From: Florian Fainelli <f.fainelli@gmail.com>
To: Amit Kucheria <amit.kucheria@verdurent.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Markus Mayer <mmayer@broadcom.com>,
"maintainer:BROADCOM STB AVS TMON DRIVER"
<bcm-kernel-feedback-list@broadcom.com>,
Zhang Rui <rui.zhang@intel.com>,
Eduardo Valentin <edubezval@gmail.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"open list:BROADCOM STB AVS TMON DRIVER"
<linux-pm@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
"moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/6] thermal: brcmstb_thermal: Do not use DT coefficients
Date: Wed, 4 Dec 2019 09:41:16 -0800 [thread overview]
Message-ID: <9adf0bd8-99ee-0f38-4608-67c92ba42c88@gmail.com> (raw)
In-Reply-To: <CAHLCerP6ricempeG=x-a2_aA6__YqADPKAEG5y7qPYNcD2=47Q@mail.gmail.com>
On 12/4/19 12:41 AM, Amit Kucheria wrote:
> On Wed, Oct 30, 2019 at 11:51 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
>>
>> At the time the brcmstb_thermal driver and its binding were merged, the
>> DT binding did not make the coefficients properties a mandatory one,
>> therefore all users of the brcmstb_thermal driver out there have a non
>> functional implementation with zero coefficients. Even if these
>> properties were provided, the formula used for computation is incorrect.
>>
>> The coefficients are entirely process specific (right now, only 28nm is
>> supported) and not board or SoC specific, it is therefore appropriate to
>> hard code them in the driver given the compatibility string we are
>> probed with which has to be updated whenever a new process is
>> introduced.
>>
>> We remove the existing coefficients definition since subsequent patches
>> are going to add support for a new process and will introduce new
>> coefficients as well.
>>
>> Fixes: 9e03cf1b2dd5 ("thermal: add brcmstb AVS TMON driver")
>
> I think you should fix the computation formula as the first patch and
> then merge the rest of this patch into your second patch.
>
> I don't think the intermediate state of converting named constants to
> magic numbers is needed just to convert it over to another set of
> parameters.
ok, so you would rather see this patch using the defined constants while
fixing the formula, and in a subsequent patch getting rid of the
constant names since they are going to be added to a per-process table,
does that sound reasonable?
>
> Regards,
> Amit
>
>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>> ---
>> drivers/thermal/broadcom/brcmstb_thermal.c | 37 ++++------------------
>> 1 file changed, 6 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/thermal/broadcom/brcmstb_thermal.c b/drivers/thermal/broadcom/brcmstb_thermal.c
>> index 5825ac581f56..42482af0422e 100644
>> --- a/drivers/thermal/broadcom/brcmstb_thermal.c
>> +++ b/drivers/thermal/broadcom/brcmstb_thermal.c
>> @@ -48,15 +48,6 @@
>> #define AVS_TMON_TEMP_INT_CODE 0x1c
>> #define AVS_TMON_TP_TEST_ENABLE 0x20
>>
>> -/* Default coefficients */
>> -#define AVS_TMON_TEMP_SLOPE -487
>> -#define AVS_TMON_TEMP_OFFSET 410040
>> -
>> -/* HW related temperature constants */
>> -#define AVS_TMON_TEMP_MAX 0x3ff
>> -#define AVS_TMON_TEMP_MIN -88161
>> -#define AVS_TMON_TEMP_MASK AVS_TMON_TEMP_MAX
>> -
>> enum avs_tmon_trip_type {
>> TMON_TRIP_TYPE_LOW = 0,
>> TMON_TRIP_TYPE_HIGH,
>> @@ -108,23 +99,11 @@ struct brcmstb_thermal_priv {
>> struct thermal_zone_device *thermal;
>> };
>>
>> -static void avs_tmon_get_coeffs(struct thermal_zone_device *tz, int *slope,
>> - int *offset)
>> -{
>> - *slope = thermal_zone_get_slope(tz);
>> - *offset = thermal_zone_get_offset(tz);
>> -}
>> -
>> /* Convert a HW code to a temperature reading (millidegree celsius) */
>> static inline int avs_tmon_code_to_temp(struct thermal_zone_device *tz,
>> u32 code)
>> {
>> - const int val = code & AVS_TMON_TEMP_MASK;
>> - int slope, offset;
>> -
>> - avs_tmon_get_coeffs(tz, &slope, &offset);
>> -
>> - return slope * val + offset;
>> + return (410040 - (int)((code & 0x3FF) * 487));
>> }
>>
>> /*
>> @@ -136,20 +115,16 @@ static inline int avs_tmon_code_to_temp(struct thermal_zone_device *tz,
>> static inline u32 avs_tmon_temp_to_code(struct thermal_zone_device *tz,
>> int temp, bool low)
>> {
>> - int slope, offset;
>> -
>> - if (temp < AVS_TMON_TEMP_MIN)
>> - return AVS_TMON_TEMP_MAX; /* Maximum code value */
>> -
>> - avs_tmon_get_coeffs(tz, &slope, &offset);
>> + if (temp < -88161)
>> + return 0x3FF; /* Maximum code value */
>>
>> - if (temp >= offset)
>> + if (temp >= 410040)
>> return 0; /* Minimum code value */
>>
>> if (low)
>> - return (u32)(DIV_ROUND_UP(offset - temp, abs(slope)));
>> + return (u32)(DIV_ROUND_UP(410040 - temp, 487));
>> else
>> - return (u32)((offset - temp) / abs(slope));
>> + return (u32)((410040 - temp) / 487);
>> }
>>
>> static int brcmstb_get_temp(void *data, int *temp)
>> --
>> 2.17.1
>>
--
Florian
next prev parent reply other threads:[~2019-12-04 17:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 18:21 [PATCH 0/6] brcmstb_thermal updates for new processes Florian Fainelli
2019-10-30 18:21 ` [PATCH 1/6] thermal: brcmstb_thermal: Do not use DT coefficients Florian Fainelli
2019-12-04 8:41 ` Amit Kucheria
2019-12-04 17:41 ` Florian Fainelli [this message]
2019-12-04 19:01 ` Amit Kucheria
2019-10-30 18:21 ` [PATCH 2/6] thermal: brcmstb_thermal: Prepare to support a different process Florian Fainelli
2019-10-30 18:21 ` [PATCH 3/6] dt-bindings: thermal: Define BCM7216 thermal sensor compatible Florian Fainelli
2019-11-06 3:55 ` Rob Herring
2019-10-30 18:21 ` [PATCH 4/6] thermal: brcmstb_thermal: Add 16nm process thermal parameters Florian Fainelli
2019-12-04 8:43 ` Amit Kucheria
2019-10-30 18:21 ` [PATCH 5/6] thermal: brcmstb_thermal: Restructure interrupt registration Florian Fainelli
2019-12-04 9:38 ` Amit Kucheria
2019-10-30 18:21 ` [PATCH 6/6] thermal: brcmstb_thermal: Register different ops per process Florian Fainelli
2019-12-04 9:38 ` Amit Kucheria
2019-11-20 18:43 ` [PATCH 0/6] brcmstb_thermal updates for new processes Florian Fainelli
2019-12-04 4:50 ` Florian Fainelli
2019-12-09 9:04 ` Daniel Lezcano
2019-12-09 17:36 ` Florian Fainelli
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