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