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From: <kostap@marvell.com>
To: <linux-spi@vger.kernel.org>
Cc: <devicetree@vger.kernel.org>, <broonie@kernel.org>,
	<robh+dt@kernel.org>, <mw@semihalf.com>, <jaz@semihalf.com>,
	<nadavh@marvell.com>, <bpeled@marvell.com>, <stefanc@marvell.com>,
	Konstantin Porotchkin <kostap@marvell.com>
Subject: [PATCH v2 1/2] spi: orion: enable clocks before spi_setup
Date: Thu, 17 Dec 2020 19:09:31 +0200	[thread overview]
Message-ID: <20201217170933.10717-2-kostap@marvell.com> (raw)
In-Reply-To: <20201217170933.10717-1-kostap@marvell.com>

From: Marcin Wojtas <mw@semihalf.com>

The spi-orion driver disables its clocks whenever it is not used.
In usual case during boot (i.e. using SPI flash) it is not a problem,
as the child device driver is present and probed along with
spi_register_master() execution.

However in case the child device driver is not ready
(e.g. when its type is module_spi_driver) the spi_setup() callback
can be called after the spi-orion probe. It may happen,
that as a result there will be an attempt to access controller's
registers with the clocks disabled.

Prevent such situations and make sure the clocks are on,
each time the spi_setup() is called.

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
---
 drivers/spi/spi-orion.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
index b57b8b3cc26e..3bfda4225d45 100644
--- a/drivers/spi/spi-orion.c
+++ b/drivers/spi/spi-orion.c
@@ -507,6 +507,16 @@ static int orion_spi_transfer_one(struct spi_master *master,
 
 static int orion_spi_setup(struct spi_device *spi)
 {
+	struct orion_spi *orion_spi = spi_master_get_devdata(spi->master);
+
+	/*
+	 * Make sure the clocks are enabled before
+	 * configuring the SPI controller.
+	 */
+	clk_prepare_enable(orion_spi->clk);
+	if (!IS_ERR(orion_spi->axi_clk))
+		clk_prepare_enable(orion_spi->axi_clk);
+
 	return orion_spi_setup_transfer(spi, NULL);
 }
 
-- 
2.17.1


  reply	other threads:[~2020-12-17 17:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-17 17:09 [PATCH v2 0/2] spi: new feature and fix for Marvell Orion driver kostap
2020-12-17 17:09 ` kostap [this message]
2020-12-17 17:25   ` [PATCH v2 1/2] spi: orion: enable clocks before spi_setup Mark Brown
2020-12-22 12:46     ` [EXT] " Kostya Porotchkin
2020-12-22 16:56       ` Mark Brown
2020-12-17 17:09 ` [PATCH v2 2/2] spi: orion: enable support for switching CS every transferred byte kostap
2020-12-17 17:42   ` Mark Brown
2020-12-17 17:09 ` [PATCH v2 0/2] spi: new feature and fix for Marvell Orion driver kostap

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