From 619787e6d2f4dbf3c860d3b70657e1d62a3cf7a6 Mon Sep 17 00:00:00 2001
From: kahrendt <kahrendt@gmail.com>
Date: Fri, 1 Sep 2023 16:55:59 -0400
Subject: [PATCH] Bugfix: disable channels after IO if multiple tca9548a  I2C
 multiplexers are configured (#5317)

---
 esphome/components/tca9548a/tca9548a.cpp | 27 ++++++++++++++----------
 esphome/components/tca9548a/tca9548a.h   |  4 +++-
 2 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/esphome/components/tca9548a/tca9548a.cpp b/esphome/components/tca9548a/tca9548a.cpp
index caa3dd0655..770fd5e47c 100644
--- a/esphome/components/tca9548a/tca9548a.cpp
+++ b/esphome/components/tca9548a/tca9548a.cpp
@@ -7,23 +7,27 @@ namespace tca9548a {
 static const char *const TAG = "tca9548a";
 
 i2c::ErrorCode TCA9548AChannel::readv(uint8_t address, i2c::ReadBuffer *buffers, size_t cnt) {
-  auto err = parent_->switch_to_channel(channel_);
+  auto err = this->parent_->switch_to_channel(channel_);
   if (err != i2c::ERROR_OK)
     return err;
-  return parent_->bus_->readv(address, buffers, cnt);
+  err = this->parent_->bus_->readv(address, buffers, cnt);
+  this->parent_->disable_all_channels();
+  return err;
 }
 i2c::ErrorCode TCA9548AChannel::writev(uint8_t address, i2c::WriteBuffer *buffers, size_t cnt, bool stop) {
-  auto err = parent_->switch_to_channel(channel_);
+  auto err = this->parent_->switch_to_channel(channel_);
   if (err != i2c::ERROR_OK)
     return err;
-  return parent_->bus_->writev(address, buffers, cnt, stop);
+  err = this->parent_->bus_->writev(address, buffers, cnt, stop);
+  this->parent_->disable_all_channels();
+  return err;
 }
 
 void TCA9548AComponent::setup() {
   ESP_LOGCONFIG(TAG, "Setting up TCA9548A...");
   uint8_t status = 0;
   if (this->read(&status, 1) != i2c::ERROR_OK) {
-    ESP_LOGI(TAG, "TCA9548A failed");
+    ESP_LOGE(TAG, "TCA9548A failed");
     this->mark_failed();
     return;
   }
@@ -37,15 +41,16 @@ void TCA9548AComponent::dump_config() {
 i2c::ErrorCode TCA9548AComponent::switch_to_channel(uint8_t channel) {
   if (this->is_failed())
     return i2c::ERROR_NOT_INITIALIZED;
-  if (current_channel_ == channel)
-    return i2c::ERROR_OK;
 
   uint8_t channel_val = 1 << channel;
-  auto err = this->write(&channel_val, 1);
-  if (err == i2c::ERROR_OK) {
-    current_channel_ = channel;
+  return this->write(&channel_val, 1);
+}
+
+void TCA9548AComponent::disable_all_channels() {
+  if (this->write(&TCA9548A_DISABLE_CHANNELS_COMMAND, 1) != i2c::ERROR_OK) {
+    ESP_LOGE(TAG, "Failed to disable all channels.");
+    this->status_set_error();  // couldn't disable channels, set error status
   }
-  return err;
 }
 
 }  // namespace tca9548a
diff --git a/esphome/components/tca9548a/tca9548a.h b/esphome/components/tca9548a/tca9548a.h
index 02553f8cd0..08f1674d11 100644
--- a/esphome/components/tca9548a/tca9548a.h
+++ b/esphome/components/tca9548a/tca9548a.h
@@ -6,6 +6,8 @@
 namespace esphome {
 namespace tca9548a {
 
+static const uint8_t TCA9548A_DISABLE_CHANNELS_COMMAND = 0x00;
+
 class TCA9548AComponent;
 class TCA9548AChannel : public i2c::I2CBus {
  public:
@@ -28,10 +30,10 @@ class TCA9548AComponent : public Component, public i2c::I2CDevice {
   void update();
 
   i2c::ErrorCode switch_to_channel(uint8_t channel);
+  void disable_all_channels();
 
  protected:
   friend class TCA9548AChannel;
-  uint8_t current_channel_ = 255;
 };
 }  // namespace tca9548a
 }  // namespace esphome