diff options
Diffstat (limited to 'drivers/thermal')
| -rw-r--r-- | drivers/thermal/imx_thermal.c | 26 |
1 files changed, 11 insertions, 15 deletions
diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c index 41e15cf5ffd7..a67781b7a0b2 100644 --- a/drivers/thermal/imx_thermal.c +++ b/drivers/thermal/imx_thermal.c @@ -70,10 +70,6 @@ enum imx_thermal_trip { #define IMX_POLLING_DELAY 2000 /* millisecond */ #define IMX_PASSIVE_DELAY 1000 -#define FACTOR0 10000000 -#define FACTOR1 15976 -#define FACTOR2 4297157 - #define TEMPMON_IMX6Q 1 #define TEMPMON_IMX6SX 2 @@ -350,7 +346,7 @@ static struct thermal_zone_device_ops imx_tz_ops = { static int imx_init_calib(struct platform_device *pdev, u32 ocotp_ana1) { struct imx_thermal_data *data = platform_get_drvdata(pdev); - int t1, n1; + int n1; u64 temp64; if (ocotp_ana1 == 0 || ocotp_ana1 == ~0) { @@ -365,25 +361,25 @@ static int imx_init_calib(struct platform_device *pdev, u32 ocotp_ana1) * To find the actual temperature T, the following formula has to be used * when reading value n from the sensor: * - * T = T1 + (N - N1) / (0.4297157 - 0.0015976 * N1) °C - * = [T1 - N1 / (0.4297157 - 0.0015976 * N1) °C] + N / (0.4297157 - 0.0015976 * N1) °C - * = [T1 + N1 / (0.0015976 * N1 - 0.4297157) °C] - N / (0.0015976 * N1 - 0.4297157) °C + * T = T1 + (N - N1) / (0.4148468 - 0.0015423 * N1) °C + 3.580661 °C + * = [T1' - N1 / (0.4148468 - 0.0015423 * N1) °C] + N / (0.4148468 - 0.0015423 * N1) °C + * = [T1' + N1 / (0.0015423 * N1 - 0.4148468) °C] - N / (0.0015423 * N1 - 0.4148468) °C * = c2 - c1 * N * * with * - * c1 = 1 / (0.0015976 * N1 - 0.4297157) °C - * c2 = T1 + N1 / (0.0015976 * N1 - 0.4297157) °C - * = T1 + N1 * C1 + * T1' = 28.580661 °C + * c1 = 1 / (0.0015423 * N1 - 0.4297157) °C + * c2 = T1' + N1 / (0.0015423 * N1 - 0.4148468) °C + * = T1' + N1 * c1 */ n1 = ocotp_ana1 >> 20; - t1 = 25; /* °C */ - temp64 = FACTOR0; /* 10^7 for FACTOR1 and FACTOR2 */ + temp64 = 10000000; /* use 10^7 as fixed point constant for values in formula */ temp64 *= 1000; /* to get result in °mC */ - do_div(temp64, FACTOR1 * n1 - FACTOR2); + do_div(temp64, 15423 * n1 - 4148468); data->c1 = temp64; - data->c2 = n1 * data->c1 + 1000 * t1; + data->c2 = n1 * data->c1 + 28581; return 0; } |