From f93882570496aa02ba8a47bfaf81cce43046b978 Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Wed, 28 Mar 2012 18:01:09 +0900 Subject: mmc: sh_mmcif: double clock speed Correct an off-by one error when calculating the clock divisor in cases where the host clock is a power of two of the target clock. Previously the divisor was one greater than the correct value in these cases leading to the clock being set at half the desired speed. Thanks to Guennadi Liakhovetski for working with me on the logic for this change. Tested-by: Cao Minh Hiep Acked-by: Guennadi Liakhovetski Signed-off-by: Simon Horman Signed-off-by: Chris Ball --- drivers/mmc/host/sh_mmcif.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/host/sh_mmcif.c') diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c index aafaf0b6eb1c..d79c6430c164 100644 --- a/drivers/mmc/host/sh_mmcif.c +++ b/drivers/mmc/host/sh_mmcif.c @@ -454,7 +454,8 @@ 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); } -- cgit v1.2.3 From 930f152cc9998388031af577843baae572ac8ab6 Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Wed, 28 Mar 2012 18:01:10 +0900 Subject: mmc: sh_mmcif: mmc->f_max should be half of the bus clock mmc->f_max should be half of the bus clock. And now that mmc->f_max is not equal to the bus clock the latter should be used directly to calculate mmc->f_min. Cc: Magnus Damm Tested-by: Cao Minh Hiep Acked-by: Guennadi Liakhovetski Signed-off-by: Simon Horman Signed-off-by: Chris Ball --- drivers/mmc/host/sh_mmcif.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/mmc/host/sh_mmcif.c') diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c index d79c6430c164..4bb999ed335d 100644 --- a/drivers/mmc/host/sh_mmcif.c +++ b/drivers/mmc/host/sh_mmcif.c @@ -1298,14 +1298,14 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev) spin_lock_init(&host->lock); mmc->ops = &sh_mmcif_ops; - mmc->f_max = host->clk; + mmc->f_max = host->clk / 2; /* close to 400KHz */ - if (mmc->f_max < 51200000) - mmc->f_min = mmc->f_max / 128; - else if (mmc->f_max < 102400000) - mmc->f_min = mmc->f_max / 256; + if (host->clk < 51200000) + mmc->f_min = host->clk / 128; + else if (host->clk < 102400000) + mmc->f_min = host->clk / 256; else - mmc->f_min = mmc->f_max / 512; + mmc->f_min = host->clk / 512; if (pd->ocr) mmc->ocr_avail = pd->ocr; mmc->caps = MMC_CAP_MMC_HIGHSPEED; -- cgit v1.2.3 From eb91b9118db8c05a5a1257b594b021d32b491254 Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Wed, 28 Mar 2012 18:01:11 +0900 Subject: mmc: sh_mmcif: Simplify calculation of mmc->f_min There is no need to tune mmc->f_min to a value near 400kHz as the MMC core begins testing frequencies at 400kHz regardless of the value of mmc->f_min. As suggested by Guennadi Liakhovetski. Cc: Magnus Damm Acked-by: Guennadi Liakhovetski Tested-by: Cao Minh Hiep Signed-off-by: Simon Horman Signed-off-by: Chris Ball --- drivers/mmc/host/sh_mmcif.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'drivers/mmc/host/sh_mmcif.c') diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c index 4bb999ed335d..724b35e85a26 100644 --- a/drivers/mmc/host/sh_mmcif.c +++ b/drivers/mmc/host/sh_mmcif.c @@ -1299,13 +1299,7 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev) mmc->ops = &sh_mmcif_ops; mmc->f_max = host->clk / 2; - /* close to 400KHz */ - if (host->clk < 51200000) - mmc->f_min = host->clk / 128; - else if (host->clk < 102400000) - mmc->f_min = host->clk / 256; - else - mmc->f_min = host->clk / 512; + mmc->f_min = host->clk / 512; if (pd->ocr) mmc->ocr_avail = pd->ocr; mmc->caps = MMC_CAP_MMC_HIGHSPEED; -- cgit v1.2.3