target/linux/brcm2708/patches-4.14/950-0167-mmc-bcm2835-mmc-Support-underclocking.patch

   1 From 9cd69b8f61edc246563741cd11d01fa911cd7e91 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 22 Jan 2018 12:22:01 +0000
   4 Subject: [PATCH 167/454] mmc: bcm2835-mmc: Support underclocking
   5
   6 Support underclocking of the SD bus using the max-frequency DT property
   7 (which currently has no DT parameter). The sd_overclock parameter
   8 already provides another way to achieve the same thing which should be
   9 equivalent in end result, but it is a bug not to support max-frequency
  10 as well.
  11
  12 See: https://github.com/raspberrypi/linux/issues/2350
  13
  14 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  15 ---
  16  drivers/mmc/host/bcm2835-mmc.c | 4 ++--
  17  1 file changed, 2 insertions(+), 2 deletions(-)
  18
  19 --- a/drivers/mmc/host/bcm2835-mmc.c
  20 +++ b/drivers/mmc/host/bcm2835-mmc.c
  21 @@ -1310,8 +1310,8 @@ static int bcm2835_mmc_add_host(struct b
  22
  23         host->clk_mul = 0;
  24
  25 -       mmc->f_max = host->max_clk;
  26 -       mmc->f_max = host->max_clk;
  27 +       if (!mmc->f_max || mmc->f_max > host->max_clk)
  28 +               mmc->f_max = host->max_clk;
  29         mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
  30
  31         /* SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK */