* [PATCH v2] ACPI: DPTF: Add new PCH FIVR methods
@ 2021-05-18 3:41 Srinivas Pandruvada
2021-05-18 9:36 ` Rafael J. Wysocki
0 siblings, 1 reply; 4+ messages in thread
From: Srinivas Pandruvada @ 2021-05-18 3:41 UTC (permalink / raw)
To: rjw, lenb; +Cc: linux-kernel, linux-acpi, Srinivas Pandruvada
Some additional information is required for updating PCH FIVR values
upon WiFi channel changes.
New attributes added to the existing sysfs:
fivr_switching_freq_mhz : Get the FIVR switching control frequency
using ACPI method GFCS. Refer to the
documentation for the equation.
fivr_switching_fault_status: Read the FIVR switching frequency control
fault status. Uses ACPI method GFFS
ssc_clock_info : Presents SSC (spread spectrum clock) information for EMI
(Electro magnetic interference) control. Use ACPI method GEMI. Refer
to the description of GEMI method below.
GFFS
This ACPI method is used to read the FIVR switching frequency control
fault status.
Bits Description
[0:0] Fault status when set to 1
[31:1] Reserved
GFCS
This ACPI method is used to read the FIVR switching control
frequency.
Bits Description
[11:0] Actual Frequency = value * XTAL_FREQ / 128
[31:12] Reserved
GEMI
This ACPI method is used to read the programmed register value for EMI
(Electro magnetic interference) control.
Bits Description
[7:0] Sets clock spectrum spread percentage:
0x00=0.2% , 0x3F=10%
1 LSB = 0.1% increase in spread (for
settings 0x01 thru 0x1C)
1 LSB = 0.2% increase in spread (for
settings 0x1E thru 0x3F)
[8] When set to 1, enables spread
spectrum clock
[9] 0: Triangle mode. FFC frequency
walks around the Fcenter in a linear
fashion
1: Random walk mode. FFC frequency
changes randomly within the SSC
(Spread spectrum clock) range
[10] 0: No white noise. 1: Add white noise
to spread waveform
[11] When 1, future writes are ignored.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
v2
Update documentation for fivr_switching_freq_mhz
Documentation/ABI/testing/sysfs-platform-dptf | 42 +++++++++++++++++++
drivers/acpi/dptf/dptf_pch_fivr.c | 9 ++++
2 files changed, 51 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-platform-dptf b/Documentation/ABI/testing/sysfs-platform-dptf
index 141834342a4d..fe62f024eb93 100644
--- a/Documentation/ABI/testing/sysfs-platform-dptf
+++ b/Documentation/ABI/testing/sysfs-platform-dptf
@@ -111,3 +111,45 @@ Contact: linux-acpi@vger.kernel.org
Description:
(RW) The PCH FIVR (Fully Integrated Voltage Regulator) switching frequency in MHz,
when FIVR clock is 38.4MHz.
+
+What: /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fivr_switching_freq_mhz
+Date: June, 2021
+KernelVersion: v5.14
+Contact: linux-acpi@vger.kernel.org
+Description:
+ (RO) Get the FIVR switching control frequency in MHz after applying equation
+ "fivr_switching_freq_mhz * XTAL_FREQ / 128". Here XTAL_FREQ is Crystal Oscillator frequency
+ in MHz, which is product specific.
+
+What: /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fivr_switching_fault_status
+Date: June, 2021
+KernelVersion: v5.14
+Contact: linux-acpi@vger.kernel.org
+Description:
+ (RO) Read the FIVR switching frequency control fault status.
+
+What: /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/ssc_clock_info
+Date: June, 2021
+KernelVersion: v5.14
+Contact: linux-acpi@vger.kernel.org
+Description:
+ (RO) Presents SSC (spread spectrum clock) information for EMI
+ (Electro magnetic interference) control. This is a bit mask.
+ Bits Description
+ [7:0] Sets clock spectrum spread percentage:
+ 0x00=0.2% , 0x3F=10%
+ 1 LSB = 0.1% increase in spread (for
+ settings 0x01 thru 0x1C)
+ 1 LSB = 0.2% increase in spread (for
+ settings 0x1E thru 0x3F)
+ [8] When set to 1, enables spread
+ spectrum clock
+ [9] 0: Triangle mode. FFC frequency
+ walks around the Fcenter in a linear
+ fashion
+ 1: Random walk mode. FFC frequency
+ changes randomly within the SSC
+ (Spread spectrum clock) range
+ [10] 0: No white noise. 1: Add white noise
+ to spread waveform
+ [11] When 1, future writes are ignored.
diff --git a/drivers/acpi/dptf/dptf_pch_fivr.c b/drivers/acpi/dptf/dptf_pch_fivr.c
index 5fca18296bf6..22c4ae0401ef 100644
--- a/drivers/acpi/dptf/dptf_pch_fivr.c
+++ b/drivers/acpi/dptf/dptf_pch_fivr.c
@@ -55,15 +55,24 @@ static ssize_t name##_store(struct device *dev,\
PCH_FIVR_SHOW(freq_mhz_low_clock, GFC0)
PCH_FIVR_SHOW(freq_mhz_high_clock, GFC1)
+PCH_FIVR_SHOW(ssc_clock_info, GEMI)
+PCH_FIVR_SHOW(fivr_switching_freq_mhz, GFCS)
+PCH_FIVR_SHOW(fivr_switching_fault_status, GFFS)
PCH_FIVR_STORE(freq_mhz_low_clock, RFC0)
PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)
static DEVICE_ATTR_RW(freq_mhz_low_clock);
static DEVICE_ATTR_RW(freq_mhz_high_clock);
+static DEVICE_ATTR_RO(ssc_clock_info);
+static DEVICE_ATTR_RO(fivr_switching_freq_mhz);
+static DEVICE_ATTR_RO(fivr_switching_fault_status);
static struct attribute *fivr_attrs[] = {
&dev_attr_freq_mhz_low_clock.attr,
&dev_attr_freq_mhz_high_clock.attr,
+ &dev_attr_ssc_clock_info.attr,
+ &dev_attr_fivr_switching_freq_mhz.attr,
+ &dev_attr_fivr_switching_fault_status.attr,
NULL
};
--
2.27.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] ACPI: DPTF: Add new PCH FIVR methods
2021-05-18 3:41 [PATCH v2] ACPI: DPTF: Add new PCH FIVR methods Srinivas Pandruvada
@ 2021-05-18 9:36 ` Rafael J. Wysocki
2021-05-18 10:27 ` Srinivas Pandruvada
0 siblings, 1 reply; 4+ messages in thread
From: Rafael J. Wysocki @ 2021-05-18 9:36 UTC (permalink / raw)
To: Srinivas Pandruvada
Cc: Rafael J. Wysocki, Len Brown, Linux Kernel Mailing List,
ACPI Devel Maling List
On Tue, May 18, 2021 at 5:42 AM Srinivas Pandruvada
<srinivas.pandruvada@linux.intel.com> wrote:
>
> Some additional information is required for updating PCH FIVR values
> upon WiFi channel changes.
>
> New attributes added to the existing sysfs:
> fivr_switching_freq_mhz : Get the FIVR switching control frequency
> using ACPI method GFCS. Refer to the
> documentation for the equation.
> fivr_switching_fault_status: Read the FIVR switching frequency control
> fault status. Uses ACPI method GFFS
>
> ssc_clock_info : Presents SSC (spread spectrum clock) information for EMI
> (Electro magnetic interference) control. Use ACPI method GEMI. Refer
> to the description of GEMI method below.
>
> GFFS
> This ACPI method is used to read the FIVR switching frequency control
> fault status.
> Bits Description
> [0:0] Fault status when set to 1
> [31:1] Reserved
>
> GFCS
> This ACPI method is used to read the FIVR switching control
> frequency.
> Bits Description
> [11:0] Actual Frequency = value * XTAL_FREQ / 128
> [31:12] Reserved
>
> GEMI
> This ACPI method is used to read the programmed register value for EMI
> (Electro magnetic interference) control.
>
> Bits Description
> [7:0] Sets clock spectrum spread percentage:
> 0x00=0.2% , 0x3F=10%
> 1 LSB = 0.1% increase in spread (for
> settings 0x01 thru 0x1C)
> 1 LSB = 0.2% increase in spread (for
> settings 0x1E thru 0x3F)
> [8] When set to 1, enables spread
> spectrum clock
> [9] 0: Triangle mode. FFC frequency
> walks around the Fcenter in a linear
> fashion
> 1: Random walk mode. FFC frequency
> changes randomly within the SSC
> (Spread spectrum clock) range
> [10] 0: No white noise. 1: Add white noise
> to spread waveform
> [11] When 1, future writes are ignored.
