linux-kernel - [PATCH] spi: atmel-quadspi: Disable the QSPI IP at suspend()

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Message-ID: <20210210135428.204134-1-tudor.ambarus@microchip.com>
Date:   Wed, 10 Feb 2021 15:54:28 +0200
From:   Tudor Ambarus <tudor.ambarus@...rochip.com>
To:     <broonie@...nel.org>
CC:     <nicolas.ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
        <ludovic.desroches@...rochip.com>, <linux-spi@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        "Tudor Ambarus" <tudor.ambarus@...rochip.com>
Subject: [PATCH] spi: atmel-quadspi: Disable the QSPI IP at suspend()

It is safer to disable the QSPI IP at suspend, in order to avoid
possible impact of glitches on the internal FSMs. This is a theoretical
fix, there were no problems seen as of now. Tested on sama5d2 and
sam9x60 versions of the IP.

Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
 drivers/spi/atmel-quadspi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index 10bc5390ab91..95d4fa32c299 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -657,6 +657,7 @@ static int __maybe_unused atmel_qspi_suspend(struct device *dev)
 	struct spi_controller *ctrl = dev_get_drvdata(dev);
 	struct atmel_qspi *aq = spi_controller_get_devdata(ctrl);
 
+	atmel_qspi_write(QSPI_CR_QSPIDIS, aq, QSPI_CR);
 	clk_disable_unprepare(aq->qspick);
 	clk_disable_unprepare(aq->pclk);
 
-- 
2.25.1