change(lp_adc): Cleanup LP ADC driver and example

components/ulp/lp_core/shared/ulp_lp_core_lp_adc_shared.c

@@ -19,18 +19,48 @@
 #define INV_ATTEN_6DB   (1996)  /* Inverse of 10^(-6/20) * 1000 */
 #define INV_ATTEN_12DB  (3984)  /* Inverse of 10^(-12/20) * 1000 */
 
-adc_oneshot_unit_handle_t s_adc1_handle;
+/* ADC unit handles - one for each supported ADC unit */
+static adc_oneshot_unit_handle_t s_adc_unit_handles[SOC_ADC_PERIPH_NUM] = {NULL};
 
-esp_err_t lp_core_lp_adc_init(adc_unit_t unit_id)
+/************************************************** Static Helper Functions **************************************************/
+
+static esp_err_t lp_adc_validate_unit(adc_unit_t unit_id)
 {
+    /* Currently, LP ADC2 does not work during sleep (DIG-396)
+     * TODO: Remove this check once DIG-396 is fixed
+     */
     if (unit_id != ADC_UNIT_1) {
-        // TODO: LP ADC2 does not work during sleep (DIG-396)
-        // For now, we do not allow LP ADC2 usage.
         return ESP_ERR_INVALID_ARG;
     }
 
+    /* Verify unit ID is within valid range */
+    if (unit_id >= SOC_ADC_PERIPH_NUM) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    return ESP_OK;
+}
+
+static esp_err_t lp_adc_validate_channel(adc_unit_t unit_id, adc_channel_t channel)
+{
+    if (channel >= SOC_ADC_CHANNEL_NUM(unit_id)) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    return ESP_OK;
+}
+
+/************************************************** Public API **************************************************/
+
+esp_err_t lp_core_lp_adc_init(adc_unit_t unit_id)
+{
+    esp_err_t ret = lp_adc_validate_unit(unit_id);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+
 #if IS_ULP_COCPU
-    // Not supported
+    // Not supported from LP core
     return ESP_ERR_NOT_SUPPORTED;
 #else
     /* LP ADC is being initialized from the HP core.
@@ -43,33 +73,39 @@ esp_err_t lp_core_lp_adc_init(adc_unit_t unit_id)
         .ulp_mode = ADC_ULP_MODE_LP_CORE, // LP Core will use the ADC
     };
 
-    return (adc_oneshot_new_unit(&init_config, &s_adc1_handle));
+    return (adc_oneshot_new_unit(&init_config, &s_adc_unit_handles[unit_id]));
 #endif /* IS_ULP_COCPU */
 }
 
 esp_err_t lp_core_lp_adc_deinit(adc_unit_t unit_id)
 {
-    if (unit_id != ADC_UNIT_1) {
-        return ESP_ERR_INVALID_ARG;
+    esp_err_t ret = lp_adc_validate_unit(unit_id);
+    if (ret != ESP_OK) {
+        return ret;
     }
 
 #if IS_ULP_COCPU
-    // Not supported
+    // Not supported from LP core
     return ESP_ERR_NOT_SUPPORTED;
 #else
-    return (adc_oneshot_del_unit(s_adc1_handle));
+    return (adc_oneshot_del_unit(s_adc_unit_handles[unit_id]));
 #endif /* IS_ULP_COCPU */
 }
 
 esp_err_t lp_core_lp_adc_config_channel(adc_unit_t unit_id, adc_channel_t channel, const lp_core_lp_adc_chan_cfg_t *chan_config)
 {
-    if (unit_id != ADC_UNIT_1) {
-        // TODO: LP ADC2 does not work during sleep (DIG-396)
-        // For now, we do not allow LP ADC2 usage.
-        return ESP_ERR_INVALID_ARG;
+    esp_err_t ret = lp_adc_validate_unit(unit_id);
+    if (ret != ESP_OK) {
+        return ret;
     }
+
+    ret = lp_adc_validate_channel(unit_id, channel);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+
 #if IS_ULP_COCPU
-    // Not supported
+    // Not supported from LP core
     return ESP_ERR_NOT_SUPPORTED;
 #else
     adc_oneshot_chan_cfg_t config = {
@@ -94,10 +130,20 @@ esp_err_t lp_core_lp_adc_config_channel(adc_unit_t unit_id, adc_channel_t channe
 
