From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Oltean Subject: [PATCH v2 4/6] spi: spi-fsl-dspi: Add support for LS1028A Date: Mon, 9 Mar 2020 23:07:53 +0200 Message-ID: <20200309210755.6759-5-olteanv@gmail.com> References: <20200309210755.6759-1-olteanv@gmail.com> Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, shawnguo@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, eha@deif.com, angelo@sysam.it, andrew.smirnov@gmail.com, gustavo@embeddedor.com, weic@nvidia.com, mhosny@nvidia.com, michael@walle.cc, peng.ma@nxp.com To: broonie@kernel.org Return-path: In-Reply-To: <20200309210755.6759-1-olteanv@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org From: Vladimir Oltean This is similar to the DSPI instantiation on LS1028A, except that: - The A-011218 erratum has been fixed, so DMA works - The endianness is different, which has implications on XSPI mode Some benchmarking with the following command: spidev_test --device /dev/spidev2.0 --bpw 8 --size 256 --cpha --iter 10000000 --speed 20000000 shows that in DMA mode, it can achieve around 2400 kbps, and in XSPI mode, the same command goes up to 4700 kbps. This is somewhat to be expected, since the DMA buffer size is extremely small at 8 bytes, the winner becomes whomever can prepare the buffers for transmission quicker, and DMA mode has higher overhead there. So XSPI FIFO mode has been chosen as the operating mode for this chip. Signed-off-by: Vladimir Oltean --- Changes in v2: Switch to DSPI_XSPI_MODE. drivers/spi/spi-fsl-dspi.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index 43d2d9fc8b92..cf8a141bbaf2 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -125,6 +125,7 @@ struct fsl_dspi_devtype_data { enum { LS1021A, LS1012A, + LS1028A, LS1043A, LS1046A, LS2080A, @@ -153,6 +154,12 @@ static const struct fsl_dspi_devtype_data devtype_data[] = { .max_clock_factor = 8, .fifo_size = 16, }, + [LS1028A] = { + .trans_mode = DSPI_XSPI_MODE, + .dma_bufsize = 8, + .max_clock_factor = 8, + .fifo_size = 4, + }, [LS1043A] = { /* Has A-011218 DMA erratum */ .trans_mode = DSPI_XSPI_MODE, @@ -1100,6 +1107,9 @@ static const struct of_device_id fsl_dspi_dt_ids[] = { }, { .compatible = "fsl,ls1012a-dspi", .data = &devtype_data[LS1012A], + }, { + .compatible = "fsl,ls1028a-dspi", + .data = &devtype_data[LS1028A], }, { .compatible = "fsl,ls1043a-dspi", .data = &devtype_data[LS1043A], -- 2.17.1