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