? 2015?01?22? 12:25, Daniel Kurtz ??: > On Thu, Jan 22, 2015 at 12:21 PM, Caesar Wang > <caesar.wang at rock-chips.com> wrote: >> ? 2015?01?22? 12:01, Daniel Kurtz ??: >> >>> On Thu, Jan 22, 2015 at 1:29 AM, Caesar Wang <wxt at 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 at rock-chips.com> >>>> Reviewed-by: Dmitry Torokhov <dmitry.torokhov at 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 at 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 (???) >> ??????????? >> Fuzhou Rockchip Electronics Co.Ltd >> ?????????????89????A?18??(350003) >> Addr:No.18 Building, A District, No.89, software Boulevard Fuzhou, >> Fujian,PRC >> Email:wxt at rock-chips.com >> Tel:+86-591-83991906/07->8221 >> >> > _______________________________________________ > Linux-rockchip mailing list > Linux-rockchip at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-rockchip