Re: [PATCH v7 4/5] iio: adc: versal-sysmon: add threshold event support

[Erim, Salih]

Hi Andy,

Thanks for the review, replies inline.

On 15/06/2026 15:43, Andy Shevchenko wrote:
> On Mon, Jun 15, 2026 at 12:37:21AM +0100, Salih Erim wrote:
> > Add threshold event support for temperature and supply voltage
> > channels.
> >
> > Temperature events:
> >    - Rising threshold with configurable value on the device
> >      temperature channel (current max across all satellites)
> >    - Per-channel hysteresis as a millicelsius value
> >    - Event direction is IIO_EV_DIR_RISING (hysteresis mode)
> >
> > Supply voltage events:
> >    - Rising/falling threshold per supply channel
> >    - Per-channel alarm enable via alarm configuration registers
> >
> > The hardware supports both window and hysteresis alarm modes for
> > temperature. This driver uses hysteresis mode, where the upper
> > threshold triggers the alarm and the lower threshold clears it
> > (re-arm point). The hardware has a single ISR bit per temperature
> > channel with no indication of which threshold was crossed, so
> > hysteresis mode is the natural fit. The lower threshold register
> > is computed internally as (upper - hysteresis).
> >
> > Hysteresis is stored in the driver as a millicelsius value,
> > initialized from the hardware registers at probe. Writing the
> > rising threshold or hysteresis recomputes the lower register.
> > ALARM_CONFIG is hard-coded to hysteresis mode during init.
> >
> > The hardware also provides a separate over-temperature (OT)
> > threshold, but it is not exposed through IIO as it serves as a
> > hardware safety mechanism for platform shutdown. OT will be
> > exposed through the thermal framework in a follow-up series.
> >
> > The interrupt handler masks active threshold interrupts (which are
> > level-sensitive) and schedules a delayed worker to poll for condition
> > clear before unmasking. When no hardware IRQ is available, event
> > specs are not attached and interrupt init is skipped, since the
> > I2C regmap backend cannot be called from atomic context.
> >
> > When disabling a supply channel alarm, the group interrupt remains
> > active if any other channel in the same alarm group still has an
> > alarm enabled.
> >
> > A devm cleanup action masks all interrupts on driver unbind to
> > prevent unhandled interrupt storms after the IRQ handler is freed.
>
> ...
>
> > +static void sysmon_q8p7_to_millicelsius(s16 raw_data, int *val)
> > +{
> > +     *val = (raw_data * (int)MILLI) >> SYSMON_FRACTIONAL_SHIFT;
>
> MILLIDEGREE_PER_DEGREE is defined as int.

Will use MILLIDEGREE_PER_DEGREE in both q8p7 conversion functions.

> > +}
> > +
> > +static void sysmon_millicelsius_to_q8p7(u32 *raw_data, int val)
> > +{
> > +     *raw_data = (val << SYSMON_FRACTIONAL_SHIFT) / (int)MILLI;
>
> Ditto.
>
> > +}
>
> ...
>
> > +static void sysmon_supply_processedtoraw(int val, u32 reg_val, u32 *raw_data)
> > +{
> > +     int exponent = FIELD_GET(SYSMON_MODE_MASK, reg_val);
> > +     int format = FIELD_GET(SYSMON_FMT_MASK, reg_val);
> > +     int scale, tmp;
> > +
> > +     scale = BIT(SYSMON_SUPPLY_MANTISSA_BITS - exponent);
> > +     tmp = (val * scale) / (int)MILLI;
>
> Due to agnosticism of this function, I dunno if the above can be applied here.

Agreed, this converts millivolts, not millicelsius.
MILLI with the (int) cast is correct here.

> > +     if (format)
> > +             tmp = clamp(tmp, S16_MIN, S16_MAX);
> > +     else
> > +             tmp = clamp(tmp, 0, U16_MAX);
> > +
> > +     *raw_data = (u16)tmp;
> > +}
>
> ...
>
> > +static int sysmon_read_alarm_config(struct sysmon *sysmon,
> > +                                 unsigned long address)
> > +{
> > +     u32 shift = address % SYSMON_ALARM_BITS_PER_REG;
> > +     u32 offset = SYSMON_ALARM_OFFSET(address);
> > +     unsigned int reg_val;
> > +     int ret;
> > +
> > +     ret = regmap_read(sysmon->regmap, offset, &reg_val);
> > +     if (ret)
> > +             return ret;
> > +
> > +     return !!(reg_val & BIT(shift));
>
> regmap_test_bits()?

Will switch to regmap_test_bits(). This simplifies the whole
function to a single return statement.

> > +}
>
> ...
>
> > -static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev)
> > +static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev,
> > +                        int irq)
>
> I would leave one line (82 characters IIANM).

Will join onto one line.

Thanks,
Salih

> --
> With Best Regards,
> Andy Shevchenko