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> ---
> v2
> Update documentation for fivr_switching_freq_mhz
>
> Documentation/ABI/testing/sysfs-platform-dptf | 42 +++++++++++++++++++
> drivers/acpi/dptf/dptf_pch_fivr.c | 9 ++++
> 2 files changed, 51 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-platform-dptf b/Documentation/ABI/testing/sysfs-platform-dptf
> index 141834342a4d..fe62f024eb93 100644
> --- a/Documentation/ABI/testing/sysfs-platform-dptf
> +++ b/Documentation/ABI/testing/sysfs-platform-dptf
> @@ -111,3 +111,45 @@ Contact: linux-acpi@vger.kernel.org
> Description:
> (RW) The PCH FIVR (Fully Integrated Voltage Regulator) switching frequency in MHz,
> when FIVR clock is 38.4MHz.
> +
> +What: /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fivr_switching_freq_mhz
> +Date: June, 2021
> +KernelVersion: v5.14
> +Contact: linux-acpi@vger.kernel.org
> +Description:
> + (RO) Get the FIVR switching control frequency in MHz after applying equation
> + "fivr_switching_freq_mhz * XTAL_FREQ / 128". Here XTAL_FREQ is Crystal Oscillator frequency
> + in MHz, which is product specific.
IMO it would be sufficient to say the following here:
+ (RO) PCH FIVR switching control frequency in the units
of XTAL_FREQ / 128,
+ where XTAL_FREQ is the Crystal Oscillator frequency
(product specific).
This means that it needs to be multiplied by XTAL_FREQ / 128 to get
the frequency in the whatever units XTAL_FREQ is expressed.
I can make this change when applying the patch.
> +
> +What: /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fivr_switching_fault_status
> +Date: June, 2021
> +KernelVersion: v5.14
> +Contact: linux-acpi@vger.kernel.org
> +Description:
> + (RO) Read the FIVR switching frequency control fault status.
> +
> +What: /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/ssc_clock_info
> +Date: June, 2021
> +KernelVersion: v5.14
> +Contact: linux-acpi@vger.kernel.org
> +Description:
> + (RO) Presents SSC (spread spectrum clock) information for EMI
> + (Electro magnetic interference) control. This is a bit mask.
> + Bits Description
> + [7:0] Sets clock spectrum spread percentage:
> + 0x00=0.2% , 0x3F=10%
> + 1 LSB = 0.1% increase in spread (for
> + settings 0x01 thru 0x1C)
> + 1 LSB = 0.2% increase in spread (for
> + settings 0x1E thru 0x3F)
> + [8] When set to 1, enables spread
> + spectrum clock
> + [9] 0: Triangle mode. FFC frequency
> + walks around the Fcenter in a linear
> + fashion
> + 1: Random walk mode. FFC frequency
> + changes randomly within the SSC
> + (Spread spectrum clock) range
> + [10] 0: No white noise. 1: Add white noise
> + to spread waveform
> + [11] When 1, future writes are ignored.
> diff --git a/drivers/acpi/dptf/dptf_pch_fivr.c b/drivers/acpi/dptf/dptf_pch_fivr.c
> index 5fca18296bf6..22c4ae0401ef 100644
> --- a/drivers/acpi/dptf/dptf_pch_fivr.c
> +++ b/drivers/acpi/dptf/dptf_pch_fivr.c
> @@ -55,15 +55,24 @@ static ssize_t name##_store(struct device *dev,\
>
> PCH_FIVR_SHOW(freq_mhz_low_clock, GFC0)
> PCH_FIVR_SHOW(freq_mhz_high_clock, GFC1)
> +PCH_FIVR_SHOW(ssc_clock_info, GEMI)
> +PCH_FIVR_SHOW(fivr_switching_freq_mhz, GFCS)
> +PCH_FIVR_SHOW(fivr_switching_fault_status, GFFS)
> PCH_FIVR_STORE(freq_mhz_low_clock, RFC0)
> PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)
>
> static DEVICE_ATTR_RW(freq_mhz_low_clock);
> static DEVICE_ATTR_RW(freq_mhz_high_clock);
> +static DEVICE_ATTR_RO(ssc_clock_info);
> +static DEVICE_ATTR_RO(fivr_switching_freq_mhz);
> +static DEVICE_ATTR_RO(fivr_switching_fault_status);
>
> static struct attribute *fivr_attrs[] = {
> &dev_attr_freq_mhz_low_clock.attr,
> &dev_attr_freq_mhz_high_clock.attr,
> + &dev_attr_ssc_clock_info.attr,
> + &dev_attr_fivr_switching_freq_mhz.attr,
> + &dev_attr_fivr_switching_fault_status.attr,
> NULL
> };
>
> --
> 2.27.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] ACPI: DPTF: Add new PCH FIVR methods
2021-05-18 9:36 ` Rafael J. Wysocki
@ 2021-05-18 10:27 ` Srinivas Pandruvada
2021-05-21 17:12 ` Rafael J. Wysocki
0 siblings, 1 reply; 4+ messages in thread
From: Srinivas Pandruvada @ 2021-05-18 10:27 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Rafael J. Wysocki, Len Brown, Linux Kernel Mailing List,
ACPI Devel Maling List
On Tue, 2021-05-18 at 11:36 +0200, Rafael J. Wysocki wrote:
> On Tue, May 18, 2021 at 5:42 AM Srinivas Pandruvada
> <srinivas.pandruvada@linux.intel.com> wrote:
> >
> > Some additional information is required for updating PCH FIVR
> > values
> > upon WiFi channel changes.
