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* [PATCH v3 0/1] thermal: rockchip: make temperature reporting much more accurate
@ 2015-01-21 17:29 Caesar Wang
  2015-01-21 17:29 ` [PATCH v3] " Caesar Wang
  0 siblings, 1 reply; 6+ messages in thread
From: Caesar Wang @ 2015-01-21 17:29 UTC (permalink / raw)
  To: Heiko Stuebner, Zhang Rui, Eduardo Valentin
  Cc: Dmitry Torokhov, Daniel Kurtz, Caesar Wang, linux-pm,
	linux-kernel, linux-rockchip, linux-arm-kernel


This patch is merged on chromiumos/third_party/kernel.
https://chromium-review.googlesource.com/#/c/239190/

Tested on veyron boards.


Changes in v3:
Suggested-by Daniel Kurtz,
the check doesn't reject "code == 0xfff"
Fixed in rk_tsadcv2_code_to_temp(u32 code)

Changes in v2:
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Caesar Wang (1):
  thermal: rockchip: make temperature reporting much more accurate

 drivers/thermal/rockchip_thermal.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

-- 
1.9.1



^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v3] thermal: rockchip: make temperature reporting much more accurate
  2015-01-21 17:29 [PATCH v3 0/1] thermal: rockchip: make temperature reporting much more accurate Caesar Wang
@ 2015-01-21 17:29 ` Caesar Wang
  2015-01-22  4:01   ` Daniel Kurtz
  0 siblings, 1 reply; 6+ messages in thread
From: Caesar Wang @ 2015-01-21 17:29 UTC (permalink / raw)
  To: Heiko Stuebner, Zhang Rui, Eduardo Valentin
  Cc: Dmitry Torokhov, Daniel Kurtz, Caesar Wang, linux-arm-kernel,
	linux-rockchip, linux-pm, linux-kernel

In general, the kernel should report temperature readings exactly as
reported by the hardware. The cpu / gpu thermal driver works in 5 degree
increments,but we ought to do more accurate. The temperature will do
linear interpolation between the entries in the table.

Test= $md5sum /dev/zero &
$while true; do grep "" /sys/class/thermal/thermal_zone[1-2]/temp;
sleep .5; done

e.g. We can get the result as follows:
    /sys/class/thermal/thermal_zone1/temp:39994
    /sys/class/thermal/thermal_zone2/temp:39086
    /sys/class/thermal/thermal_zone1/temp:39994
    /sys/class/thermal/thermal_zone2/temp:39540
    /sys/class/thermal/thermal_zone1/temp:39540
    /sys/class/thermal/thermal_zone2/temp:39540
    /sys/class/thermal/thermal_zone1/temp:39540
    /sys/class/thermal/thermal_zone2/temp:39994

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

---

Changes in v3:
Suggested-by Daniel Kurtz,
the check doesn't reject "code == 0xfff"
Fixed in rk_tsadcv2_code_to_temp(u32 code)

Changes in v2:
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

 drivers/thermal/rockchip_thermal.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
index 1bcddfc..ce18007 100644
--- a/drivers/thermal/rockchip_thermal.c
+++ b/drivers/thermal/rockchip_thermal.c
@@ -193,19 +193,22 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
 
 static long rk_tsadcv2_code_to_temp(u32 code)
 {
-	int high, low, mid;
-
-	low = 0;
-	high = ARRAY_SIZE(v2_code_table) - 1;
-	mid = (high + low) / 2;
+	unsigned int low = 0;
+	unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
+	unsigned int mid = (low + high) / 2;
+	unsigned int num;
+	unsigned long denom;
 
+	/* No code available, return callback */
 	if (code > v2_code_table[low].code || code < v2_code_table[high].code)
-		return 125000; /* No code available, return max temperature */
+		return rk_tsadcv2_code_to_temp(code);
 
 	while (low <= high) {
-		if (code >= v2_code_table[mid].code && code <
-		    v2_code_table[mid - 1].code)
-			return v2_code_table[mid].temp;
+		if (code >= v2_code_table[mid].code &&
+		    code < v2_code_table[mid - 1].code)
+			break;
+		else if (code == TSADCV2_DATA_MASK)
+			break;
 		else if (code < v2_code_table[mid].code)
 			low = mid + 1;
 		else
@@ -213,7 +216,16 @@ static long rk_tsadcv2_code_to_temp(u32 code)
 		mid = (low + high) / 2;
 	}
 
