Add I2C OCC support for P8 systems

P8 system uses I2C OCC and it uses different driver for occ-hwmon.
Add `--enable-i2c-occ` configure option to enable the support.

It searches i2c device names in sysfs to get all occ-hwmon devices and
use the i2c device name to bind/unbind the driver.

The occ control object path for I2C OCC hwmon becomes something like
/org/open_power/control/3_0050, where 3_0050 is the i2c address.

Change-Id: I8b9d8d4429c563528dc88fb2679b265c53d7a2d5
Signed-off-by: Lei YU <mine260309@gmail.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/i2c_occ.hpp b/i2c_occ.hpp
new file mode 100644
index 0000000..31b6721
--- /dev/null
+++ b/i2c_occ.hpp
@@ -0,0 +1,69 @@
+#pragma once
+
+#include <experimental/filesystem>
+#include <vector>
+
+#ifdef I2C_OCC
+
+namespace i2c_occ
+{
+
+namespace fs = std::experimental::filesystem;
+
+/** @brief Get file content
+ *
+ * Get at most NAME_LENGTH bytes of content from file. If the file is smaller
+ * than NAME_LENGTH bytes, return the valid parts.
+ *
+ * @param[in] f - The path of file
+ *
+ * @return The string of file content
+ */
+std::string getFileContent(const fs::path& f);
+
+/** @brief Find all devices of occ hwmon
+ *
+ * It iterates in path, finds all occ hwmon devices
+ *
+ * E.g. If "path/3-0050/name" exists and its content is "p8-occ-hwmon",
+ * "3-0050" is returned.
+ *
+ * @param[in] path - The path to search
+ *
+ * @return A vector of strings containing the occ hwmon device path
+ */
+std::vector<std::string> getOccHwmonDevices(const char* path);
+
+/** @brief Convert i2c name to DBus path
+ *
+ * It converts '-' to '_' so that it becomes a valid DBus path.
+ * E.g. 3-0050 converts to 3_0050
+ *
+ * @param[in,out] path - The i2c name to convert
+ */
+void i2cToDbus(std::string& name);
+
+/** @brief Convert DBus path to i2c name
+ *
+ * It converts '_' to '_' so that it becomes a valid i2c name
+ * E.g. 3_0050 converts to 3-0050
+ *
+ * @param[in,out] path - The DBus path to convert
+ */
+void dbusToI2c(std::string& path);
+
+/** @brief Get i2c name from full DBus path
+ *
+ * It extract the i2c name from the full DBus path.
+ * E.g. /org/open_power/control/3_0050 returns "3-0050"
+ *
+ * @param[in] dbusPath - The full DBus path
+ *
+ * @return The i2c name
+ */
+std::string getI2cDeviceName(const std::string& dbusPath);
+
+} // namespace i2c_occ
+
+#endif
+