linux-kernel - Re: [PATCH v5 1/1] thermal: thermal-generic-adc: add temperature sensor channel

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Message-ID: <20250502101907.6350fa25@jic23-huawei>
Date: Fri, 2 May 2025 10:19:07 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Svyatoslav Ryhel <clamor95@...il.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Daniel Lezcano
 <daniel.lezcano@...aro.org>, Zhang Rui <rui.zhang@...el.com>, Lukasz Luba
 <lukasz.luba@....com>, linux-pm@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-iio@...r.kernel.org
Subject: Re: [PATCH v5 1/1] thermal: thermal-generic-adc: add temperature
 sensor channel

On Wed, 30 Apr 2025 08:58:07 +0300
Svyatoslav Ryhel <clamor95@...il.com> wrote:

> To avoid duplicating sensor functionality and conversion tables, this
> design allows converting an ADC IIO channel's output directly into a
> temperature IIO channel. This is particularly useful for devices where
> hwmon isn't suitable or where temperature data must be accessible through
> IIO.
> 
> One such device is, for example, the MAX17040 fuel gauge.
> 
> Signed-off-by: Svyatoslav Ryhel <clamor95@...il.com>
Looks good to me.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
+CC linux-iio for info and maybe some more eyes.

> ---
>  drivers/thermal/thermal-generic-adc.c | 55 ++++++++++++++++++++++++++-
>  1 file changed, 54 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal-generic-adc.c b/drivers/thermal/thermal-generic-adc.c
> index ee3d0aa31406..7c844589b153 100644
> --- a/drivers/thermal/thermal-generic-adc.c
> +++ b/drivers/thermal/thermal-generic-adc.c
> @@ -7,6 +7,7 @@
>   * Author: Laxman Dewangan <ldewangan@...dia.com>
>   */
>  #include <linux/iio/consumer.h>
> +#include <linux/iio/iio.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> @@ -73,6 +74,58 @@ static const struct thermal_zone_device_ops gadc_thermal_ops = {
>  	.get_temp = gadc_thermal_get_temp,
>  };
>  
> +static const struct iio_chan_spec gadc_thermal_iio_channels[] = {
> +	{
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> +	}
> +};
> +
> +static int gadc_thermal_read_raw(struct iio_dev *indio_dev,
> +				 struct iio_chan_spec const *chan,
> +				 int *val, int *val2, long mask)
> +{
> +	struct gadc_thermal_info *gtinfo = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_PROCESSED:
> +		ret = gadc_thermal_get_temp(gtinfo->tz_dev, val);
> +		if (ret)
> +			return ret;
> +
> +		return IIO_VAL_INT;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct iio_info gadc_thermal_iio_info = {
> +	.read_raw = gadc_thermal_read_raw,
> +};
> +
> +static int gadc_iio_register(struct device *dev, struct gadc_thermal_info *gti)
> +{
> +	struct gadc_thermal_info *gtinfo;
> +	struct iio_dev *indio_dev;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*gtinfo));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	gtinfo = iio_priv(indio_dev);
> +	memcpy(gtinfo, gti, sizeof(*gtinfo));
> +
> +	indio_dev->name = dev_name(dev);
> +	indio_dev->info = &gadc_thermal_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = gadc_thermal_iio_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(gadc_thermal_iio_channels);
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}
> +
>  static int gadc_thermal_read_linear_lookup_table(struct device *dev,
>  						 struct gadc_thermal_info *gti)
>  {
> @@ -153,7 +206,7 @@ static int gadc_thermal_probe(struct platform_device *pdev)
>  
>  	devm_thermal_add_hwmon_sysfs(dev, gti->tz_dev);
>  
> -	return 0;
> +	return gadc_iio_register(&pdev->dev, gti);
>  }
>  
>  static const struct of_device_id of_adc_thermal_match[] = {