-	return 125000;
+	/*
+	 * The 5C granularity provided by the table is too much. Let's
+	 * assume that the relationship between sensor readings and
+	 * temperature between 2 table entries is linear and interpolate
+	 * to produce less granular result.
+	 */
+	num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
+	num *= v2_code_table[mid - 1].code - code;
+	denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
+	return v2_code_table[mid - 1].temp + (num / denom);
 }
 
 /**
-- 
1.9.1



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] thermal: rockchip: make temperature reporting much more accurate
  2015-01-21 17:29 ` [PATCH v3] " Caesar Wang
@ 2015-01-22  4:01   ` Daniel Kurtz
  2015-01-22  4:21     ` Caesar Wang
  0 siblings, 1 reply; 6+ messages in thread
From: Daniel Kurtz @ 2015-01-22  4:01 UTC (permalink / raw)
  To: Caesar Wang
  Cc: Heiko Stuebner, Zhang Rui, Eduardo Valentin, Dmitry Torokhov,
	linux-arm-kernel, open list:ARM/Rockchip SoC...,
	linux-pm, linux-kernel

On Thu, Jan 22, 2015 at 1:29 AM, Caesar Wang <wxt@rock-chips.com> wrote:
> In general, the kernel should report temperature readings exactly as
> reported by the hardware. The cpu / gpu thermal driver works in 5 degree
> increments,but we ought to do more accurate. The temperature will do
> linear interpolation between the entries in the table.
>
> Test= $md5sum /dev/zero &
> $while true; do grep "" /sys/class/thermal/thermal_zone[1-2]/temp;
> sleep .5; done
>
> e.g. We can get the result as follows:
>     /sys/class/thermal/thermal_zone1/temp:39994
>     /sys/class/thermal/thermal_zone2/temp:39086
>     /sys/class/thermal/thermal_zone1/temp:39994
>     /sys/class/thermal/thermal_zone2/temp:39540
>     /sys/class/thermal/thermal_zone1/temp:39540
>     /sys/class/thermal/thermal_zone2/temp:39540
>     /sys/class/thermal/thermal_zone1/temp:39540
>     /sys/class/thermal/thermal_zone2/temp:39994
>
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>
> ---
>
> Changes in v3:
> Suggested-by Daniel Kurtz,
> the check doesn't reject "code == 0xfff"
> Fixed in rk_tsadcv2_code_to_temp(u32 code)
>
> Changes in v2:
> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>
>  drivers/thermal/rockchip_thermal.c | 32 ++++++++++++++++++++++----------
>  1 file changed, 22 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
> index 1bcddfc..ce18007 100644
> --- a/drivers/thermal/rockchip_thermal.c
> +++ b/drivers/thermal/rockchip_thermal.c
> @@ -193,19 +193,22 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
>
>  static long rk_tsadcv2_code_to_temp(u32 code)
>  {
> -       int high, low, mid;
> -
> -       low = 0;
> -       high = ARRAY_SIZE(v2_code_table) - 1;
> -       mid = (high + low) / 2;
> +       unsigned int low = 0;
> +       unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
> +       unsigned int mid = (low + high) / 2;
> +       unsigned int num;
> +       unsigned long denom;
>
> +       /* No code available, return callback */
>         if (code > v2_code_table[low].code || code < v2_code_table[high].code)
> -               return 125000; /* No code available, return max temperature */
> +               return rk_tsadcv2_code_to_temp(code);

Isn't this an infinite recursion?

