENOMEM; 114 115 bl_props.max_brightness = 0x3f; 116 bl_props.power = FB_BLANK_UNBLANK; 117 118 if (pdata) { 119 bl_props.brightness = pdata->default_brightness; 120 pcf_bl->brightness_limit = pdata->default_brightness_limit; 121 } else { 122 bl_props.brightness = 0x3f; 123 pcf_bl->brightness_limit = 0x3f; 124 } 125 126 pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent); 127 128 pcf_bl->bl = backlight_device_register(pdev->name, &pdev->dev, pcf_bl, 129 &pcf50633_bl_ops, &bl_props); 130 131 if (IS_ERR(pcf_bl->bl)) { 132 ret = PTR_ERR(pcf_bl->bl); 133 goto err_free; 134 } 135 136 platform_set_drvdata(pdev, pcf_bl); 137 138 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time); 139 140 /* Should be different from bl_props.brightness, so we do not exit 141 * update_status early the first time it's called */ 142 pcf_bl->brightness = pcf_bl->bl->props.brightness + 1; 143 144 backlight_update_status(pcf_bl->bl); 145 146 return 0; 147 148 err_free: 149 kfree(pcf_bl); 150 151 return ret; 152 } 153 154 static int __devexit pcf50633_bl_remove(struct platform_device *pdev) 155 { 156 struct pcf50633_bl *pcf_bl = platform_get_drvdata(pdev); 157 158 backlight_device_unregister(pcf_bl->bl); 159 160 platform_set_drvdata(pdev, NULL); 161 162 kfree(pcf_bl); 163 164 return 0; 165 } 166 167 static struct platform_driver pcf50633_bl_driver = { 168 .probe = pcf50633_bl_probe, 169 .remove = __devexit_p(pcf50633_bl_remove), 170 .driver = { 171 .name = "pcf50633-backlight", 172 }, 173 }; 174 175 static int __init pcf50633_bl_init(void) 176 { 177 return platform_driver_register(&pcf50633_bl_driver); 178 } 179 module_init(pcf50633_bl_init); 180 181 static void __exit pcf50633_bl_exit(void) 182 { 183 platform_driver_unregister(&pcf50633_bl_driver); 184 } 185 module_exit(pcf50633_bl_exit); 186 187 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 188 MODULE_DESCRIPTION("PCF50633 backlight driver"); 189 MODULE_LICENSE("GPL"); 190 MODULE_ALIAS("platform:pcf50633-backlight"); 191