[v2] watchdog: sp805: add reset control support

[PATCH v2 1/2] watchdog: sp805_wdt: deassert the reset if available

Posted by Yang Xiwen via B4 Relay 1 year, 11 months ago

From: Yang Xiwen <forbidden405@outlook.com>

According to the datasheet, the core has an WDOGRESn input signal that
needs to be deasserted before being operational. Implement it in the
driver.

Signed-off-by: Yang Xiwen <forbidden405@outlook.com>
---
 drivers/watchdog/sp805_wdt.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
index 2756ed54ca3d..b4bcfdeb39e6 100644
--- a/drivers/watchdog/sp805_wdt.c
+++ b/drivers/watchdog/sp805_wdt.c
@@ -25,6 +25,7 @@
 #include <linux/moduleparam.h>
 #include <linux/pm.h>
 #include <linux/property.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
@@ -59,6 +60,7 @@
  * @lock: spin lock protecting dev structure and io access
  * @base: base address of wdt
  * @clk: (optional) clock structure of wdt
+ * @rst: (optional) reset control signal of wdt
  * @rate: (optional) clock rate when provided via properties
  * @adev: amba device structure of wdt
  * @status: current status of wdt
@@ -69,6 +71,7 @@ struct sp805_wdt {
 	spinlock_t			lock;
 	void __iomem			*base;
 	struct clk			*clk;
+	struct reset_control		*rst;
 	u64				rate;
 	struct amba_device		*adev;
 	unsigned int			load_val;
@@ -264,6 +267,12 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
 		return -ENODEV;
 	}
 
+	wdt->rst = devm_reset_control_get_optional(&adev->dev, NULL);
+	if (IS_ERR(wdt->rst))
+		return dev_err_probe(&adev->dev, PTR_ERR(wdt->rst), "Can not get reset\n");
+
+	reset_control_deassert(wdt->rst);
+
 	wdt->adev = adev;
 	wdt->wdd.info = &wdt_info;
 	wdt->wdd.ops = &wdt_ops;

-- 
2.43.0

Re: [PATCH v2 1/2] watchdog: sp805_wdt: deassert the reset if available

Posted by Philipp Zabel 1 year, 11 months ago

On Di, 2024-02-20 at 02:14 +0800, Yang Xiwen via B4 Relay wrote:
> From: Yang Xiwen <forbidden405@outlook.com>
> 
> According to the datasheet, the core has an WDOGRESn input signal that
> needs to be deasserted before being operational. Implement it in the
> driver.
> 
> Signed-off-by: Yang Xiwen <forbidden405@outlook.com>
> ---
>  drivers/watchdog/sp805_wdt.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
> index 2756ed54ca3d..b4bcfdeb39e6 100644
> --- a/drivers/watchdog/sp805_wdt.c
> +++ b/drivers/watchdog/sp805_wdt.c
> @@ -25,6 +25,7 @@
>  #include <linux/moduleparam.h>
>  #include <linux/pm.h>
>  #include <linux/property.h>
> +#include <linux/reset.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
>  #include <linux/types.h>
> @@ -59,6 +60,7 @@
>   * @lock: spin lock protecting dev structure and io access
>   * @base: base address of wdt
>   * @clk: (optional) clock structure of wdt
> + * @rst: (optional) reset control signal of wdt
>   * @rate: (optional) clock rate when provided via properties
>   * @adev: amba device structure of wdt
>   * @status: current status of wdt
> @@ -69,6 +71,7 @@ struct sp805_wdt {
>  	spinlock_t			lock;
>  	void __iomem			*base;
>  	struct clk			*clk;
> +	struct reset_control		*rst;

This can be a local variable in sp805_wdt_probe().

>  	u64				rate;
>  	struct amba_device		*adev;
>  	unsigned int			load_val;
> @@ -264,6 +267,12 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>  		return -ENODEV;
>  	}
>  
> +	wdt->rst = devm_reset_control_get_optional(&adev->dev, NULL);

Please use devm_reset_control_get_optional_exclusive() directly.

> +	if (IS_ERR(wdt->rst))
> +		return dev_err_probe(&adev->dev, PTR_ERR(wdt->rst), "Can not get reset\n");
> +
> +	reset_control_deassert(wdt->rst);
> +
>  	wdt->adev = adev;
>  	wdt->wdd.info = &wdt_info;
>  	wdt->wdd.ops = &wdt_ops;

regards
Philipp

Re: [PATCH v2 1/2] watchdog: sp805_wdt: deassert the reset if available

Posted by Christophe JAILLET 1 year, 11 months ago

Le 19/02/2024 à 19:14, Yang Xiwen via B4 Relay a écrit :
> From: Yang Xiwen <forbidden405-1ViLX0X+lBJBDgjK7y7TUQ@public.gmane.org>
> 
> According to the datasheet, the core has an WDOGRESn input signal that
> needs to be deasserted before being operational. Implement it in the
> driver.
> 
> Signed-off-by: Yang Xiwen <forbidden405-1ViLX0X+lBJBDgjK7y7TUQ@public.gmane.org>
> ---
>   drivers/watchdog/sp805_wdt.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
> index 2756ed54ca3d..b4bcfdeb39e6 100644
> --- a/drivers/watchdog/sp805_wdt.c
> +++ b/drivers/watchdog/sp805_wdt.c
> @@ -25,6 +25,7 @@
>   #include <linux/moduleparam.h>
>   #include <linux/pm.h>
>   #include <linux/property.h>
> +#include <linux/reset.h>
>   #include <linux/slab.h>
>   #include <linux/spinlock.h>
>   #include <linux/types.h>
> @@ -59,6 +60,7 @@
>    * @lock: spin lock protecting dev structure and io access
>    * @base: base address of wdt
>    * @clk: (optional) clock structure of wdt
> + * @rst: (optional) reset control signal of wdt
>    * @rate: (optional) clock rate when provided via properties
>    * @adev: amba device structure of wdt
>    * @status: current status of wdt
> @@ -69,6 +71,7 @@ struct sp805_wdt {
>   	spinlock_t			lock;
>   	void __iomem			*base;
>   	struct clk			*clk;
> +	struct reset_control		*rst;
>   	u64				rate;
>   	struct amba_device		*adev;
>   	unsigned int			load_val;
> @@ -264,6 +267,12 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>   		return -ENODEV;
>   	}
>   
> +	wdt->rst = devm_reset_control_get_optional(&adev->dev, NULL);
> +	if (IS_ERR(wdt->rst))
> +		return dev_err_probe(&adev->dev, PTR_ERR(wdt->rst), "Can not get reset\n");
> +
> +	reset_control_deassert(wdt->rst);
> +

Hi,

Is a corresponding reset_control_assert() needed in the remove function?

CJ

>   	wdt->adev = adev;
>   	wdt->wdd.info = &wdt_info;
>   	wdt->wdd.ops = &wdt_ops;
>