linux-kernel - [PATCH v3 3/4] spi: bcm63xx-hsspi: add reset support

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Message-Id: <20200616070223.3401282-4-noltari@gmail.com>
Date:   Tue, 16 Jun 2020 09:02:22 +0200
From:   Álvaro Fernández Rojas 
        <noltari@...il.com>
To:     broonie@...nel.org, f.fainelli@...il.com,
        bcm-kernel-feedback-list@...adcom.com, p.zabel@...gutronix.de,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     Álvaro Fernández Rojas 
        <noltari@...il.com>
Subject: [PATCH v3 3/4] spi: bcm63xx-hsspi: add reset support

bcm63xx arch resets the HSSPI controller at early boot. However, bmips arch
needs to perform a reset when probing the driver.

Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
Reviewed-by: Philipp Zabel <p.zabel@...gutronix.de>
---
 v3: use devm_reset_control_get_optional_exclusive
 v2: use devm_reset_control_get_exclusive

 drivers/spi/spi-bcm63xx-hsspi.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/spi/spi-bcm63xx-hsspi.c b/drivers/spi/spi-bcm63xx-hsspi.c
index 6c235306c0e4..45e2b0942e64 100644
--- a/drivers/spi/spi-bcm63xx-hsspi.c
+++ b/drivers/spi/spi-bcm63xx-hsspi.c
@@ -20,6 +20,7 @@
 #include <linux/spi/spi.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
+#include <linux/reset.h>
 
 #define HSSPI_GLOBAL_CTRL_REG			0x0
 #define GLOBAL_CTRL_CS_POLARITY_SHIFT		0
@@ -334,6 +335,7 @@ static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 	struct clk *clk, *pll_clk = NULL;
 	int irq, ret;
 	u32 reg, rate, num_cs = HSSPI_SPI_MAX_CS;
+	struct reset_control *reset;
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
@@ -348,10 +350,25 @@ static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);
 
+	reset = devm_reset_control_get_optional_exclusive(dev, NULL);
+	if (IS_ERR(reset)) {
+		ret = PTR_ERR(reset);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev,
+				"failed to get reset controller: %d\n", ret);
+		return ret;
+	}
+
 	ret = clk_prepare_enable(clk);
 	if (ret)
 		return ret;
 
+	ret = reset_control_reset(reset);
+	if (ret) {
+		dev_err(dev, "unable to reset device: %d\n", ret);
+		goto out_disable_clk;
+	}
+
 	rate = clk_get_rate(clk);
 	if (!rate) {
 		pll_clk = devm_clk_get(dev, "pll");
-- 
2.27.0