rdtech-dps: touch up comments

[libsigrok.git] / src / hardware / rdtech-dps / protocol.c

diff --git a/src/hardware/rdtech-dps/protocol.c b/src/hardware/rdtech-dps/protocol.c
index 236cc90a4e5e281e8242ae9fa78962c0ab60be43..d5e63bf8e32c60cb5d991cbcfd61ce3954e72dc8 100644 (file)
--- a/src/hardware/rdtech-dps/protocol.c
+++ b/src/hardware/rdtech-dps/protocol.c
@@ -26,7 +26,7 @@
 
 #include "protocol.h"
 
-/* These are the Modbus RTU registers for the family of rdtech-dps devices. */
+/* These are the Modbus RTU registers for the DPS family of devices. */
 enum rdtech_dps_register {
        REG_DPS_USET       = 0x00, /* Mirror of 0x50 */
        REG_DPS_ISET       = 0x01, /* Mirror of 0x51 */
@@ -72,8 +72,9 @@ enum rdtech_dps_regulation_mode {
 };
 
 /*
- * Some registers are specific to a certain device. For example,
- * REG_RD_RANGE is specific to RD6012P.
+ * These are the Modbus RTU registers for the RD family of devices.
+ * Some registers are device specific, like REG_RD_RANGE of RD6012P
+ * which could be battery related in other devices.
  */
 enum rdtech_rd_register {
        REG_RD_MODEL = 0, /* u16 */
@@ -649,25 +650,30 @@ SR_PRIV int rdtech_dps_set_state(const struct sr_dev_inst *sdi,
                reg_value = state->range;
                switch (devc->model->model_type) {
                case MODEL_DPS:
+                       /* DPS models don't support current ranges at all. */
                        if (reg_value > 0)
                                return SR_ERR_ARG;
                        break;
                case MODEL_RD:
+                       /*
+                        * Need not set the range when the device only
+                        * supports a single fixed range.
+                        */
                        if (devc->model->n_ranges == 1)
-                               /* No need to set. */
                                return SR_OK;
                        ret = rdtech_rd_set_reg(sdi, REG_RD_RANGE, reg_value);
                        if (ret != SR_OK)
                                return ret;
+                       /*
+                        * Immediately update internal state outside of
+                        * an acquisition. Assume that in-acquisition
+                        * activity will update internal state. This is
+                        * essential for meta package emission.
+                        */
                        if (!devc->acquisition_started) {
                                devc->curr_range = reg_value ? 1 : 0;
                                rdtech_dps_update_multipliers(sdi);
                        }
-                       /*
-                        * We rely on the data acquisition to update
-                        * devc->curr_range. If we do it here, there
-                        * will be no range meta package.
-                        */
                        break;
                default:
                        return SR_ERR_ARG;