diff options
| author | Anson Huang <b20788@freescale.com> | 2013-03-22 09:16:12 +0800 |
|---|---|---|
| committer | Anson Huang <b20788@freescale.com> | 2013-03-27 16:42:59 -0400 |
| commit | 7232c7ce56a9743996814783a886f5c299b5bbc2 (patch) | |
| tree | 2a3785dabd1acef2c9095cc3b38354ba24d61f7b | |
| parent | 82a4725015d9e0e31544c0ab853ef8f2889c53f2 (diff) | |
ENGR00255481 mx6: Update equation for thermal sensor
Use universal equation and 25C's calibration data to
get thermal sensor's ratio.
Signed-off-by: Anson Huang <b20788@freescale.com>
| -rw-r--r-- | cpu/arm_cortexa8/mx6/generic.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/cpu/arm_cortexa8/mx6/generic.c b/cpu/arm_cortexa8/mx6/generic.c index 8f0f1e670c..880374d25a 100644 --- a/cpu/arm_cortexa8/mx6/generic.c +++ b/cpu/arm_cortexa8/mx6/generic.c @@ -108,6 +108,9 @@ enum pll_clocks { #define TEMPERATURE_HOT 80 #define TEMPERATURE_MAX 125 #define REG_VALUE_TO_CEL(ratio, raw) ((raw_n40c - raw) * 100 / ratio - 40) +#define FACTOR1 15976 +#define FACTOR2 4297157 + static int cpu_tmp; static unsigned int fuse; @@ -877,7 +880,7 @@ static inline int read_cpu_temperature(void) MXC_CCM_CCGR2); fuse = readl(OCOTP_BASE_ADDR + OCOTP_THERMAL_OFFSET); writel(ccm_ccgr2, MXC_CCM_CCGR2); - if (fuse == 0 || fuse == 0xffffffff) + if (fuse == 0 || fuse == 0xffffffff || (fuse & 0xfff00000) == 0) return TEMPERATURE_MIN; /* Fuse data layout: @@ -888,7 +891,25 @@ static inline int read_cpu_temperature(void) raw_hot = (fuse & 0xfff00) >> 8; hot_temp = fuse & 0xff; + /* + * Only when it is i.MX6Q and high temperature calibration + * data not used, we use universal equation to get thermal + * sensor's ratio. + */ +#if (defined(CONFIG_MX6Q) && !defined(USE_CALIBRATION)) + /* + * The universal equation for thermal sensor + * is slope = 0.4297157 - (0.0015976 * 25C fuse), + * here we convert them to integer to make them + * easy for counting, FACTOR1 is 15976, + * FACTOR2 is 4297157. Our ratio = -100 * slope. + */ + ratio = ((FACTOR1 * raw_25c - FACTOR2) + 50000) / 100000; +#else ratio = ((raw_25c - raw_hot) * 100) / (hot_temp - 25); +#endif + + printf("Thermal sensor with ratio = %d\n", ratio); raw_n40c = raw_25c + (13 * ratio) / 20; /* now we only using single measure, every time we measure |