Re: [RFC PATCH 3/3] iio: proximity: srf04: Add Cytron HC-SR04 support

[Jonathan Cameron]

On Thu, 16 Jul 2026 19:35:56 +0200
Paweł Wiśniewski <pawel.wis.me@xxxxxxxxx> wrote:

> Tested on a Raspberry Pi 3 Model B+ running
> 6.18.34+rpt-rpi-v8. The sensor was instantiated using only the
> cytron,hc-sr04 compatible, with trigger connected to GPIO17 and echo
> connected to GPIO27 through a 5 V to 3.3 V resistor divider. The
> driver bound to the device, registered an IIO device, and returned
> changing distance readings through in_distance_raw.
> 
> Assisted-by: ChatGPT:GPT-5.6 Thinking
> Signed-off-by: Paweł Wiśniewski <pawel.wis.me@xxxxxxxxx>

This suggests that it is very much suited to a fallback compatible to the
Devantech SRF04 (see comment I made on the binding).

With that in place, we probably don't need a driver change.

Thanks,

Jonathan

> ---
>  drivers/iio/proximity/Kconfig | 1 +
>  drivers/iio/proximity/srf04.c | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
> index bb77fad2a1b3..89e9d57ceba6 100644
> --- a/drivers/iio/proximity/Kconfig
> +++ b/drivers/iio/proximity/Kconfig
> @@ -139,6 +139,7 @@ config SRF04
>  	  ranger sensor. This driver can be used to measure the distance
>  	  of objects. It is using two GPIOs.
>  	  Actually Supported types are:
> +	  - Cytron HC-SR04
>  	  - Devantech SRF04
>  	  - Maxbotix mb1000
>  	  - Maxbotix mb1010
> diff --git a/drivers/iio/proximity/srf04.c b/drivers/iio/proximity/srf04.c
> index 7be50bdebfcb..f5ee7d6572b5 100644
> --- a/drivers/iio/proximity/srf04.c
> +++ b/drivers/iio/proximity/srf04.c
> @@ -231,6 +231,7 @@ static const struct iio_chan_spec srf04_chan_spec[] = {
>  };
>  
>  static const struct of_device_id of_srf04_match[] = {
> +	{ .compatible = "cytron,hc-sr04", .data = &srf04_cfg },
>  	{ .compatible = "devantech,srf04", .data = &srf04_cfg },
>  	{ .compatible = "maxbotix,mb1000", .data = &mb_lv_cfg },
>  	{ .compatible = "maxbotix,mb1010", .data = &mb_lv_cfg },