drivers/video/backlight/da903x_bl.c

   1 /*
   2  * Backlight driver for Dialog Semiconductor DA9030/DA9034
   3  *
   4  * Copyright (C) 2008 Compulab, Ltd.
   5  *      Mike Rapoport <mike@compulab.co.il>
   6  *
   7  * Copyright (C) 2006-2008 Marvell International Ltd.
   8  *      Eric Miao <eric.miao@marvell.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/fb.h>
  19 #include <linux/backlight.h>
  20 #include <linux/mfd/da903x.h>
  21 #include <linux/slab.h>
  22 #include <linux/module.h>
  23
  24 #define DA9030_WLED_CONTROL     0x25
  25 #define DA9030_WLED_CP_EN       (1 << 6)
  26 #define DA9030_WLED_TRIM(x)     ((x) & 0x7)
  27
  28 #define DA9034_WLED_CONTROL1    0x3C
  29 #define DA9034_WLED_CONTROL2    0x3D
  30 #define DA9034_WLED_ISET(x)     ((x) & 0x1f)
  31
  32 #define DA9034_WLED_BOOST_EN    (1 << 5)
  33
  34 #define DA9030_MAX_BRIGHTNESS   7
  35 #define DA9034_MAX_BRIGHTNESS   0x7f
  36
  37 struct da903x_backlight_data {
  38         struct device *da903x_dev;
  39         int id;
  40         int current_brightness;
  41 };
  42
  43 static int da903x_backlight_set(struct backlight_device *bl, int brightness)
  44 {
  45         struct da903x_backlight_data *data = bl_get_data(bl);
  46         struct device *dev = data->da903x_dev;
  47         uint8_t val;
  48         int ret = 0;
  49
  50         switch (data->id) {
  51         case DA9034_ID_WLED:
  52                 ret = da903x_update(dev, DA9034_WLED_CONTROL1,
  53                                 brightness, 0x7f);
  54                 if (ret)
  55                         return ret;
  56
  57                 if (data->current_brightness && brightness == 0)
  58                         ret = da903x_clr_bits(dev,
  59                                         DA9034_WLED_CONTROL2,
  60                                         DA9034_WLED_BOOST_EN);
  61
  62                 if (data->current_brightness == 0 && brightness)
  63                         ret = da903x_set_bits(dev,
  64                                         DA9034_WLED_CONTROL2,
  65                                         DA9034_WLED_BOOST_EN);
  66                 break;
  67         case DA9030_ID_WLED:
  68                 val = DA9030_WLED_TRIM(brightness);
  69                 val |= brightness ? DA9030_WLED_CP_EN : 0;
  70                 ret = da903x_write(dev, DA9030_WLED_CONTROL, val);
  71                 break;
  72         }
  73
  74         if (ret)
  75                 return ret;
  76
  77         data->current_brightness = brightness;
  78         return 0;
  79 }
  80
  81 static int da903x_backlight_update_status(struct backlight_device *bl)
  82 {
  83         int brightness = bl->props.brightness;
  84
  85         if (bl->props.power != FB_BLANK_UNBLANK)
  86                 brightness = 0;
  87
  88         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
  89                 brightness = 0;
  90
  91         if (bl->props.state & BL_CORE_SUSPENDED)
  92                 brightness = 0;
  93
  94         return da903x_backlight_set(bl, brightness);
  95 }
  96
  97 static int da903x_backlight_get_brightness(struct backlight_device *bl)
  98 {
  99         struct da903x_backlight_data *data = bl_get_data(bl);
 100
 101         return data->current_brightness;
 102 }
 103
 104 static const struct backlight_ops da903x_backlight_ops = {
 105         .options        = BL_CORE_SUSPENDRESUME,
 106         .update_status  = da903x_backlight_update_status,
 107         .get_brightness = da903x_backlight_get_brightness,
 108 };
 109
 110 static int da903x_backlight_probe(struct platform_device *pdev)
 111 {
 112         struct da9034_backlight_pdata *pdata = pdev->dev.platform_data;
 113         struct da903x_backlight_data *data;
 114         struct backlight_device *bl;
 115         struct backlight_properties props;
 116         int max_brightness;
 117
 118         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 119         if (data == NULL)
 120                 return -ENOMEM;
 121
 122         switch (pdev->id) {
 123         case DA9030_ID_WLED:
 124                 max_brightness = DA9030_MAX_BRIGHTNESS;
 125                 break;
 126         case DA9034_ID_WLED:
 127                 max_brightness = DA9034_MAX_BRIGHTNESS;
 128                 break;
 129         default:
 130                 dev_err(&pdev->dev, "invalid backlight device ID(%d)\n",
 131                                 pdev->id);
 132                 return -EINVAL;
 133         }
 134
 135         data->id = pdev->id;
 136         data->da903x_dev = pdev->dev.parent;
 137         data->current_brightness = 0;
 138
 139         /* adjust the WLED output current */
 140         if (pdata)
 141                 da903x_write(data->da903x_dev, DA9034_WLED_CONTROL2,
 142                                 DA9034_WLED_ISET(pdata->output_current));
 143
 144         memset(&props, 0, sizeof(props));
 145         props.type = BACKLIGHT_RAW;
 146         props.max_brightness = max_brightness;
 147         bl = backlight_device_register(pdev->name, data->da903x_dev, data,
 148                                        &da903x_backlight_ops, &props);
 149         if (IS_ERR(bl)) {
 150                 dev_err(&pdev->dev, "failed to register backlight\n");
 151                 return PTR_ERR(bl);
 152         }
 153
 154         bl->props.brightness = max_brightness;
 155
 156         platform_set_drvdata(pdev, bl);
 157         backlight_update_status(bl);
 158         return 0;
 159 }
 160
 161 static int da903x_backlight_remove(struct platform_device *pdev)
 162 {
 163         struct backlight_device *bl = platform_get_drvdata(pdev);
 164
 165         backlight_device_unregister(bl);
 166         return 0;
 167 }
 168
 169 static struct platform_driver da903x_backlight_driver = {
 170         .driver         = {
 171                 .name   = "da903x-backlight",
 172                 .owner  = THIS_MODULE,
 173         },
 174         .probe          = da903x_backlight_probe,
 175         .remove         = da903x_backlight_remove,
 176 };
 177
 178 module_platform_driver(da903x_backlight_driver);
 179
 180 MODULE_DESCRIPTION("Backlight Driver for Dialog Semiconductor DA9030/DA9034");
 181 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 182 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
 183 MODULE_LICENSE("GPL");
 184 MODULE_ALIAS("platform:da903x-backlight");