linux-kernel - Re: [PATCH 3/5] mfd: arizona: Don't use devres for DCVDD

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Date:	Tue, 17 Jun 2014 15:36:10 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Cc:	sameo@...ux.intel.com, patches@...nsource.wolfsonmicro.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] mfd: arizona: Don't use devres for DCVDD

On Mon, 02 Jun 2014, Charles Keepax wrote:

> Currently the Arizona core uses a devm_regulator_get against its own
> device node to obtain DCVDD. The Arizona core is an MFD device and DCVDD
> is usually supplied by a child node (arizona-ldo1) of the core. As
> devres destruction for the MFD device will run after all its children
> have been destroyed, the regulator will be destroyed before devres
> calls regulator_put. This causes a warning from both the destruction of
> the child node, as the regulator is still open, and from the put of the
> regulator as the regulator device has already been destroyed.
> 
> This patch handles the regulator get and put without devres to avoid
> this issue.
> 
> Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> ---
>  drivers/mfd/arizona-core.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)

For the fear of someone coming along and undoing this work, can you
write a nice succinct comment above regulator_get() that describes why
you're not using managed resources as a subsequent patch please?

Patch applied though.

> diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
> index 48acac6..7678e84 100644
> --- a/drivers/mfd/arizona-core.c
> +++ b/drivers/mfd/arizona-core.c
> @@ -676,7 +676,7 @@ int arizona_dev_init(struct arizona *arizona)
>  		goto err_early;
>  	}
>  
> -	arizona->dcvdd = devm_regulator_get(arizona->dev, "DCVDD");
> +	arizona->dcvdd = regulator_get(arizona->dev, "DCVDD");
>  	if (IS_ERR(arizona->dcvdd)) {
>  		ret = PTR_ERR(arizona->dcvdd);
>  		dev_err(dev, "Failed to request DCVDD: %d\n", ret);
> @@ -690,7 +690,7 @@ int arizona_dev_init(struct arizona *arizona)
>  				       "arizona /RESET");
>  		if (ret != 0) {
>  			dev_err(dev, "Failed to request /RESET: %d\n", ret);
> -			goto err_early;
> +			goto err_dcvdd;
>  		}
>  	}
>  
> @@ -699,7 +699,7 @@ int arizona_dev_init(struct arizona *arizona)
>  	if (ret != 0) {
>  		dev_err(dev, "Failed to enable core supplies: %d\n",
>  			ret);
> -		goto err_early;
> +		goto err_dcvdd;
>  	}
>  
>  	ret = regulator_enable(arizona->dcvdd);
> @@ -1016,6 +1016,8 @@ err_reset:
>  err_enable:
>  	regulator_bulk_disable(arizona->num_core_supplies,
>  			       arizona->core_supplies);
> +err_dcvdd:
> +	regulator_put(arizona->dcvdd);
>  err_early:
>  	mfd_remove_devices(dev);
>  	return ret;
> @@ -1027,6 +1029,7 @@ int arizona_dev_exit(struct arizona *arizona)
>  	pm_runtime_disable(arizona->dev);
>  
>  	regulator_disable(arizona->dcvdd);
> +	regulator_put(arizona->dcvdd);
>  
>  	mfd_remove_devices(arizona->dev);
>  	arizona_free_irq(arizona, ARIZONA_IRQ_UNDERCLOCKED, arizona);

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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