1 From 0dcafa8ab800d1f534bb0cb51cd02a082cf34be6 Mon Sep 17 00:00:00 2001
2 From: Phil Elwell <phil@raspberrypi.com>
3 Date: Thu, 30 Apr 2020 12:43:05 +0100
4 Subject: [PATCH] ARM: dts: bcm2711: Allow 40-bit DMA for SPI
6 Add the spi_dma4 DT parameter to enable use of the 40-bit DMA channels
7 to drive SPI. Note that there are only 3-4 40-bit channels available,
8 and using this parameter claims 2 of them.
10 Usage: dtparam=spi_dma4
12 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
14 arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 2 ++
15 arch/arm/boot/dts/overlays/README | 4 ++++
16 2 files changed, 6 insertions(+)
18 --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
19 +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
21 eth_led0 = <&phy1>,"led-modes:0";
22 eth_led1 = <&phy1>,"led-modes:4";
24 + spi_dma4 = <&spi0>, "dmas:0=", <&dma40>,
25 + <&spi0>, "dmas:8=", <&dma40>;
28 --- a/arch/arm/boot/dts/overlays/README
29 +++ b/arch/arm/boot/dts/overlays/README
30 @@ -159,6 +159,10 @@ Params:
31 spi Set to "on" to enable the spi interfaces
34 + spi_dma4 Use to enable 40-bit DMA on spi interfaces
35 + (the assigned value doesn't matter)
38 random Set to "on" to enable the hardware random
39 number generator (default "on")