linux-kernel - Re: [PATCH] regulator: change devm_regulator_get_enable

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Date: Tue, 23 Apr 2024 05:14:27 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Matti Vaittinen <mazziesaccount@...il.com>
Cc: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org,
	Aleksander Mazur <deweloper@...pl>
Subject: Re: [PATCH] regulator: change devm_regulator_get_enable_optional()
 stub to return Ok

On Tue, Apr 23, 2024 at 02:38:28PM +0300, Matti Vaittinen wrote:
> The devm_regulator_get_enable_optional() should be a 'call and forget'
> API, meaning, when it is used to enable the regulators, the API does not
> provide a handle to do any further control of the regulators. It gives
> no real benefit to return an error from the stub if CONFIG_REGULATOR is
> not set.
> 
> On the contrary, returning an error is causing problems to drivers when
> hardware is such it works out just fine with no regulator control.
> Returning an error forces drivers to specifically handle the case where
> CONFIG_REGULATOR is not set, making the mere existence of the stub
> questionalble.
> 
> Change the stub implementation for the
> devm_regulator_get_enable_optional() to return Ok so drivers do not
> separately handle the case where the CONFIG_REGULATOR is not set.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
> Fixes: da279e6965b3 ("regulator: Add devm helpers for get and enable")

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  include/linux/regulator/consumer.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
> index 71232fb7dda3..ed180ca419da 100644
> --- a/include/linux/regulator/consumer.h
> +++ b/include/linux/regulator/consumer.h
> @@ -326,7 +326,7 @@ static inline int devm_regulator_get_enable(struct device *dev, const char *id)
>  static inline int devm_regulator_get_enable_optional(struct device *dev,
>  						     const char *id)
>  {
> -	return -ENODEV;
> +	return 0;
>  }
>  
>  static inline struct regulator *__must_check
> 
> base-commit: f7638784bd0cf2ca9daebd47477983811f832300
> -- 
> 2.43.2
> 
> 
> -- 
> Matti Vaittinen, Linux device drivers
> ROHM Semiconductors, Finland SWDC
> Kiviharjunlenkki 1E
> 90220 OULU
> FINLAND
> 
> ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
> Simon says - in Latin please.
> ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
> Thanks to Simon Glass for the translation =]