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esp32/clk: remove unused code

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When 32k XTAL was selected as clock source, if the first calibration
attempt failed, the code would fall back to 150kHz internal clock.
Calibration with the internal clock will always succeed.
Therefore `wait` would always be either 0 or 1. Based on this, some
code in this routine can be eliminated.
This commit is contained in:
Ivan Grokhotkov 2018-08-13 01:09:06 +03:00
parent e3d76d13b4
commit 9efc06be0f
1 changed files with 1 additions and 16 deletions
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17
components/esp32/clk.c
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@ -120,11 +120,7 @@ void IRAM_ATTR ets_update_cpu_frequency(uint32_t ticks_per_us)
static void select_rtc_slow_clk(rtc_slow_freq_t slow_clk) static void select_rtc_slow_clk(rtc_slow_freq_t slow_clk)
{ {
uint32_t cal_val = 0; uint32_t cal_val = 0;
uint32_t wait = 0;
uint32_t freq_hz = ((slow_clk == RTC_SLOW_FREQ_32K_XTAL) ? 32768 : 150000); uint32_t freq_hz = ((slow_clk == RTC_SLOW_FREQ_32K_XTAL) ? 32768 : 150000);
uint32_t warning_timeout = 3 /* sec */ * freq_hz /* Hz */ / (SLOW_CLK_CAL_CYCLES + 1);
warning_timeout = ((warning_timeout == 0) ? 3 /* sec */ : warning_timeout);
bool changing_clock_to_150k = false;
do { do {
if (slow_clk == RTC_SLOW_FREQ_32K_XTAL) { if (slow_clk == RTC_SLOW_FREQ_32K_XTAL) {
/* 32k XTAL oscillator needs to be enabled and running before it can /* 32k XTAL oscillator needs to be enabled and running before it can
@ -140,20 +136,12 @@ static void select_rtc_slow_clk(rtc_slow_freq_t slow_clk)
if (SLOW_CLK_CAL_CYCLES > 0) { if (SLOW_CLK_CAL_CYCLES > 0) {
cal_val = rtc_clk_cal(RTC_CAL_32K_XTAL, SLOW_CLK_CAL_CYCLES); cal_val = rtc_clk_cal(RTC_CAL_32K_XTAL, SLOW_CLK_CAL_CYCLES);
if (cal_val == 0 || cal_val < 15000000L) { if (cal_val == 0 || cal_val < 15000000L) {
ESP_EARLY_LOGE(TAG, "RTC: Not found External 32 kHz XTAL. Switching to Internal 150 kHz RC chain");
slow_clk = RTC_SLOW_FREQ_RTC; slow_clk = RTC_SLOW_FREQ_RTC;
changing_clock_to_150k = true; ESP_EARLY_LOGW(TAG, "32 kHz XTAL not found, switching to internal 150 kHz oscillator");
} }
} }
} }
rtc_clk_slow_freq_set(slow_clk); rtc_clk_slow_freq_set(slow_clk);
if (changing_clock_to_150k == true && wait > 1){
// This helps when there are errors when switching the clock from External 32 kHz XTAL to Internal 150 kHz RC chain.
rtc_clk_32k_enable(false);
uint32_t min_bootstrap = 5; // Min bootstrapping for continue switching the clock.
rtc_clk_32k_bootstrap(min_bootstrap);
rtc_clk_32k_enable(true);
}
if (SLOW_CLK_CAL_CYCLES > 0) { if (SLOW_CLK_CAL_CYCLES > 0) {
/* TODO: 32k XTAL oscillator has some frequency drift at startup. /* TODO: 32k XTAL oscillator has some frequency drift at startup.
@ -164,9 +152,6 @@ static void select_rtc_slow_clk(rtc_slow_freq_t slow_clk)
const uint64_t cal_dividend = (1ULL << RTC_CLK_CAL_FRACT) * 1000000ULL; const uint64_t cal_dividend = (1ULL << RTC_CLK_CAL_FRACT) * 1000000ULL;
cal_val = (uint32_t) (cal_dividend / rtc_clk_slow_freq_get_hz()); cal_val = (uint32_t) (cal_dividend / rtc_clk_slow_freq_get_hz());
} }
if (++wait % warning_timeout == 0) {
ESP_EARLY_LOGW(TAG, "still waiting for source selection RTC");
}
} while (cal_val == 0); } while (cal_val == 0);
ESP_EARLY_LOGD(TAG, "RTC_SLOW_CLK calibration value: %d", cal_val); ESP_EARLY_LOGD(TAG, "RTC_SLOW_CLK calibration value: %d", cal_val);
esp_clk_slowclk_cal_set(cal_val); esp_clk_slowclk_cal_set(cal_val);