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OCPC: Expand resistance statistics 

Previously, some statistics were added to the combined system and
battery resistance OCPC parameter. Namely, calculating the mean and
standard deviation in order to filter out outliers.  However, for OCPC
systems which can calculate both resistances separately, similar
statistics should be performed.

This commit expands the resistance statistics to cover the individual
Rsys and Rbatt OCPC parameters.

Additionally, fixes were made to ensure that the resistance could
never become negative.

BUG=b:170974274 b:175063502
BRANCH=dedede
TEST=Build and flash drawcia, charge from the sub board, enable OCPC
debug output and verify that resistance is still calculated, never
negative, and statistics are computed.
TEST=Repeat above test for madoo.

Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Change-Id: I57a4af0cbbd0fa9f4bc1354a79b4ba97ffbad6d2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2587817
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Diana Z <dzigterman@chromium.org>
Commit-Queue: Diana Z <dzigterman@chromium.org>
Auto-Submit: Aseda Aboagye <aaboagye@chromium.org>
This commit is contained in:
Aseda Aboagye 2020-12-11 15:45:30 -08:00 committed by Commit Bot
parent bce4e485bb
commit ca355523ad
1 changed files with 111 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

145
common/ocpc.c
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@ -41,6 +41,12 @@ do { \
if (debug_output) \
cprints(CC_CHARGER, format, ## args); \
} while (0)
#define CPRINTF_DBG(format, args...) \
do { \
if (debug_output) \
cprintf(CC_CHARGER, format, ## args); \
} while (0)
/* Code refactor will be needed if more than 2 charger chips are present */
BUILD_ASSERT(CHARGER_NUM == 2);
@ -55,14 +61,25 @@ static int debug_output;
static int viz_output;
#define NUM_RESISTANCE_SAMPLES 8
static int resistance_tbl[NUM_RESISTANCE_SAMPLES] = {
CONFIG_OCPC_DEF_RBATT_MOHMS
#define COMBINED_IDX 0
#define RBATT_IDX 1
#define RSYS_IDX 2
static int resistance_tbl[NUM_RESISTANCE_SAMPLES][3] = {
/* Rsys+Rbatt Rbatt Rsys */
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
{CONFIG_OCPC_DEF_RBATT_MOHMS, CONFIG_OCPC_DEF_RBATT_MOHMS, 0},
};
static int resistance_tbl_idx;
static int mean_resistance;
static int stddev_resistance;
static int ub;
static int lb;
static int mean_resistance[3];
static int stddev_resistance[3];
static int ub[3];
static int lb[3];
enum phase {
PHASE_UNKNOWN = -1,
@ -78,28 +95,71 @@ __overridable void board_ocpc_init(struct ocpc_data *ocpc)
static enum ec_error_list ocpc_precharge_enable(bool enable);
static void calc_resistance_stats(void)
static void calc_resistance_stats(struct ocpc_data *ocpc)
{
int i;
int sum = 0;
int j;
int sum;
int cols = 3;
int act_chg = ocpc->active_chg_chip;
/* Only perform separate stats on Rsys and Rbatt if necessary. */
if ((ocpc->chg_flags[act_chg] & OCPC_NO_ISYS_MEAS_CAP))
cols = 1;
/* Calculate mean */
for (i = 0; i < NUM_RESISTANCE_SAMPLES; i++)
sum += resistance_tbl[i];
for (i = 0; i < cols; i++) {
sum = 0;
for (j = 0; j < NUM_RESISTANCE_SAMPLES; j++) {
sum += resistance_tbl[j][i];
CPRINTF_DBG("%d ", resistance_tbl[j][i]);
}
CPRINTF_DBG("\n");
mean_resistance = sum / NUM_RESISTANCE_SAMPLES;
mean_resistance[i] = sum / NUM_RESISTANCE_SAMPLES;
/* Calculate standard deviation */
sum = 0;
for (i = 0; i < NUM_RESISTANCE_SAMPLES; i++)
sum += POW2(resistance_tbl[i] - mean_resistance);
/* Calculate standard deviation */
sum = 0;
for (j = 0; j < NUM_RESISTANCE_SAMPLES; j++)
sum += POW2(resistance_tbl[j][i] - mean_resistance[i]);
stddev_resistance = fp_sqrtf(INT_TO_FP(sum / NUM_RESISTANCE_SAMPLES));
