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Date:   Fri, 23 Mar 2018 12:46:47 +0000
From:   Jonathan Cameron <Jonathan.Cameron@huawei.com>
To:     =?ISO-8859-1?Q?Hern=E1n?= Gonzalez <hernan@vanguardiasur.com.ar>
CC:     <lars@metafoo.de>, <Michael.Hennerich@analog.com>,
        <jic23@kernel.org>, <knaack.h@gmx.de>, <pmeerw@pmeerw.net>,
        <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 06/11] staging: iio: ad7746: Add dt-bindings
Message-ID: <20180323134647.0000654d@huawei.com>
In-Reply-To: <1521642539-4845-7-git-send-email-hernan@vanguardiasur.com.ar>
References: <1521642539-4845-1-git-send-email-hernan@vanguardiasur.com.ar>
        <1521642539-4845-7-git-send-email-hernan@vanguardiasur.com.ar>
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On Wed, 21 Mar 2018 11:28:54 -0300
Hern?n Gonzalez <hernan@vanguardiasur.com.ar> wrote:

> This patch adds dt bindings by populating a pdata struct in order to
> modify as little as possible the existing code. It supports both
> platform_data and dt-bindings but uses only one depending on
> CONFIG_OF's value.
> 
> Signed-off-by: Hern?n Gonzalez <hernan@vanguardiasur.com.ar>
> ---
>  drivers/staging/iio/cdc/ad7746.c | 55 +++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 54 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/iio/cdc/ad7746.c b/drivers/staging/iio/cdc/ad7746.c
> index cba8cd1..815573c 100644
> --- a/drivers/staging/iio/cdc/ad7746.c
> +++ b/drivers/staging/iio/cdc/ad7746.c
> @@ -658,6 +658,44 @@ static const struct iio_info ad7746_info = {
>  /*
>   * device probe and remove
>   */
> +#ifdef CONFIG_OF
> +static struct ad7746_platform_data *ad7746_parse_dt(struct device *dev)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct ad7746_platform_data *pdata;
> +	unsigned int tmp;
> +	int ret;
> +
> +	/* The default excitation outputs are not inverted, it should be stated
> +	 * in the dt if needed.
> +	 */
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return NULL;
> +
> +	tmp = 0;
> +	ret = of_property_read_u32(np, "adi,exclvl", &tmp);
It's not an optional read so why would temp be unset in any
paths where it is used?

> +	if (ret || tmp > 3) {
> +		dev_warn(dev, "Wrong exclvl value, using default\n");
> +		pdata->exclvl = 3; /* default value */
> +	} else {
> +		pdata->exclvl = tmp;
> +	}
> +
> +	pdata->exca_inv_en = of_property_read_bool(np, "adi,nexca_en");
> +	pdata->excb_inv_en = of_property_read_bool(np, "adi,nexcb_en");
> +	pdata->exca_en = !pdata->exca_inv_en;
> +	pdata->excb_en = !pdata->excb_inv_en;
> +
> +	return pdata;
> +}
> +#else
> +static struct ad7746_platform_data *ad7746_parse_dt(struct device *dev)
> +{
> +	return NULL;
> +}
> +#endif
>  
>  static int ad7746_probe(struct i2c_client *client,
>  			const struct i2c_device_id *id)
> @@ -668,6 +706,11 @@ static int ad7746_probe(struct i2c_client *client,
>  	unsigned char regval = 0;
>  	int ret = 0;
>  
> +	if (client->dev.of_node)
> +		pdata = ad7746_parse_dt(&client->dev);
> +	else
> +		pdata = client->dev.platform_data;
> +
>  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
>  	if (!indio_dev)
>  		return -ENOMEM;
> @@ -731,12 +774,22 @@ static const struct i2c_device_id ad7746_id[] = {
>  	{ "ad7747", 7747 },
>  	{}
>  };
> -
>  MODULE_DEVICE_TABLE(i2c, ad7746_id);
>  
> +#ifdef CONFIG_OF
> +static const struct of_device_id ad7746_of_match[] = {
> +	{ .compatible = "adi,ad7745" },
> +	{ .compatible = "adi,ad7746" },
> +	{ .compatible = "adi,ad7747" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, ad7746_of_match);
> +#endif
> +
>  static struct i2c_driver ad7746_driver = {
>  	.driver = {
>  		.name = KBUILD_MODNAME,
> +		.of_match_table = of_match_ptr(ad7746_of_match),
>  	},
>  	.probe = ad7746_probe,
>  	.id_table = ad7746_id,