drivers/video/backlight/max8925_bl.c

   1 /*
   2  * Backlight driver for Maxim MAX8925
   3  *
   4  * Copyright (C) 2009 Marvell International Ltd.
   5  *      Haojian Zhuang <haojian.zhuang@marvell.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/fb.h>
  16 #include <linux/i2c.h>
  17 #include <linux/backlight.h>
  18 #include <linux/mfd/max8925.h>
  19 #include <linux/slab.h>
  20
  21 #define MAX_BRIGHTNESS          (0xff)
  22 #define MIN_BRIGHTNESS          (0)
  23
  24 #define LWX_FREQ(x)             (((x - 601) / 100) & 0x7)
  25
  26 struct max8925_backlight_data {
  27         struct max8925_chip     *chip;
  28
  29         int             current_brightness;
  30 };
  31
  32 static int max8925_backlight_set(struct backlight_device *bl, int brightness)
  33 {
  34         struct max8925_backlight_data *data = bl_get_data(bl);
  35         struct max8925_chip *chip = data->chip;
  36         unsigned char value;
  37         int ret;
  38
  39         if (brightness > MAX_BRIGHTNESS)
  40                 value = MAX_BRIGHTNESS;
  41         else
  42                 value = brightness;
  43
  44         ret = max8925_reg_write(chip->i2c, MAX8925_WLED_CNTL, value);
  45         if (ret < 0)
  46                 goto out;
  47
  48         if (!data->current_brightness && brightness)
  49                 /* enable WLED output */
  50                 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 1);
  51         else if (!brightness)
  52                 /* disable WLED output */
  53                 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 0);
  54         if (ret < 0)
  55                 goto out;
  56         dev_dbg(chip->dev, "set brightness %d\n", value);
  57         data->current_brightness = value;
  58         return 0;
  59 out:
  60         dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
  61                 value, ret);
  62         return ret;
  63 }
  64
  65 static int max8925_backlight_update_status(struct backlight_device *bl)
  66 {
  67         int brightness = bl->props.brightness;
  68
  69         if (bl->props.power != FB_BLANK_UNBLANK)
  70                 brightness = 0;
  71
  72         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
  73                 brightness = 0;
  74
  75         if (bl->props.state & BL_CORE_SUSPENDED)
  76                 brightness = 0;
  77
  78         return max8925_backlight_set(bl, brightness);
  79 }
  80
  81 static int max8925_backlight_get_brightness(struct backlight_device *bl)
  82 {
  83         struct max8925_backlight_data *data = bl_get_data(bl);
  84         struct max8925_chip *chip = data->chip;
  85         int ret;
  86
  87         ret = max8925_reg_read(chip->i2c, MAX8925_WLED_CNTL);
  88         if (ret < 0)
  89                 return -EINVAL;
  90         data->current_brightness = ret;
  91         dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
  92         return ret;
  93 }
  94
  95 static struct backlight_ops max8925_backlight_ops = {
  96         .options        = BL_CORE_SUSPENDRESUME,
  97         .update_status  = max8925_backlight_update_status,
  98         .get_brightness = max8925_backlight_get_brightness,
  99 };
 100
 101 static int __devinit max8925_backlight_probe(struct platform_device *pdev)
 102 {
 103         struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
 104         struct max8925_platform_data *max8925_pdata;
 105         struct max8925_backlight_pdata *pdata = NULL;
 106         struct max8925_backlight_data *data;
 107         struct backlight_device *bl;
 108         struct backlight_properties props;
 109         struct resource *res;
 110         char name[MAX8925_NAME_SIZE];
 111         unsigned char value;
 112         int ret;
 113
 114         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 115         if (res == NULL) {
 116                 dev_err(&pdev->dev, "No I/O resource!\n");
 117                 return -EINVAL;
 118         }
 119
 120         if (pdev->dev.parent->platform_data) {
 121                 max8925_pdata = pdev->dev.parent->platform_data;
 122                 pdata = max8925_pdata->backlight;
 123         }
 124
 125         if (!pdata) {
 126                 dev_err(&pdev->dev, "platform data isn't assigned to "
 127                         "backlight\n");
 128                 return -EINVAL;
 129         }
 130
 131         data = kzalloc(sizeof(struct max8925_backlight_data), GFP_KERNEL);
 132         if (data == NULL)
 133                 return -ENOMEM;
 134         strncpy(name, res->name, MAX8925_NAME_SIZE);
 135         data->chip = chip;
 136         data->current_brightness = 0;
 137
 138         memset(&props, 0, sizeof(struct backlight_properties));
 139         props.max_brightness = MAX_BRIGHTNESS;
 140         bl = backlight_device_register(name, &pdev->dev, data,
 141                                         &max8925_backlight_ops, &props);
 142         if (IS_ERR(bl)) {
 143                 dev_err(&pdev->dev, "failed to register backlight\n");
 144                 kfree(data);
 145                 return PTR_ERR(bl);
 146         }
 147         bl->props.brightness = MAX_BRIGHTNESS;
 148
 149         platform_set_drvdata(pdev, bl);
 150
 151         value = 0;
 152         if (pdata->lxw_scl)
 153                 value |= (1 << 7);
 154         if (pdata->lxw_freq)
 155                 value |= (LWX_FREQ(pdata->lxw_freq) << 4);
 156         if (pdata->dual_string)
 157                 value |= (1 << 1);
 158         ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 0xfe, value);
 159         if (ret < 0)
 160                 goto out;
 161
 162         backlight_update_status(bl);
 163         return 0;
 164 out:
 165         kfree(data);
 166         return ret;
 167 }
 168
 169 static int __devexit max8925_backlight_remove(struct platform_device *pdev)
 170 {
 171         struct backlight_device *bl = platform_get_drvdata(pdev);
 172         struct max8925_backlight_data *data = bl_get_data(bl);
 173
 174         backlight_device_unregister(bl);
 175         kfree(data);
 176         return 0;
 177 }
 178
 179 static struct platform_driver max8925_backlight_driver = {
 180         .driver         = {
 181                 .name   = "max8925-backlight",
 182                 .owner  = THIS_MODULE,
 183         },
 184         .probe          = max8925_backlight_probe,
 185         .remove         = __devexit_p(max8925_backlight_remove),
 186 };
 187
 188 static int __init max8925_backlight_init(void)
 189 {
 190         return platform_driver_register(&max8925_backlight_driver);
 191 }
 192 module_init(max8925_backlight_init);
 193
 194 static void __exit max8925_backlight_exit(void)
 195 {
 196         platform_driver_unregister(&max8925_backlight_driver);
 197 };
 198 module_exit(max8925_backlight_exit);
 199
 200 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
 201 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 202 MODULE_LICENSE("GPL");
 203 MODULE_ALIAS("platform:max8925-backlight");