stddev_resistance = FP_TO_INT(stddev_resistance);
CPRINTS_DBG("Rbatt+Rsys: mean: %d stddev: %d", mean_resistance,
stddev_resistance);
lb = MAX(0, mean_resistance - (3 * stddev_resistance));
ub = mean_resistance + (3 * stddev_resistance);
stddev_resistance[i] = fp_sqrtf(INT_TO_FP(sum /
NUM_RESISTANCE_SAMPLES));
stddev_resistance[i] = FP_TO_INT(stddev_resistance[i]);
/*
* Don't let our stddev collapse to 0 to continually consider
* new values.
*/
stddev_resistance[i] = MAX(stddev_resistance[i], 1);
CPRINTS_DBG("%d: mean: %d stddev: %d", i, mean_resistance[i],
stddev_resistance[i]);
lb[i] = MAX(0, mean_resistance[i] - (3 * stddev_resistance[i]));
ub[i] = mean_resistance[i] + (3 * stddev_resistance[i]);
}
}
static bool is_within_range(struct ocpc_data *ocpc, int combined, int rbatt,
int rsys)
{
int act_chg = ocpc->active_chg_chip;
bool valid;
/* Discard measurements not within a 6 std. dev. window. */
if ((ocpc->chg_flags[act_chg] & OCPC_NO_ISYS_MEAS_CAP)) {
/* We only know the combined Rsys+Rbatt */
valid = (combined > 0) &&
(combined <= ub[COMBINED_IDX]) &&
(combined >= lb[COMBINED_IDX]);
} else {
valid = (rsys <= ub[RSYS_IDX]) && (rsys >= lb[RSYS_IDX]) &&
(rbatt <= ub[RBATT_IDX]) && (rbatt >= lb[RBATT_IDX]) &&
(rsys > 0) && (rbatt > 0);
}
if (!valid)
CPRINTS_DBG("Discard Rc:%d Rb:%d Rs:%d", combined, rbatt, rsys);
return valid;
}
enum ec_error_list ocpc_calc_resistances(struct ocpc_data *ocpc,
@ -108,7 +168,9 @@ enum ec_error_list ocpc_calc_resistances(struct ocpc_data *ocpc,
int act_chg = ocpc->active_chg_chip;
static bool seeded;
static int initial_samples;
int val;
int combined;
int rsys = -1;
int rbatt = -1;
/*
* In order to actually calculate the resistance, we need to make sure
@ -133,30 +195,45 @@ enum ec_error_list ocpc_calc_resistances(struct ocpc_data *ocpc,
* There's no provision to measure Isys, so we cannot separate
* out Rsys from Rbatt.
*/
val = ((ocpc->vsys_aux_mv - battery->voltage) * 1000) /
battery->current;
combined = ((ocpc->vsys_aux_mv - battery->voltage) * 1000) /
battery->current;
} else {
ocpc->rsys_mo = ((ocpc->vsys_aux_mv - ocpc->vsys_mv) * 1000) /
rsys = ((ocpc->vsys_aux_mv - ocpc->vsys_mv) * 1000) /
ocpc->isys_ma;
ocpc->rbatt_mo = ((ocpc->vsys_mv - battery->voltage) * 1000) /
rbatt = ((ocpc->vsys_mv - battery->voltage) * 1000) /
battery->current;
val = ocpc->rsys_mo + ocpc->rbatt_mo;
CPRINTS_DBG("Rsys: %dmOhm Rbatt: %dmOhm", ocpc->rsys_mo,
ocpc->rbatt_mo);
combined = rsys + rbatt;
}
/* Discard measurements not within a 6 std dev window. */
if ((!seeded) ||
(seeded && ((val <= ub) && (val >= lb)))) {
resistance_tbl[resistance_tbl_idx] = val;
calc_resistance_stats();
(seeded && is_within_range(ocpc, combined, rbatt, rsys))) {
if (!(ocpc->chg_flags[act_chg] & OCPC_NO_ISYS_MEAS_CAP)) {
resistance_tbl[resistance_tbl_idx][RSYS_IDX] =
MAX(rsys, 0);
resistance_tbl[resistance_tbl_idx][RBATT_IDX] =
MAX(rbatt, CONFIG_OCPC_DEF_RBATT_MOHMS);
}
resistance_tbl[resistance_tbl_idx][COMBINED_IDX] =
MAX(combined, CONFIG_OCPC_DEF_RBATT_MOHMS);
calc_resistance_stats(ocpc);
resistance_tbl_idx = (resistance_tbl_idx + 1) %
NUM_RESISTANCE_SAMPLES;
}
if (seeded) {
ocpc->combined_rsys_rbatt_mo = MAX(mean_resistance,
CONFIG_OCPC_DEF_RBATT_MOHMS);
ocpc->combined_rsys_rbatt_mo =
MAX(mean_resistance[COMBINED_IDX],
CONFIG_OCPC_DEF_RBATT_MOHMS);
if (!(ocpc->chg_flags[act_chg] & OCPC_NO_ISYS_MEAS_CAP)) {
ocpc->rsys_mo = mean_resistance[RSYS_IDX];
ocpc->rbatt_mo = MAX(mean_resistance[RBATT_IDX],
CONFIG_OCPC_DEF_RBATT_MOHMS);
CPRINTS_DBG("Rsys: %dmOhm Rbatt: %dmOhm",
ocpc->rsys_mo, ocpc->rbatt_mo);
}
CPRINTS_DBG("Rsys+Rbatt: %dmOhm", ocpc->combined_rsys_rbatt_mo);
} else {
seeded = ++initial_samples >= (2 * NUM_RESISTANCE_SAMPLES) ?