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* [PATCH v5 0/1] thermal: rockchip: make temperature reporting much more accurate
@ 2015-01-23 15:49 Caesar Wang
  2015-01-23 15:49 ` [PATCH v5] " Caesar Wang
  0 siblings, 1 reply; 3+ messages in thread
From: Caesar Wang @ 2015-01-23 15:49 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 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>

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

 drivers/thermal/rockchip_thermal.c | 38 +++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

-- 
1.9.1



^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH v5] thermal: rockchip: make temperature reporting much more accurate
  2015-01-23 15:49 [PATCH v5 0/1] thermal: rockchip: make temperature reporting much more accurate Caesar Wang
@ 2015-01-23 15:49 ` Caesar Wang
  2015-01-25  1:58   ` Daniel Kurtz
  0 siblings, 1 reply; 3+ messages in thread
From: Caesar Wang @ 2015-01-23 15:49 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 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;
 		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] 3+ messages in thread

* Re: [PATCH v5] thermal: rockchip: make temperature reporting much more accurate
  2015-01-23 15:49 ` [PATCH v5] " Caesar Wang
@ 2015-01-25  1:58   ` Daniel Kurtz
  0 siblings, 0 replies; 3+ messages in thread
From: Daniel Kurtz @ 2015-01-25  1:58 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 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
>
>

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2015-01-23 15:49 [PATCH v5 0/1] thermal: rockchip: make temperature reporting much more accurate Caesar Wang
2015-01-23 15:49 ` [PATCH v5] " Caesar Wang
2015-01-25  1:58   ` Daniel Kurtz

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