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

   1 From 263629c941a7da06b8cce7f73fe8d8d20d1357b7 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 136/381] BCM270X_DT: Add sdio_overclock parameter to sdio
   5  overlay
   6
   7 The sdio_overclock parameter is like the overclock_50 parameter, i.e.
   8 it sets an alternate frequency (in MHz) to use when the MMC framework
   9 requests 50MHz, except that it applies to the SDIO bus.
  10
  11 Be aware that the actual frequencies achievable are limited to even integer
  12 divisions of 250MHz, and that the driver will round up to include fractions
  13 (e.g. 62 will include 62.5) but then round down to the nearest frequency.
  14 In other words, the chosen frequency is the highest possible that is less than
  15 the parameter value + 1. In practise this means that 62 is the only sensible
  16 value.
  17
  18 Examples:
  19   250MHz/4 = 62.5MHz (sdio_overclock=62)
  20   250MHz/2 = 125MHz (sdio_overclock=125) # Too fast
  21 ---
  22  arch/arm/boot/dts/overlays/README           | 9 ++++++---
  23  arch/arm/boot/dts/overlays/sdio-overlay.dts | 2 ++
  24  2 files changed, 8 insertions(+), 3 deletions(-)
  25
  26 --- a/arch/arm/boot/dts/overlays/README
  27 +++ b/arch/arm/boot/dts/overlays/README
  28 @@ -53,8 +53,8 @@ have its contents deleted (or commented
  29  Using Overlays
  30  ==============
  31
  32 -Overlays are loaded using the "dtoverlay" directive. As an example, consider the
  33 -popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
  34 +Overlays are loaded using the "dtoverlay" directive. As an example, consider
  35 +the popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
  36  pre-DT world this would be loaded from /etc/modules, with an explicit
  37  "modprobe lirc-rpi" command, or programmatically by lircd. With DT enabled,
  38  this becomes a line in config.txt:
  39 @@ -621,9 +621,12 @@ Name:   sdio
  40  Info:   Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
  41          and enables SDIO via GPIOs 22-27.
  42  Load:   dtoverlay=sdio,<param>=<val>
  43 -Params: overclock_50             Clock (in MHz) to use when the MMC framework
  44 +Params: overclock_50             SD Clock (in MHz) to use when the MMC framework
  45                                   requests 50MHz
  46
  47 +        sdio_overclock           SDIO Clock (in MHz) to use when the MMC
  48 +                                 framework requests 50MHz
  49 +
  50          force_pio                Disable DMA support (default off)
  51
  52          pio_limit                Number of blocks above which to use DMA
  53 --- a/arch/arm/boot/dts/overlays/sdio-overlay.dts
  54 +++ b/arch/arm/boot/dts/overlays/sdio-overlay.dts
  55 @@ -12,6 +12,7 @@
  56                         pinctrl-0 = <&sdio_pins>;
  57                         non-removable;
  58                         bus-width = <4>;
  59 +                       brcm,overclock-50 = <0>;
  60                         status = "okay";
  61                 };
  62         };
  63 @@ -30,5 +31,6 @@
  64         __overrides__ {
  65                 poll_once = <&sdio_mmc>,"non-removable?";
  66                 bus_width = <&sdio_mmc>,"bus-width:0";
  67 +               sdio_overclock = <&sdio_mmc>,"brcm,overclock-50:0";
  68         };
  69  };