Merge pull request #2729 from cekstam/add-scale-and-shift-to-modbus

diff --cc src/collectd.conf.in
index 30791bd,6ec61f3..662b483
--- 1/src/collectd.conf.in
--- 2/src/collectd.conf.in
+++ b/src/collectd.conf.in
@@@ -834,6 -809,6 +834,8 @@@
  #             RegisterType float
  #             Type gauge
  #             Instance "..."
++#             #Scale 1.0
++#             #Shift 0.0
  #     </Data>
  #
  #     <Host "name">

diff --cc src/collectd.conf.pod
index 36794cd,329671e..7a21ba2
--- 1/src/collectd.conf.pod
--- 2/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@@ -4242,8 -4059,8 +4242,9 @@@ which the sizes of physical memory vary
  
  The B<modbus plugin> connects to a Modbus "slave" via Modbus/TCP or Modbus/RTU and
  reads register values. It supports reading single registers (unsigned 16E<nbsp>bit
--values), large integer values (unsigned 32E<nbsp>bit values) and floating point
--values (two registers interpreted as IEEE floats in big endian notation).
++values), large integer values (unsigned 32E<nbsp>bit and 64E<nbsp>bit values) and
++floating point values (two registers interpreted as IEEE floats in big endian
++notation).
  
  B<Synopsis:>
  
@@@ -4253,6 -4070,6 +4254,8 @@@
     RegisterCmd ReadHolding
     Type voltage
     Instance "input-1"
++   #Scale 1.0
++   #Shift 0.0
   </Data>
  
   <Data "voltage-input-2">
@@@ -4341,9 -4155,19 +4344,19 @@@ supported
  
  =item B<Instance> I<Instance>
  
--Sets the type instance to use when dispatching the value to I<collectd>. If
++Sets the type instance to use when dispatching the value to I<Instance>. If
  unset, an empty string (no type instance) is used.
  
 -The values taken from collectd are multiplied by I<Value>. The field is optional
+ =item B<Scale> I<Value>
+ 
 -I<Value> is added to values from collectd after they have been multiplied by
++The values taken from device are multiplied by I<Value>. The field is optional
+ and the default is B<1.0>.
+ 
+ =item B<Shift> I<Value>
+ 
++I<Value> is added to values from device after they have been multiplied by
+ B<Scale> value. The field is optional and the default value is B<0.0>.
+ 
  =back
  
  =item E<lt>B<Host> I<Name>E<gt> blocks

diff --cc src/modbus.c
index 40e0079,6422774..bb9eaa0
--- 1/src/modbus.c
--- 2/src/modbus.c
+++ b/src/modbus.c
@@@ -613,35 -608,8 +615,35 @@@ static int mb_read_data(mb_host_t *host
            "Returned uint32 value is %" PRIu32,
            v32);
  
-     CAST_TO_VALUE_T(ds, vt, v32);
+     CAST_TO_VALUE_T(ds, vt, v32, data->scale, data->shift);
      mb_submit(host, slave, data, vt);
-     CAST_TO_VALUE_T(ds, vt, v64);
 +  } else if (data->register_type == REG_TYPE_UINT64) {
 +    uint64_t v64;
 +    value_t vt;
 +
 +    v64 = (((uint64_t)values[0]) << 48) | (((uint64_t)values[1]) << 32) |
 +          (((uint64_t)values[2]) << 16) | (((uint64_t)values[3]));
 +    DEBUG("Modbus plugin: mb_read_data: "
 +          "Returned uint64 value is %" PRIu64,
 +          v64);
 +
-     CAST_TO_VALUE_T(ds, vt, v.i64);
++    CAST_TO_VALUE_T(ds, vt, v64, data->scale, data->shift);
 +    mb_submit(host, slave, data, vt);
 +  } else if (data->register_type == REG_TYPE_INT64) {
 +    union {
 +      uint64_t u64;
 +      int64_t i64;
 +    } v;
 +    value_t vt;
 +
 +    v.u64 = (((uint64_t)values[0]) << 48) | (((uint64_t)values[1]) << 32) |
 +            (((uint64_t)values[2]) << 16) | ((uint64_t)values[3]);
 +    DEBUG("Modbus plugin: mb_read_data: "
 +          "Returned uint64 value is %" PRIi64,
 +          v.i64);
 +
++    CAST_TO_VALUE_T(ds, vt, v.i64, data->scale, data->shift);
 +    mb_submit(host, slave, data, vt);
    } else /* if (data->register_type == REG_TYPE_UINT16) */
    {
      value_t vt;