>
>         while (low <= high) {
> -               if (code >= v2_code_table[mid].code && code <
> -                   v2_code_table[mid - 1].code)
> -                       return v2_code_table[mid].temp;
> +               if (code >= v2_code_table[mid].code &&
> +                   code < v2_code_table[mid - 1].code)
> +                       break;
> +               else if (code == TSADCV2_DATA_MASK)
> +                       break;
>                 else if (code < v2_code_table[mid].code)
>                         low = mid + 1;
>                 else
> @@ -213,7 +216,16 @@ static long rk_tsadcv2_code_to_temp(u32 code)
>                 mid = (low + high) / 2;
>         }
>
> -       return 125000;
> +       /*
> +        * The 5C granularity provided by the table is too much. Let's
> +        * assume that the relationship between sensor readings and
> +        * temperature between 2 table entries is linear and interpolate
> +        * to produce less granular result.
> +        */
> +       num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
> +       num *= v2_code_table[mid - 1].code - code;
> +       denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
> +       return v2_code_table[mid - 1].temp + (num / denom);
>  }
>
>  /**
> --
> 1.9.1
>
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] thermal: rockchip: make temperature reporting much more accurate
  2015-01-22  4:01   ` Daniel Kurtz
@ 2015-01-22  4:21     ` Caesar Wang
  2015-01-22  4:25       ` Daniel Kurtz
  0 siblings, 1 reply; 6+ messages in thread
From: Caesar Wang @ 2015-01-22  4:21 UTC (permalink / raw)
  To: Daniel Kurtz, Caesar Wang
  Cc: Heiko Stuebner, Zhang Rui, Eduardo Valentin, Dmitry Torokhov,
	linux-arm-kernel, open list:ARM/Rockchip SoC...,
	linux-pm, linux-kernel


在 2015年01月22日 12:01, Daniel Kurtz 写道:
> On Thu, Jan 22, 2015 at 1:29 AM, Caesar Wang <wxt@rock-chips.com> wrote:
>> In general, the kernel should report temperature readings exactly as
>> reported by the hardware. The cpu / gpu thermal driver works in 5 degree
>> increments,but we ought to do more accurate. The temperature will do
>> linear interpolation between the entries in the table.
>>
>> Test= $md5sum /dev/zero &
>> $while true; do grep "" /sys/class/thermal/thermal_zone[1-2]/temp;
>> sleep .5; done
>>
>> e.g. We can get the result as follows:
>>      /sys/class/thermal/thermal_zone1/temp:39994
>>      /sys/class/thermal/thermal_zone2/temp:39086
>>      /sys/class/thermal/thermal_zone1/temp:39994
>>      /sys/class/thermal/thermal_zone2/temp:39540
>>      /sys/class/thermal/thermal_zone1/temp:39540
>>      /sys/class/thermal/thermal_zone2/temp:39540
>>      /sys/class/thermal/thermal_zone1/temp:39540
>>      /sys/class/thermal/thermal_zone2/temp:39994
>>
>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>
>> ---
>>
>> Changes in v3:
>> Suggested-by Daniel Kurtz,
>> the check doesn't reject "code == 0xfff"
>> Fixed in rk_tsadcv2_code_to_temp(u32 code)
>>
>> Changes in v2:
>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>
>>   drivers/thermal/rockchip_thermal.c | 32 ++++++++++++++++++++++----------
>>   1 file changed, 22 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
>> index 1bcddfc..ce18007 100644
>> --- a/drivers/thermal/rockchip_thermal.c
>> +++ b/drivers/thermal/rockchip_thermal.c
>> @@ -193,19 +193,22 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
>>
>>   static long rk_tsadcv2_code_to_temp(u32 code)
>>   {
>> -       int high, low, mid;
>> -
>> -       low = 0;
>> -       high = ARRAY_SIZE(v2_code_table) - 1;
>> -       mid = (high + low) / 2;
>> +       unsigned int low = 0;
>> +       unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
>> +       unsigned int mid = (low + high) / 2;
>> +       unsigned int num;
>> +       unsigned long denom;
>>
>> +       /* No code available, return callback */
>>          if (code > v2_code_table[low].code || code < v2_code_table[high].code)
>> -               return 125000; /* No code available, return max temperature */
>> +               return rk_tsadcv2_code_to_temp(code);
> Isn't this an infinite recursion?

No, I think we can try check if it  is happened.
Maybe we can return a warning/error for it.
>>          while (low <= high) {
>> -               if (code >= v2_code_table[mid].code && code <
>> -                   v2_code_table[mid - 1].code)
>> -                       return v2_code_table[mid].temp;
>> +               if (code >= v2_code_table[mid].code &&
>> +                   code < v2_code_table[mid - 1].code)
>> +                       break;
>> +               else if (code == TSADCV2_DATA_MASK)
>> +                       break;
>>                  else if (code < v2_code_table[mid].code)
>>                          low = mid + 1;
>>                  else
>> @@ -213,7 +216,16 @@ static long rk_tsadcv2_code_to_temp(u32 code)
>>                  mid = (low + high) / 2;
>>          }
>>
>> -       return 125000;
>> +       /*
>> +        * The 5C granularity provided by the table is too much. Let's
>> +        * assume that the relationship between sensor readings and
>> +        * temperature between 2 table entries is linear and interpolate
>> +        * to produce less granular result.
>> +        */
>> +       num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
>> +       num *= v2_code_table[mid - 1].code - code;
>> +       denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
>> +       return v2_code_table[mid - 1].temp + (num / denom);
>>   }
>>
>>   /**
>> --
>> 1.9.1
>>
>>
>
>

-- 
Best regards
Caesar Wang (王晓腾)
福州瑞芯微电子有限公司
Fuzhou Rockchip Electronics Co.Ltd
福建省福州市铜盘路软件大道89号软件园A区18号楼(350003)
Addr:No.18 Building, A District, No.89, software Boulevard Fuzhou, Fujian,PRC
Email:wxt@rock-chips.com
Tel:+86-591-83991906/07->8221



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] thermal: rockchip: make temperature reporting much more accurate
  2015-01-22  4:21     ` Caesar Wang
@ 2015-01-22  4:25       ` Daniel Kurtz
  2015-01-22  4:57         ` Caesar Wang
  0 siblings, 1 reply; 6+ messages in thread
From: Daniel Kurtz @ 2015-01-22  4:25 UTC (permalink / raw)
  To: Caesar Wang
  Cc: Caesar Wang, Heiko Stuebner, Zhang Rui, Eduardo Valentin,
	Dmitry Torokhov, linux-arm-kernel, open list:ARM/Rockchip SoC...,
	linux-pm, linux-kernel

On Thu, Jan 22, 2015 at 12:21 PM, Caesar Wang
<caesar.wang@rock-chips.com> wrote:
>
> 在 2015年01月22日 12:01, Daniel Kurtz 写道:
>
>> On Thu, Jan 22, 2015 at 1:29 AM, Caesar Wang <wxt@rock-chips.com> wrote:
>>>
>>> In general, the kernel should report temperature readings exactly as
>>> reported by the hardware. The cpu / gpu thermal driver works in 5 degree
>>> increments,but we ought to do more accurate. The temperature will do
>>> linear interpolation between the entries in the table.
>>>
>>> Test= $md5sum /dev/zero &
>>> $while true; do grep "" /sys/class/thermal/thermal_zone[1-2]/temp;
>>> sleep .5; done
>>>
>>> e.g. We can get the result as follows:
>>>      /sys/class/thermal/thermal_zone1/temp:39994
>>>      /sys/class/thermal/thermal_zone2/temp:39086
>>>      /sys/class/thermal/thermal_zone1/temp:39994
>>>      /sys/class/thermal/thermal_zone2/temp:39540
>>>      /sys/class/thermal/thermal_zone1/temp:39540
>>>      /sys/class/thermal/thermal_zone2/temp:39540
>>>      /sys/class/thermal/thermal_zone1/temp:39540
>>>      /sys/class/thermal/thermal_zone2/temp:39994
>>>
>>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>>
>>> ---
>>>
>>> Changes in v3:
>>> Suggested-by Daniel Kurtz,
>>> the check doesn't reject "code == 0xfff"
>>> Fixed in rk_tsadcv2_code_to_temp(u32 code)
>>>
>>> Changes in v2:
>>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>>
>>>   drivers/thermal/rockchip_thermal.c | 32
>>> ++++++++++++++++++++++----------
>>>   1 file changed, 22 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/thermal/rockchip_thermal.c
>>> b/drivers/thermal/rockchip_thermal.c
>>> index 1bcddfc..ce18007 100644
>>> --- a/drivers/thermal/rockchip_thermal.c
>>> +++ b/drivers/thermal/rockchip_thermal.c
>>> @@ -193,19 +193,22 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
>>>
>>>   static long rk_tsadcv2_code_to_temp(u32 code)
>>>   {
>>> -       int high, low, mid;
>>> -
>>> -       low = 0;
>>> -       high = ARRAY_SIZE(v2_code_table) - 1;
>>> -       mid = (high + low) / 2;
>>> +       unsigned int low = 0;
>>> +       unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
>>> +       unsigned int mid = (low + high) / 2;
>>> +       unsigned int num;
>>> +       unsigned long denom;
>>>
>>> +       /* No code available, return callback */
>>>          if (code > v2_code_table[low].code || code <
>>> v2_code_table[high].code)
>>> -               return 125000; /* No code available, return max
>>> temperature */
>>> +               return rk_tsadcv2_code_to_temp(code);
>>
>> Isn't this an infinite recursion?
>
>
> No, I think we can try check if it  is happened.
> Maybe we can return a warning/error for it.

I mean, if the 'if' condition is true, then this will just call the
same function again with the same code, and again, and again...
Just return an error code here, -ENOENT maybe?
I am not sure what error code is appropriate.


>
>>>          while (low <= high) {
>>> -               if (code >= v2_code_table[mid].code && code <
>>> -                   v2_code_table[mid - 1].code)
>>> -                       return v2_code_table[mid].temp;
>>> +               if (code >= v2_code_table[mid].code &&
>>> +                   code < v2_code_table[mid - 1].code)
>>> +                       break;
>>> +               else if (code == TSADCV2_DATA_MASK)
>>> +                       break;
>>>                  else if (code < v2_code_table[mid].code)
>>>                          low = mid + 1;
>>>                  else
>>> @@ -213,7 +216,16 @@ static long rk_tsadcv2_code_to_temp(u32 code)
>>>                  mid = (low + high) / 2;
>>>          }
>>>
>>> -       return 125000;
>>> +       /*
>>> +        * The 5C granularity provided by the table is too much. Let's
>>> +        * assume that the relationship between sensor readings and
>>> +        * temperature between 2 table entries is linear and interpolate
>>> +        * to produce less granular result.
>>> +        */
>>> +       num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
>>> +       num *= v2_code_table[mid - 1].code - code;
>>> +       denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
>>> +       return v2_code_table[mid - 1].temp + (num / denom);
>>>   }
>>>
>>>   /**
>>> --
>>> 1.9.1
>>>
>>>
>>
>>
>
> --
> Best regards
> Caesar Wang (王晓腾)
> 福州瑞芯微电子有限公司
> Fuzhou Rockchip Electronics Co.Ltd
> 福建省福州市铜盘路软件大道89号软件园A区18号楼(350003)
> Addr:No.18 Building, A District, No.89, software Boulevard Fuzhou,
> Fujian,PRC
> Email:wxt@rock-chips.com
> Tel:+86-591-83991906/07->8221
>
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] thermal: rockchip: make temperature reporting much more accurate
  2015-01-22  4:25       ` Daniel Kurtz
@ 2015-01-22  4:57         ` Caesar Wang
  0 siblings, 0 replies; 6+ messages in thread
From: Caesar Wang @ 2015-01-22  4:57 UTC (permalink / raw)
  To: Daniel Kurtz, Caesar Wang
  Cc: Heiko Stuebner, linux-pm, Dmitry Torokhov, linux-kernel,
	Eduardo Valentin, open list:ARM/Rockchip SoC...,
	Zhang Rui, linux-arm-kernel, Caesar Wang


