1 From 22c2725b4321128985d9780152d85a8dd1ace706 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] BCM270X_DT: Add the sdtweak overlay, for tuning sdhost
6 The sdhost overlay declares the sdhost interface and allows parameters
7 to be set. This is overkill for situations where the user just wants to
8 tweak the parameters of a pre-declared sdhost interface, so create an
9 sdtweak overlay that does just that.
11 arch/arm/boot/dts/overlays/Makefile | 1 +
12 arch/arm/boot/dts/overlays/README | 14 ++++++++++++++
13 arch/arm/boot/dts/overlays/sdtweak-overlay.dts | 21 +++++++++++++++++++++
14 3 files changed, 36 insertions(+)
15 create mode 100644 arch/arm/boot/dts/overlays/sdtweak-overlay.dts
17 --- a/arch/arm/boot/dts/overlays/Makefile
18 +++ b/arch/arm/boot/dts/overlays/Makefile
19 @@ -53,6 +53,7 @@ dtb-$(RPI_DT_OVERLAYS) += rpi-proto-over
20 dtb-$(RPI_DT_OVERLAYS) += rpi-sense-overlay.dtb
21 dtb-$(RPI_DT_OVERLAYS) += sdhost-overlay.dtb
22 dtb-$(RPI_DT_OVERLAYS) += sdio-overlay.dtb
23 +dtb-$(RPI_DT_OVERLAYS) += sdtweak-overlay.dtb
24 dtb-$(RPI_DT_OVERLAYS) += smi-dev-overlay.dtb
25 dtb-$(RPI_DT_OVERLAYS) += smi-nand-overlay.dtb
26 dtb-$(RPI_DT_OVERLAYS) += smi-overlay.dtb
27 --- a/arch/arm/boot/dts/overlays/README
28 +++ b/arch/arm/boot/dts/overlays/README
29 @@ -635,6 +635,20 @@ Params: overclock_50 Clock (
30 (default on: polling once at boot-time)
34 +Info: Tunes the bcm2835-sdhost SD/MMC driver
35 +Load: dtoverlay=sdtweak,<param>=<val>
36 +Params: overclock_50 Clock (in MHz) to use when the MMC framework
39 + force_pio Disable DMA support (default off)
41 + pio_limit Number of blocks above which to use DMA
44 + debug Enable debug output (default off)
48 Info: Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25!
51 +++ b/arch/arm/boot/dts/overlays/sdtweak-overlay.dts
57 + compatible = "brcm,bcm2708";
61 + frag1: __overlay__ {
62 + brcm,overclock-50 = <0>;
63 + brcm,pio-limit = <1>;
68 + overclock_50 = <&frag1>,"brcm,overclock-50:0";
69 + force_pio = <&frag1>,"brcm,force-pio?";
70 + pio_limit = <&frag1>,"brcm,pio-limit:0";
71 + debug = <&frag1>,"brcm,debug?";