arch/arm/plat-samsung/dev-backlight.c

   1 /* linux/arch/arm/plat-samsung/dev-backlight.c
   2  *
   3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * Common infrastructure for PWM Backlight for Samsung boards
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/gpio.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16 #include <linux/io.h>
  17 #include <linux/pwm_backlight.h>
  18
  19 #include <plat/devs.h>
  20 #include <plat/gpio-cfg.h>
  21 #include <plat/backlight.h>
  22
  23 struct samsung_bl_drvdata {
  24         struct platform_pwm_backlight_data plat_data;
  25         struct samsung_bl_gpio_info *gpio_info;
  26 };
  27
  28 static int samsung_bl_init(struct device *dev)
  29 {
  30         int ret = 0;
  31         struct platform_pwm_backlight_data *pdata = dev->platform_data;
  32         struct samsung_bl_drvdata *drvdata = container_of(pdata,
  33                                         struct samsung_bl_drvdata, plat_data);
  34         struct samsung_bl_gpio_info *bl_gpio_info = drvdata->gpio_info;
  35
  36         ret = gpio_request(bl_gpio_info->no, "Backlight");
  37         if (ret) {
  38                 printk(KERN_ERR "failed to request GPIO for LCD Backlight\n");
  39                 return ret;
  40         }
  41
  42         /* Configure GPIO pin with specific GPIO function for PWM timer */
  43         s3c_gpio_cfgpin(bl_gpio_info->no, bl_gpio_info->func);
  44
  45         return 0;
  46 }
  47
  48 static void samsung_bl_exit(struct device *dev)
  49 {
  50         struct platform_pwm_backlight_data *pdata = dev->platform_data;
  51         struct samsung_bl_drvdata *drvdata = container_of(pdata,
  52                                         struct samsung_bl_drvdata, plat_data);
  53         struct samsung_bl_gpio_info *bl_gpio_info = drvdata->gpio_info;
  54
  55         s3c_gpio_cfgpin(bl_gpio_info->no, S3C_GPIO_OUTPUT);
  56         gpio_free(bl_gpio_info->no);
  57 }
  58
  59 /* Initialize few important fields of platform_pwm_backlight_data
  60  * structure with default values. These fields can be overridden by
  61  * board-specific values sent from machine file.
  62  * For ease of operation, these fields are initialized with values
  63  * used by most samsung boards.
  64  * Users has the option of sending info about other parameters
  65  * for their specific boards
  66  */
  67
  68 static struct samsung_bl_drvdata samsung_dfl_bl_data __initdata = {
  69         .plat_data = {
  70                 .max_brightness = 255,
  71                 .dft_brightness = 255,
  72                 .pwm_period_ns  = 78770,
  73                 .init           = samsung_bl_init,
  74                 .exit           = samsung_bl_exit,
  75         },
  76 };
  77
  78 static struct platform_device samsung_dfl_bl_device __initdata = {
  79         .name           = "pwm-backlight",
  80 };
  81
  82 /* samsung_bl_set - Set board specific data (if any) provided by user for
  83  * PWM Backlight control and register specific PWM and backlight device.
  84  * @gpio_info:  structure containing GPIO info for PWM timer
  85  * @bl_data:    structure containing Backlight control data
  86  */
  87 void __init samsung_bl_set(struct samsung_bl_gpio_info *gpio_info,
  88         struct platform_pwm_backlight_data *bl_data)
  89 {
  90         int ret = 0;
  91         struct platform_device *samsung_bl_device;
  92         struct samsung_bl_drvdata *samsung_bl_drvdata;
  93         struct platform_pwm_backlight_data *samsung_bl_data;
  94
  95         samsung_bl_device = kmemdup(&samsung_dfl_bl_device,
  96                         sizeof(struct platform_device), GFP_KERNEL);
  97         if (!samsung_bl_device) {
  98                 printk(KERN_ERR "%s: no memory for platform dev\n", __func__);
  99                 return;
 100         }
 101
 102         samsung_bl_drvdata = kmemdup(&samsung_dfl_bl_data,
 103                                 sizeof(samsung_dfl_bl_data), GFP_KERNEL);
 104         if (!samsung_bl_drvdata) {
 105                 printk(KERN_ERR "%s: no memory for platform dev\n", __func__);
 106                 goto err_data;
 107         }
 108         samsung_bl_device->dev.platform_data = &samsung_bl_drvdata->plat_data;
 109         samsung_bl_drvdata->gpio_info = gpio_info;
 110         samsung_bl_data = &samsung_bl_drvdata->plat_data;
 111
 112         /* Copy board specific data provided by user */
 113         samsung_bl_data->pwm_id = bl_data->pwm_id;
 114         samsung_bl_device->dev.parent = &samsung_device_pwm.dev;
 115
 116         if (bl_data->max_brightness)
 117                 samsung_bl_data->max_brightness = bl_data->max_brightness;
 118         if (bl_data->dft_brightness)
 119                 samsung_bl_data->dft_brightness = bl_data->dft_brightness;
 120         if (bl_data->lth_brightness)
 121                 samsung_bl_data->lth_brightness = bl_data->lth_brightness;
 122         if (bl_data->pwm_period_ns)
 123                 samsung_bl_data->pwm_period_ns = bl_data->pwm_period_ns;
 124         if (bl_data->init)
 125                 samsung_bl_data->init = bl_data->init;
 126         if (bl_data->notify)
 127                 samsung_bl_data->notify = bl_data->notify;
 128         if (bl_data->notify_after)
 129                 samsung_bl_data->notify_after = bl_data->notify_after;
 130         if (bl_data->exit)
 131                 samsung_bl_data->exit = bl_data->exit;
 132         if (bl_data->check_fb)
 133                 samsung_bl_data->check_fb = bl_data->check_fb;
 134
 135         /* Register the Backlight dev */
 136         ret = platform_device_register(samsung_bl_device);
 137         if (ret) {
 138                 printk(KERN_ERR "failed to register backlight device: %d\n", ret);
 139                 goto err_plat_reg2;
 140         }
 141
 142         return;
 143
 144 err_plat_reg2:
 145         kfree(samsung_bl_data);
 146 err_data:
 147         kfree(samsung_bl_device);
 148         return;
 149 }