linux-kernel - Re: [PATCH] staging: iio: ad9834: convert to device-managed functions in probe

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Message-ID: <20210313185453.76f2518c@archlinux>
Date:   Sat, 13 Mar 2021 18:54:53 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <aardelean@...iqon.com>
Cc:     linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, Michael.Hennerich@...log.com,
        gregkh@...uxfoundation.org, linux@...iqon.com
Subject: Re: [PATCH] staging: iio: ad9834: convert to device-managed
 functions in probe

On Wed, 10 Mar 2021 11:51:31 +0200
Alexandru Ardelean <aardelean@...iqon.com> wrote:

> This change converts the driver to use device-managed functions in the
> probe function. For the clock and regulator disable, some
> devm_add_action_or_reset() calls are required, and then
> devm_iio_device_register() function can be used register the IIO device.
> 
> The final aim here would be for IIO to export only the device-managed
> functions of it's API. That's a long way to go and this a small step in
> that direction.
> 
> Signed-off-by: Alexandru Ardelean <aardelean@...iqon.com>

I tweaked this a little to drop st->reg as it's no longer used.

Applied to the togreg branch of iio.git and pushed out as testing for
allow the autobuilders to poke randomly at it.

Thanks,

Jonathan

> ---
>  drivers/staging/iio/frequency/ad9834.c | 64 +++++++++++++-------------
>  1 file changed, 31 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/staging/iio/frequency/ad9834.c b/drivers/staging/iio/frequency/ad9834.c
> index 262c3590e64e..b063cfd0e0e1 100644
> --- a/drivers/staging/iio/frequency/ad9834.c
> +++ b/drivers/staging/iio/frequency/ad9834.c
> @@ -390,6 +390,20 @@ static const struct iio_info ad9833_info = {
>  	.attrs = &ad9833_attribute_group,
>  };
>  
> +static void ad9834_disable_reg(void *data)
> +{
> +	struct regulator *reg = data;
> +
> +	regulator_disable(reg);
> +}
> +
> +static void ad9834_disable_clk(void *data)
> +{
> +	struct clk *clk = data;
> +
> +	clk_disable_unprepare(clk);
> +}
> +
>  static int ad9834_probe(struct spi_device *spi)
>  {
>  	struct ad9834_state *st;
> @@ -407,26 +421,33 @@ static int ad9834_probe(struct spi_device *spi)
>  		return ret;
>  	}
>  
> +	ret = devm_add_action_or_reset(&spi->dev, ad9834_disable_reg, reg);
> +	if (ret)
> +		return ret;
> +
>  	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
>  	if (!indio_dev) {
>  		ret = -ENOMEM;
> -		goto error_disable_reg;
> +		return ret;
>  	}
> -	spi_set_drvdata(spi, indio_dev);
>  	st = iio_priv(indio_dev);
>  	mutex_init(&st->lock);
>  	st->mclk = devm_clk_get(&spi->dev, NULL);
>  	if (IS_ERR(st->mclk)) {
>  		ret = PTR_ERR(st->mclk);
> -		goto error_disable_reg;
> +		return ret;
>  	}
>  
>  	ret = clk_prepare_enable(st->mclk);
>  	if (ret) {
>  		dev_err(&spi->dev, "Failed to enable master clock\n");
> -		goto error_disable_reg;
> +		return ret;
>  	}
>  
> +	ret = devm_add_action_or_reset(&spi->dev, ad9834_disable_clk, st->mclk);
> +	if (ret)
> +		return ret;
> +
>  	st->spi = spi;
>  	st->devid = spi_get_device_id(spi)->driver_data;
>  	st->reg = reg;
> @@ -470,48 +491,26 @@ static int ad9834_probe(struct spi_device *spi)
>  	ret = spi_sync(st->spi, &st->msg);
>  	if (ret) {
>  		dev_err(&spi->dev, "device init failed\n");
> -		goto error_clock_unprepare;
> +		return ret;
>  	}
>  
>  	ret = ad9834_write_frequency(st, AD9834_REG_FREQ0, 1000000);
>  	if (ret)
> -		goto error_clock_unprepare;
> +		return ret;
>  
>  	ret = ad9834_write_frequency(st, AD9834_REG_FREQ1, 5000000);
>  	if (ret)
> -		goto error_clock_unprepare;
> +		return ret;
>  
>  	ret = ad9834_write_phase(st, AD9834_REG_PHASE0, 512);
>  	if (ret)
> -		goto error_clock_unprepare;
> +		return ret;
>  
>  	ret = ad9834_write_phase(st, AD9834_REG_PHASE1, 1024);
>  	if (ret)
> -		goto error_clock_unprepare;
> -
> -	ret = iio_device_register(indio_dev);
> -	if (ret)
> -		goto error_clock_unprepare;
> -
> -	return 0;
> -error_clock_unprepare:
> -	clk_disable_unprepare(st->mclk);
> -error_disable_reg:
> -	regulator_disable(reg);
> -
> -	return ret;
> -}
> -
> -static int ad9834_remove(struct spi_device *spi)
> -{
> -	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> -	struct ad9834_state *st = iio_priv(indio_dev);
> -
> -	iio_device_unregister(indio_dev);
> -	clk_disable_unprepare(st->mclk);
> -	regulator_disable(st->reg);
> +		return ret;
>  
> -	return 0;
> +	return devm_iio_device_register(&spi->dev, indio_dev);
>  }
>  
>  static const struct spi_device_id ad9834_id[] = {
> @@ -539,7 +538,6 @@ static struct spi_driver ad9834_driver = {
>  		.of_match_table = ad9834_of_match
>  	},
>  	.probe		= ad9834_probe,
> -	.remove		= ad9834_remove,
>  	.id_table	= ad9834_id,
>  };
>  module_spi_driver(ad9834_driver);