pmbus.hpp

#pragma once

#include <experimental/filesystem>
#include <string>
#include <vector>

namespace witherspoon
{
namespace pmbus
{

/**
 * @class PMBus
 *
 * This class is an interface to communicating with PMBus devices
 * by reading and writing sysfs files.
 */
class PMBus
{
    public:

        PMBus() = delete;
        ~PMBus() = default;
        PMBus(const PMBus&) = default;
        PMBus& operator=(const PMBus&) = default;
        PMBus(PMBus&&) = default;
        PMBus& operator=(PMBus&&) = default;

        /**
         * Constructor
         *
         * @param[in] path - path to the sysfs directory
         */
        PMBus(const std::string& path) :
            basePath(path)
        {
        }

        /**
         * Reads a file in sysfs that represents a single bit,
         * therefore doing a PMBus read.
         *
         * @param[in] name - path concatenated to
         *                   basePath to read
         *
         * @return bool - false if result was 0, else true
         */
        bool readBit(const std::string& name);

        /**
         * Reads a file in sysfs that represents a single bit,
         * where the page number passed in is substituted
         * into the name in place of the 'P' character in it.
         *
         * @param[in] name - path concatenated to
         *                   basePath to read
         * @param[in] page - page number
         *
         * @return bool - false if result was 0, else true
         */
        bool readBitInPage(const std::string& name,
                           size_t page);

        /**
         * Writes an integer value to the file, therefore doing
         * a PMBus write.
         *
         * @param[in] name - path concatenated to
         *                   basePath to write
         * @param[in] value - the value to write
         */
        void write(const std::string& name, int value);

        /**
         * Returns the sysfs base path of this device
         */
        inline const auto& path() const
        {
            return basePath;
        }

        /**
         * Replaces the 'P' in the string passed in with
         * the page number passed in.
         *
         * For example:
         *   insertPageNum("inP_enable", 42)
         *   returns "in42_enable"
         *
         * @param[in] templateName - the name string, with a 'P' in it
         * @param[in] page - the page number to insert where the P was
         *
         * @return string - the new string with the page number in it
         */
        static std::string insertPageNum(const std::string& templateName,
                                         size_t page);

    private:

        /**
         * The sysfs device path
         */
        std::experimental::filesystem::path basePath;

};

}
}