linux-kernel - Re: [PATCH 1/3] regulator: wm8994: Revert back to using devres

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Message-ID: <a57ae625-222d-09eb-62a2-f2262d8a4914@samsung.com>
Date:   Fri, 23 Nov 2018 10:24:28 +0100
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Charles Keepax <ckeepax@...nsource.cirrus.com>, broonie@...nel.org
Cc:     linus.walleij@...aro.org, lgirdwood@...il.com,
        linux-kernel@...r.kernel.org, patches@...nsource.cirrus.com
Subject: Re: [PATCH 1/3] regulator: wm8994: Revert back to using devres

Hi Charles,

On 2018-11-22 18:30, Charles Keepax wrote:
> This reverts commit 466affa06703 ("regulator: wm8994: Don't
> use devres for enable GPIOs"). Whilst that did work around the
> issue in question there are complications on the error paths of
> regulator_register. In the success case clearly the regulator
> core owns the GPIO, however, in the failure case it is unclear
> what should happen. The regulator core could always free the
> GPIO but that may not make sense from the perspective of the
> calling code. Alternatively the regulator core could never free
> the GPIO but that makes the handling in the regulator core rather
> complex. Ultimately it makes more sense to handle the shared GPIO
> in the core.
>
> Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>

Thanks for sorting this out! Works fine on Trats2:

Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

> ---
>  drivers/regulator/wm8994-regulator.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/regulator/wm8994-regulator.c b/drivers/regulator/wm8994-regulator.c
> index 46e6b4ee1491a..d7fec533c4032 100644
> --- a/drivers/regulator/wm8994-regulator.c
> +++ b/drivers/regulator/wm8994-regulator.c
> @@ -147,14 +147,11 @@ static int wm8994_ldo_probe(struct platform_device *pdev)
>  	config.regmap = wm8994->regmap;
>  	config.init_data = &ldo->init_data;
>  
> -	/*
> -	 * Look up LDO enable GPIO from the parent device node, we don't
> -	 * use devm because the regulator core will free the GPIO
> -	 */
> -	gpiod = gpiod_get_optional(pdev->dev.parent,
> -				   id ? "wlf,ldo2ena" : "wlf,ldo1ena",
> -				   GPIOD_OUT_LOW |
> -				   GPIOD_FLAGS_BIT_NONEXCLUSIVE);
> +	/* Look up LDO enable GPIO from the parent device node */
> +	gpiod = devm_gpiod_get_optional(pdev->dev.parent,
> +					id ? "wlf,ldo2ena" : "wlf,ldo1ena",
> +					GPIOD_OUT_LOW |
> +					GPIOD_FLAGS_BIT_NONEXCLUSIVE);
>  	if (IS_ERR(gpiod))
>  		return PTR_ERR(gpiod);
>  	config.ena_gpiod = gpiod;
> @@ -187,7 +184,6 @@ static int wm8994_ldo_probe(struct platform_device *pdev)
>  	return 0;
>  
>  err:
> -	gpiod_put(gpiod);
>  	return ret;
>  }
>  

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland