[PATCH] mmc, AT91: fix init fequency problem

[Prchal Jiří]

Hi,
this patch fixes problem with some SD cards during initialization. Not all SD(HC) card can run at even 375kHz. Sets
minimal frequency to 200kHz.
And in function "at91_mci_set_ios" is limit to maximum division, it's only 8 bit value.

Kernel version: 2.6.38
Signed-off-by: Jiri Prchal <jiri.prchal@xxxxxxxxxxx>
---

diff -uprN -X linux-2.6.38-vanilla/Documentation/dontdiff linux-2.6.38-vanilla/drivers/mmc/host/at91_mci.c
/home/prchal/arm/fw-cdu/linux/linux-2.6.38/drivers/mmc/host/at91_mci.c
--- linux-2.6.38-vanilla/drivers/mmc/host/at91_mci.c	2011-03-15 02:20:32.000000000 +0100
+++ /home/prchal/arm/fw-cdu/linux/linux-2.6.38/drivers/mmc/host/at91_mci.c	2011-03-24 09:20:22.869370179 +0100
@@ -724,6 +724,10 @@ static void at91_mci_set_ios(struct mmc_
 		else
 			clkdiv = (at91_master_clock / ios->clock) / 2;

+		/* set maximum divider */
+		if (clkdiv > 255)
+			clkdiv = 255;
+
 		pr_debug("clkdiv = %d. mcck = %ld\n", clkdiv,
 			at91_master_clock / (2 * (clkdiv + 1)));
 	}
@@ -944,7 +948,7 @@ static int __init at91_mci_probe(struct
 	}

 	mmc->ops = &at91_mci_ops;
-	mmc->f_min = 375000;
+	mmc->f_min = 200000; /* not all cards can run at 375kHz */
 	mmc->f_max = 25000000;
 	mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
 	mmc->caps = 0;
--
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