mmc: bcm2835: Don't overwrite max frequency unconditionally

The optional DT parameter max-frequency could init the max bus frequency.
So take care of this, before setting the max bus frequency.

Fixes: 660fc733bd74 ("mmc: bcm2835: Add new driver for the sdhost controller.")
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Cc: <stable@vger.kernel.org> # 4.12+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
index 229dc18..768972a 100644 (file)
--- a/drivers/mmc/host/bcm2835.c
+++ b/drivers/mmc/host/bcm2835.c
@@ -1265,7 +1265,8 @@ static int bcm2835_add_host(struct bcm2835_host *host)
        char pio_limit_string[20];
        int ret;
 
-       mmc->f_max = host->max_clk;
+       if (!mmc->f_max || mmc->f_max > host->max_clk)
+               mmc->f_max = host->max_clk;
        mmc->f_min = host->max_clk / SDCDIV_MAX_CDIV;
 
        mmc->max_busy_timeout = ~0 / (mmc->f_max / 1000);