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From 0c30ca161cd0aeda5ce514055897c07dcdf8e5cb Mon Sep 17 00:00:00 2001
From: campag <dave-lowe@ntlworld.com>
Date: Wed, 24 Feb 2016 16:45:42 +0000
Subject: [PATCH] BCM270X_DT: Add 1-bit SDIO using minimal pins...
... for that mode: GPIOs 22-25.
---
arch/arm/boot/dts/overlays/README | 21 ++++++++++++++
arch/arm/boot/dts/overlays/sdio-1bit-overlay.dts | 36 ++++++++++++++++++++++++
2 files changed, 57 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/sdio-1bit-overlay.dts
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -709,6 +709,27 @@ Params: overclock_50 SD Clock
bus_width Set the SDIO host bus width (default 4 bits)
+Name: sdio-1bit
+Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
+ and enables 1-bit SDIO via GPIOs 22-25.
+Load: dtoverlay=sdio-1bit,<param>=<val>
+Params: overclock_50 SD Clock (in MHz) to use when the MMC framework
+ requests 50MHz
+
+ sdio_overclock SDIO Clock (in MHz) to use when the MMC
+ framework requests 50MHz
+
+ force_pio Disable DMA support (default off)
+
+ pio_limit Number of blocks above which to use DMA
+ (default 1)
+
+ debug Enable debug output (default off)
+
+ poll_once Disable SDIO-device polling every second
+ (default on: polling once at boot-time)
+
+
Name: sdtweak
Info: Tunes the bcm2835-sdhost SD/MMC driver
Load: dtoverlay=sdtweak,<param>=<val>
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/sdio-1bit-overlay.dts
@@ -0,0 +1,36 @@
+/* Enable 1-bit SDIO from MMC interface via GPIOs 22-25. Includes sdhost overlay. */
+
+/include/ "sdhost-overlay.dts"
+
+/{
+ compatible = "brcm,bcm2708";
+
+ fragment@3 {
+ target = <&mmc>;
+ sdio_mmc: __overlay__ {
+ compatible = "brcm,bcm2835-mmc";
+ pinctrl-names = "default";
+ pinctrl-0 = <&sdio_pins>;
+ non-removable;
+ bus-width = <1>;
+ brcm,overclock-50 = <0>;
+ status = "okay";
+ };
+ };
+
+ fragment@4 {
+ target = <&gpio>;
+ __overlay__ {
+ sdio_pins: sdio_pins {
+ brcm,pins = <22 23 24 25>;
+ brcm,function = <7 7 7 7>; /* ALT3 = SD1 */
+ brcm,pull = <0 2 2 2>;
+ };
+ };
+ };
+
+ __overrides__ {
+ poll_once = <&sdio_mmc>,"non-removable?";
+ sdio_overclock = <&sdio_mmc>,"brcm,overclock-50:0";
+ };
+};
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