lkml.org 
[lkml]   [2020]   [Apr]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 001/199] bus: sunxi-rsb: Return correct data when mixing 16-bit and 8-bit reads
    Date
    From: Ondrej Jirman <megous@megous.com>

    [ Upstream commit a43ab30dcd4a1abcdd0d2461bf1cf7c0817f6cd3 ]

    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: Sasha Levin <sashal@kernel.org>
    ---
    drivers/bus/sunxi-rsb.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
    index 1b76d95859027..2ca2cc56bcef6 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);
    --
    2.20.1


    \
     
     \ /
      Last update: 2020-04-22 12:54    [W:2.719 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site