drivers: can_mcp251xfd: Delay initialization after reset

Mcp251xfd devices occasionally fail to initialize after board
resets. It was experimentally found that adding a 5ms delay fixes
the problem.

Fixes #73586.

Original patch by melvinvdb from #73714.

Signed-off-by: Andriy Gelman <[email protected]>

Author: talih0

drivers/can/can_mcp251xfd.c

@@ -1497,7 +1497,10 @@ static int mcp251xfd_reset(const struct device *dev)
 		return ret;
 	}
 
-	return spi_write_dt(&dev_cfg->bus, &tx);
+	ret = spi_write_dt(&dev_cfg->bus, &tx);
+	/* Adding delay after init to fix occasional init issue. Delay time found experimentally. */
+	k_sleep(K_USEC(MCP251XFD_RESET_DELAY_USEC));
+	return ret;
 }
 
 static int mcp251xfd_init(const struct device *dev)

drivers/can/can_mcp251xfd.h

@@ -69,6 +69,8 @@ BUILD_ASSERT(MCP251XFD_TEF_FIFO_SIZE + MCP251XFD_TX_QUEUE_SIZE +
 #define MCP251XFD_MAX_INT_HANDLER_CALLS  10
 #define MCP251XFD_INT_HANDLER_SLEEP_USEC 10000
 
+/* Delay time found experimentally to fix occasional init issue */
+#define MCP251XFD_RESET_DELAY_USEC 5000
 
 struct mcp251xfd_mailbox {
 	can_tx_callback_t cb;