From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752694AbcKSElb (ORCPT ); Fri, 18 Nov 2016 23:41:31 -0500 Received: from vern.gendns.com ([206.190.152.46]:33396 "EHLO vern.gendns.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751690AbcKSEl3 (ORCPT ); Fri, 18 Nov 2016 23:41:29 -0500 From: David Lechner To: Mark Brown Cc: David Lechner , nsekhar@ti.com, khilman@kernel.org, linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] spi: davinci: Allow device tree devices to use DMA Date: Fri, 18 Nov 2016 22:41:04 -0600 Message-Id: <1479530464-12538-1-git-send-email-david@lechnology.com> X-Mailer: git-send-email 2.7.4 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This makes SPI devices specified in a device tree use DMA when the master controller has DMA configured. Since device tree is supposed to only describe the hardware, adding a configuration option to device tree to enable DMA per-device would not be acceptable. So, this is the best we can do for now to get SPI devices working with DMA when using device tree. Unfortunately, this excludes the possibility of using one SPI device with DMA and one without on the same master. I have tested this on LEGO MINDSTORMS EV3 using the NOR flash. Reading the flash memory would fail with -EIO when DMA is not enabled for the device. Signed-off-by: David Lechner --- drivers/spi/spi-davinci.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c index d36c11b..c6cf73a 100644 --- a/drivers/spi/spi-davinci.c +++ b/drivers/spi/spi-davinci.c @@ -388,6 +388,7 @@ static int davinci_spi_setup_transfer(struct spi_device *spi, static int davinci_spi_of_setup(struct spi_device *spi) { struct davinci_spi_config *spicfg = spi->controller_data; + struct davinci_spi *dspi = spi_master_get_devdata(spi->master); struct device_node *np = spi->dev.of_node; u32 prop; @@ -400,6 +401,9 @@ static int davinci_spi_of_setup(struct spi_device *spi) if (!of_property_read_u32(np, "ti,spi-wdelay", &prop)) spicfg->wdelay = (u8)prop; spi->controller_data = spicfg; + /* Use DMA for device if master supports it */ + if (dspi->dma_rx) + spicfg->io_type = SPI_IO_TYPE_DMA; } return 0; -- 2.7.4