在 2015年01月22日 12:25, Daniel Kurtz 写道:
> On Thu, Jan 22, 2015 at 12:21 PM, Caesar Wang
> <caesar.wang@rock-chips.com> wrote:
>> 在 2015年01月22日 12:01, Daniel Kurtz 写道:
>>
>>> On Thu, Jan 22, 2015 at 1:29 AM, Caesar Wang <wxt@rock-chips.com> wrote:
>>>> In general, the kernel should report temperature readings exactly as
>>>> reported by the hardware. The cpu / gpu thermal driver works in 5 degree
>>>> increments,but we ought to do more accurate. The temperature will do
>>>> linear interpolation between the entries in the table.
>>>>
>>>> Test= $md5sum /dev/zero &
>>>> $while true; do grep "" /sys/class/thermal/thermal_zone[1-2]/temp;
>>>> sleep .5; done
>>>>
>>>> e.g. We can get the result as follows:
>>>>       /sys/class/thermal/thermal_zone1/temp:39994
>>>>       /sys/class/thermal/thermal_zone2/temp:39086
>>>>       /sys/class/thermal/thermal_zone1/temp:39994
>>>>       /sys/class/thermal/thermal_zone2/temp:39540
>>>>       /sys/class/thermal/thermal_zone1/temp:39540
>>>>       /sys/class/thermal/thermal_zone2/temp:39540
>>>>       /sys/class/thermal/thermal_zone1/temp:39540
>>>>       /sys/class/thermal/thermal_zone2/temp:39994
>>>>
>>>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>>>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>>>
>>>> ---
>>>>
>>>> Changes in v3:
>>>> Suggested-by Daniel Kurtz,
>>>> the check doesn't reject "code == 0xfff"
>>>> Fixed in rk_tsadcv2_code_to_temp(u32 code)
>>>>
>>>> Changes in v2:
>>>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>>>
>>>>    drivers/thermal/rockchip_thermal.c | 32
>>>> ++++++++++++++++++++++----------
>>>>    1 file changed, 22 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/thermal/rockchip_thermal.c
>>>> b/drivers/thermal/rockchip_thermal.c
>>>> index 1bcddfc..ce18007 100644
>>>> --- a/drivers/thermal/rockchip_thermal.c
>>>> +++ b/drivers/thermal/rockchip_thermal.c
>>>> @@ -193,19 +193,22 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
>>>>
>>>>    static long rk_tsadcv2_code_to_temp(u32 code)
>>>>    {
>>>> -       int high, low, mid;
>>>> -
>>>> -       low = 0;
>>>> -       high = ARRAY_SIZE(v2_code_table) - 1;
>>>> -       mid = (high + low) / 2;
>>>> +       unsigned int low = 0;
>>>> +       unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
>>>> +       unsigned int mid = (low + high) / 2;
>>>> +       unsigned int num;
>>>> +       unsigned long denom;
>>>>
>>>> +       /* No code available, return callback */
>>>>           if (code > v2_code_table[low].code || code <
>>>> v2_code_table[high].code)
>>>> -               return 125000; /* No code available, return max
>>>> temperature */
>>>> +               return rk_tsadcv2_code_to_temp(code);
>>> Isn't this an infinite recursion?
>>
>> No, I think we can try check if it  is happened.
>> Maybe we can return a warning/error for it.
> I mean, if the 'if' condition is true, then this will just call the
> same function again with the same code, and again, and again...
> Just return an error code here, -ENOENT maybe?
> I am not sure what error code is appropriate.

Maybe "return -EAGAIN"
>
>>>>           while (low <= high) {
>>>> -               if (code >= v2_code_table[mid].code && code <
>>>> -                   v2_code_table[mid - 1].code)
>>>> -                       return v2_code_table[mid].temp;
>>>> +               if (code >= v2_code_table[mid].code &&
>>>> +                   code < v2_code_table[mid - 1].code)
>>>> +                       break;
>>>> +               else if (code == TSADCV2_DATA_MASK)
>>>> +                       break;
>>>>                   else if (code < v2_code_table[mid].code)
>>>>                           low = mid + 1;
>>>>                   else
>>>> @@ -213,7 +216,16 @@ static long rk_tsadcv2_code_to_temp(u32 code)
>>>>                   mid = (low + high) / 2;
>>>>           }
>>>>
>>>> -       return 125000;
>>>> +       /*
>>>> +        * The 5C granularity provided by the table is too much. Let's
>>>> +        * assume that the relationship between sensor readings and
>>>> +        * temperature between 2 table entries is linear and interpolate
>>>> +        * to produce less granular result.
>>>> +        */
>>>> +       num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
>>>> +       num *= v2_code_table[mid - 1].code - code;
>>>> +       denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
>>>> +       return v2_code_table[mid - 1].temp + (num / denom);
>>>>    }
>>>>
>>>>    /**
>>>> --
>>>> 1.9.1
>>>>
>>>>
>>>
>> --
>> Best regards
>> Caesar Wang (王晓腾)
>> 福州瑞芯微电子有限公司
>> Fuzhou Rockchip Electronics Co.Ltd
>> 福建省福州市铜盘路软件大道89号软件园A区18号楼(350003)
>> Addr:No.18 Building, A District, No.89, software Boulevard Fuzhou,
>> Fujian,PRC
>> Email:wxt@rock-chips.com
>> Tel:+86-591-83991906/07->8221
>>
>>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip



^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2015-01-22  4:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-01-21 17:29 [PATCH v3 0/1] thermal: rockchip: make temperature reporting much more accurate Caesar Wang
2015-01-21 17:29 ` [PATCH v3] " Caesar Wang
2015-01-22  4:01   ` Daniel Kurtz
2015-01-22  4:21     ` Caesar Wang
2015-01-22  4:25       ` Daniel Kurtz
2015-01-22  4:57         ` Caesar Wang

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