drivers/video/backlight/rk29_backlight.c

   1 /* drivers/video/backlight/rk29_backlight.c
   2  *
   3  * Copyright (C) 2009-2011 Rockchip Corporation.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/err.h>
  20 #include <linux/delay.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/backlight.h>
  23 #include <linux/fb.h>
  24 #include <linux/clk.h>
  25
  26 #include <linux/earlysuspend.h>
  27 #include <asm/io.h>
  28 #include <mach/rk29_iomap.h>
  29 #include <mach/board.h>
  30
  31 #include "rk2818_backlight.h"
  32
  33 /*
  34  * Debug
  35  */
  36 #if 0
  37 #define DBG(x...)       printk(KERN_INFO x)
  38 #else
  39 #define DBG(x...)
  40 #endif
  41
  42
  43 #define write_pwm_reg(id, addr, val)        __raw_writel(val, addr+(RK29_PWM_BASE+id*0x10))
  44 #define read_pwm_reg(id, addr)              __raw_readl(addr+(RK29_PWM_BASE+id*0x10))
  45
  46 static struct clk *pwm_clk;
  47 static struct backlight_device *rk29_bl;
  48 static int suspend_flag = 0;
  49
  50 static int rk29_bl_update_status(struct backlight_device *bl)
  51 {
  52         u32 divh,div_total;
  53         struct rk29_bl_info *rk29_bl_info = bl_get_data(bl);
  54         u32 id = rk29_bl_info->pwm_id;
  55         u32 ref = rk29_bl_info->bl_ref;
  56
  57         if (suspend_flag)
  58                 return 0;
  59
  60         if (bl->props.brightness < rk29_bl_info->min_brightness)        /*avoid can't view screen when close backlight*/
  61                 bl->props.brightness = rk29_bl_info->min_brightness;
  62
  63         div_total = read_pwm_reg(id, PWM_REG_LRC);
  64         if (ref) {
  65                 divh = div_total*(bl->props.brightness)/BL_STEP;
  66         } else {
  67                 divh = div_total*(BL_STEP-bl->props.brightness)/BL_STEP;
  68         }
  69         write_pwm_reg(id, PWM_REG_HRC, divh);
  70
  71         DBG(">>>%s-->%d brightness = %d, div_total = %d, divh = %d\n",__FUNCTION__,__LINE__,bl->props.brightness, div_total, divh);
  72         return 0;
  73 }
  74
  75 static int rk29_bl_get_brightness(struct backlight_device *bl)
  76 {
  77         u32 divh,div_total;
  78         struct rk29_bl_info *rk29_bl_info = bl_get_data(bl);
  79         u32 id = rk29_bl_info->pwm_id;
  80         u32 ref = rk29_bl_info->bl_ref;
  81
  82         div_total = read_pwm_reg(id, PWM_REG_LRC);
  83         divh = read_pwm_reg(id, PWM_REG_HRC);
  84
  85         if (!div_total)
  86                 return 0;
  87
  88         if (ref) {
  89                 return BL_STEP*divh/div_total;
  90         } else {
  91                 return BL_STEP-(BL_STEP*divh/div_total);
  92         }
  93 }
  94
  95 static struct backlight_ops rk29_bl_ops = {
  96         .update_status  = rk29_bl_update_status,
  97         .get_brightness = rk29_bl_get_brightness,
  98 };
  99
 100 static void rk29_backlight_work_func(struct work_struct *work)
 101 {
 102         suspend_flag = 0;
 103         rk29_bl_update_status(rk29_bl);
 104 }
 105 static DECLARE_DELAYED_WORK(rk29_backlight_work, rk29_backlight_work_func);
 106
 107 #ifdef CONFIG_HAS_EARLYSUSPEND
 108 static void rk29_bl_suspend(struct early_suspend *h)
 109 {
 110         struct rk29_bl_info *rk29_bl_info = bl_get_data(rk29_bl);
 111         int brightness = rk29_bl->props.brightness;
 112
 113         cancel_delayed_work_sync(&rk29_backlight_work);
 114
 115         if (rk29_bl->props.brightness) {
 116                 rk29_bl->props.brightness = 0;
 117                 rk29_bl_update_status(rk29_bl);
 118                 rk29_bl->props.brightness = brightness;
 119         }
 120
 121         if (!suspend_flag) {
 122                 clk_disable(pwm_clk);
 123                 if (rk29_bl_info->pwm_suspend)
 124                         rk29_bl_info->pwm_suspend();
 125         }
 126
 127         suspend_flag = 1;
 128 }
 129
 130 static void rk29_bl_resume(struct early_suspend *h)
 131 {
 132         struct rk29_bl_info *rk29_bl_info = bl_get_data(rk29_bl);
 133         DBG("%s : %s\n", __FILE__, __FUNCTION__);
 134
 135         if (rk29_bl_info->pwm_resume)
 136                 rk29_bl_info->pwm_resume();
 137
 138         clk_enable(pwm_clk);
 139
 140         schedule_delayed_work(&rk29_backlight_work, msecs_to_jiffies(rk29_bl_info->delay_ms));
 141 }
 142
 143 static struct early_suspend bl_early_suspend = {
 144         .suspend = rk29_bl_suspend,
 145         .resume = rk29_bl_resume,
 146         .level = EARLY_SUSPEND_LEVEL_BLANK_SCREEN - 1,
 147 };
 148 #endif
 149 void rk29_backlight_set(bool on)
 150 {
 151         printk("%s: set %d\n", __func__, on);
 152         if(on)
 153                 rk29_bl_resume(NULL);
