linux-kernel - [PATCH] spi: spi-axi-spi-engine: Access register after clock initialization

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Date:   Thu,  9 Apr 2020 17:56:21 +0200
From:   Rafał Hibner <rafal.hibner@...om.com.pl>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Rafał Hibner <rafal.hibner@...om.com.pl>,
        Alexandru Ardelean <alexandru.ardelean@...log.com>,
        Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] spi: spi-axi-spi-engine: Access register after clock  initialization

Move register access after clock initialization.
Clock "s_axi_aclk" is needed for register access. Without the clock running
AXI bus hangs and causes kernel freeze.

Cc: Alexandru Ardelean <alexandru.ardelean@...log.com>
Signed-off-by: Rafał Hibner <rafal.hibner@...om.com.pl>
---
 drivers/spi/spi-axi-spi-engine.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c
index eb9b78a90d..af86e6d6e1 100644
--- a/drivers/spi/spi-axi-spi-engine.c
+++ b/drivers/spi/spi-axi-spi-engine.c
@@ -489,22 +489,6 @@ static int spi_engine_probe(struct platform_device *pdev)
 
 	spin_lock_init(&spi_engine->lock);
 
-	spi_engine->base = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(spi_engine->base)) {
-		ret = PTR_ERR(spi_engine->base);
-		goto err_put_master;
-	}
-
-	version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
-	if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
-		dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
-			SPI_ENGINE_VERSION_MAJOR(version),
-			SPI_ENGINE_VERSION_MINOR(version),
-			SPI_ENGINE_VERSION_PATCH(version));
-		ret = -ENODEV;
-		goto err_put_master;
-	}
-
 	spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
 	if (IS_ERR(spi_engine->clk)) {
 		ret = PTR_ERR(spi_engine->clk);
@@ -525,6 +509,22 @@ static int spi_engine_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_clk_disable;
 
+	spi_engine->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(spi_engine->base)) {
+		ret = PTR_ERR(spi_engine->base);
+		goto err_ref_clk_disable;
+	}
+
+	version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
+	if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
+		dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
+			SPI_ENGINE_VERSION_MAJOR(version),
+			SPI_ENGINE_VERSION_MINOR(version),
+			SPI_ENGINE_VERSION_PATCH(version));
+		ret = -ENODEV;
+		goto err_ref_clk_disable;
+	}
+
 	writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET);
 	writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
 	writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
-- 
2.24.1