update: 重写PWM驱动, 支持1hz-80Mhz任意频率,重写占空比的计算函数

luatos/components/luat/port/luat_pwm_idf5.c

@@ -9,53 +9,125 @@
 #include "luat_log.h"
 #define LUAT_LOG_TAG "pwm"
 
-static uint8_t luat_pwm_idf[LEDC_TIMER_MAX] = {0};
+typedef struct pwm_cont {
+    luat_pwm_conf_t pc;
+    uint8_t is_opened;
+}pwm_conf_t;
+
+static pwm_conf_t luat_pwm_idf[LEDC_TIMER_MAX];
+
+#define LEDC_LL_FRACTIONAL_BITS (8)
+#define LEDC_LL_FRACTIONAL_MAX     ((1 << LEDC_LL_FRACTIONAL_BITS) - 1)
+#define LEDC_TIMER_DIV_NUM_MAX    (0x3FFFF)
+#define LEDC_IS_DIV_INVALID(div)  ((div) <= LEDC_LL_FRACTIONAL_MAX || (div) > LEDC_TIMER_DIV_NUM_MAX)
+
+static inline uint32_t ilog2(uint32_t i)
+{
+    assert(i > 0);
+    uint32_t log = 0;
+    while (i >>= 1) {
+        ++log;
+    }
+    return log;
+}
+
+static inline uint32_t ledc_calculate_divisor(uint32_t src_clk_freq, int freq_hz, uint32_t precision)
+{
+    uint64_t fp = freq_hz;
+    fp *= precision;
+    return ( ( (uint64_t) src_clk_freq << LEDC_LL_FRACTIONAL_BITS ) + (fp / 2 ) ) / fp;
+}
+
+// https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf#ledpwm
+static uint32_t ledc_find_suitable_duty_resolution(uint32_t src_clk_freq, uint32_t timer_freq)
+{
+    uint32_t div = (src_clk_freq + timer_freq / 2) / timer_freq; // rounded
+    uint32_t duty_resolution = ilog2(div);
+    if ( duty_resolution >= SOC_LEDC_TIMER_BIT_WIDTH) {
+        duty_resolution = SOC_LEDC_TIMER_BIT_WIDTH - 1;
+    }
+    uint32_t div_param = ledc_calculate_divisor(src_clk_freq, timer_freq, 1 << duty_resolution);
+    if (LEDC_IS_DIV_INVALID(div_param)) {
+        div = src_clk_freq / timer_freq; // truncated
+        duty_resolution = ilog2(div);
+        if ( duty_resolution > SOC_LEDC_TIMER_BIT_WIDTH - 1) {
+            duty_resolution = SOC_LEDC_TIMER_BIT_WIDTH - 1;
+        }
+        div_param = ledc_calculate_divisor(src_clk_freq, timer_freq, 1 << duty_resolution);
+        if (LEDC_IS_DIV_INVALID(div_param)) {
+            duty_resolution = 0;
+        }
+    }
+    return duty_resolution;
+}
 
 int luat_pwm_setup(luat_pwm_conf_t *conf){
-    int resolution = 0;
+    int duty_resolution = 0;
     int timer = -1;
     int ret = -1;
     if (conf->channel < 0)
         return -1;
-    for (size_t i = 0; i < LEDC_TIMER_MAX; i++){
-        if (luat_pwm_idf[i]==0 || luat_pwm_idf[i]==conf->channel+1){
+    for (size_t i = 0; i < LEDC_TIMER_MAX; i++)
+    {
+        if (luat_pwm_idf[i].is_opened && luat_pwm_idf[i].pc.channel == conf->channel) {
+            timer = i;
+            break;
+        }
+        if (!luat_pwm_idf[i].is_opened) {
             timer = i;
+            break;
         }
     }
     if (timer < 0) {
         LLOGE("too many PWM!!! only %d channels supported", LEDC_TIMER_MAX);
         return -1;
     }
-    resolution = ceil(log2(conf->precision));
-    if (luat_pwm_idf[timer] == 0){
+    if (conf->pulse > conf->precision) {
+        conf->pulse = conf->precision;
+    }
+
+
+    duty_resolution = ledc_find_suitable_duty_resolution(80*1000*1000, conf->period);
+    
+    int duty = (conf->pulse * (1 << duty_resolution)) / conf->precision;
+    // LLOGD("freq=%d, pulse=%d, precision=%d, resolution=%08X, duty=%08X", (int)conf->period, (int)conf->pulse, (int)conf->precision, (int)(1 << duty_resolution), (int)duty);
+
+    int speed_mode = LEDC_LOW_SPEED_MODE;
+    
+    // 判断一下是否需要完全重新配置
+    if (conf->period != luat_pwm_idf[timer].pc.period || // 频率是否相同
+         conf->precision != luat_pwm_idf[timer].pc.precision || // 占空比精度是否相同
+         conf->pnum != luat_pwm_idf[timer].pc.pnum // 输出脉冲数是否相同
+        ) {
+        // LLOGD("need to reconfig channel %d period %d", conf->channel, conf->period);
         ledc_timer_config_t ledc_timer = {
-            .speed_mode = LEDC_LOW_SPEED_MODE,
+            .speed_mode = speed_mode,
             .timer_num = timer,
             .freq_hz = conf->period,
             .clk_cfg = LEDC_AUTO_CLK,
+            .duty_resolution = duty_resolution
         };
-        ledc_timer.duty_resolution = resolution;
-
+        // LLOGD("duty_resolution %d %04X", duty_resolution, 1 << duty_resolution);
         ret = ledc_timer_config(&ledc_timer);
         if (ret) {
             return -1;
         }
 
         ledc_channel_config_t ledc_channel = {
-            .speed_mode = LEDC_LOW_SPEED_MODE,
+            .speed_mode = speed_mode,
             .channel = timer,
             .timer_sel = timer,
             .intr_type = LEDC_INTR_DISABLE,
             .gpio_num = conf->channel,
-            .duty = 0,
+            .duty = duty,
             .hpoint = 0,
         };
         ledc_channel_config(&ledc_channel);
-        luat_pwm_idf[timer] = conf->channel+1;//避免使用0
     }
-    ledc_set_freq(LEDC_LOW_SPEED_MODE, timer, conf->period);
-    ledc_set_duty(LEDC_LOW_SPEED_MODE, timer, pow(2, resolution) * conf->pulse / conf->precision );
-    ledc_update_duty(LEDC_LOW_SPEED_MODE, timer);
+    ledc_set_duty(speed_mode, timer, duty);
+    ledc_update_duty(speed_mode, timer);
+    memcpy( &luat_pwm_idf[timer].pc, conf, sizeof(luat_pwm_conf_t));
+    luat_pwm_idf[timer].is_opened = 1;
     return 0;
 }
 
@@ -64,7 +136,7 @@ int luat_pwm_close(int channel){
     if (channel < 0)
         return -1;
     for (size_t i = 0; i < LEDC_TIMER_MAX; i++){
-        if (luat_pwm_idf[i]==channel+1){
+        if (luat_pwm_idf[i].is_opened && luat_pwm_idf[i].pc.channel == channel){
             timer = i;
             break;
         }
@@ -77,7 +149,8 @@ int luat_pwm_close(int channel){
         return -1;
     }
     gpio_reset_pin(channel);
-    luat_pwm_idf[timer] = 0;
+    luat_pwm_idf[timer].is_opened = 0;
+    memset(&luat_pwm_idf[timer].pc, 0, sizeof(luat_pwm_conf_t) );
     return 0;
 }