rdtech-dps: research to reduce serial comm transfer volume again

[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 9f45fc4f6d8fa974f37b78b807859faabd5f3e9b..7005a7a114fdfec65764e56b1c164159b1c51f54 100644 (file)
--- a/src/hardware/rdtech-dps/protocol.c
+++ b/src/hardware/rdtech-dps/protocol.c
@@ -254,10 +254,11 @@ static int send_value(const struct sr_dev_inst *sdi,
  * when the UART bitrate is only 9600bps?
  */
 SR_PRIV int rdtech_dps_get_state(const struct sr_dev_inst *sdi,
-       struct rdtech_dps_state *state)
+       struct rdtech_dps_state *state, enum rdtech_dps_state_context reason)
 {
        struct dev_context *devc;
        struct sr_modbus_dev_inst *modbus;
+       gboolean get_config, get_init_state, get_curr_meas;
        uint16_t registers[12];
        int ret;
        const uint8_t *rdptr;
@@ -276,6 +277,37 @@ SR_PRIV int rdtech_dps_get_state(const struct sr_dev_inst *sdi,
        if (!state)
                return SR_ERR_ARG;
 
+       /* Determine the requested level of response detail. */
+       get_config = FALSE;
+       get_init_state = FALSE;
+       get_curr_meas = FALSE;
+       switch (reason) {
+       case ST_CTX_CONFIG:
+               get_config = TRUE;
+               get_init_state = TRUE;
+               get_curr_meas = TRUE;
+               break;
+       case ST_CTX_PRE_ACQ:
+               get_init_state = TRUE;
+               get_curr_meas = TRUE;
+               break;
+       case ST_CTX_IN_ACQ:
+               get_curr_meas = TRUE;
+               break;
+       default:
+               /* EMPTY */
+               break;
+       }
+       /*
+        * TODO Make use of this information to reduce the transfer
+        * volume, especially on low bitrate serial connections. Though
+        * the device firmware's samplerate is probably more limiting
+        * than communication bandwidth is.
+        */
+       (void)get_config;
+       (void)get_init_state;
+       (void)get_curr_meas;
+
        switch (devc->model->model_type) {
        case MODEL_DPS:
                /*
@@ -285,9 +317,6 @@ SR_PRIV int rdtech_dps_get_state(const struct sr_dev_inst *sdi,
                 * and the sequence of the registers and how to interpret
                 * their bit fields. But then this is not too unusual for
                 * a hardware specific device driver ...
-                *
-                * TODO Optionally reduce the transfer volume depending
-                * on the caller specified state query context.
                 */
                g_mutex_lock(&devc->rw_mutex);
                ret = rdtech_dps_read_holding_registers(modbus,
@@ -393,7 +422,13 @@ SR_PRIV int rdtech_dps_get_state(const struct sr_dev_inst *sdi,
                return SR_ERR_ARG;
        }
 
-       /* Store gathered details in the high level container. */
+       /*
+        * Store gathered details in the high level container.
+        *
+        * TODO Make use of the caller's context. The register access
+        * code path above need not have gathered every detail in every
+        * invocation.
+        */
        memset(state, 0, sizeof(*state));
        state->lock = is_lock;
        state->mask |= STATE_LOCK;
@@ -551,7 +586,7 @@ SR_PRIV int rdtech_dps_seed_receive(const struct sr_dev_inst *sdi)
        struct rdtech_dps_state state;
        int ret;
 
-       ret = rdtech_dps_get_state(sdi, &state);
+       ret = rdtech_dps_get_state(sdi, &state, ST_CTX_PRE_ACQ);
        if (ret != SR_OK)
                return ret;
 
@@ -586,7 +621,7 @@ SR_PRIV int rdtech_dps_receive_data(int fd, int revents, void *cb_data)
        devc = sdi->priv;
 
        /* Get the device's current state. */
-       ret = rdtech_dps_get_state(sdi, &state);
+       ret = rdtech_dps_get_state(sdi, &state, ST_CTX_IN_ACQ);
        if (ret != SR_OK)
                return ret;