> >
> > New attributes added to the existing sysfs:
> > fivr_switching_freq_mhz : Get the FIVR switching control frequency
> > using ACPI method GFCS. Refer to the
> > documentation for the equation.
> > fivr_switching_fault_status: Read the FIVR switching frequency
> > control
> > fault status. Uses ACPI method GFFS
> >
> > ssc_clock_info : Presents SSC (spread spectrum clock) information
> > for EMI
> > (Electro magnetic interference) control. Use ACPI method GEMI.
> > Refer
> > to the description of GEMI method below.
> >
> > GFFS
> > This ACPI method is used to read the FIVR switching frequency
> > control
> > fault status.
> > Bits Description
> > [0:0] Fault status when set to 1
> > [31:1] Reserved
> >
> > GFCS
> > This ACPI method is used to read the FIVR switching control
> > frequency.
> > Bits Description
> > [11:0] Actual Frequency = value * XTAL_FREQ / 128
> > [31:12] Reserved
> >
> > GEMI
> > This ACPI method is used to read the programmed register value for
> > EMI
> > (Electro magnetic interference) control.
> >
> > Bits Description
> > [7:0] Sets clock spectrum spread percentage:
> > 0x00=0.2% , 0x3F=10%
> > 1 LSB = 0.1% increase in spread (for
> > settings 0x01 thru 0x1C)
> > 1 LSB = 0.2% increase in spread (for
> > settings 0x1E thru 0x3F)
> > [8] When set to 1, enables spread
> > spectrum clock
> > [9] 0: Triangle mode. FFC frequency
> > walks around the Fcenter in a linear
> > fashion
> > 1: Random walk mode. FFC frequency
> > changes randomly within the SSC
> > (Spread spectrum clock) range
> > [10] 0: No white noise. 1: Add white noise
> > to spread waveform
> > [11] When 1, future writes are ignored.
> >
> > Signed-off-by: Srinivas Pandruvada <
> > srinivas.pandruvada@linux.intel.com>
> > ---
> > v2
> > Update documentation for fivr_switching_freq_mhz
> >
> > Documentation/ABI/testing/sysfs-platform-dptf | 42
> > +++++++++++++++++++
> > drivers/acpi/dptf/dptf_pch_fivr.c | 9 ++++
> > 2 files changed, 51 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-platform-dptf
> > b/Documentation/ABI/testing/sysfs-platform-dptf
> > index 141834342a4d..fe62f024eb93 100644
> > --- a/Documentation/ABI/testing/sysfs-platform-dptf
> > +++ b/Documentation/ABI/testing/sysfs-platform-dptf
> > @@ -111,3 +111,45 @@ Contact: linux-acpi@vger.kernel.org
> > Description:
> > (RW) The PCH FIVR (Fully Integrated Voltage
> > Regulator) switching frequency in MHz,
> > when FIVR clock is 38.4MHz.
> > +
> > +What:
> > /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fiv
> > r_switching_freq_mhz
> > +Date: June, 2021
> > +KernelVersion: v5.14
> > +Contact: linux-acpi@vger.kernel.org
> > +Description:
> > + (RO) Get the FIVR switching control frequency in
> > MHz after applying equation
> > + "fivr_switching_freq_mhz * XTAL_FREQ / 128". Here
> > XTAL_FREQ is Crystal Oscillator frequency
> > + in MHz, which is product specific.
>
> IMO it would be sufficient to say the following here:
>
> + (RO) PCH FIVR switching control frequency in the
> units
> of XTAL_FREQ / 128,
> + where XTAL_FREQ is the Crystal Oscillator frequency
> (product specific).
