diff mbox series

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

Message ID 20200615090943.2936839-2-noltari@gmail.com
State New, archived
Headers show
Series [v2,1/4] spi: bcm63xx-spi: add reset support | expand

Commit Message

Álvaro Fernández Rojas June 15, 2020, 9:09 a.m. UTC
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 <noltari@gmail.com>
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(+)

Comments

Florian Fainelli June 15, 2020, 4:26 p.m. UTC | #1
On 6/15/2020 2:09 AM, Álvaro Fernández Rojas wrote:
> 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 <noltari@gmail.com>
> 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.
diff mbox series

Patch

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;
+	}
+
 	master = spi_alloc_master(dev, sizeof(*bs));
 	if (!master) {
 		dev_err(dev, "out of memory\n");
@@ -579,6 +590,12 @@  static int bcm63xx_spi_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_err;
 
+	ret = reset_control_reset(reset);
+	if (ret) {
+		dev_err(dev, "unable to reset device: %d\n", ret);
+		goto out_clk_disable;
+	}
+
 	bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
 
 	/* register and we are done */