Messages in this thread | | | Subject | Re: [PATCH] spi: spi-bcm2835.c: Fix 3-wire mode | From | Stefan Wahren <> | Date | Fri, 28 Jun 2019 17:23:54 +0200 |
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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?
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