[esp32_can] Support 20 kbit/s on ESP32 revision 2 or later (#20426)

esphome/components/esp32_can/canbus.py

@@ -6,6 +6,8 @@ import esphome.codegen as cg
 from esphome.components import canbus
 from esphome.components.canbus import CONF_BIT_RATE, CanbusComponent, CanSpeed
 from esphome.components.esp32 import (
+    CONF_MINIMUM_CHIP_REVISION,
+    KEY_ESP32,
     VARIANT_ESP32,
     VARIANT_ESP32C3,
     VARIANT_ESP32C5,
@@ -20,6 +22,8 @@ from esphome.components.esp32 import (
 )
 import esphome.config_validation as cv
 from esphome.const import (
+    CONF_ADVANCED,
+    CONF_FRAMEWORK,
     CONF_ID,
     CONF_MODE,
     CONF_RX_PIN,
@@ -27,6 +31,7 @@ from esphome.const import (
     CONF_TX_PIN,
     CONF_TX_QUEUE_LEN,
 )
+import esphome.final_validate as fv
 from esphome.types import ConfigType
 
 CODEOWNERS = ["@Sympatron"]
@@ -49,6 +54,7 @@ CAN_MODES = {
 # See ESP-IDF Programming Guide --> API Reference --> Two-Wire Automotive Interface (TWAI)
 
 CAN_SPEEDS_ESP32 = {
+    "20KBPS": CanSpeed.CAN_20KBPS,
     "25KBPS": CanSpeed.CAN_25KBPS,
     "50KBPS": CanSpeed.CAN_50KBPS,
     "100KBPS": CanSpeed.CAN_100KBPS,
@@ -114,6 +120,22 @@ CONFIG_SCHEMA = canbus.CANBUS_SCHEMA.extend(
 )
 
 
+def _final_validate(config: ConfigType) -> None:
+    if get_esp32_variant() == VARIANT_ESP32 and config[CONF_BIT_RATE] == "20KBPS":
+        esp32_config = fv.full_config.get()[KEY_ESP32]
+        min_revision = esp32_config[CONF_FRAMEWORK][CONF_ADVANCED].get(
+            CONF_MINIMUM_CHIP_REVISION
+        )
+        if min_revision is None or min_revision < "2.0":
+            raise cv.Invalid(
+                "20KBPS on ESP32 requires esp32.framework.advanced.minimum_chip_revision: '2.0' or higher",
+                path=[CONF_BIT_RATE],
+            )
+
+
+FINAL_VALIDATE_SCHEMA = _final_validate
+
+
 def get_default_tx_enqueue_timeout(bit_rate: str) -> int:
     bit_rate_numeric = canbus.get_rate(bit_rate)
     bits_per_packet = 140  # ~max CAN message length

esphome/components/esp32_can/esp32_can.cpp

@@ -33,6 +33,10 @@ static bool get_bitrate(canbus::CanSpeed bitrate, twai_timing_config_t *t_config
     case canbus::CAN_16KBPS:
       *t_config = (twai_timing_config_t) TWAI_TIMING_CONFIG_16KBITS();
       return true;
+#endif
+#if defined(USE_ESP32_VARIANT_ESP32C3) || defined(USE_ESP32_VARIANT_ESP32C6) || defined(USE_ESP32_VARIANT_ESP32C61) || \
+    defined(USE_ESP32_VARIANT_ESP32H2) || defined(USE_ESP32_VARIANT_ESP32P4) || defined(USE_ESP32_VARIANT_ESP32S2) || \
+    defined(USE_ESP32_VARIANT_ESP32S3) || (defined(USE_ESP32_VARIANT_ESP32) && CONFIG_ESP32_REV_MIN_FULL >= 200)
     case canbus::CAN_20KBPS:
       *t_config = (twai_timing_config_t) TWAI_TIMING_CONFIG_20KBITS();
       return true;

tests/components/esp32_can/test-20kbps.esp32-idf.yaml

@@ -0,0 +1,11 @@
+esp32:
+  framework:
+    advanced:
+      minimum_chip_revision: "2.0"
+
+canbus:
+  - platform: esp32_can
+    rx_pin: GPIO14
+    tx_pin: GPIO12
+    can_id: 4
+    bit_rate: 20kbps

tests/unit_tests/components/test_esp32_can.py

@@ -0,0 +1,54 @@
+"""Tests for ESP32 CAN bitrate validation."""
+
+import pytest
+
+from esphome.components.esp32 import KEY_ESP32, KEY_VARIANT
+from esphome.components.esp32_can import canbus
+import esphome.config_validation as cv
+from esphome.core import CORE
+import esphome.final_validate as fv
+
+
+@pytest.mark.parametrize(
+    ("revision", "supported"),
+    [
+        (None, False),
+        ("0.0", False),
+        ("1.0", False),
+        ("1.1", False),
+        ("2.0", True),
+        ("3.0", True),
+        ("3.1", True),
+    ],
+)
+def test_esp32_20kbps_minimum_revision(revision: str | None, supported: bool) -> None:
+    """Require the chip revision needed by the ESP-IDF timing macro."""
+    CORE.data[KEY_ESP32] = {KEY_VARIANT: "ESP32"}
+    advanced = {} if revision is None else {"minimum_chip_revision": revision}
+    token = fv.full_config.set({"esp32": {"framework": {"advanced": advanced}}})
+    try:
+        config = {"bit_rate": canbus.validate_bit_rate("20kbps")}
+        if supported:
+            canbus.FINAL_VALIDATE_SCHEMA(config)
+        else:
+            with pytest.raises(cv.Invalid, match="minimum_chip_revision") as error:
+                canbus.FINAL_VALIDATE_SCHEMA(config)
+            assert error.value.path == ["bit_rate"]
+    finally:
+        fv.full_config.reset(token)
+
+
+@pytest.mark.parametrize("variant", ["ESP32", "ESP32C3", "ESP32S3"])
+def test_other_bitrates(variant: str) -> None:
+    """Existing bitrates must not require a minimum chip revision."""
+    CORE.data[KEY_ESP32] = {KEY_VARIANT: variant}
+    config = {"bit_rate": canbus.validate_bit_rate("25kbps")}
+    canbus.FINAL_VALIDATE_SCHEMA(config)
+
+
+@pytest.mark.parametrize("variant", ["ESP32C3", "ESP32S2", "ESP32S3", "ESP32C6"])
+def test_other_variants_20kbps(variant: str) -> None:
+    """Other supported ESP32 variants must retain 20 kbit/s support."""
+    CORE.data[KEY_ESP32] = {KEY_VARIANT: variant}
+    config = {"bit_rate": canbus.validate_bit_rate("20kbps")}
+    canbus.FINAL_VALIDATE_SCHEMA(config)