diff mbox

[v5] thermal: rockchip: make temperature reporting much more accurate

Message ID 1422028154-2349-2-git-send-email-wxt@rock-chips.com (mailing list archive)
State New, archived
Headers show

Commit Message

Caesar Wang Jan. 23, 2015, 3:49 p.m. UTC
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 v5:
Fixed some style.

Changes in v4:
"return -EAGAIN" instead of "return rk_tsadcv2_code_to_temp(code)"

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 | 38 +++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

Comments

Daniel Kurtz Jan. 25, 2015, 1:58 a.m. UTC | #1
On Fri, Jan 23, 2015 at 11:49 PM, 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 v5:
> Fixed some style.
>
> Changes in v4:
> "return -EAGAIN" instead of "return rk_tsadcv2_code_to_temp(code)"
>
> 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 | 38 +++++++++++++++++++++++++-------------
>  1 file changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
> index 1bcddfc..83bdf82 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;
> -
> -       if (code > v2_code_table[low].code || code < v2_code_table[high].code)
> -               return 125000; /* No code available, return max temperature */
> +       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;
> +
> +       /* Invalid code, return -EAGAIN */
> +       if (code > TSADCV2_DATA_MASK)
> +               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;
> +       while (low <= high && mid) {
> +               if (code >= v2_code_table[mid].code &&
> +                   code < v2_code_table[mid - 1].code)
> +                       break;
> +               else if (code == TSADCV2_DATA_MASK)
> +                       break;

I don't think you need this check since this is v2_code_table[0].
But, it doesn't hurt, so either way, this is:

Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>

>                 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
>
>
Caesar Wang Jan. 25, 2015, 2:12 a.m. UTC | #2
? 2015?01?25? 09:58, Daniel Kurtz ??:
> On Fri, Jan 23, 2015 at 11:49 PM, 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 v5:
>> Fixed some style.
>>
>> Changes in v4:
>> "return -EAGAIN" instead of "return rk_tsadcv2_code_to_temp(code)"
>>
>> 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 | 38 +++++++++++++++++++++++++-------------
>>   1 file changed, 25 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
>> index 1bcddfc..83bdf82 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;
>> -
>> -       if (code > v2_code_table[low].code || code < v2_code_table[high].code)
>> -               return 125000; /* No code available, return max temperature */
>> +       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;
>> +
>> +       /* Invalid code, return -EAGAIN */
>> +       if (code > TSADCV2_DATA_MASK)
>> +               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;
>> +       while (low <= high && mid) {
>> +               if (code >= v2_code_table[mid].code &&
>> +                   code < v2_code_table[mid - 1].code)
>> +                       break;
>> +               else if (code == TSADCV2_DATA_MASK)
>> +                       break;
> I don't think you need this check since this is v2_code_table[0].
> But, it doesn't hurt, so either way, this is:
>
> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Fixed, Thanks.
>>                  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
>>
>>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip
Wang Caesar Jan. 25, 2015, 2:12 a.m. UTC | #3
? 2015?01?25? 09:58, Daniel Kurtz ??:
> On Fri, Jan 23, 2015 at 11:49 PM, 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 v5:
>> Fixed some style.
>>
>> Changes in v4:
>> "return -EAGAIN" instead of "return rk_tsadcv2_code_to_temp(code)"
>>
>> 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 | 38 +++++++++++++++++++++++++-------------
>>   1 file changed, 25 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
>> index 1bcddfc..83bdf82 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;
>> -
>> -       if (code > v2_code_table[low].code || code < v2_code_table[high].code)
>> -               return 125000; /* No code available, return max temperature */
>> +       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;
>> +
>> +       /* Invalid code, return -EAGAIN */
>> +       if (code > TSADCV2_DATA_MASK)
>> +               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;
>> +       while (low <= high && mid) {
>> +               if (code >= v2_code_table[mid].code &&
>> +                   code < v2_code_table[mid - 1].code)
>> +                       break;
>> +               else if (code == TSADCV2_DATA_MASK)
>> +                       break;
> I don't think you need this check since this is v2_code_table[0].
> But, it doesn't hurt, so either way, this is:
>
> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Fixed, Thanks.
>>                  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
>>
>>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip
diff mbox

Patch

diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
index 1bcddfc..83bdf82 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;
-
-	if (code > v2_code_table[low].code || code < v2_code_table[high].code)
-		return 125000; /* No code available, return max temperature */
+	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;
+
+	/* Invalid code, return -EAGAIN */
+	if (code > TSADCV2_DATA_MASK)
+		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;
+	while (low <= high && mid) {
+		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);
 }
 
 /**