Add shunt resistance value configuration option to libsigrok. Implement
support for this option in ACME driver in the form of key-value pair
where key is the probe ID and value is the desired shunt resistance in
mOhms.
Signed-off-by: Bartosz Golaszewski <bgolaszew...@baylibre.com>
---
include/libsigrok/libsigrok.h | 6 ++
src/hardware/acme/acme.c | 132 +++++++++++++++++++++++++++++++++++++++++-
src/hwdriver.c | 2 +
3 files changed, 138 insertions(+), 2 deletions(-)
diff --git a/include/libsigrok/libsigrok.h b/include/libsigrok/libsigrok.h
index 65e9da8..2f4c4fc 100644
--- a/include/libsigrok/libsigrok.h
+++ b/include/libsigrok/libsigrok.h
@@ -903,6 +903,12 @@ enum sr_configkey {
*/
SR_CONF_DATA_SOURCE,
+ /**
+ * The device is a power-monitor supporting setting
+ * shunt resistance values.
+ */
+ SR_CONF_SHUNT_RESISTANCE,
+
/*--- Acquisition modes, sample limiting ----------------------------*/
/**
diff --git a/src/hardware/acme/acme.c b/src/hardware/acme/acme.c
index 3af77a4..6799428 100644
--- a/src/hardware/acme/acme.c
+++ b/src/hardware/acme/acme.c
@@ -63,6 +63,7 @@ static const uint32_t devopts[] = {
SR_CONF_LIMIT_SAMPLES | SR_CONF_GET | SR_CONF_SET,
SR_CONF_LIMIT_MSEC | SR_CONF_GET | SR_CONF_SET,
SR_CONF_SAMPLERATE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
+ SR_CONF_SHUNT_RESISTANCE | SR_CONF_GET | SR_CONF_SET,
};
#define MAX_SAMPLE_RATE 500 /* In HZ */
@@ -102,6 +103,8 @@ struct dev_context {
int64_t last_sample_fin;
int pipe_fds[2];
GIOChannel *channel;
+
+ struct channel_group_priv *probes[MAX_PROBES];
};
SR_PRIV struct sr_dev_driver acme_driver_info;
@@ -240,8 +243,11 @@ static gboolean register_probe(struct sr_dev_inst *sdi,
{
struct sr_channel_group *chg;
struct channel_group_priv *cgp;
+ struct dev_context *devc;
int hwmon;
+ devc = sdi->priv;
+
/* Obtain the hwmon index. */
hwmon = get_hwmon_index(addr);
if (hwmon < 0)
@@ -266,6 +272,7 @@ static gboolean register_probe(struct sr_dev_inst *sdi,
}
sdi->channel_groups = g_slist_append(sdi->channel_groups, chg);
+ devc->probes[prb_num - 1] = cgp;
return TRUE;
}
@@ -398,12 +405,99 @@ static int cleanup(void)
return SR_OK;
}
+static int read_shunt_values(const struct sr_dev_inst *sdi, GVariant **data)
+{
+ struct sr_channel_group *chg;
+ struct channel_group_priv *chgp;
+ char path[256];
+ uint32_t in = 0, shunt;
+ GSList *chgl;
+ gboolean status;
+ gchar *contents, buf[512];
+ gsize size;
+ GError *err;
+
+ for (chgl = sdi->channel_groups; chgl; chgl = chgl->next) {
+ chg = chgl->data;
+ chgp = chg->priv;
+
+ in += snprintf(buf + in, sizeof(buf) - in, "%s: ", chg->name);
+ if (chgp->prb_type == PROBE_TEMP) {
+ in += snprintf(buf + in, sizeof(buf) - in, "N/A, ");
+ } else {
+ snprintf(path, sizeof(path),
+ "/sys/class/hwmon/hwmon%d/shunt_resistor",
+ chgp->hwmon_num);
+ status = g_file_get_contents(path, &contents,
+ &size, &err);
+ if (!status) {
+ sr_err("Error reading shunt resistance: %s",
+ err->message);
+ return -1;
+ }
+
+ shunt = strtol(contents, NULL, 10) / 1000;
+ in += snprintf(buf + in, sizeof(buf) - in,
+ "%u mOhms, ", shunt);
+ g_free(contents);
+ }
+ }
+
+ buf[in - 2] = '\0';
+ *data = g_variant_new_string(buf);
