linux-kernel - Re: [PATCH v3 2/2] staging: iio: cdc: ad7746: use dt for capacitive channel setup.

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Date:   Mon, 3 May 2021 13:07:20 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Lucas Stankus <lucas.p.stankus@...il.com>
Cc:     lars@...afoo.de, Michael.Hennerich@...log.com, jic23@...nel.org,
        gregkh@...uxfoundation.org, linux-iio@...r.kernel.org,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v3 2/2] staging: iio: cdc: ad7746: use dt for capacitive
 channel setup.

On Sat, May 01, 2021 at 09:32:53AM -0300, Lucas Stankus wrote:
> diff --git a/drivers/staging/iio/cdc/ad7746.c b/drivers/staging/iio/cdc/ad7746.c
> index dfd71e99e872..531f1b96dea2 100644
> --- a/drivers/staging/iio/cdc/ad7746.c
> +++ b/drivers/staging/iio/cdc/ad7746.c
> @@ -18,8 +18,6 @@
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
>  
> -#include "ad7746.h"
> -
>  /*
>   * AD7746 Register Definition
>   */
> @@ -676,10 +674,11 @@ static const struct iio_info ad7746_info = {
>  static int ad7746_probe(struct i2c_client *client,
>  			const struct i2c_device_id *id)
>  {
> -	struct ad7746_platform_data *pdata = client->dev.platform_data;
> +	struct device *dev = &client->dev;
>  	struct ad7746_chip_info *chip;
>  	struct iio_dev *indio_dev;
>  	unsigned char regval = 0;
> +	unsigned int vdd_permille;
>  	int ret = 0;
>  
>  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> @@ -703,26 +702,39 @@ static int ad7746_probe(struct i2c_client *client,
>  	indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
> -	if (pdata) {
> -		if (pdata->exca_en) {
> -			if (pdata->exca_inv_en)
> -				regval |= AD7746_EXCSETUP_NEXCA;
> -			else
> -				regval |= AD7746_EXCSETUP_EXCA;
> -		}
> +	if (device_property_read_bool(dev, "adi,exca-output-en")) {
> +		if (device_property_read_bool(dev, "adi,exca-output-invert"))
> +			regval |= AD7746_EXCSETUP_NEXCA;
> +		else
> +			regval |= AD7746_EXCSETUP_EXCA;
> +	}
>  
> -		if (pdata->excb_en) {
> -			if (pdata->excb_inv_en)
> -				regval |= AD7746_EXCSETUP_NEXCB;
> -			else
> -				regval |= AD7746_EXCSETUP_EXCB;
> -		}
> +	if (device_property_read_bool(dev, "adi,excb-output-en")) {
> +		if (device_property_read_bool(dev, "adi,excb-output-invert"))
> +			regval |= AD7746_EXCSETUP_NEXCB;
> +		else
> +			regval |= AD7746_EXCSETUP_EXCB;
> +	}
>  
> -		regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
> -	} else {
> -		dev_warn(&client->dev, "No platform data? using default\n");
> -		regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
> -			AD7746_EXCSETUP_EXCLVL(3);
> +	ret = device_property_read_u32(dev, "adi,excitation-vdd-permille",
> +				       &vdd_permille);
> +	if (!ret) {

This test is reversed.  I wonder if the static checkers can catch the
uninitialized variable bug...  It's probably better to write it as:

	if (device_property_read_u32(dev, "adi,excitation-vdd-permille",
				     &vdd_permille) {

So it matches the others.

regards,
dan carpenter;

> +		switch (vdd_permille) {
> +		case 125:
> +			regval |= AD7746_EXCSETUP_EXCLVL(0);
> +			break;
> +		case 250:
> +			regval |= AD7746_EXCSETUP_EXCLVL(1);
> +			break;
> +		case 375:
> +			regval |= AD7746_EXCSETUP_EXCLVL(2);
> +			break;
> +		case 500:
> +			regval |= AD7746_EXCSETUP_EXCLVL(3);
> +			break;
> +		default:
> +			break;
> +		}
>  	}
>  
>  	ret = i2c_smbus_write_byte_data(chip->client,