 esp_err_t lp_core_lp_adc_read_channel_raw(adc_unit_t unit_id, adc_channel_t channel, int *adc_raw)
 {
-    if (unit_id != ADC_UNIT_1 || adc_raw == NULL) {
+    if (adc_raw == NULL) {
         return ESP_ERR_INVALID_ARG;
     }
 
+    esp_err_t ret = lp_adc_validate_unit(unit_id);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+
+    ret = lp_adc_validate_channel(unit_id, channel);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+
 #if IS_ULP_COCPU
     uint32_t event = ADC_LL_EVENT_ADC1_ONESHOT_DONE;
 
@@ -114,7 +160,7 @@ esp_err_t lp_core_lp_adc_read_channel_raw(adc_unit_t unit_id, adc_channel_t chan
 
     adc_oneshot_ll_disable_all_unit();
 #else
-    return (adc_oneshot_read(s_adc1_handle, channel, adc_raw));
+    return (adc_oneshot_read(s_adc_unit_handles[unit_id], channel, adc_raw));
 #endif /* IS_ULP_COCPU */
 
     return ESP_OK;
@@ -122,12 +168,20 @@ esp_err_t lp_core_lp_adc_read_channel_raw(adc_unit_t unit_id, adc_channel_t chan
 
 esp_err_t lp_core_lp_adc_read_channel_converted(adc_unit_t unit_id, adc_channel_t channel, int *voltage_mv)
 {
-    esp_err_t ret = ESP_OK;
-
-    if (unit_id != ADC_UNIT_1 || voltage_mv == NULL) {
+    if (voltage_mv == NULL) {
         return ESP_ERR_INVALID_ARG;
     }
 
+    esp_err_t ret = lp_adc_validate_unit(unit_id);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+
+    ret = lp_adc_validate_channel(unit_id, channel);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+
     /* Read the raw ADC value */
     int adc_raw;
     ret = lp_core_lp_adc_read_channel_raw(unit_id, channel, &adc_raw);

examples/system/ulp/lp_core/lp_adc/main/lp_adc_main.c

@@ -33,7 +33,7 @@ static void lp_uart_init(void)
 
 static void lp_core_init(void)
 {
-    /* Set LP core wakeup source as the HP CPU */
+    /* Set LP core wakeup source as the LP timer */
     ulp_lp_core_cfg_t cfg = {
         .wakeup_source = ULP_LP_CORE_WAKEUP_SOURCE_LP_TIMER,
         .lp_timer_sleep_duration_us = 1000000,

examples/system/ulp/lp_core/lp_adc/main/lp_core/main.c

@@ -8,6 +8,7 @@
 #include "sdkconfig.h"
 #include "ulp_lp_core_print.h"
 #include "ulp_lp_core_lp_adc_shared.h"
+#include "ulp_lp_core_uart.h"
 
 #define EXAMPLE_LP_ADC1_CHAN0   CONFIG_EXAMPLE_LP_ADC1_CHANNEL_0_SELECT
 #define EXAMPLE_LP_ADC1_CHAN1   CONFIG_EXAMPLE_LP_ADC1_CHANNEL_1_SELECT
@@ -28,6 +29,7 @@ int main (void)
     lp_core_printf("lpadc1 chan1 converted value = %d mV\r\n", adc_converted_value[1]);
 
     lp_core_printf("\n");
+    lp_core_uart_tx_flush(LP_UART_NUM_0);
 
     return 0;
 }