>
> This means that it needs to be multiplied by XTAL_FREQ / 128 to get
> the frequency in the whatever units XTAL_FREQ is expressed.
>
Looks good.
> I can make this change when applying the patch.
>
Thanks,
Srinivas
> > +What:
> > /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fiv
> > r_switching_fault_status
> > +Date: June, 2021
> > +KernelVersion: v5.14
> > +Contact: linux-acpi@vger.kernel.org
> > +Description:
> > + (RO) Read the FIVR switching frequency control
> > fault status.
> > +
> > +What:
> > /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/ssc
> > _clock_info
> > +Date: June, 2021
> > +KernelVersion: v5.14
> > +Contact: linux-acpi@vger.kernel.org
> > +Description:
> > + (RO) Presents SSC (spread spectrum clock)
> > information for EMI
> > + (Electro magnetic interference) control. This is a
> > bit mask.
> > + Bits Description
> > + [7:0] Sets clock spectrum spread percentage:
> > + 0x00=0.2% , 0x3F=10%
> > + 1 LSB = 0.1% increase in spread (for
> > + settings 0x01 thru 0x1C)
> > + 1 LSB = 0.2% increase in spread (for
> > + settings 0x1E thru 0x3F)
> > + [8] When set to 1, enables spread
> > + spectrum clock
> > + [9] 0: Triangle mode. FFC frequency
> > + walks around the Fcenter in a linear
> > + fashion
> > + 1: Random walk mode. FFC frequency
> > + changes randomly within the SSC
> > + (Spread spectrum clock) range
> > + [10] 0: No white noise. 1: Add white noise
> > + to spread waveform
> > + [11] When 1, future writes are ignored.
> > diff --git a/drivers/acpi/dptf/dptf_pch_fivr.c
> > b/drivers/acpi/dptf/dptf_pch_fivr.c
> > index 5fca18296bf6..22c4ae0401ef 100644
> > --- a/drivers/acpi/dptf/dptf_pch_fivr.c
> > +++ b/drivers/acpi/dptf/dptf_pch_fivr.c
> > @@ -55,15 +55,24 @@ static ssize_t name##_store(struct device
> > *dev,\
> >
> > PCH_FIVR_SHOW(freq_mhz_low_clock, GFC0)
> > PCH_FIVR_SHOW(freq_mhz_high_clock, GFC1)
> > +PCH_FIVR_SHOW(ssc_clock_info, GEMI)
> > +PCH_FIVR_SHOW(fivr_switching_freq_mhz, GFCS)
> > +PCH_FIVR_SHOW(fivr_switching_fault_status, GFFS)
> > PCH_FIVR_STORE(freq_mhz_low_clock, RFC0)
> > PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)
> >
> > static DEVICE_ATTR_RW(freq_mhz_low_clock);
> > static DEVICE_ATTR_RW(freq_mhz_high_clock);
> > +static DEVICE_ATTR_RO(ssc_clock_info);
> > +static DEVICE_ATTR_RO(fivr_switching_freq_mhz);
> > +static DEVICE_ATTR_RO(fivr_switching_fault_status);
> >
> > static struct attribute *fivr_attrs[] = {
> > &dev_attr_freq_mhz_low_clock.attr,
> > &dev_attr_freq_mhz_high_clock.attr,
> > + &dev_attr_ssc_clock_info.attr,
> > + &dev_attr_fivr_switching_freq_mhz.attr,
> > + &dev_attr_fivr_switching_fault_status.attr,
> > NULL
> > };
> >
> > --
> > 2.27.0
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] ACPI: DPTF: Add new PCH FIVR methods
2021-05-18 10:27 ` Srinivas Pandruvada
@ 2021-05-21 17:12 ` Rafael J. Wysocki
0 siblings, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2021-05-21 17:12 UTC (permalink / raw)
To: Srinivas Pandruvada
Cc: Rafael J. Wysocki, Rafael J. Wysocki, Len Brown,
Linux Kernel Mailing List, ACPI Devel Maling List
On Tue, May 18, 2021 at 12:27 PM Srinivas Pandruvada
<srinivas.pandruvada@linux.intel.com> wrote:
>
> On Tue, 2021-05-18 at 11:36 +0200, Rafael J. Wysocki wrote:
> > On Tue, May 18, 2021 at 5:42 AM Srinivas Pandruvada
> > <srinivas.pandruvada@linux.intel.com> wrote:
> > >
> > > Some additional information is required for updating PCH FIVR
> > > values
> > > upon WiFi channel changes.
