drivers/video/backlight/adx_bl.c

   1 /*
   2  * linux/drivers/video/backlight/adx.c
   3  *
   4  * Copyright (C) 2009 Avionic Design GmbH
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Written by Thierry Reding <thierry.reding@avionic-design.de>
  11  */
  12
  13 #include <linux/backlight.h>
  14 #include <linux/fb.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18
  19 /* register definitions */
  20 #define ADX_BACKLIGHT_CONTROL           0x00
  21 #define ADX_BACKLIGHT_CONTROL_ENABLE    (1 << 0)
  22 #define ADX_BACKLIGHT_BRIGHTNESS        0x08
  23 #define ADX_BACKLIGHT_STATUS            0x10
  24 #define ADX_BACKLIGHT_ERROR             0x18
  25
  26 struct adxbl {
  27         void __iomem *base;
  28 };
  29
  30 static int adx_backlight_update_status(struct backlight_device *bldev)
  31 {
  32         struct adxbl *bl = bl_get_data(bldev);
  33         u32 value;
  34
  35         value = bldev->props.brightness;
  36         writel(value, bl->base + ADX_BACKLIGHT_BRIGHTNESS);
  37
  38         value = readl(bl->base + ADX_BACKLIGHT_CONTROL);
  39
  40         if (bldev->props.state & BL_CORE_FBBLANK)
  41                 value &= ~ADX_BACKLIGHT_CONTROL_ENABLE;
  42         else
  43                 value |= ADX_BACKLIGHT_CONTROL_ENABLE;
  44
  45         writel(value, bl->base + ADX_BACKLIGHT_CONTROL);
  46
  47         return 0;
  48 }
  49
  50 static int adx_backlight_get_brightness(struct backlight_device *bldev)
  51 {
  52         struct adxbl *bl = bl_get_data(bldev);
  53         u32 brightness;
  54
  55         brightness = readl(bl->base + ADX_BACKLIGHT_BRIGHTNESS);
  56         return brightness & 0xff;
  57 }
  58
  59 static int adx_backlight_check_fb(struct backlight_device *bldev, struct fb_info *fb)
  60 {
  61         return 1;
  62 }
  63
  64 static const struct backlight_ops adx_backlight_ops = {
  65         .options = 0,
  66         .update_status = adx_backlight_update_status,
  67         .get_brightness = adx_backlight_get_brightness,
  68         .check_fb = adx_backlight_check_fb,
  69 };
  70
  71 static int __devinit adx_backlight_probe(struct platform_device *pdev)
  72 {
  73         struct backlight_properties props;
  74         struct backlight_device *bldev;
  75         struct resource *res;
  76         struct adxbl *bl;
  77         int ret = 0;
  78
  79         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  80         if (!res) {
  81                 ret = -ENXIO;
  82                 goto out;
  83         }
  84
  85         res = devm_request_mem_region(&pdev->dev, res->start,
  86                         resource_size(res), res->name);
  87         if (!res) {
  88                 ret = -ENXIO;
  89                 goto out;
  90         }
  91
  92         bl = devm_kzalloc(&pdev->dev, sizeof(*bl), GFP_KERNEL);
  93         if (!bl) {
  94                 ret = -ENOMEM;
  95                 goto out;
  96         }
  97
  98         bl->base = devm_ioremap_nocache(&pdev->dev, res->start,
  99                         resource_size(res));
 100         if (!bl->base) {
 101                 ret = -ENXIO;
 102                 goto out;
 103         }
 104
 105         memset(&props, 0, sizeof(struct backlight_properties));
 106         props.max_brightness = 0xff;
 107         bldev = backlight_device_register(dev_name(&pdev->dev), &pdev->dev,
 108                                           bl, &adx_backlight_ops, &props);
 109         if (!bldev) {
 110                 ret = -ENOMEM;
 111                 goto out;
 112         }
 113
 114         bldev->props.brightness = 0xff;
 115         bldev->props.power = FB_BLANK_UNBLANK;
 116
 117         platform_set_drvdata(pdev, bldev);
 118
 119 out:
 120         return ret;
 121 }
 122
 123 static int __devexit adx_backlight_remove(struct platform_device *pdev)
 124 {
 125         struct backlight_device *bldev;
 126         int ret = 0;
 127
 128         bldev = platform_get_drvdata(pdev);
 129         bldev->props.power = FB_BLANK_UNBLANK;
 130         bldev->props.brightness = 0xff;
 131         backlight_update_status(bldev);
 132         backlight_device_unregister(bldev);
 133         platform_set_drvdata(pdev, NULL);
 134
 135         return ret;
 136 }
 137
 138 #ifdef CONFIG_PM
 139 static int adx_backlight_suspend(struct platform_device *pdev,
 140                 pm_message_t state)
 141 {
 142         return 0;
 143 }
 144
 145 static int adx_backlight_resume(struct platform_device *pdev)
 146 {
 147         return 0;
 148 }
 149 #else
 150 #define adx_backlight_suspend NULL
 151 #define adx_backlight_resume NULL
 152 #endif
 153
 154 static struct platform_driver adx_backlight_driver = {
 155         .probe = adx_backlight_probe,
 156         .remove = __devexit_p(adx_backlight_remove),
 157         .suspend = adx_backlight_suspend,
 158         .resume = adx_backlight_resume,
 159         .driver = {
 160                 .name = "adx-backlight",
 161                 .owner = THIS_MODULE,
 162         },
 163 };
 164
 165 static int __init adx_backlight_init(void)
 166 {
 167         return platform_driver_register(&adx_backlight_driver);
 168 }
 169
 170 static void __exit adx_backlight_exit(void)
 171 {
 172         platform_driver_unregister(&adx_backlight_driver);
 173 }
 174
 175 module_init(adx_backlight_init);
 176 module_exit(adx_backlight_exit);
 177
 178 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 179 MODULE_DESCRIPTION("Avionic Design Xanthos Backlight Driver");
 180 MODULE_LICENSE("GPL v2");