[PATCH -next 2/2] iio: adc: mt6577_auxadc: Simplify with device managed function

[Jonathan Cameron]

On Sat, 26 Aug 2023 11:54:02 +0800
Jinjie Ruan <ruanjinjie at huawei.com> wrote:

> Add a device managed hook, via devm_add_action_or_reset() and
> mt6577_power_off(), to power off on device detach.
> 
> Replace iio_device_register() by devm_iio_device_register() and remove
> the mt6577_auxadc_remove() function used to unregister the device and
> power off the device.
> 
> Remove platform_set_drvdata() from the probe function, since
> platform_get_drvdata() is not used anymore.
> 
> Remove mt6577_auxadc_mod_reg() call from the probe function error path.
> 
> Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.com>
> Suggested-by: Jonathan Cameron <jic23 at kernel.org>
> ---
>  drivers/iio/adc/mt6577_auxadc.c | 40 +++++++++++++--------------------
>  1 file changed, 15 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/iio/adc/mt6577_auxadc.c b/drivers/iio/adc/mt6577_auxadc.c
> index 935cf560e238..c8f7bfa59146 100644
> --- a/drivers/iio/adc/mt6577_auxadc.c
> +++ b/drivers/iio/adc/mt6577_auxadc.c
> @@ -246,6 +246,14 @@ static int mt6577_auxadc_suspend(struct device *dev)
>  	return 0;
>  }
>  
> +static void mt6577_power_off(void *data)
> +{
> +	struct mt6577_auxadc_device *adc_dev = data;
> +
> +	mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC,
> +			      0, MT6577_AUXADC_PDN_EN);
> +}
> +
>  static int mt6577_auxadc_probe(struct platform_device *pdev)
>  {
>  	struct mt6577_auxadc_device *adc_dev;
> @@ -286,31 +294,14 @@ static int mt6577_auxadc_probe(struct platform_device *pdev)
>  			      MT6577_AUXADC_PDN_EN, 0);
>  	mdelay(MT6577_AUXADC_POWER_READY_MS);
>  
> -	platform_set_drvdata(pdev, indio_dev);
> -
> -	ret = iio_device_register(indio_dev);
> -	if (ret < 0) {
> -		dev_err(&pdev->dev, "failed to register iio device\n");
> -		goto err_power_off;
> -	}
> -
> -	return 0;
> +	ret = devm_add_action_or_reset(&pdev->dev, mt6577_power_off, adc_dev);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "Failed to add action to managed power off: %d\n", ret);
The return code is already printed when dev_err_probe() formats the line, so I've
dropped that last bit whilst applying.

The way these two patches were separated is a little odd as you ignore
a few dev_err() cases in patch 1 because they don't make sense until patch 2.
I think this would have made more sense with the two patches reversed.

Still that's a very small thing (and I might be wrong as I didn't try it ;)
Applied to the togreg branch of iio.git and pushed out as testing for 0-day
etc to play with this.  I'll be rebasing on rc1 and it won't hit linux-next
until after that.

Thanks,

Jonathan

>  
> -err_power_off:
> -	mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC,
> -			      0, MT6577_AUXADC_PDN_EN);
> -	return ret;
> -}
> -
> -static int mt6577_auxadc_remove(struct platform_device *pdev)
> -{
> -	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> -	struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev);
> -
> -	iio_device_unregister(indio_dev);
> -
> -	mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC,
> -			      0, MT6577_AUXADC_PDN_EN);
> +	ret = devm_iio_device_register(&pdev->dev, indio_dev);
> +	if (ret < 0)
> +		return dev_err_probe(&pdev->dev, ret, "failed to register iio device\n");
>  
>  	return 0;
>  }
> @@ -337,7 +328,6 @@ static struct platform_driver mt6577_auxadc_driver = {
>  		.pm = pm_sleep_ptr(&mt6577_auxadc_pm_ops),
>  	},
>  	.probe	= mt6577_auxadc_probe,
> -	.remove	= mt6577_auxadc_remove,
>  };
>  module_platform_driver(mt6577_auxadc_driver);
>