Wire: reset ring buffer during requestFrom() call

JZimnol · JZimnol · commit 147d04f05a3b · 2026-03-25T11:29:54.000+01:00
Implemented flush() function to clear the rx buffer. The buffer needs to be flushed so the next read() call returns the proper data.

Signed-off-by: Jakub Zimnol &lt;zimnol.jakub@gmail.com&gt;
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp
@@ -48,6 +48,9 @@ size_t arduino::ZephyrI2C::requestFrom(uint8_t address, size_t len,
     printk("\n\nERR: i2c burst read fails\n\n\n");
     return 0;
   }
+
+  /* Flush the receive buffer so another read() call returns the correct data */
+  flush();
   ret = ring_buf_put(&rxRingBuffer.rb, rxRingBuffer.buffer, len);
   if (ret == 0)
   {
@@ -101,7 +104,9 @@ int arduino::ZephyrI2C::peek() {
   return (int)buf[0];
 }
 
-void arduino::ZephyrI2C::flush() {}
+void arduino::ZephyrI2C::flush() {
+  ring_buf_reset(&rxRingBuffer.rb);
+}
 
 void arduino::ZephyrI2C::onReceive(voidFuncPtrParamInt cb) {}
 void arduino::ZephyrI2C::onRequest(voidFuncPtr cb) {}

Original file line number	Diff line number	Diff line change
`@@ -48,6 +48,9 @@ size_t arduino::ZephyrI2C::requestFrom(uint8_t address, size_t len,`
`48`	`48`	`printk("\n\nERR: i2c burst read fails\n\n\n");`
`49`	`49`	`return 0;`
`50`	`50`	`}`
	`51`	`+`
	`52`	`+ /* Flush the receive buffer so another read() call returns the correct data */`
	`53`	`+ flush();`
`51`	`54`	`ret = ring_buf_put(&rxRingBuffer.rb, rxRingBuffer.buffer, len);`
`52`	`55`	`if (ret == 0)`
`53`	`56`	`{`
`@@ -101,7 +104,9 @@ int arduino::ZephyrI2C::peek() {`
`101`	`104`	`return (int)buf[0];`
`102`	`105`	`}`
`103`	`106`
`104`		`-void arduino::ZephyrI2C::flush() {}`
	`107`	`+void arduino::ZephyrI2C::flush() {`
	`108`	`+ ring_buf_reset(&rxRingBuffer.rb);`
	`109`	`+}`
`105`	`110`
`106`	`111`	`void arduino::ZephyrI2C::onReceive(voidFuncPtrParamInt cb) {}`
`107`	`112`	`void arduino::ZephyrI2C::onRequest(voidFuncPtr cb) {}`