MTK 驱动（47）---使用PWM配置背光如何配置，及频率计算

时间：2024-03-30 08:06:46
[MT6582_LCD]使用PWM配置背光如何配置，及频率计算
2016年07月08日 10:10:22
阅读数：1175

MT6582 使用PWM配置背光及频率计算
 
 
[SOLUTION]
 

以GPIO52 pin为例：

Mode0

Mode1

Mode2

Mode3

GPIO52

LPD8

PWM_BL

PWM_A

 /mediatek/custom/XXXXXXXXX/lk/inc/cust_leds.h

./mediatek/custom/XXXXXXXXX/kernel/leds/mt65xx/cust_leds.c


./mediatek/custom/XXXXXXXXX/lk/cust_leds.c


alps\mediatek\kernel\drivers\leds\leds_drv.c

static int mt65xx_led_set_cust(struct cust_mt65xx_led *cust, int level)

{

 #ifdef CONTROL_BL_TEMPERATURE

 mutex_lock(&bl_level_limit_mutex);

 current_level = level;

 //LEDS_DRV_DEBUG("brightness_set_cust:current_level=%d\n", current_level);

 if(0 == limit_flag){

  last_level = level;

  //LEDS_DRV_DEBUG("brightness_set_cust:last_level=%d\n", last_level);

 }else {

  if(limit < current_level){

   level = limit;

   //LEDS_DRV_DEBUG("backlight_set_cust: control level=%d\n", level);

  }

 }

 mutex_unlock(&bl_level_limit_mutex);

 #endif

 #ifdef LED_INCREASE_LED_LEVEL_MTKPATCH

  if(MT65XX_LED_MODE_CUST_BLS_PWM == cust->mode) {

   mt_mt65xx_led_set_cust(cust, ((((1 << LED_INTERNAL_LEVEL_BIT_CNT) - 1)*level + 127)/500));   //降低亮度

  }else {

   mt_mt65xx_led_set_cust(cust, level);

  }

 #else

  mt_mt65xx_led_set_cust(cust, level);

 #endif

 return -1;

}

m0022\mediatek\platform\mt6582\kernel\drivers\leds\leds.c


     LEDS_DEBUG("[LED]Set Backlight directly %d at time %lu\n",led_data->level,jiffies);

行 960     if(MT65XX_LED_MODE_CUST_BLS_PWM == led_data->cust.mode)

     {

      mt_mt65xx_led_set_cust(&led_data->cust, ((((1 << MT_LED_INTERNAL_LEVEL_BIT_CNT) - 1)*level + 127)/500));


一、将GPIO52在DCT tool配置成PWM1，用于背光。

static struct cust_mt65xx_led cust_led_list[MT65XX_LED_TYPE_TOTAL] = {

                {"red",               MT65XX_LED_MODE_NONE, -1,{0}},

                {"green",             MT65XX_LED_MODE_NONE, -1,{0}},

                {"blue",              MT65XX_LED_MODE_NONE, -1,{0}},

                {"jogball-backlight", MT65XX_LED_MODE_NONE, -1,{0}},

                {"keyboard-backlight",MT65XX_LED_MODE_NONE, -1,{0}},

                {"button-backlight",  MT65XX_LED_MODE_NONE, -1,{0,0,0,0,0}},

                {"lcd-backlight",     MT65XX_LED_MODE_PWM, PWM1, {0,0,0,0,0}},

};

 1. PWM config data结构体解析

   clock_source: clock source frequency, can be 0/1

   div: clock division, can be any value within 0~7 (i.e. 1/2^(div) = /1, /2, /4, /8, /16, /32, /64, /128)

   low_duration: only for BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT

   High_duration: only for BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT

 2. PWM频率计算：

  If BACKLIGHT_LEVEL_PWM_MODE_CONFIG = BACKLIGHT_LEVEL_PWM_256_SUPPORT,

             PWM freq. = clock source / 2^(div) / 256 

  If BACKLIGHT_LEVEL_PWM_MODE_CONFIG = BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT,

             PWM freq. = clock source / 2^(div) / [(High_duration+1)(Level')+(low_duration+1)(64 - Level')]

                        = clock source / 2^(div) / [(High_duration+1)*64]     (when low_duration = High_duration)

