xref: /openbmc/phosphor-power/phosphor-regulators/src/actions/i2c_write_byte_action.cpp (revision f1c9061cebc6227744af996805d5477d1cb1e9ad)
1 /**
2  * Copyright © 2020 IBM Corporation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "i2c_write_byte_action.hpp"
18 
19 #include "action_error.hpp"
20 #include "i2c_interface.hpp"
21 
22 #include <exception>
23 #include <ios>
24 #include <sstream>
25 
26 namespace phosphor::power::regulators
27 {
28 
execute(ActionEnvironment & environment)29 bool I2CWriteByteAction::execute(ActionEnvironment& environment)
30 {
31     try
32     {
33         i2c::I2CInterface& interface = getI2CInterface(environment);
34         uint8_t valueToWrite;
35         if (mask == 0xFF)
36         {
37             valueToWrite = value;
38         }
39         else
40         {
41             // Read current value of device register
42             uint8_t currentValue{0x00};
43             interface.read(reg, currentValue);
44 
45             // Combine value to write with current value
46             valueToWrite = (value & mask) | (currentValue & (~mask));
47         }
48 
49         // Write value to device register
50         interface.write(reg, valueToWrite);
51     }
52     catch (const i2c::I2CException& e)
53     {
54         // Nest I2CException within an ActionError so caller will have both the
55         // low level I2C error information and the action information
56         std::throw_with_nested(ActionError(*this));
57     }
58     return true;
59 }
60 
toString() const61 std::string I2CWriteByteAction::toString() const
62 {
63     std::ostringstream ss;
64     ss << "i2c_write_byte: { register: 0x" << std::hex << std::uppercase
65        << static_cast<uint16_t>(reg) << ", value: 0x"
66        << static_cast<uint16_t>(value) << ", mask: 0x"
67        << static_cast<uint16_t>(mask) << " }";
68     return ss.str();
69 }
70 
71 } // namespace phosphor::power::regulators
72