xref: /openbmc/phosphor-power/tools/i2c/i2c.hpp (revision e83604be)
1 #pragma once
2 
3 #include "i2c_interface.hpp"
4 
5 namespace i2c
6 {
7 
8 class I2CDevice : public I2CInterface
9 {
10   private:
11     I2CDevice() = delete;
12 
13     /** @brief Constructor
14      *
15      * Construct I2CDevice object from the bus id and device address
16      *
17      * Automatically opens the I2CDevice if initialState is OPEN.
18      *
19      * @param[in] busId - The i2c bus ID
20      * @param[in] devAddr - The device address of the I2C device
21      * @param[in] initialState - Initial state of the I2CDevice object
22      */
23     explicit I2CDevice(uint8_t busId, uint8_t devAddr,
24                        InitialState initialState = InitialState::OPEN) :
25         busId(busId),
26         devAddr(devAddr)
27     {
28         busStr = "/dev/i2c-" + std::to_string(busId);
29         if (initialState == InitialState::OPEN)
30         {
31             open();
32         }
33     }
34 
35     /** @brief Invalid file descriptor */
36     static constexpr int INVALID_FD = -1;
37 
38     /** @brief Empty adapter functionality value with no bit flags set */
39     static constexpr unsigned long NO_FUNCS = 0;
40 
41     /** @brief The I2C bus ID */
42     uint8_t busId;
43 
44     /** @brief The i2c device address in the bus */
45     uint8_t devAddr;
46 
47     /** @brief The file descriptor of the opened i2c device */
48     int fd = INVALID_FD;
49 
50     /** @brief The i2c bus path in /dev */
51     std::string busStr;
52 
53     /** @brief Cached I2C adapter functionality value */
54     unsigned long cachedFuncs = NO_FUNCS;
55 
56     /** @brief Check that device interface is open
57      *
58      * @throw I2CException if device is not open
59      */
60     void checkIsOpen() const
61     {
62         if (!isOpen())
63         {
64             throw I2CException("Device not open", busStr, devAddr);
65         }
66     }
67 
68     /** @brief Close device without throwing an exception if an error occurs */
69     void closeWithoutException() noexcept
70     {
71         try
72         {
73             close();
74         }
75         catch (...)
76         {
77         }
78     }
79 
80     /** @brief Get I2C adapter functionality
81      *
82      * Caches the adapter functionality value since it shouldn't change after
83      * opening the device.
84      *
85      * @throw I2CException on error
86      * @return Adapter functionality value
87      */
88     unsigned long getFuncs();
89 
90     /** @brief Check i2c adapter read functionality
91      *
92      * Check if the i2c adapter has the functionality specified by the SMBus
93      * transaction type
94      *
95      * @param[in] type - The SMBus transaction type defined in linux/i2c.h
96      *
97      * @throw I2CException if the function is not supported
98      */
99     void checkReadFuncs(int type);
100 
101     /** @brief Check i2c adapter write functionality
102      *
103      * Check if the i2c adapter has the functionality specified by the SMBus
104      * transaction type
105      *
106      * @param[in] type - The SMBus transaction type defined in linux/i2c.h
107      *
108      * @throw I2CException if the function is not supported
109      */
110     void checkWriteFuncs(int type);
111 
112   public:
113     /** @copydoc I2CInterface::~I2CInterface() */
114     ~I2CDevice()
115     {
116         if (isOpen())
117         {
118             // Note: destructors must not throw exceptions
119             closeWithoutException();
120         }
121     }
122 
123     /** @copydoc I2CInterface::open() */
124     void open();
125 
126     /** @copydoc I2CInterface::isOpen() */
127     bool isOpen() const
128     {
129         return (fd != INVALID_FD);
130     }
131 
132     /** @copydoc I2CInterface::close() */
133     void close();
134 
135     /** @copydoc I2CInterface::read(uint8_t&) */
136     void read(uint8_t& data) override;
137 
138     /** @copydoc I2CInterface::read(uint8_t,uint8_t&) */
139     void read(uint8_t addr, uint8_t& data) override;
140 
141     /** @copydoc I2CInterface::read(uint8_t,uint16_t&) */
142     void read(uint8_t addr, uint16_t& data) override;
143 
144     /** @copydoc I2CInterface::read(uint8_t,uint8_t&,uint8_t*,Mode) */
145     void read(uint8_t addr, uint8_t& size, uint8_t* data,
146               Mode mode = Mode::SMBUS) override;
147 
148     /** @copydoc I2CInterface::write(uint8_t) */
149     void write(uint8_t data) override;
150 
151     /** @copydoc I2CInterface::write(uint8_t,uint8_t) */
152     void write(uint8_t addr, uint8_t data) override;
153 
154     /** @copydoc I2CInterface::write(uint8_t,uint16_t) */
155     void write(uint8_t addr, uint16_t data) override;
156 
157     /** @copydoc I2CInterface::write(uint8_t,uint8_t,const uint8_t*,Mode) */
158     void write(uint8_t addr, uint8_t size, const uint8_t* data,
159                Mode mode = Mode::SMBUS) override;
160 
161     /** @brief Create an I2CInterface instance
162      *
163      * Automatically opens the I2CInterface if initialState is OPEN.
164      *
165      * @param[in] busId - The i2c bus ID
166      * @param[in] devAddr - The device address of the i2c
167      * @param[in] initialState - Initial state of the I2CInterface object
168      *
169      * @return The unique_ptr holding the I2CInterface
170      */
171     static std::unique_ptr<I2CInterface>
172         create(uint8_t busId, uint8_t devAddr,
173                InitialState initialState = InitialState::OPEN);
174 };
175 
176 } // namespace i2c
177