Thread (17 messages) flat view 17 messages, 4 authors, 2020-06-15

Re: [PATCH v2 1/4] spi: bcm63xx-spi: add reset support

From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2020-06-15 16:26:14
Also in: linux-spi, lkml


On 6/15/2020 2:09 AM, Álvaro Fernández Rojas wrote:
quoted hunk ↗ jump to hunk
bcm63xx arch resets the SPI controller at early boot. However, bmips arch
needs to perform a reset when probing the driver.

Signed-off-by: Álvaro Fernández Rojas <redacted>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 v2: use devm_reset_control_get_exclusive

 drivers/spi/spi-bcm63xx.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
index 0f1b10a4ef0c..8ab04affaf7b 100644
--- a/drivers/spi/spi-bcm63xx.c
+++ b/drivers/spi/spi-bcm63xx.c
@@ -18,6 +18,7 @@
 #include <linux/err.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
+#include <linux/reset.h>
 
 /* BCM 6338/6348 SPI core */
 #define SPI_6348_RSET_SIZE		64
@@ -493,6 +494,7 @@ static int bcm63xx_spi_probe(struct platform_device *pdev)
 	struct bcm63xx_spi *bs;
 	int ret;
 	u32 num_cs = BCM63XX_SPI_MAX_CS;
+	struct reset_control *reset;
 
 	if (dev->of_node) {
 		const struct of_device_id *match;
@@ -529,6 +531,15 @@ static int bcm63xx_spi_probe(struct platform_device *pdev)
 		return PTR_ERR(clk);
 	}
 
+	reset = devm_reset_control_get_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;
+	}
This should be devm_reset_control_get_exclusive_optional() for a number
of reasons the first one being the most important as it reflects reality
of the HW:

- not all BCM63xx platforms have a dedicated reset line for the SPI
controller (like the ARM-based SoCs)

- until you also update all Device Tree sources to have a 'resets'
property in their SPI controller node, this is likely going to be failing

This also applies to patch 3.
-- 
Florian

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