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 <meg...@megous.com>
---
drivers/bus/sunxi-rsb.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
index b8043b58568ac..8ab6a3865f569 100644
--- a/drivers/bus/sunxi-rsb.c
+++ b/drivers/bus/sunxi-rsb.c
@@ -316,6 +316,7 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr,
u8 addr,
{
u32 cmd;
int ret;
+ u32 mask;
if (!buf)
return -EINVAL;
@@ -323,12 +324,15 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8
rtaddr, u8 addr,
switch (len) {
case 1:
cmd = RSB_CMD_RD8;
+ mask = 0xffu;
break;
case 2:
cmd = RSB_CMD_RD16;
+ mask = 0xffffu;
break;
case 4:
cmd = RSB_CMD_RD32;
+ mask = 0xffffffffu;
break;
default:
dev_err(rsb->dev, "Invalid access width: %zd\n", len);
@@ -345,7 +349,7 @@ 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) & mask;
unlock:
mutex_unlock(&rsb->lock);
--
2.25.1
--
You received this message because you are subscribed to the Google Groups
"linux-sunxi" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to linux-sunxi+unsubscr...@googlegroups.com.
To view this discussion on the web, visit
https://groups.google.com/d/msgid/linux-sunxi/20200219010951.395599-1-megous%40megous.com.
