rdtech-dps: Retry sr_modbus_read_holding_registers() up to 3 times.

[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 565a2e0246190611f7be0b5c9ad26fa1bac20457..fe34b25700184fef2bb0428838a9c76e83eee235 100644 (file)
--- a/src/hardware/rdtech-dps/protocol.c
+++ b/src/hardware/rdtech-dps/protocol.c
@@ -21,6 +21,21 @@
 #include <config.h>
 #include "protocol.h"
 
+SR_PRIV int rdtech_dps_read_holding_registers(struct sr_modbus_dev_inst *modbus,
+               int address, int nb_registers, uint16_t *registers)
+{
+       int i, ret;
+
+       i = 0;
+       do {
+               ret = sr_modbus_read_holding_registers(modbus,
+                       address, nb_registers, registers);
+               ++i;
+       } while (ret != SR_OK && i < 3);
+
+       return ret;
+}
+
 SR_PRIV int rdtech_dps_get_reg(const struct sr_dev_inst *sdi,
                uint16_t address, uint16_t *value)
 {
@@ -33,7 +48,7 @@ SR_PRIV int rdtech_dps_get_reg(const struct sr_dev_inst *sdi,
        modbus = sdi->conn;
 
        g_mutex_lock(&devc->rw_mutex);
-       ret = sr_modbus_read_holding_registers(modbus, address, 1, registers);
+       ret = rdtech_dps_read_holding_registers(modbus, address, 1, registers);
        g_mutex_unlock(&devc->rw_mutex);
        *value = RB16(registers + 0);
        return ret;
@@ -67,7 +82,7 @@ SR_PRIV int rdtech_dps_get_model_version(struct sr_modbus_dev_inst *modbus,
         * No mutex here, because there is no sr_dev_inst when this function
         * is called.
         */
-       ret = sr_modbus_read_holding_registers(modbus, REG_MODEL, 2, registers);
+       ret = rdtech_dps_read_holding_registers(modbus, REG_MODEL, 2, registers);
        if (ret == SR_OK) {
                *model = RB16(registers + 0);
                *version = RB16(registers + 1);
@@ -119,6 +134,10 @@ SR_PRIV int rdtech_dps_receive_data(int fd, int revents, void *cb_data)
        devc = sdi->priv;
 
        g_mutex_lock(&devc->rw_mutex);
+       /*
+        * Using the libsigrok function here, because it doesn't matter if the
+        * reading fails. It will be done again in the next acquision cycle anyways.
+        */
        ret = sr_modbus_read_holding_registers(modbus, REG_UOUT, 3, registers);
        g_mutex_unlock(&devc->rw_mutex);