target/linux/brcm2708/patches-4.4/0124-BCM270X_DT-Add-the-sdtweak-overlay-for-tuning-sdhost.patch

   1 From 1c2a3feefc21f0d4050de15d54a07219c90d6ef1 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 4 Jan 2016 14:42:17 +0000
   4 Subject: [PATCH 124/156] BCM270X_DT: Add the sdtweak overlay, for tuning
   5  sdhost
   6
   7 The sdhost overlay declares the sdhost interface and allows parameters
   8 to be set. This is overkill for situations where the user just wants to
   9 tweak the parameters of a pre-declared sdhost interface, so create an
  10 sdtweak overlay that does just that.
  11 ---
  12  arch/arm/boot/dts/overlays/Makefile            |  1 +
  13  arch/arm/boot/dts/overlays/README              | 14 ++++++++++++++
  14  arch/arm/boot/dts/overlays/sdtweak-overlay.dts | 21 +++++++++++++++++++++
  15  3 files changed, 36 insertions(+)
  16  create mode 100644 arch/arm/boot/dts/overlays/sdtweak-overlay.dts
  17
  18 --- a/arch/arm/boot/dts/overlays/Makefile
  19 +++ b/arch/arm/boot/dts/overlays/Makefile
  20 @@ -53,6 +53,7 @@ dtb-$(RPI_DT_OVERLAYS) += rpi-proto-over
  21  dtb-$(RPI_DT_OVERLAYS) += rpi-sense-overlay.dtb
  22  dtb-$(RPI_DT_OVERLAYS) += sdhost-overlay.dtb
  23  dtb-$(RPI_DT_OVERLAYS) += sdio-overlay.dtb
  24 +dtb-$(RPI_DT_OVERLAYS) += sdtweak-overlay.dtb
  25  dtb-$(RPI_DT_OVERLAYS) += smi-dev-overlay.dtb
  26  dtb-$(RPI_DT_OVERLAYS) += smi-nand-overlay.dtb
  27  dtb-$(RPI_DT_OVERLAYS) += smi-overlay.dtb
  28 --- a/arch/arm/boot/dts/overlays/README
  29 +++ b/arch/arm/boot/dts/overlays/README
  30 @@ -635,6 +635,20 @@ Params: overclock_50             Clock (
  31                                   (default on: polling once at boot-time)
  32
  33
  34 +Name:   sdtweak
  35 +Info:   Tunes the bcm2835-sdhost SD/MMC driver
  36 +Load:   dtoverlay=sdtweak,<param>=<val>
  37 +Params: overclock_50             Clock (in MHz) to use when the MMC framework
  38 +                                 requests 50MHz
  39 +
  40 +        force_pio                Disable DMA support (default off)
  41 +
  42 +        pio_limit                Number of blocks above which to use DMA
  43 +                                 (default 1)
  44 +
  45 +        debug                    Enable debug output (default off)
  46 +
  47 +
  48  Name:   smi
  49  Info:   Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25!
  50  Load:   dtoverlay=smi
  51 --- /dev/null
  52 +++ b/arch/arm/boot/dts/overlays/sdtweak-overlay.dts
  53 @@ -0,0 +1,21 @@
  54 +/dts-v1/;
  55 +/plugin/;
  56 +
  57 +/{
  58 +       compatible = "brcm,bcm2708";
  59 +
  60 +       fragment@0 {
  61 +               target = <&sdhost>;
  62 +               frag1: __overlay__ {
  63 +                       brcm,overclock-50 = <0>;
  64 +                       brcm,pio-limit = <1>;
  65 +               };
  66 +       };
  67 +
  68 +       __overrides__ {
  69 +               overclock_50     = <&frag1>,"brcm,overclock-50:0";
  70 +               force_pio        = <&frag1>,"brcm,force-pio?";
  71 +               pio_limit        = <&frag1>,"brcm,pio-limit:0";
  72 +               debug            = <&frag1>,"brcm,debug?";
  73 +       };
  74 +};