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