This corrects an off-by one error when calculating the clock divisor. The code previously assumed that for example a divisor of 2 is set using a value of 0001 (the inverse of 1/2), a divisor of 4 is set using a value of 0010 (the inverse of 1/4) etc.. However, the correct values are 0000, 0001, etc...
The use of DIV_ROUND_UP() was suggested by Guennadi Liakhovetski to avoid understating the divisor by one in the case where the host clock is not a binary power of the MMCIF clock. Cc: Guennadi Liakhovetski <[email protected]> Tested-by: Cao Minh Hiep <[email protected]> Signed-off-by: Simon Horman <[email protected]> --- drivers/mmc/host/sh_mmcif.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c index 8057bf3..5014bc4 100644 --- a/drivers/mmc/host/sh_mmcif.c +++ b/drivers/mmc/host/sh_mmcif.c @@ -453,7 +453,8 @@ static void sh_mmcif_clock_control(struct sh_mmcif_host *host, unsigned int clk) sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_SUP_PCLK); else sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_CLEAR & - ((fls(host->clk / clk) - 1) << 16)); + ((fls(DIV_ROUND_UP(host->clk, + clk) - 1) - 1) << 16)); sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_ENABLE); } -- 1.7.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
