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Ondrej Jirmangregkh
Ondrej Jirman
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bus: sunxi-rsb: Return correct data when mixing 16-bit and 8-bit reads
[ Upstream commit a43ab30 ] 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 <[email protected]> Acked-by: Chen-Yu Tsai <[email protected]> Signed-off-by: Maxime Ripard <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
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drivers/bus/sunxi-rsb.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -345,7 +345,7 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
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if (ret)
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goto unlock;
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*buf = readl(rsb->regs + RSB_DATA);
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*buf = readl(rsb->regs + RSB_DATA) & GENMASK(len * 8 - 1, 0);
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unlock:
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mutex_unlock(&rsb->lock);

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