ARM: 6033/1: ARM: MMCI: pass max frequency from platform

This introduce the field f_max into the mmci_platform_data,
making it possible to pass in a desired block clocking frequency
from a board configuration. This is often more desirable than
using a module parameter. We keep the module parameter as a
fallback as well as the default frequency specified for this
parameter if a parameter is not provided.

This also adds some kerneldoc style documentation to the
platform data struct in mmci.h.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 7e70c1a06d8a..ff115d920888 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -631,7 +631,18 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 
         mmc->ops = &mmci_ops;
         mmc->f_min = (host->mclk + 511) / 512;
-        mmc->f_max = min(host->mclk, fmax);
+        /*
+         * If the platform data supplies a maximum operating
+         * frequency, this takes precedence. Else, we fall back
+         * to using the module parameter, which has a (low)
+         * default value in case it is not specified. Either
+         * value must not exceed the clock rate into the block,
+         * of course.
+         */
+        if (plat->f_max)
+                mmc->f_max = min(host->mclk, plat->f_max);
+        else
+                mmc->f_max = min(host->mclk, fmax);
         dev_dbg(mmc_dev(mmc), "clocking block at %u Hz\n", mmc->f_max);
 
 #ifdef CONFIG_REGULATOR