Re: [PATCH v2] drm/i915/hwmon: expose package temperature

[Raag Jadav <raag.jadav@intel.com>]

On Fri, Sep 06, 2024 at 03:15:01PM +0530, Riana Tauro wrote:
> Hi Raag
> 
> On 9/6/2024 3:01 PM, Raag Jadav wrote:
> > Add hwmon support for temp1_input attribute, which will expose package
> > temperature in millidegree Celsius. With this in place we can monitor
> > package temperature using lm-sensors tool.
> > 
> > $ sensors
> > i915-pci-0300
> > Adapter: PCI adapter
> > in0:         990.00 mV
> > fan1:        1260 RPM
> > temp1:        +45.0°C
> > power1:           N/A  (max =  35.00 W)
> > energy1:      12.62 kJ
> > 
> > v2: Use switch case (Anshuman)
> > 
> > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11276
> > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
> > ---
> >   .../ABI/testing/sysfs-driver-intel-i915-hwmon |  8 ++++
> >   drivers/gpu/drm/i915/i915_hwmon.c             | 40 +++++++++++++++++++
> >   drivers/gpu/drm/i915/intel_mchbar_regs.h      |  4 ++
> >   3 files changed, 52 insertions(+)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> > index be4141a7522f..a885e5316d02 100644
> > --- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> > +++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> > @@ -83,3 +83,11 @@ Contact:	intel-gfx@lists.freedesktop.org
> >   Description:	RO. Fan speed of device in RPM.
> >   		Only supported for particular Intel i915 graphics platforms.
> > +
> > +What:		/sys/bus/pci/drivers/i915/.../hwmon/hwmon<i>/temp1_input
> > +Date:		November 2024
> > +KernelVersion:	6.12
> > +Contact:	intel-gfx@lists.freedesktop.org
> > +Description:	RO. GPU package temperature in millidegree Celsius.
> > +
> > +		Only supported for particular Intel i915 graphics platforms.
> > diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
> > index 17d30f6b84b0..0a9f483b4105 100644
> > --- a/drivers/gpu/drm/i915/i915_hwmon.c
> > +++ b/drivers/gpu/drm/i915/i915_hwmon.c
> > @@ -7,6 +7,7 @@
> >   #include <linux/hwmon-sysfs.h>
> >   #include <linux/jiffies.h>
> >   #include <linux/types.h>
> > +#include <linux/units.h>
> >   #include "i915_drv.h"
> >   #include "i915_hwmon.h"
> > @@ -32,6 +33,7 @@
> >   struct hwm_reg {
> >   	i915_reg_t gt_perf_status;
> > +	i915_reg_t pkg_temp;
> place it alphabetically after rapl_limit

This follows the ordering of enum hwmon_sensor_types (as the rest of the patch).

> >   	i915_reg_t pkg_power_sku_unit;
> >   	i915_reg_t pkg_power_sku;
> >   	i915_reg_t pkg_rapl_limit;
> > @@ -280,6 +282,7 @@ static const struct attribute_group *hwm_groups[] = {
> >   };
> >   static const struct hwmon_channel_info * const hwm_info[] = {
> > +	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
> >   	HWMON_CHANNEL_INFO(in, HWMON_I_INPUT),
> >   	HWMON_CHANNEL_INFO(power, HWMON_P_MAX | HWMON_P_RATED_MAX | HWMON_P_CRIT),
> >   	HWMON_CHANNEL_INFO(energy, HWMON_E_INPUT),
> > @@ -310,6 +313,37 @@ static int hwm_pcode_write_i1(struct drm_i915_private *i915, u32 uval)
> >   				  POWER_SETUP_SUBCOMMAND_WRITE_I1, 0, uval);
> >   }
> > +static umode_t
> > +hwm_temp_is_visible(const struct hwm_drvdata *ddat, u32 attr)
> > +{
> > +	struct i915_hwmon *hwmon = ddat->hwmon;
> > +
> > +	if (attr == hwmon_temp_input && i915_mmio_reg_valid(hwmon->rg.pkg_temp))
> > +		return 0444;
> > +
> > +	return 0;
> > +}
> > +
> > +static int
> > +hwm_temp_read(struct hwm_drvdata *ddat, u32 attr, long *val)
> > +{
> > +	struct i915_hwmon *hwmon = ddat->hwmon;
> > +	intel_wakeref_t wakeref;
> > +	u32 reg_val;
> > +
> > +	switch (attr) {
> > +	case hwmon_temp_input:
> > +		with_intel_runtime_pm(ddat->uncore->rpm, wakeref)
> > +			reg_val = intel_uncore_read(ddat->uncore, hwmon->rg.pkg_temp);
> > +
> > +		/* HW register value is in degrees, convert to millidegrees. */
> use millidegree Celsius here

The intent here is to signify the conversion rather than the unit.
But okay, will add if we have another version.

Raag