blob: c591a9504f816609496d924767e9291f38a016f3 [file] [log] [blame]
From f089665597d2cf7d31400408316ad4e27b4df192 Mon Sep 17 00:00:00 2001
From: Ondrej Jirman <megous@megous.com>
Date: Fri, 21 Feb 2020 21:27:26 +0100
Subject: [PATCH] bus: sunxi-rsb: Return correct data when mixing 16-bit and
8-bit reads
commit a43ab30dcd4a1abcdd0d2461bf1cf7c0817f6cd3 upstream.
When doing a 16-bit read that returns data in the MSB byte, the
RSB_DATA register will keep the MSB byte unchanged when doing
the following 8-bit read. sunxi_rsb_read() will then return
a result that contains high byte from 16-bit read mixed with
the 8-bit result.
The consequence is that after this happens the PMIC's regmap will
look like this: (0x33 is the high byte from the 16-bit read)
% cat /sys/kernel/debug/regmap/sunxi-rsb-3a3/registers
00: 33
01: 33
02: 33
03: 33
04: 33
05: 33
06: 33
07: 33
08: 33
09: 33
0a: 33
0b: 33
0c: 33
0d: 33
0e: 33
[snip]
Fix this by masking the result of the read with the correct mask
based on the size of the read. There are no 16-bit users in the
mainline kernel, so this doesn't need to get into the stable tree.
Signed-off-by: Ondrej Jirman <megous@megous.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
index 1b76d9585902..2ca2cc56bcef 100644
--- a/drivers/bus/sunxi-rsb.c
+++ b/drivers/bus/sunxi-rsb.c
@@ -345,7 +345,7 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
if (ret)
goto unlock;
- *buf = readl(rsb->regs + RSB_DATA);
+ *buf = readl(rsb->regs + RSB_DATA) & GENMASK(len * 8 - 1, 0);
unlock:
mutex_unlock(&rsb->lock);
--
2.7.4