acid-drop

- Hacking the planet from a LilyGo T-Deck using custom firmware
git clone git://git.acid.vegas/acid-drop.git
lv_hal_tick.c (2373B)
      1 /**
      2  * @file lv_hal_tick.c
      3  * Provide access to the system tick with 1 millisecond resolution
      4  */
      5 
      6 /*********************
      7  *      INCLUDES
      8  *********************/
      9 #include "lv_hal_tick.h"
     10 #include <stddef.h>
     11 
     12 #if LV_TICK_CUSTOM == 1
     13     #include LV_TICK_CUSTOM_INCLUDE
     14 #endif
     15 
     16 /*********************
     17  *      DEFINES
     18  *********************/
     19 
     20 /**********************
     21  *      TYPEDEFS
     22  **********************/
     23 
     24 /**********************
     25  *  STATIC PROTOTYPES
     26  **********************/
     27 
     28 /**********************
     29  *  STATIC VARIABLES
     30  **********************/
     31 #if !LV_TICK_CUSTOM
     32     static uint32_t sys_time = 0;
     33     static volatile uint8_t tick_irq_flag;
     34 #endif
     35 
     36 /**********************
     37  *      MACROS
     38  **********************/
     39 
     40 /**********************
     41  *   GLOBAL FUNCTIONS
     42  **********************/
     43 
     44 #if !LV_TICK_CUSTOM
     45 /**
     46  * You have to call this function periodically
     47  * @param tick_period the call period of this function in milliseconds
     48  */
     49 LV_ATTRIBUTE_TICK_INC void lv_tick_inc(uint32_t tick_period)
     50 {
     51     tick_irq_flag = 0;
     52     sys_time += tick_period;
     53 }
     54 #endif
     55 
     56 /**
     57  * Get the elapsed milliseconds since start up
     58  * @return the elapsed milliseconds
     59  */
     60 uint32_t lv_tick_get(void)
     61 {
     62 #if LV_TICK_CUSTOM == 0
     63 
     64     /*If `lv_tick_inc` is called from an interrupt while `sys_time` is read
     65      *the result might be corrupted.
     66      *This loop detects if `lv_tick_inc` was called while reading `sys_time`.
     67      *If `tick_irq_flag` was cleared in `lv_tick_inc` try to read again
     68      *until `tick_irq_flag` remains `1`.*/
     69     uint32_t result;
     70     do {
     71         tick_irq_flag = 1;
     72         result        = sys_time;
     73     } while(!tick_irq_flag); /*Continue until see a non interrupted cycle*/
     74 
     75     return result;
     76 #else
     77     return LV_TICK_CUSTOM_SYS_TIME_EXPR;
     78 #endif
     79 }
     80 
     81 /**
     82  * Get the elapsed milliseconds since a previous time stamp
     83  * @param prev_tick a previous time stamp (return value of lv_tick_get() )
     84  * @return the elapsed milliseconds since 'prev_tick'
     85  */
     86 uint32_t lv_tick_elaps(uint32_t prev_tick)
     87 {
     88     uint32_t act_time = lv_tick_get();
     89 
     90     /*If there is no overflow in sys_time simple subtract*/
     91     if(act_time >= prev_tick) {
     92         prev_tick = act_time - prev_tick;
     93     }
     94     else {
     95         prev_tick = UINT32_MAX - prev_tick + 1;
     96         prev_tick += act_time;
     97     }
     98 
     99     return prev_tick;
    100 }
    101 
    102 /**********************
    103  *   STATIC FUNCTIONS
    104  **********************/