drivers/video/backlight/platform_lcd.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* drivers/video/backlight/platform_lcd.c
   3  *
   4  * Copyright 2008 Simtec Electronics
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * Generic platform-device LCD power control interface.
   8 */
   9
  10 #include <linux/module.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/lcd.h>
  13 #include <linux/slab.h>
  14
  15 #include <video/platform_lcd.h>
  16
  17 struct platform_lcd {
  18         struct device           *us;
  19         struct lcd_device       *lcd;
  20         struct plat_lcd_data    *pdata;
  21
  22         unsigned int             power;
  23         unsigned int             suspended:1;
  24 };
  25
  26 static inline struct platform_lcd *to_our_lcd(struct lcd_device *lcd)
  27 {
  28         return lcd_get_data(lcd);
  29 }
  30
  31 static int platform_lcd_get_power(struct lcd_device *lcd)
  32 {
  33         struct platform_lcd *plcd = to_our_lcd(lcd);
  34
  35         return plcd->power;
  36 }
  37
  38 static int platform_lcd_set_power(struct lcd_device *lcd, int power)
  39 {
  40         struct platform_lcd *plcd = to_our_lcd(lcd);
  41         int lcd_power = 1;
  42
  43         if (power == LCD_POWER_OFF || plcd->suspended)
  44                 lcd_power = 0;
  45
  46         plcd->pdata->set_power(plcd->pdata, lcd_power);
  47         plcd->power = power;
  48
  49         return 0;
  50 }
  51
  52 static bool platform_lcd_controls_device(struct lcd_device *lcd, struct device *display_device)
  53 {
  54         struct platform_lcd *plcd = to_our_lcd(lcd);
  55
  56         return plcd->us->parent == display_device;
  57 }
  58
  59 static const struct lcd_ops platform_lcd_ops = {
  60         .get_power              = platform_lcd_get_power,
  61         .set_power              = platform_lcd_set_power,
  62         .controls_device        = platform_lcd_controls_device,
  63 };
  64
  65 static int platform_lcd_probe(struct platform_device *pdev)
  66 {
  67         struct plat_lcd_data *pdata;
  68         struct platform_lcd *plcd;
  69         struct device *dev = &pdev->dev;
  70         int err;
  71
  72         pdata = dev_get_platdata(&pdev->dev);
  73         if (!pdata) {
  74                 dev_err(dev, "no platform data supplied\n");
  75                 return -EINVAL;
  76         }
  77
  78         if (pdata->probe) {
  79                 err = pdata->probe(pdata);
  80                 if (err)
  81                         return err;
  82         }
  83
  84         plcd = devm_kzalloc(&pdev->dev, sizeof(struct platform_lcd),
  85                             GFP_KERNEL);
  86         if (!plcd)
  87                 return -ENOMEM;
  88
  89         plcd->us = dev;
  90         plcd->pdata = pdata;
  91         plcd->lcd = devm_lcd_device_register(&pdev->dev, dev_name(dev), dev,
  92                                                 plcd, &platform_lcd_ops);
  93         if (IS_ERR(plcd->lcd)) {
  94                 dev_err(dev, "cannot register lcd device\n");
  95                 return PTR_ERR(plcd->lcd);
  96         }
  97
  98         platform_set_drvdata(pdev, plcd);
  99         platform_lcd_set_power(plcd->lcd, LCD_POWER_REDUCED);
 100
 101         return 0;
 102 }
 103
 104 #ifdef CONFIG_PM_SLEEP
 105 static int platform_lcd_suspend(struct device *dev)
 106 {
 107         struct platform_lcd *plcd = dev_get_drvdata(dev);
 108
 109         plcd->suspended = 1;
 110         platform_lcd_set_power(plcd->lcd, plcd->power);
 111
 112         return 0;
 113 }
 114
 115 static int platform_lcd_resume(struct device *dev)
 116 {
 117         struct platform_lcd *plcd = dev_get_drvdata(dev);
 118
 119         plcd->suspended = 0;
 120         platform_lcd_set_power(plcd->lcd, plcd->power);
 121
 122         return 0;
 123 }
 124 #endif
 125
 126 static SIMPLE_DEV_PM_OPS(platform_lcd_pm_ops, platform_lcd_suspend,
 127                         platform_lcd_resume);
 128
 129 static struct platform_driver platform_lcd_driver = {
 130         .driver         = {
 131                 .name   = "platform-lcd",
 132                 .pm     = &platform_lcd_pm_ops,
 133         },
 134         .probe          = platform_lcd_probe,
 135 };
 136
 137 module_platform_driver(platform_lcd_driver);
 138
 139 MODULE_AUTHOR("Ben Dooks <ben-linux@fluff.org>");
 140 MODULE_DESCRIPTION("Generic platform-device LCD power control interface");
 141 MODULE_LICENSE("GPL v2");
 142 MODULE_ALIAS("platform:platform-lcd");