From d589f10fad74a4d71e2afaaf4e616097a92ec759 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Mon, 20 Jun 2022 11:49:24 +0200
Subject: [PATCH 02/28] can: mcp251xfd: mcp251xfd_register_get_dev_id(): fix
 endianness conversion
Git-commit: 1c0e78a287e3493e22bde8553d02f3b89177eaf7
Patch-mainline: v5.19-rc16
References: git-fixes

In mcp251xfd_register_get_dev_id() the device ID register is read with
handcrafted SPI transfers. As all registers, this register is in
little endian. Further it is not naturally aligned in struct
mcp251xfd_map_buf_nocrc::data. However after the transfer the register
content is converted from big endian to CPU endianness not taking care
of being unaligned.

Fix the conversion by converting from little endian to CPU endianness
taking the unaligned source into account.

Side note: So far the register content is 0x0 on all mcp251xfd
compatible chips, and is only used for an informative printk.

Link: https://lore.kernel.org/all/20220627092859.809042-1-mkl@pengutronix.de
Fixes: 55e5b97f003e ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN")
Reviewed-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 100cd7d3b244..2afb659a0f0c 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -12,6 +12,7 @@
 // Copyright (c) 2019 Martin Sperl <kernel@martin.sperl.org>
 //
 
+#include <asm/unaligned.h>
 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/device.h>
@@ -2692,7 +2693,7 @@ mcp251xfd_register_get_dev_id(const struct mcp251xfd_priv *priv,
 	if (err)
 		goto out_kfree_buf_tx;
 
-	*dev_id = be32_to_cpup((__be32 *)buf_rx->data);
+	*dev_id = get_unaligned_le32(buf_rx->data);
 	*effective_speed_hz = xfer->effective_speed_hz;
 
  out_kfree_buf_tx:
-- 
2.16.4