From c8df9a53e8d16877fc0b268b002af2a47a14643a Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Tue, 29 Apr 2008 09:34:07 +0100 Subject: [PATCH] [ARM] 5024/1: Fix some minor clk issues in the MMCI PL18x driver This fixes some two minor clk issues. The first is a comparison where a byte will probably wrap around to 0 instead of being saturated to 255, shouldn't be triggered very often but need fixing. The second is an attempt by the driver to adjust MCLK down to the maximum frequency according to the spec, so we don't accidentally overclock the PL18x block. None of the mach-{versatile|integrator|lh7a40x} that use it in-tree seem to have a problem with this (all are well below 100MHz, typically 33MHz), but some day there will be a problem. This is not applied on top of the earlier mmci patch for race condition but rather a clean 2.6.25, but I guess it applies without major protests anyway. Signed-off-by: Linus Walleij Signed-off-by: Russell King --- drivers/mmc/host/mmci.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c index 626ac083f4e..da5fecad74d 100644 --- a/drivers/mmc/host/mmci.c +++ b/drivers/mmc/host/mmci.c @@ -425,7 +425,7 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) host->cclk = host->mclk; } else { clk = host->mclk / (2 * ios->clock) - 1; - if (clk > 256) + if (clk >= 256) clk = 255; host->cclk = host->mclk / (2 * (clk + 1)); } @@ -512,6 +512,18 @@ static int mmci_probe(struct amba_device *dev, void *id) host->plat = plat; host->mclk = clk_get_rate(host->clk); + /* + * According to the spec, mclk is max 100 MHz, + * so we try to adjust the clock down to this, + * (if possible). + */ + if (host->mclk > 100000000) { + ret = clk_set_rate(host->clk, 100000000); + if (ret < 0) + goto clk_disable; + host->mclk = clk_get_rate(host->clk); + DBG(host, "eventual mclk rate: %u Hz\n", host->mclk); + } host->mmc = mmc; host->base = ioremap(dev->res.start, SZ_4K); if (!host->base) { -- 2.41.1