target/linux/brcm2708/patches-4.4/0136-BCM270X_DT-Add-sdio_overclock-parameter-to-sdio-over.patch

   1 From 1bb36898f708926752ef4afa43c62056b376d7a4 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 25 Jan 2016 09:12:06 +0000
   4 Subject: [PATCH] BCM270X_DT: Add sdio_overclock parameter to sdio overlay
   5
   6 The sdio_overclock parameter is like the overclock_50 parameter, i.e.
   7 it sets an alternate frequency (in MHz) to use when the MMC framework
   8 requests 50MHz, except that it applies to the SDIO bus.
   9
  10 Be aware that the actual frequencies achievable are limited to even integer
  11 divisions of 250MHz, and that the driver will round up to include fractions
  12 (e.g. 62 will include 62.5) but then round down to the nearest frequency.
  13 In other words, the chosen frequency is the highest possible that is less than
  14 the parameter value + 1. In practise this means that 62 is the only sensible
  15 value.
  16
  17 Examples:
  18   250MHz/4 = 62.5MHz (sdio_overclock=62)
  19   250MHz/2 = 125MHz (sdio_overclock=125) # Too fast
  20 ---
  21  arch/arm/boot/dts/overlays/README           | 9 ++++++---
  22  arch/arm/boot/dts/overlays/sdio-overlay.dts | 2 ++
  23  2 files changed, 8 insertions(+), 3 deletions(-)
  24
  25 --- a/arch/arm/boot/dts/overlays/README
  26 +++ b/arch/arm/boot/dts/overlays/README
  27 @@ -53,8 +53,8 @@ have its contents deleted (or commented
  28  Using Overlays
  29  ==============
  30
  31 -Overlays are loaded using the "dtoverlay" directive. As an example, consider the
  32 -popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
  33 +Overlays are loaded using the "dtoverlay" directive. As an example, consider
  34 +the popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
  35  pre-DT world this would be loaded from /etc/modules, with an explicit
  36  "modprobe lirc-rpi" command, or programmatically by lircd. With DT enabled,
  37  this becomes a line in config.txt:
  38 @@ -621,9 +621,12 @@ Name:   sdio
  39  Info:   Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
  40          and enables SDIO via GPIOs 22-27.
  41  Load:   dtoverlay=sdio,<param>=<val>
  42 -Params: overclock_50             Clock (in MHz) to use when the MMC framework
  43 +Params: overclock_50             SD Clock (in MHz) to use when the MMC framework
  44                                   requests 50MHz
  45
  46 +        sdio_overclock           SDIO Clock (in MHz) to use when the MMC
  47 +                                 framework requests 50MHz
  48 +
  49          force_pio                Disable DMA support (default off)
  50
  51          pio_limit                Number of blocks above which to use DMA
  52 --- a/arch/arm/boot/dts/overlays/sdio-overlay.dts
  53 +++ b/arch/arm/boot/dts/overlays/sdio-overlay.dts
  54 @@ -12,6 +12,7 @@
  55                         pinctrl-0 = <&sdio_pins>;
  56                         non-removable;
  57                         bus-width = <4>;
  58 +                       brcm,overclock-50 = <0>;
  59                         status = "okay";
  60                 };
  61         };
  62 @@ -30,5 +31,6 @@
  63         __overrides__ {
  64                 poll_once = <&sdio_mmc>,"non-removable?";
  65                 bus_width = <&sdio_mmc>,"bus-width:0";
  66 +               sdio_overclock = <&sdio_mmc>,"brcm,overclock-50:0";
  67         };
  68  };