lkml.org 
[lkml]   [2019]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] spi: spi-bcm2835.c: Fix 3-wire mode
From
Date
Hi Nuno,

Am 28.06.19 um 14:30 schrieb Nuno Sá:
> As stated in
> https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md,
> one of rx or tx buffer's must be null. However, if DMA is enabled, the
> driver sets the SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX on the
> controller flags. Hence, the spi core will provide dummy buffers even if
> one of the buffers was set to null by the device driver. Thus, the
> communication with the 3-wire device fails.
>
> This patch uses the prepare_message callback to look for the device mode
> and sets/clears the SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX on a
> per spi message basis. It also assumes that DMA is not supported on
> half-duplex devices.
>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>

i never tested the 3-wire mode. Could you please describe your test setup?

@Martin, @Lukas Are you fine with this patch?

\
 
 \ /
  Last update: 2019-06-28 17:25    [W:0.114 / U:0.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site