diff options
| author | Anton Vorontsov | 2009-09-22 16:45:16 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2009-09-23 07:39:37 -0700 |
| commit | ad1e597d4199ffcdee04b9fb402e45c5be6a5052 (patch) | |
| tree | 55792614ebf09ff2d293a1f190979eede5066f8c /drivers/mmc | |
| parent | 8226a219254bbcd20492df185f191a11a7a81dcd (diff) | |
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 <avorontsov@ru.mvista.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Ben Dooks <ben@fluff.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/sdhci-of.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/drivers/mmc/host/sdhci-of.c b/drivers/mmc/host/sdhci-of.c index c8dab07e34b8..01ab916c2802 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--; |