пт, 28 лют. 2025 р. о 15:11 Lukasz Luba <lukasz.luba@xxxxxxx> пише:
>
> Hi Svyatoslav,
>
> On 2/19/25 08:28, Svyatoslav Ryhel wrote:
> > Add IIO sensor channel along with existing thermal sensor cell. This
> > would benefit devices that use adc sensors to detect temperature and
> > need a custom conversion table.
> >
> > Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > ---
> > drivers/thermal/thermal-generic-adc.c | 54 ++++++++++++++++++++++++++-
> > 1 file changed, 53 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/thermal/thermal-generic-adc.c b/drivers/thermal/thermal-generic-adc.c
> > index ee3d0aa31406..a8f3b965b39b 100644
> > --- a/drivers/thermal/thermal-generic-adc.c
> > +++ b/drivers/thermal/thermal-generic-adc.c
> > @@ -7,6 +7,7 @@
> > * Author: Laxman Dewangan <ldewangan@xxxxxxxxxx>
> > */
> > #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 +74,57 @@ 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_channel[] = {
> > + {
> > + .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 *temp, int *val2, long mask)
> > +{
> > + struct gadc_thermal_info *gtinfo = iio_priv(indio_dev);
> > + int ret;
> > +
> > + if (mask != IIO_CHAN_INFO_PROCESSED)
> > + return -EINVAL;
> > +
> > + ret = gadc_thermal_get_temp(gtinfo->tz_dev, temp);
> > + if (ret < 0)
> > + return ret;
> > +
> > + *temp /= 1000;
> > +
> > + return IIO_VAL_INT;
> > +}
> > +
> > +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(struct gadc_thermal_info));
> > + if (!indio_dev)
> > + return -ENOMEM;
> > +
> > + gtinfo = iio_priv(indio_dev);
> > + memcpy(gtinfo, gti, sizeof(struct gadc_thermal_info));
> > +
> > + 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_channel;
> > + indio_dev->num_channels = ARRAY_SIZE(gadc_thermal_iio_channel);
> > +
> > + return devm_iio_device_register(dev, indio_dev);
>
> I don't get the idea why we need iio device, while we already have the
> hwmon.
>
Idea behind this is to be able to convert adc iio channel into temp
iio channel without introducing a new sensor which will duplicate
behavior of existing one (by this I mean conversion table use). Not
all devices can or have to use hwmon and some may require iio channel
hooked up.
Real life example. I own a device (LG P985) which has a fuel gauge
that does not support battery thermal readings. Vendor provided a
dedicated adc sensor and one of its channels is used as thermal sensor
with device specific conversion table. Fuel gauge on the other hand
supports linking in a dedicated temp iio channel to get thermal
readings.
> Could you explain this a bit more, the cover letter also misses
> such justification and details.
>
> Regards,
> Lukasz
