rdtech-dps: Synchronize read and write operations.

[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 4df1a7012b80e9ca864311b5d171a36fca06aa89..f01e5742542ea336033d3b789b48f3f762400f9a 100644 (file)
--- a/src/hardware/rdtech-dps/protocol.c
+++ b/src/hardware/rdtech-dps/protocol.c
@@ -2,6 +2,7 @@
  * This file is part of the libsigrok project.
  *
  * Copyright (C) 2018 James Churchill <pelrun@gmail.com>
+ * Copyright (C) 2019 Frank Stettner <frank-stettner@gmx.net>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,21 +21,40 @@
 #include <config.h>
 #include "protocol.h"
 
-SR_PRIV int rdtech_dps_get_reg(struct sr_modbus_dev_inst *modbus,
+SR_PRIV int rdtech_dps_get_reg(const struct sr_dev_inst *sdi,
                uint16_t address, uint16_t *value)
 {
+       struct dev_context *devc;
+       struct sr_modbus_dev_inst *modbus;
        uint16_t registers[1];
-       int ret = sr_modbus_read_holding_registers(modbus, address, 1, registers);
+       int ret;
+
+       devc = sdi->priv;
+       modbus = sdi->conn;
+
+       g_mutex_lock(&devc->rw_mutex);
+       ret = sr_modbus_read_holding_registers(modbus, address, 1, registers);
+       g_mutex_unlock(&devc->rw_mutex);
        *value = RB16(registers + 0);
        return ret;
 }
 
-SR_PRIV int rdtech_dps_set_reg(struct sr_modbus_dev_inst *modbus,
+SR_PRIV int rdtech_dps_set_reg(const struct sr_dev_inst *sdi,
                uint16_t address, uint16_t value)
 {
+       struct dev_context *devc;
+       struct sr_modbus_dev_inst *modbus;
        uint16_t registers[1];
+       int ret;
+
+       devc = sdi->priv;
+       modbus = sdi->conn;
+
        WB16(registers, value);
-       return sr_modbus_write_multiple_registers(modbus, address, 1, registers);
+       g_mutex_lock(&devc->rw_mutex);
+       ret = sr_modbus_write_multiple_registers(modbus, address, 1, registers);
+       g_mutex_unlock(&devc->rw_mutex);
+       return ret;
 }
 
 SR_PRIV int rdtech_dps_get_model_version(struct sr_modbus_dev_inst *modbus,
@@ -42,6 +62,11 @@ SR_PRIV int rdtech_dps_get_model_version(struct sr_modbus_dev_inst *modbus,
 {
        uint16_t registers[2];
        int ret;
+
+       /*
+        * 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);
        if (ret == SR_OK) {
                *model = RB16(registers + 0);
@@ -74,20 +99,6 @@ static void send_value(const struct sr_dev_inst *sdi, struct sr_channel *ch,
        g_slist_free(analog.meaning->channels);
 }
 
-SR_PRIV int rdtech_dps_capture_start(const struct sr_dev_inst *sdi)
-{
-       struct dev_context *devc;
-       struct sr_modbus_dev_inst *modbus;
-       int ret;
-
-       modbus = sdi->conn;
-       devc = sdi->priv;
-
-       if ((ret = sr_modbus_read_holding_registers(modbus, REG_UOUT, 3, NULL)) == SR_OK)
-               devc->expecting_registers = 2;
-       return ret;
-}
-
 SR_PRIV int rdtech_dps_receive_data(int fd, int revents, void *cb_data)
 {
        struct sr_dev_inst *sdi;
@@ -95,6 +106,7 @@ SR_PRIV int rdtech_dps_receive_data(int fd, int revents, void *cb_data)
        struct sr_modbus_dev_inst *modbus;
        struct sr_datafeed_packet packet;
        uint16_t registers[3];
+       int ret;
 
        (void)fd;
        (void)revents;
@@ -105,8 +117,11 @@ SR_PRIV int rdtech_dps_receive_data(int fd, int revents, void *cb_data)
        modbus = sdi->conn;
        devc = sdi->priv;
 
-       devc->expecting_registers = 0;
-       if (sr_modbus_read_holding_registers(modbus, -1, 3, registers) == SR_OK) {
+       g_mutex_lock(&devc->rw_mutex);
+       ret = sr_modbus_read_holding_registers(modbus, REG_UOUT, 3, registers);
+       g_mutex_unlock(&devc->rw_mutex);
+
+       if (ret == SR_OK) {
                packet.type = SR_DF_FRAME_BEGIN;
                sr_session_send(sdi, &packet);
 
@@ -130,6 +145,5 @@ SR_PRIV int rdtech_dps_receive_data(int fd, int revents, void *cb_data)
                return TRUE;
        }
 
-       rdtech_dps_capture_start(sdi);
        return TRUE;
 }