linux-kernel - Re: [PATCH 4/4] iio: proximity: vl53l0x-i2c: Use raw I2C access and read full device ID

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Message-ID: <aW57j-zfhKGp1VTm@smile.fi.intel.com>
Date: Mon, 19 Jan 2026 20:44:31 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: petr.hodina@...tonmail.com
Cc: Song Qiang <songqiang1304521@...il.com>,
	Jonathan Cameron <jic23@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	Nuno Sá <nuno.sa@...log.com>,
	Andy Shevchenko <andy@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>, David Heidelberg <david@...t.cz>,
	linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] iio: proximity: vl53l0x-i2c: Use raw I2C access and
 read full device ID

On Mon, Jan 19, 2026 at 06:19:58PM +0100, Petr Hodina via B4 Relay wrote:

> Replace SMBus byte reads with raw I2C transfers when reading the device
> identification registers.
> 
> The VL53L0X exposes its model and revision as 16-bit registers, which are
> more accurately accessed using standard I2C send/receive operations.
> This also avoids depending on SMBus byte data support, which is not
> guaranteed on all I2C adapters.
> 
> Read and log both model and revision IDs, and validate the model ID
> during probe to ensure the expected device is present.

...

>  };
>  
> +

Stray blank line addition.

> +static int vl53l0x_read_word(struct i2c_client *client, u8 reg, u16 *val)
> +{
> +	int ret;
> +	u8 buf[2];

Here and everywhere else, please, keep the reversed xmas tree ordering.

> +	ret = i2c_master_send(client, &reg, 1);
> +	if (ret < 0)
> +		return ret;
> +	if (ret != 1)
> +		return -EIO;
> +
> +	ret = i2c_master_recv(client, buf, 2);

sizeof(buf)

> +	if (ret < 0)
> +		return ret;
> +	if (ret != 2)

Ditto.

> +		return -EIO;
> +
> +	*val = (buf[0] << 8) | buf[1];

Actually define

	__be16 buf;

and use

	*val = be16_to_cpu(buf);

> +	return 0;
> +}

...

>  static int vl53l0x_probe(struct i2c_client *client)
>  {
>  	struct vl53l0x_data *data;
>  	struct iio_dev *indio_dev;
>  	int ret;
> +	u16 model, rev;
>  

Use reversed xmas tree ordering.

-- 
With Best Regards,
Andy Shevchenko