在 2015年01月22日 12:01, Daniel Kurtz 写道:
On Thu, Jan 22, 2015 at 1:29 AM, Caesar Wang <w...@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 <w...@rock-chips.com>
Reviewed-by: Dmitry Torokhov <dmitry.torok...@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.torok...@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:w...@rock-chips.com
Tel:+86-591-83991906/07->8221
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