Add gain setting for rc522 component

esphome/components/rc522/__init__.py

@@ -3,6 +3,7 @@ import esphome.config_validation as cv
 from esphome import automation, pins
 from esphome.components import i2c
 from esphome.const import (
+    CONF_GAIN,
     CONF_ON_TAG,
     CONF_ON_TAG_REMOVED,
     CONF_TRIGGER_ID,
@@ -20,6 +21,18 @@ RC522Trigger = rc522_ns.class_(
     "RC522Trigger", automation.Trigger.template(cg.std_string)
 )
 
+RC522Gain = rc522_ns.enum("RC522Gain")
+GAIN = {
+    "18dB": RC522Gain.RC522_GAIN_18DB,
+    "23dB": RC522Gain.RC522_GAIN_23DB,
+    "18dB_a": RC522Gain.RC522_GAIN_18DBA,
+    "23dB_a": RC522Gain.RC522_GAIN_23DBA,
+    "33dB": RC522Gain.RC522_GAIN_33DB,
+    "38dB": RC522Gain.RC522_GAIN_38DB,
+    "43dB": RC522Gain.RC522_GAIN_43DB,
+    "48dB": RC522Gain.RC522_GAIN_48DB,
+}
+
 RC522_SCHEMA = cv.Schema(
     {
         cv.GenerateID(): cv.declare_id(RC522),
@@ -34,6 +47,7 @@ RC522_SCHEMA = cv.Schema(
                 cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(RC522Trigger),
             }
         ),
+        cv.Optional(CONF_GAIN, default="38dB"): cv.enum(GAIN, string=True),
     }
 ).extend(cv.polling_component_schema("1s"))
 
@@ -54,3 +68,5 @@ async def setup_rc522(var, config):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID])
         cg.add(var.register_ontagremoved_trigger(trigger))
         await automation.build_automation(trigger, [(cg.std_string, "x")], conf)
+
+    cg.add(var.set_gain(config[CONF_GAIN]))

esphome/components/rc522/rc522.cpp

@@ -37,6 +37,29 @@ std::string format_uid(std::vector<uint8_t> &uid) {
   return std::string(buf);
 }
 
+const LogString *rc522_gain_to_string(RC522Gain gain) {
+  switch (gain) {
+    case RC522Gain::RC522_GAIN_18DB:
+      return LOG_STR("18dB");
+    case RC522Gain::RC522_GAIN_18DBA:
+      return LOG_STR("18dB_a");
+    case RC522Gain::RC522_GAIN_23DB:
+      return LOG_STR("23dB");
+    case RC522Gain::RC522_GAIN_23DBA:
+      return LOG_STR("23dB_a");
+    case RC522Gain::RC522_GAIN_33DB:
+      return LOG_STR("33dB");
+    case RC522Gain::RC522_GAIN_38DB:
+      return LOG_STR("38dB");
+    case RC522Gain::RC522_GAIN_43DB:
+      return LOG_STR("43dB");
+    case RC522Gain::RC522_GAIN_48DB:
+      return LOG_STR("48dB");
+    default:
+      return LOG_STR("UNKNOWN");
+  }
+}
+
 void RC522::setup() {
   state_ = STATE_SETUP;
   // Pull device out of power down / reset state.
@@ -82,6 +105,10 @@ void RC522::initialize_() {
   pcd_write_register(T_MODE_REG, 0x80);  // TAuto=1; timer starts automatically at the end of the transmission in all
                                          // communication modes at all speeds
 
+  pcd_clear_register_bit_mask_(RF_CFG_REG, (0x07 << 4));
+  pcd_write_register(RF_CFG_REG, gain_ & (0x07 << 4));
+  ESP_LOGI(TAG, "Gain Setting: %s", LOG_STR_ARG(rc522_gain_to_string(this->gain_)));
+
   // TPreScaler = TModeReg[3..0]:TPrescalerReg, ie 0x0A9 = 169 => f_timer=40kHz, ie a timer period of 25μs.
   pcd_write_register(T_PRESCALER_REG, 0xA9);
   pcd_write_register(T_RELOAD_REG_H, 0x03);  // Reload timer with 0x3E8 = 1000, ie 25ms before timeout.
@@ -107,6 +134,8 @@ void RC522::dump_config() {
 
   LOG_PIN("  RESET Pin: ", this->reset_pin_);
 
+  ESP_LOGCONFIG(TAG, "Gain Setting: %s", LOG_STR_ARG(rc522_gain_to_string(this->gain_)));
+
   LOG_UPDATE_INTERVAL(this);
 
   for (auto *child : this->binary_sensors_) {

esphome/components/rc522/rc522.h

@@ -4,12 +4,29 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/automation.h"
 #include "esphome/components/binary_sensor/binary_sensor.h"
+#include "esphome/core/log.h"
 
 #include <vector>
+#include <map>
 
 namespace esphome {
 namespace rc522 {
 
+// based on register bit descriptions in 9.3.3.6 Table 98. https://www.nxp.com/docs/en/data-sheet/MFRC522.pdf
+enum RC522Gain {
+  RC522_GAIN_18DB = 0x00 << 4,
+  RC522_GAIN_23DB = 0x01 << 4,
+  RC522_GAIN_18DBA = 0x02 << 4,
+  RC522_GAIN_23DBA = 0x03 << 4,
+  RC522_GAIN_33DB = 0x04 << 4,
+  RC522_GAIN_38DB = 0x05 << 4,
+  RC522_GAIN_43DB = 0x06 << 4,
+  RC522_GAIN_48DB = 0x07 << 4,
+};
+
+/// Convert the given Gain config value to a human-readable string.
+const LogString *rc522_gain_to_string(RC522Gain gain);
+
 class RC522BinarySensor;
 class RC522Trigger;
 class RC522 : public PollingComponent {
@@ -28,6 +45,7 @@ class RC522 : public PollingComponent {
   void register_ontagremoved_trigger(RC522Trigger *trig) { this->triggers_ontagremoved_.push_back(trig); }
 
   void set_reset_pin(GPIOPin *reset) { this->reset_pin_ = reset; }
+  void set_gain(RC522Gain gain) { this->gain_ = gain; }
 
  protected:
   // Return codes from the functions in this class. Remember to update GetStatusCodeName() if you add more.
@@ -238,6 +256,7 @@ class RC522 : public PollingComponent {
   uint8_t error_counter_ = 0;  // to reset if unresponsive
   uint8_t rx_align_;
   uint8_t *valid_bits_;
+  RC522Gain gain_;
 
   GPIOPin *reset_pin_{nullptr};
   uint8_t reset_count_{0};

tests/components/rc522_spi/test.esp32.yaml

@@ -7,6 +7,7 @@ spi:
 rc522_spi:
   id: rc522_nfcc
   cs_pin: 12
+  gain: 48dB
 
 binary_sensor:
   - platform: rc522