 时钟源:

             0: block clock/1625 = 26M/1625 = 16K (MT6571)

             1: block clock = 26M (MT6571)

 Div: 0~7

 例如, in MT6571, PWM_config = {1,1,0,0,0}

             ==> PWM freq. = 26M/2^1/256                 =            50.78 KHz ( when BACKLIGHT_LEVEL_PWM_256_SUPPORT )

             ==> PWM freq. = 26M/2^1/(0+1)*64 = 203.13 KHz ( when BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT )


MTK 驱动（47）---使用PWM配置背光如何配置，及频率计算

二、将GPIO52在DCT Tool配置成PWM_BL.

mediatek\custom\gxq82_wet_jb5\kernel\leds\mt65xx\cust_leds.c

 static struct cust_mt65xx_led cust_led_list[MT65XX_LED_TYPE_TOTAL] = {

                {"red",               MT65XX_LED_MODE_NONE, -1,{0}},

                {"green",             MT65XX_LED_MODE_NONE, -1,{0}},

                {"blue",              MT65XX_LED_MODE_NONE, -1,{0}},

                {"jogball-backlight", MT65XX_LED_MODE_NONE, -1,{0}},

                {"keyboard-backlight",MT65XX_LED_MODE_NONE, -1,{0}},

                {"button-backlight",  MT65XX_LED_MODE_NONE, -1,{0,0,0,0,0}},

                {"lcd-backlight",     MT65XX_LED_MODE_CUST_BLS_PWM, (int)disp_bls_set_backlight, {0,0,0,0,0}},

                 {"lcd-backlight",     MT65XX_LED_MODE_CUST_BLS_PWM, (int)disp_bls_set_backlight,{0,0,1,2,0}},  //降低亮度

};

1. PWM config data结构体解析

             clock_source: clock source frequency, can be 0/1/2/3

             div: clock division, can be any value within 0~1023

             low_duration: non-use

             High_duration: non-use

             pmic_pad: non-use

 

 2. 频率计算

PWM freq.= clock source / (div + 1) /1024

Clock source:

             0: 26 MHz

             1: 104 MHz

Div: 0~1023

 By default, clock_source = 0 and div = 0 => PWM freq. = 26 KHz

MT6582 使用PWM配置背光及频率计算
 
 
[SOLUTION]
 

以GPIO52 pin为例：

Mode0

Mode1

Mode2

Mode3

GPIO52

LPD8

PWM_BL

PWM_A

 /mediatek/custom/XXXXXXXXX/lk/inc/cust_leds.h

./mediatek/custom/XXXXXXXXX/kernel/leds/mt65xx/cust_leds.c


./mediatek/custom/XXXXXXXXX/lk/cust_leds.c


alps\mediatek\kernel\drivers\leds\leds_drv.c

static int mt65xx_led_set_cust(struct cust_mt65xx_led *cust, int level)

{

 #ifdef CONTROL_BL_TEMPERATURE

 mutex_lock(&bl_level_limit_mutex);

 current_level = level;

 //LEDS_DRV_DEBUG("brightness_set_cust:current_level=%d\n", current_level);

 if(0 == limit_flag){

  last_level = level;

  //LEDS_DRV_DEBUG("brightness_set_cust:last_level=%d\n", last_level);

 }else {

  if(limit < current_level){

   level = limit;

   //LEDS_DRV_DEBUG("backlight_set_cust: control level=%d\n", level);

  }

 }

 mutex_unlock(&bl_level_limit_mutex);

 #endif

 #ifdef LED_INCREASE_LED_LEVEL_MTKPATCH

  if(MT65XX_LED_MODE_CUST_BLS_PWM == cust->mode) {

   mt_mt65xx_led_set_cust(cust, ((((1 << LED_INTERNAL_LEVEL_BIT_CNT) - 1)*level + 127)/500));   //降低亮度

  }else {

   mt_mt65xx_led_set_cust(cust, level);

  }

 #else

  mt_mt65xx_led_set_cust(cust, level);

 #endif

 return -1;

}

m0022\mediatek\platform\mt6582\kernel\drivers\leds\leds.c


     LEDS_DEBUG("[LED]Set Backlight directly %d at time %lu\n",led_data->level,jiffies);

