From 793ca6d7a48120722e848f408e363345ee63fd09 Mon Sep 17 00:00:00 2001
From: Omar Chebib <omar.chebib@espressif.com>
Date: Mon, 28 Aug 2023 17:57:26 +0800
Subject: [PATCH] fix(i2c): fix issues related to timeout and alive interval
 tick

Fixes https://github.com/espressif/esp-idf/issues/4999

Former usage of I2C_CMD_ALIVE_INTERVAL_TICK macro overrode the ticks_to_wait
parameter when the latter was too big
---
 components/driver/i2c/i2c.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/components/driver/i2c/i2c.c b/components/driver/i2c/i2c.c
index fc46628fa45..4f76cd31d5a 100644
--- a/components/driver/i2c/i2c.c
+++ b/components/driver/i2c/i2c.c
@@ -1526,7 +1526,7 @@ esp_err_t i2c_master_cmd_begin(i2c_port_t i2c_num, i2c_cmd_handle_t cmd_handle,
     // Sometimes when the FSM get stuck, the ACK_ERR interrupt will occur endlessly until we reset the FSM and clear bus.
     esp_err_t ret = ESP_FAIL;
     i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];
-    TickType_t ticks_start = xTaskGetTickCount();
+    const TickType_t ticks_start = xTaskGetTickCount();
     BaseType_t res = xSemaphoreTake(p_i2c->cmd_mux, ticks_to_wait);
     if (res == pdFALSE) {
         return ESP_ERR_TIMEOUT;
@@ -1566,13 +1566,15 @@ esp_err_t i2c_master_cmd_begin(i2c_port_t i2c_num, i2c_cmd_handle_t cmd_handle,
     i2c_cmd_evt_t evt;
     while (1) {
         TickType_t wait_time = xTaskGetTickCount();
-        if (wait_time - ticks_start > ticks_to_wait) { // out of time
-            wait_time = I2C_CMD_ALIVE_INTERVAL_TICK;
+        const TickType_t elapsed = wait_time - ticks_start;
+        if (elapsed >= ticks_to_wait) { // out of time
+            /* Before triggering a timeout, empty the queue by giving a wait_time of 0:
+             * - if the queue is empty, `pdFALSE` will be returned and the loop will be exited
+             * - if the queue is not empty, we will pop an element and come back here again
+             */
+            wait_time = 0;
         } else {
-            wait_time = ticks_to_wait - (wait_time - ticks_start);
-            if (wait_time < I2C_CMD_ALIVE_INTERVAL_TICK) {
-                wait_time = I2C_CMD_ALIVE_INTERVAL_TICK;
-            }
+            wait_time = MIN(ticks_to_wait - elapsed, I2C_CMD_ALIVE_INTERVAL_TICK);
         }
         // In master mode, since we don't have an interrupt to detective bus error or FSM state, what we do here is to make
         // sure the interrupt mechanism for master mode is still working.