> > >
> > > New attributes added to the existing sysfs:
> > > fivr_switching_freq_mhz : Get the FIVR switching control frequency
> > > using ACPI method GFCS. Refer to the
> > > documentation for the equation.
> > > fivr_switching_fault_status: Read the FIVR switching frequency
> > > control
> > > fault status. Uses ACPI method GFFS
> > >
> > > ssc_clock_info : Presents SSC (spread spectrum clock) information
> > > for EMI
> > > (Electro magnetic interference) control. Use ACPI method GEMI.
> > > Refer
> > > to the description of GEMI method below.
> > >
> > > GFFS
> > > This ACPI method is used to read the FIVR switching frequency
> > > control
> > > fault status.
> > > Bits Description
> > > [0:0] Fault status when set to 1
> > > [31:1] Reserved
> > >
> > > GFCS
> > > This ACPI method is used to read the FIVR switching control
> > > frequency.
> > > Bits Description
> > > [11:0] Actual Frequency = value * XTAL_FREQ / 128
> > > [31:12] Reserved
> > >
> > > GEMI
> > > This ACPI method is used to read the programmed register value for
> > > EMI
> > > (Electro magnetic interference) control.
> > >
> > > Bits Description
> > > [7:0] Sets clock spectrum spread percentage:
> > > 0x00=0.2% , 0x3F=10%
> > > 1 LSB = 0.1% increase in spread (for
> > > settings 0x01 thru 0x1C)
> > > 1 LSB = 0.2% increase in spread (for
> > > settings 0x1E thru 0x3F)
> > > [8] When set to 1, enables spread
> > > spectrum clock
> > > [9] 0: Triangle mode. FFC frequency
> > > walks around the Fcenter in a linear
> > > fashion
> > > 1: Random walk mode. FFC frequency
> > > changes randomly within the SSC
> > > (Spread spectrum clock) range
> > > [10] 0: No white noise. 1: Add white noise
> > > to spread waveform
> > > [11] When 1, future writes are ignored.
> > >
> > > Signed-off-by: Srinivas Pandruvada <
> > > srinivas.pandruvada@linux.intel.com>
> > > ---
> > > v2
> > > Update documentation for fivr_switching_freq_mhz
> > >
> > > Documentation/ABI/testing/sysfs-platform-dptf | 42
> > > +++++++++++++++++++
> > > drivers/acpi/dptf/dptf_pch_fivr.c | 9 ++++
> > > 2 files changed, 51 insertions(+)
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-platform-dptf
> > > b/Documentation/ABI/testing/sysfs-platform-dptf
> > > index 141834342a4d..fe62f024eb93 100644
> > > --- a/Documentation/ABI/testing/sysfs-platform-dptf
> > > +++ b/Documentation/ABI/testing/sysfs-platform-dptf
> > > @@ -111,3 +111,45 @@ Contact: linux-acpi@vger.kernel.org
> > > Description:
> > > (RW) The PCH FIVR (Fully Integrated Voltage
> > > Regulator) switching frequency in MHz,
> > > when FIVR clock is 38.4MHz.
> > > +
> > > +What:
> > > /sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fiv
> > > r_switching_freq_mhz
> > > +Date: June, 2021
> > > +KernelVersion: v5.14
> > > +Contact: linux-acpi@vger.kernel.org
> > > +Description:
> > > + (RO) Get the FIVR switching control frequency in
> > > MHz after applying equation
> > > + "fivr_switching_freq_mhz * XTAL_FREQ / 128". Here
> > > XTAL_FREQ is Crystal Oscillator frequency
> > > + in MHz, which is product specific.
> >
> > IMO it would be sufficient to say the following here:
> >
> > + (RO) PCH FIVR switching control frequency in the
> > units
> > of XTAL_FREQ / 128,
> > + where XTAL_FREQ is the Crystal Oscillator frequency
> > (product specific).
> >
> > This means that it needs to be multiplied by XTAL_FREQ / 128 to get
> > the frequency in the whatever units XTAL_FREQ is expressed.
> >
> Looks good.
So applied as 5.14 material, thanks!
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-05-21 17:12 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-18 3:41 [PATCH v2] ACPI: DPTF: Add new PCH FIVR methods Srinivas Pandruvada
2021-05-18 9:36 ` Rafael J. Wysocki
2021-05-18 10:27 ` Srinivas Pandruvada
2021-05-21 17:12 ` Rafael J. Wysocki
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