行 960     if(MT65XX_LED_MODE_CUST_BLS_PWM == led_data->cust.mode)

     {

      mt_mt65xx_led_set_cust(&led_data->cust, ((((1 << MT_LED_INTERNAL_LEVEL_BIT_CNT) - 1)*level + 127)/500));


一、将GPIO52在DCT tool配置成PWM1，用于背光。

static struct cust_mt65xx_led cust_led_list[MT65XX_LED_TYPE_TOTAL] = {

                {"red",               MT65XX_LED_MODE_NONE, -1,{0}},

                {"green",             MT65XX_LED_MODE_NONE, -1,{0}},

                {"blue",              MT65XX_LED_MODE_NONE, -1,{0}},

                {"jogball-backlight", MT65XX_LED_MODE_NONE, -1,{0}},

                {"keyboard-backlight",MT65XX_LED_MODE_NONE, -1,{0}},

                {"button-backlight",  MT65XX_LED_MODE_NONE, -1,{0,0,0,0,0}},

                {"lcd-backlight",     MT65XX_LED_MODE_PWM, PWM1, {0,0,0,0,0}},

};

 1. PWM config data结构体解析

   clock_source: clock source frequency, can be 0/1

   div: clock division, can be any value within 0~7 (i.e. 1/2^(div) = /1, /2, /4, /8, /16, /32, /64, /128)

   low_duration: only for BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT

   High_duration: only for BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT

 2. PWM频率计算：

  If BACKLIGHT_LEVEL_PWM_MODE_CONFIG = BACKLIGHT_LEVEL_PWM_256_SUPPORT,

             PWM freq. = clock source / 2^(div) / 256 

  If BACKLIGHT_LEVEL_PWM_MODE_CONFIG = BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT,

             PWM freq. = clock source / 2^(div) / [(High_duration+1)(Level')+(low_duration+1)(64 - Level')]

                        = clock source / 2^(div) / [(High_duration+1)*64]     (when low_duration = High_duration)

 时钟源:

             0: block clock/1625 = 26M/1625 = 16K (MT6571)

             1: block clock = 26M (MT6571)

 Div: 0~7

 例如, in MT6571, PWM_config = {1,1,0,0,0}

             ==> PWM freq. = 26M/2^1/256                 =            50.78 KHz ( when BACKLIGHT_LEVEL_PWM_256_SUPPORT )

             ==> PWM freq. = 26M/2^1/(0+1)*64 = 203.13 KHz ( when BACKLIGHT_LEVEL_PWM_64_FIFO_MODE_SUPPORT )


MTK 驱动（47）---使用PWM配置背光如何配置，及频率计算

二、将GPIO52在DCT Tool配置成PWM_BL.

mediatek\custom\gxq82_wet_jb5\kernel\leds\mt65xx\cust_leds.c

 static struct cust_mt65xx_led cust_led_list[MT65XX_LED_TYPE_TOTAL] = {

                {"red",               MT65XX_LED_MODE_NONE, -1,{0}},

                {"green",             MT65XX_LED_MODE_NONE, -1,{0}},

                {"blue",              MT65XX_LED_MODE_NONE, -1,{0}},

                {"jogball-backlight", MT65XX_LED_MODE_NONE, -1,{0}},

                {"keyboard-backlight",MT65XX_LED_MODE_NONE, -1,{0}},

                {"button-backlight",  MT65XX_LED_MODE_NONE, -1,{0,0,0,0,0}},

                {"lcd-backlight",     MT65XX_LED_MODE_CUST_BLS_PWM, (int)disp_bls_set_backlight, {0,0,0,0,0}},

                 {"lcd-backlight",     MT65XX_LED_MODE_CUST_BLS_PWM, (int)disp_bls_set_backlight,{0,0,1,2,0}},  //降低亮度

};

1. PWM config data结构体解析

             clock_source: clock source frequency, can be 0/1/2/3

             div: clock division, can be any value within 0~1023

             low_duration: non-use

             High_duration: non-use

             pmic_pad: non-use

 

 2. 频率计算

PWM freq.= clock source / (div + 1) /1024

Clock source:

             0: 26 MHz

             1: 104 MHz

Div: 0~1023

 By default, clock_source = 0 and div = 0 => PWM freq. = 26 KHz