Re: [PATCH v9 4/5] iio: adc: versal-sysmon: add threshold event support

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Wed, Jun 17, 2026 at 07:01:46PM +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.

A couple of nit-picks below, otherwise
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

...

>  #include <linux/cleanup.h>
>  #include <linux/device.h>
>  #include <linux/err.h>
> +#include <linux/interrupt.h>

+ limits.h // U16_MAX, et cetera

> +#include <linux/minmax.h>
>  #include <linux/module.h>
>  #include <linux/overflow.h>
>  #include <linux/property.h>

...

> -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)
>  {
>  	unsigned int num_chan, num_static, idx, temp_chan_idx, volt_chan_idx;
> -	unsigned int num_supply, num_temp;
>  	struct iio_chan_spec *sysmon_channels;
> +	unsigned int num_supply, num_temp;

Stray change, and I would expect to see all num_* on one line, and
all *_idx on another.

	unsigned int num_chan, num_static, num_supply, num_temp;
	unsigned int idx, temp_chan_idx, volt_chan_idx;
	struct iio_chan_spec *sysmon_channels;

TL;DR:
in this patch the above should not be modified as the previous one should
provide already a nice structure.

>  	const char *label;
>  	u32 reg;
>  	int ret;

-- 
With Best Regards,
Andy Shevchenko