+
+ return 0;
+}
+
+static int set_shunt(const struct dev_context *devc,
+ unsigned probe, unsigned shunt)
+{
+ char path[256], out[32];
+ int ret = 0, fd;
+
+ if (probe > MAX_PROBES) {
+ sr_err("Invalid probe number");
+ ret = -1;
+ goto out;
+ }
+
+ if (devc->probes[probe - 1] == NULL) {
+ sr_err("Probe %u not present", probe);
+ ret = -1;
+ goto out;
+ }
+
+ if (devc->probes[probe - 1]->prb_type == PROBE_TEMP) {
+ sr_err("Unable to set shunt on a temperature probe");
+ ret = -1;
+ goto out;
+ }
+
+ snprintf(path, sizeof(path),
+ "/sys/class/hwmon/hwmon%u/shunt_resistor",
+ devc->probes[probe - 1]->hwmon_num);
+ snprintf(out, sizeof(out), "%u\n", shunt * 1000);
+
+ fd = open(path, O_WRONLY);
+ if (fd < 0) {
+ sr_err("Error opening: %s\n", strerror(errno));
+ ret = -1;
+ goto out;
+ }
+
+ write(fd, out, strlen(out));
+ close(fd);
+
+out:
+ return ret;
+}
+
static int config_get(uint32_t key, GVariant **data,
const struct sr_dev_inst *sdi,
const struct sr_channel_group *cg)
{
struct dev_context *devc;
- int ret;
+ int ret, status;
(void)sdi;
(void)data;
@@ -422,6 +516,11 @@ static int config_get(uint32_t key, GVariant **data,
case SR_CONF_SAMPLERATE:
*data = g_variant_new_uint64(devc->samplerate);
break;
+ case SR_CONF_SHUNT_RESISTANCE:
+ status = read_shunt_values(sdi, data);
+ if (status < 0)
+ ret = SR_ERR_BUG;
+ break;
default:
return SR_ERR_NA;
}
@@ -435,7 +534,11 @@ static int config_set(uint32_t key, GVariant *data,
{
struct dev_context *devc;
uint64_t samplerate;
- int ret;
+ int ret, status;
+ GVariantIter iter_arr, iter_pair;
+ GVariant *keyval, *probe_var, *shunt_var = NULL;
+ const char *probe_str, *shunt_str;
+ unsigned probe, shunt;
(void)data;
(void)cg;
@@ -468,6 +571,31 @@ static int config_set(uint32_t key, GVariant *data,
devc->samplerate = samplerate;
sr_dbg("Setting samplerate to %" PRIu64, devc->samplerate);
break;
+ case SR_CONF_SHUNT_RESISTANCE:
+ g_variant_iter_init(&iter_arr, data);
+ keyval = g_variant_iter_next_value(&iter_arr);
+ g_variant_iter_init(&iter_pair, keyval);
+ probe_var = g_variant_iter_next_value(&iter_pair);
+ if (probe_var)
+ shunt_var = g_variant_iter_next_value(&iter_pair);
+ if (!shunt_var) {
+ sr_err("Invalid value");
+ ret = SR_ERR_ARG;
+ break;
+ }
+
+ probe_str = g_variant_get_string(probe_var, NULL);
+ shunt_str = g_variant_get_string(shunt_var, NULL);
+ probe = strtoul(probe_str, NULL, 10);
+ shunt = strtoul(shunt_str, NULL, 10);
+ status = set_shunt(devc, probe, shunt);
+ if (status < 0) {
+ ret = SR_ERR_ARG;
+ break;
+ }
+
+ sr_dbg("Shunt resistance for probe %u set to %u", probe, shunt);
+ break;
default:
ret = SR_ERR_NA;
}
diff --git a/src/hwdriver.c b/src/hwdriver.c
index 239592d..1848a08 100644
--- a/src/hwdriver.c
+++ b/src/hwdriver.c
@@ -183,6 +183,8 @@ static struct sr_config_info sr_config_info_data[] = {
"Power off", NULL},
{SR_CONF_DATA_SOURCE, SR_T_STRING, "data_source",
"Data source", NULL},
+ {SR_CONF_SHUNT_RESISTANCE, SR_T_KEYVALUE, "shunt",
+ "Shunt resistance", NULL},
/* Acquisition modes, sample limiting */
{SR_CONF_LIMIT_MSEC, SR_T_UINT64, "limit_time",
--
2.1.4
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