 154         else
 155                 rk29_bl_suspend(NULL);
 156         return;
 157 }
 158 EXPORT_SYMBOL(rk29_backlight_set);
 159
 160 static int rk29_backlight_probe(struct platform_device *pdev)
 161 {
 162         int ret = 0;
 163         struct rk29_bl_info *rk29_bl_info = pdev->dev.platform_data;
 164         u32 id  =  rk29_bl_info->pwm_id;
 165         u32 divh, div_total;
 166         unsigned long pwm_clk_rate;
 167
 168         if (rk29_bl) {
 169                 DBG(KERN_CRIT "%s: backlight device register has existed \n",
 170                                 __func__);
 171                 return -EEXIST;
 172         }
 173
 174         if (!rk29_bl_info->delay_ms)
 175                 rk29_bl_info->delay_ms = 30;
 176
 177         if (rk29_bl_info->min_brightness < 0 || rk29_bl_info->min_brightness > BL_STEP)
 178                 rk29_bl_info->min_brightness = 52;
 179
 180         if (rk29_bl_info && rk29_bl_info->io_init) {
 181                 rk29_bl_info->io_init();
 182         }
 183
 184         rk29_bl = backlight_device_register("rk28_bl", &pdev->dev, rk29_bl_info, &rk29_bl_ops);
 185         if (!rk29_bl) {
 186                 DBG(KERN_CRIT "%s: backlight device register error\n",
 187                                 __func__);
 188                 return -ENODEV;
 189         }
 190
 191         pwm_clk = clk_get(NULL, "pwm");
 192         if (IS_ERR(pwm_clk)) {
 193                 printk(KERN_ERR "failed to get pwm clock source\n");
 194                 return -ENODEV;
 195         }
 196         pwm_clk_rate = clk_get_rate(pwm_clk);
 197         div_total = pwm_clk_rate / PWM_APB_PRE_DIV;
 198
 199         div_total >>= (1 + (PWM_DIV >> 9));
 200         div_total = (div_total) ? div_total : 1;
 201
 202         if(rk29_bl_info->bl_ref) {
 203                 divh = 0;
 204         } else {
 205                 divh = div_total;
 206         }
 207
 208         clk_enable(pwm_clk);
 209         write_pwm_reg(id, PWM_REG_CTRL, PWM_DIV|PWM_RESET);
 210         write_pwm_reg(id, PWM_REG_LRC, div_total);
 211         write_pwm_reg(id, PWM_REG_HRC, divh);
 212         write_pwm_reg(id, PWM_REG_CNTR, 0x0);
 213         write_pwm_reg(id, PWM_REG_CTRL, PWM_DIV|PWM_ENABLE|PWM_TIME_EN);
 214
 215         rk29_bl->props.power = FB_BLANK_UNBLANK;
 216         rk29_bl->props.fb_blank = FB_BLANK_UNBLANK;
 217         rk29_bl->props.max_brightness = BL_STEP;
 218         rk29_bl->props.brightness = BL_STEP / 2;
 219
 220         schedule_delayed_work(&rk29_backlight_work, msecs_to_jiffies(rk29_bl_info->delay_ms));
 221
 222         register_early_suspend(&bl_early_suspend);
 223
 224         printk("RK29 Backlight Driver Initialized.\n");
 225         return ret;
 226 }
 227
 228 static int rk29_backlight_remove(struct platform_device *pdev)
 229 {
 230         struct rk29_bl_info *rk29_bl_info = pdev->dev.platform_data;
 231
 232         if (rk29_bl) {
 233                 backlight_device_unregister(rk29_bl);
 234                 unregister_early_suspend(&bl_early_suspend);
 235                 clk_disable(pwm_clk);
 236                 clk_put(pwm_clk);
 237                 if (rk29_bl_info && rk29_bl_info->io_deinit) {
 238                         rk29_bl_info->io_deinit();
 239                 }
 240                 return 0;
 241         } else {
 242                 DBG(KERN_CRIT "%s: no backlight device has registered\n",
 243                                 __func__);
 244                 return -ENODEV;
 245         }
 246 }
 247
 248 static void rk29_backlight_shutdown(struct platform_device *pdev)
 249 {
 250         struct rk29_bl_info *rk29_bl_info = pdev->dev.platform_data;
 251
 252         rk29_bl->props.brightness >>= 1;
 253         rk29_bl_update_status(rk29_bl);
 254         mdelay(100);
 255
 256         rk29_bl->props.brightness >>= 1;
 257         rk29_bl_update_status(rk29_bl);
 258         mdelay(100);
 259
 260         rk29_bl->props.brightness = 0;
 261         rk29_bl_update_status(rk29_bl);
 262
 263         if (rk29_bl_info && rk29_bl_info->io_deinit)
 264                 rk29_bl_info->io_deinit();
 265 }
 266
 267 static struct platform_driver rk29_backlight_driver = {
 268         .probe  = rk29_backlight_probe,
 269         .remove = rk29_backlight_remove,
 270         .driver = {
 271                 .name   = "rk29_backlight",
 272                 .owner  = THIS_MODULE,
 273         },
 274         .shutdown       = rk29_backlight_shutdown,
 275 };
 276
 277 static int __init rk29_backlight_init(void)
 278 {
 279         platform_driver_register(&rk29_backlight_driver);
 280         return 0;
 281 }
 282 fs_initcall_sync(rk29_backlight_init);