From ad1e597d4199ffcdee04b9fb402e45c5be6a5052 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Tue, 22 Sep 2009 16:45:16 -0700 Subject: sdhci-of: cleanup eSDHC's set_clock() a little bit - Get rid of incomprehensible "if { for { if } }" construction for the exponential divisor calculation. The first if statement isn't correct at all, since it should check for "host->max_clk / pre_div / 16 > clock". The error doesn't cause any bugs because the check in the for loop does the right thing, and so the outer check becomes useless; - For the linear divisor do the same: a single while statement is more readable than for + if construction; - Add dev_dbg() that prints desired and actual clock frequency. Signed-off-by: Anton Vorontsov Cc: Pierre Ossman Cc: Kumar Gala Cc: David Vrabel Cc: Ben Dooks Cc: Sascha Hauer Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/mmc/host/sdhci-of.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'drivers/mmc/host/sdhci-of.c') diff --git a/drivers/mmc/host/sdhci-of.c b/drivers/mmc/host/sdhci-of.c index c8dab07..01ab916 100644 --- a/drivers/mmc/host/sdhci-of.c +++ b/drivers/mmc/host/sdhci-of.c @@ -121,8 +121,8 @@ static void esdhc_writeb(struct sdhci_host *host, u8 val, int reg) static void esdhc_set_clock(struct sdhci_host *host, unsigned int clock) { - int div; int pre_div = 2; + int div = 1; clrbits32(host->ioaddr + ESDHC_SYSTEM_CONTROL, ESDHC_CLOCK_IPGEN | ESDHC_CLOCK_HCKEN | ESDHC_CLOCK_PEREN | ESDHC_CLOCK_MASK); @@ -130,17 +130,14 @@ static void esdhc_set_clock(struct sdhci_host *host, unsigned int clock) if (clock == 0) goto out; - if (host->max_clk / 16 > clock) { - for (; pre_div < 256; pre_div *= 2) { - if (host->max_clk / pre_div < clock * 16) - break; - } - } + while (host->max_clk / pre_div / 16 > clock && pre_div < 256) + pre_div *= 2; - for (div = 1; div <= 16; div++) { - if (host->max_clk / (div * pre_div) <= clock) - break; - } + while (host->max_clk / pre_div / div > clock && div < 16) + div++; + + dev_dbg(mmc_dev(host->mmc), "desired SD clock: %d, actual: %d\n", + clock, host->max_clk / pre_div / div); pre_div >>= 1; div--; -- cgit v1.1