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From 0dcafa8ab800d1f534bb0cb51cd02a082cf34be6 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Thu, 30 Apr 2020 12:43:05 +0100
Subject: [PATCH] ARM: dts: bcm2711: Allow 40-bit DMA for SPI
Add the spi_dma4 DT parameter to enable use of the 40-bit DMA channels
to drive SPI. Note that there are only 3-4 40-bit channels available,
and using this parameter claims 2 of them.
Usage: dtparam=spi_dma4
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 2 ++
arch/arm/boot/dts/overlays/README | 4 ++++
2 files changed, 6 insertions(+)
--- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
+++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
@@ -554,5 +554,7 @@
eth_led0 = <&phy1>,"led-modes:0";
eth_led1 = <&phy1>,"led-modes:4";
+ spi_dma4 = <&spi0>, "dmas:0=", <&dma40>,
+ <&spi0>, "dmas:8=", <&dma40>;
};
};
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -159,6 +159,10 @@ Params:
spi Set to "on" to enable the spi interfaces
(default "off")
+ spi_dma4 Use to enable 40-bit DMA on spi interfaces
+ (the assigned value doesn't matter)
+ (2711 only)
+
random Set to "on" to enable the hardware random
number generator (default "on")
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