diff options
| author | Nick Sanders <nsanders@chromium.org> | 2017-07-18 18:10:08 -0700 |
|---|---|---|
| committer | chrome-bot <chrome-bot@chromium.org> | 2017-07-24 22:54:04 -0700 |
| commit | 9e1e58b62ab70edb54065412584e8b36fba1e71b (patch) | |
| tree | 559d0df7814b3c26279f11e63b86d715920e599d | |
| parent | 15c3bec8a52fae390cb759c6eba7f52216319b54 (diff) | |
| download | chrome-ec-9e1e58b62ab70edb54065412584e8b36fba1e71b.tar.gz | |
sweetberry: allow larger sense resistors
Currently sweetberry hits an integer truncation issue
at 2.4 ohm when uA per div goes below 1. We can use 100ths
of a uA as the current per div scale.
BRANCH=None
BUG=chromium:608039
TEST=log from sweetberry with 10 ohm config.
Signed-off-by: Nick Sanders <nsanders@chromium.org>
Change-Id: I9e9216230329483fd0bfcb44ce23cd15bae864b3
Reviewed-on: https://chromium-review.googlesource.com/577051
Commit-Ready: Nick Sanders <nsanders@chromium.org>
Tested-by: Nick Sanders <nsanders@chromium.org>
Reviewed-by: Nick Sanders <nsanders@chromium.org>
| -rw-r--r-- | chip/stm32/usb_power.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/chip/stm32/usb_power.c b/chip/stm32/usb_power.c index 60e104a953..f2517dd24c 100644 --- a/chip/stm32/usb_power.c +++ b/chip/stm32/usb_power.c @@ -458,15 +458,20 @@ static int usb_power_init_inas(struct usb_power_config const *config) /* * Calculate INA231 Calibration register * CurrentLSB = uA per div = 80mV / (Rsh * 2^15) - * CurrentLSB uA = 80000000nV / (Rsh mOhm * 0x8000) + * CurrentLSB 100x uA = 100x 80000000nV / (Rsh mOhm * 0x8000) */ - ina->scale = 80000000 / (ina->rs * 0x8000); + if (ina->rs == 0) + return -1; + + ina->scale = (100 * (80000000 / 0x8000)) / ina->rs; /* * CAL = .00512 / (CurrentLSB * Rsh) * CAL = 5120000 / (uA * mOhm) */ - value = 5120000 / (ina->scale * ina->rs); + if (ina->scale == 0) + return -1; + value = (5120000 * 100) / (ina->scale * ina->rs); ret = ina2xx_write(ina->port, ina->addr, INA231_REG_CAL, value); if (ret != EC_SUCCESS) { CPRINTS("[CAP] usb_power_init_inas CAL FAIL: %d", ret); @@ -478,7 +483,7 @@ static int usb_power_init_inas(struct usb_power_config const *config) actual = ina2xx_read(ina->port, ina->addr, INA231_REG_CAL); CPRINTS("[CAP] scale: %d uA/div, %d uW/div, cal:%x act:%x", - ina->scale, ina->scale*25, value, actual); + ina->scale / 100, ina->scale*25/100, value, actual); } #endif /* Conversion time, shunt + bus, set average. */ @@ -586,8 +591,8 @@ static int usb_power_get_samples(struct usb_power_config const *config) int uV = ((int)voltage * 25) / 10; int mV = ((int)bvoltage * 125) / 100; int uA = (uV * 1000) / ina->rs; - int CuA = ((int)current * ina->scale); - int uW = ((int)power * ina->scale*25); + int CuA = (((int)current * ina->scale) / 100); + int uW = (((int)power * ina->scale*25)/100); CPRINTS("[CAP] %d (%d,0x%02x): %dmV / %dmO = %dmA", i, ina->port, ina->addr, uV/1000, ina->rs, uA/1000); |