linux-kernel - [PATCH v2 7/8] spi: imx: defer spi initialization, if DMA engine is pending

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Message-ID: <42b82309e539e8a5523dca5364846c472ab9dcee.1442923630.git.anton_bondarenko@mentor.com>
Date:	Fri, 25 Sep 2015 19:57:14 +0200
From:	Anton Bondarenko <anton_bondarenko@...tor.com>
To:	<broonie@...nel.org>
CC:	<linux-kernel@...r.kernel.org>, <linux-spi@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <jiada_wang@...tor.com>,
	<muzaffar_mahmood@...ay1.mentorg.com>,
	<vladimir_zapolskiy@...tor.com>, <b38343@...escale.com>
Subject: [PATCH v2 7/8] spi: imx: defer spi initialization, if DMA engine is pending

If SPI device supports DMA mode, but DMA controller is not yet
available due to e.g. a delay in the corresponding kernel module
initialization, retry to initialize SPI driver later on instead of
falling back into PIO only mode.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
Signed-off-by: Anton Bondarenko <anton_bondarenko@...tor.com>
---
 drivers/spi/spi-imx.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 44d3cf0..1bf0739a 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -1343,9 +1343,15 @@ static int spi_imx_probe(struct platform_device *pdev)
 	 * Only validated on i.mx6 now, can remove the constrain if validated on
 	 * other chips.
 	 */
-	if (is_imx5x_ecspi(spi_imx) &&
-	    spi_imx_sdma_init(&pdev->dev, spi_imx, master))
-		dev_err(&pdev->dev, "dma setup error,use pio instead\n");
+	if (is_imx5x_ecspi(spi_imx)) {
+		ret = spi_imx_sdma_init(&pdev->dev, spi_imx, master);
+		if (ret == -EPROBE_DEFER)
+			goto out_clk_put;
+
+		if (ret < 0)
+			dev_err(&pdev->dev, "dma setup error %d, use pio\n",
+				ret);
+	}
 
 	spi_imx->devtype_data->reset(spi_imx);
 
-- 
2.5.2

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