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 static int samsung_bl_init(struct device *dev)
  24 {
  25         int ret = 0;
  26         struct platform_device *timer_dev =
  27                         container_of(dev->parent, struct platform_device, dev);
  28         struct samsung_bl_gpio_info *bl_gpio_info =
  29                         timer_dev->dev.platform_data;
  30
  31         ret = gpio_request(bl_gpio_info->no, "Backlight");
  32         if (ret) {
  33                 printk(KERN_ERR "failed to request GPIO for LCD Backlight\n");
  34                 return ret;
  35         }
  36
  37         /* Configure GPIO pin with specific GPIO function for PWM timer */
  38         s3c_gpio_cfgpin(bl_gpio_info->no, bl_gpio_info->func);
  39
  40         return 0;
  41 }
  42
  43 static void samsung_bl_exit(struct device *dev)
  44 {
  45         struct platform_device *timer_dev =
  46                         container_of(dev->parent, struct platform_device, dev);
  47         struct samsung_bl_gpio_info *bl_gpio_info =
  48                         timer_dev->dev.platform_data;
  49
  50         s3c_gpio_cfgpin(bl_gpio_info->no, S3C_GPIO_OUTPUT);
  51         gpio_free(bl_gpio_info->no);
  52 }
  53
  54 /* Initialize few important fields of platform_pwm_backlight_data
  55  * structure with default values. These fields can be overridden by
  56  * board-specific values sent from machine file.
  57  * For ease of operation, these fields are initialized with values
  58  * used by most samsung boards.
  59  * Users has the option of sending info about other parameters
  60  * for their specific boards
  61  */
  62
  63 static struct platform_pwm_backlight_data samsung_dfl_bl_data __initdata = {
  64         .max_brightness = 255,
  65         .dft_brightness = 255,
  66         .pwm_period_ns  = 78770,
  67         .init           = samsung_bl_init,
  68         .exit           = samsung_bl_exit,
  69 };
  70
  71 static struct platform_device samsung_dfl_bl_device __initdata = {
  72         .name           = "pwm-backlight",
  73 };
  74
  75 /* samsung_bl_set - Set board specific data (if any) provided by user for
  76  * PWM Backlight control and register specific PWM and backlight device.
  77  * @gpio_info:  structure containing GPIO info for PWM timer
  78  * @bl_data:    structure containing Backlight control data
  79  */
  80 void samsung_bl_set(struct samsung_bl_gpio_info *gpio_info,
  81         struct platform_pwm_backlight_data *bl_data)
  82 {
  83         int ret = 0;
  84         struct platform_device *samsung_bl_device;
  85         struct platform_pwm_backlight_data *samsung_bl_data;
  86
  87         samsung_bl_device = kmemdup(&samsung_dfl_bl_device,
  88                         sizeof(struct platform_device), GFP_KERNEL);
  89         if (!samsung_bl_device) {
  90                 printk(KERN_ERR "%s: no memory for platform dev\n", __func__);
  91                 return;
  92         }
  93
  94         samsung_bl_data = s3c_set_platdata(&samsung_dfl_bl_data,
  95                 sizeof(struct platform_pwm_backlight_data), samsung_bl_device);
  96         if (!samsung_bl_data) {
  97                 printk(KERN_ERR "%s: no memory for platform dev\n", __func__);
  98                 goto err_data;
  99         }
 100
 101         /* Copy board specific data provided by user */
 102         samsung_bl_data->pwm_id = bl_data->pwm_id;
 103         samsung_bl_device->dev.parent =
 104                         &s3c_device_timer[samsung_bl_data->pwm_id].dev;
 105
 106         if (bl_data->max_brightness)
 107                 samsung_bl_data->max_brightness = bl_data->max_brightness;
 108         if (bl_data->dft_brightness)
 109                 samsung_bl_data->dft_brightness = bl_data->dft_brightness;
 110         if (bl_data->lth_brightness)
 111                 samsung_bl_data->lth_brightness = bl_data->lth_brightness;
 112         if (bl_data->pwm_period_ns)
 113                 samsung_bl_data->pwm_period_ns = bl_data->pwm_period_ns;
 114         if (bl_data->init)
 115                 samsung_bl_data->init = bl_data->init;
 116         if (bl_data->notify)
 117                 samsung_bl_data->notify = bl_data->notify;
 118         if (bl_data->exit)
 119                 samsung_bl_data->exit = bl_data->exit;
 120         if (bl_data->check_fb)
 121                 samsung_bl_data->check_fb = bl_data->check_fb;
 122
 123         /* Keep the GPIO info for future use */
 124         s3c_device_timer[samsung_bl_data->pwm_id].dev.platform_data = gpio_info;
 125
 126         /* Register the specific PWM timer dev for Backlight control */
 127         ret = platform_device_register(
 128                         &s3c_device_timer[samsung_bl_data->pwm_id]);
 129         if (ret) {
 130                 printk(KERN_ERR "failed to register pwm timer for backlight: %d\n", ret);
 131                 goto err_plat_reg1;
 132         }
 133
 134         /* Register the Backlight dev */
 135         ret = platform_device_register(samsung_bl_device);
 136         if (ret) {
 137                 printk(KERN_ERR "failed to register backlight device: %d\n", ret);
 138                 goto err_plat_reg2;
 139         }
 140
 141         return;
 142
 143 err_plat_reg2:
 144         platform_device_unregister(&s3c_device_timer[samsung_bl_data->pwm_id]);
 145 err_plat_reg1:
 146         kfree(samsung_bl_data);
 147 err_data:
 148         kfree(samsung_bl_device);
 149         return;
 150 }