linux-kernel - [PATCH 4/5] spi: img-spfi: Setup TRANSACTION register before CONTROL register

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Message-Id: <1428355747-16822-4-git-send-email-abrestic@chromium.org>
Date:	Mon,  6 Apr 2015 14:29:06 -0700
From:	Andrew Bresticker <abrestic@...omium.org>
To:	Mark Brown <broonie@...nel.org>
Cc:	linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org,
	Sifan Naeem <sifan.naeem@...tec.com>,
	Andrew Bresticker <abrestic@...omium.org>
Subject: [PATCH 4/5] spi: img-spfi: Setup TRANSACTION register before CONTROL register

From: Sifan Naeem <sifan.naeem@...tec.com>

Setting the transfer length in the TRANSACTION register after the
CONTROL register is programmed causes intermittent timeout issues in
SPFI transfers when using the SPI framework to control the CS GPIO
lines.  To avoid this issue, set transfer length before programming
the CONTROL register.

Signed-off-by: Sifan Naeem <sifan.naeem@...tec.com>
Signed-off-by: Andrew Bresticker <abrestic@...omium.org>
---
 drivers/spi/spi-img-spfi.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-img-spfi.c b/drivers/spi/spi-img-spfi.c
index 30c89f9..adeaa2f 100644
--- a/drivers/spi/spi-img-spfi.c
+++ b/drivers/spi/spi-img-spfi.c
@@ -458,6 +458,9 @@ static void img_spfi_config(struct spi_master *master, struct spi_device *spi,
 	val |= div << SPFI_DEVICE_PARAMETER_BITCLK_SHIFT;
 	spfi_writel(spfi, val, SPFI_DEVICE_PARAMETER(spi->chip_select));
 
+	spfi_writel(spfi, xfer->len << SPFI_TRANSACTION_TSIZE_SHIFT,
+		    SPFI_TRANSACTION);
+
 	val = spfi_readl(spfi, SPFI_CONTROL);
 	val &= ~(SPFI_CONTROL_SEND_DMA | SPFI_CONTROL_GET_DMA);
 	if (xfer->tx_buf)
@@ -476,8 +479,6 @@ static void img_spfi_config(struct spi_master *master, struct spi_device *spi,
 					      &master->cur_msg->transfers))
 		val |= SPFI_CONTROL_CONTINUE;
 	spfi_writel(spfi, val, SPFI_CONTROL);
-	spfi_writel(spfi, xfer->len << SPFI_TRANSACTION_TSIZE_SHIFT,
-		    SPFI_TRANSACTION);
 }
 
 static int img_spfi_transfer_one(struct spi_master *master,
-- 
2.2.0.rc0.207.ga3a616c

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