[PATCH v2] regulator: fixed: remove duplicate always-on handling

[PATCH v2] regulator: fixed: remove duplicate always-on handling

[Ahmad Fatoum]

Regulator core already handles always-on property by enabling always-on
regulators at registration time, so we can remove duplicate handling in
the fixed-regulator driver. To avoid regressions due to previously
unnoticed unbalanced regulator usage, maintain a positive use count
always like Linux does and additionally warn on violation attempt.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
v1 -> v2:
  - prevent use count dipping below 1 due to unbalanced use.
    This should avoid regressions and still warn us if they occur
---
 drivers/regulator/core.c  |  9 +++++++--
 drivers/regulator/fixed.c | 10 ----------
 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index af8a0cb4fc3e..1fb344656f38 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -66,6 +66,7 @@ static int regulator_enable_internal(struct regulator_internal *ri)
 
 static int regulator_disable_internal(struct regulator_internal *ri)
 {
+	struct regulator_dev *rdev = ri->rdev;
 	int ret;
 
 	if (!ri->enable_count)
@@ -76,10 +77,14 @@ static int regulator_disable_internal(struct regulator_internal *ri)
 		return 0;
 	}
 
-	if (!ri->rdev->desc->ops->disable)
+	/* Crisis averted, be loud about the unbalanced regulator use */
+	if (WARN_ON(rdev->always_on))
+		return -EPERM;
+
+	if (!rdev->desc->ops->disable)
 		return -ENOSYS;
 
-	ret = ri->rdev->desc->ops->disable(ri->rdev);
+	ret = rdev->desc->ops->disable(rdev);
 	if (ret)
 		return ret;
 
diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
index c5f97d78df40..ec64f39b86c7 100644
--- a/drivers/regulator/fixed.c
+++ b/drivers/regulator/fixed.c
@@ -15,7 +15,6 @@
 
 struct regulator_fixed {
 	int gpio;
-	int always_on;
 	struct regulator_dev rdev;
 	struct regulator_desc rdesc;
 };
@@ -34,9 +33,6 @@ static int regulator_fixed_disable(struct regulator_dev *rdev)
 {
 	struct regulator_fixed *fix = container_of(rdev, struct regulator_fixed, rdev);
 
-	if (fix->always_on)
-		return 0;
-
 	if (!gpio_is_valid(fix->gpio))
 		return 0;
 
@@ -76,12 +72,6 @@ static int regulator_fixed_probe(struct device_d *dev)
 	if (!of_property_read_u32(np, "off-on-delay-us", &delay))
 		fix->rdesc.off_on_delay = delay;
 
-	if (of_find_property(np, "regulator-always-on", NULL) ||
-	    of_find_property(np, "regulator-boot-on", NULL)) {
-		fix->always_on = 1;
-		regulator_fixed_enable(&fix->rdev);
-	}
-
 	ret = of_regulator_register(&fix->rdev, np);
 	if (ret)
 		goto err;
-- 
2.34.1

Re: [PATCH v2] regulator: fixed: remove duplicate always-on handling

[Sascha Hauer]

On Fri, Jul 08, 2022 at 08:15:40AM +0200, Ahmad Fatoum wrote:
> Regulator core already handles always-on property by enabling always-on
> regulators at registration time, so we can remove duplicate handling in
> the fixed-regulator driver. To avoid regressions due to previously
> unnoticed unbalanced regulator usage, maintain a positive use count
> always like Linux does and additionally warn on violation attempt.
> 
> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> ---
> v1 -> v2:
>   - prevent use count dipping below 1 due to unbalanced use.
>     This should avoid regressions and still warn us if they occur
> ---
>  drivers/regulator/core.c  |  9 +++++++--
>  drivers/regulator/fixed.c | 10 ----------
>  2 files changed, 7 insertions(+), 12 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index af8a0cb4fc3e..1fb344656f38 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -66,6 +66,7 @@ static int regulator_enable_internal(struct regulator_internal *ri)
>  
>  static int regulator_disable_internal(struct regulator_internal *ri)
>  {
> +	struct regulator_dev *rdev = ri->rdev;
>  	int ret;
>  
>  	if (!ri->enable_count)
> @@ -76,10 +77,14 @@ static int regulator_disable_internal(struct regulator_internal *ri)
>  		return 0;
>  	}
>  
> -	if (!ri->rdev->desc->ops->disable)
> +	/* Crisis averted, be loud about the unbalanced regulator use */
> +	if (WARN_ON(rdev->always_on))
> +		return -EPERM;
> +
> +	if (!rdev->desc->ops->disable)
>  		return -ENOSYS;
>  
> -	ret = ri->rdev->desc->ops->disable(ri->rdev);
> +	ret = rdev->desc->ops->disable(rdev);
>  	if (ret)
>  		return ret;
>  
> diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
> index c5f97d78df40..ec64f39b86c7 100644
> --- a/drivers/regulator/fixed.c
> +++ b/drivers/regulator/fixed.c
> @@ -15,7 +15,6 @@
>  
>  struct regulator_fixed {
>  	int gpio;
> -	int always_on;
>  	struct regulator_dev rdev;
>  	struct regulator_desc rdesc;
>  };
> @@ -34,9 +33,6 @@ static int regulator_fixed_disable(struct regulator_dev *rdev)
>  {
>  	struct regulator_fixed *fix = container_of(rdev, struct regulator_fixed, rdev);
>  
> -	if (fix->always_on)
> -		return 0;
> -
>  	if (!gpio_is_valid(fix->gpio))
>  		return 0;
>  
> @@ -76,12 +72,6 @@ static int regulator_fixed_probe(struct device_d *dev)
>  	if (!of_property_read_u32(np, "off-on-delay-us", &delay))
>  		fix->rdesc.off_on_delay = delay;
>  
> -	if (of_find_property(np, "regulator-always-on", NULL) ||
> -	    of_find_property(np, "regulator-boot-on", NULL)) {
> -		fix->always_on = 1;
> -		regulator_fixed_enable(&fix->rdev);
> -	}
> -
>  	ret = of_regulator_register(&fix->rdev, np);
>  	if (ret)
>  		goto err;
> -- 
> 2.34.1
> 
> 
> 

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