regulators: Implement i2c_compare_bit action
Implement the i2c_compare_bit action in the JSON config file. See
i2c_compare_bit.md for more information about this action.
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: Idb5a2cc9bac3f8b392c0230fbb8bfa0e1b08f3c0
diff --git a/phosphor-regulators/src/actions/i2c_compare_bit_action.hpp b/phosphor-regulators/src/actions/i2c_compare_bit_action.hpp
new file mode 100644
index 0000000..ac28898
--- /dev/null
+++ b/phosphor-regulators/src/actions/i2c_compare_bit_action.hpp
@@ -0,0 +1,154 @@
+/**
+ * Copyright © 2020 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include "action_environment.hpp"
+#include "i2c_action.hpp"
+
+#include <cstdint>
+#include <stdexcept>
+#include <string>
+
+namespace phosphor::power::regulators
+{
+
+/**
+ * @class I2CCompareBitAction
+ *
+ * Compares a bit in a device register to a value. Communicates with the device
+ * directly using the I2C interface.
+ *
+ * Implements the i2c_compare_bit action in the JSON config file.
+ */
+class I2CCompareBitAction : public I2CAction
+{
+ public:
+ // Specify which compiler-generated methods we want
+ I2CCompareBitAction() = delete;
+ I2CCompareBitAction(const I2CCompareBitAction&) = delete;
+ I2CCompareBitAction(I2CCompareBitAction&&) = delete;
+ I2CCompareBitAction& operator=(const I2CCompareBitAction&) = delete;
+ I2CCompareBitAction& operator=(I2CCompareBitAction&&) = delete;
+ virtual ~I2CCompareBitAction() = default;
+
+ /**
+ * Constructor.
+ *
+ * Throws an exception if any of the input parameters are invalid.
+ *
+ * @param reg Device register address. Note: named 'reg' because 'register'
+ * is a reserved keyword.
+ * @param position Bit position. Must be in the range 0-7. Bit 0 is the
+ * least significant bit.
+ * @param value Expected bit value. Must be 0 or 1.
+ */
+ explicit I2CCompareBitAction(uint8_t reg, uint8_t position, uint8_t value) :
+ reg{reg}, position{position}, value{value}
+ {
+ if (position > 7)
+ {
+ throw std::invalid_argument{
+ "Invalid bit position: " +
+ std::to_string(static_cast<unsigned>(position))};
+ }
+
+ if (value > 1)
+ {
+ throw std::invalid_argument{
+ "Invalid bit value: " +
+ std::to_string(static_cast<unsigned>(value))};
+ }
+ }
+
+ /**
+ * Executes this action.
+ *
+ * Compares a bit in a device register to a value using the I2C interface.
+ *
+ * The device register, bit position, and bit value were specified in the
+ * constructor.
+ *
+ * The device is obtained from the specified action environment.
+ *
+ * Throws an exception if an error occurs.
+ *
+ * @param environment action execution environment
+ * @return true if the register bit contained the expected value, otherwise
+ * returns false.
+ */
+ virtual bool execute(ActionEnvironment& environment) override;
+
+ /**
+ * Returns the device register address.
+ *
+ * @return register address
+ */
+ uint8_t getRegister() const
+ {
+ return reg;
+ }
+
+ /**
+ * Returns the bit position.
+ *
+ * Value is in the range 0-7. Bit 0 is the least significant bit.
+ *
+ * @return bit position
+ */
+ uint8_t getPosition() const
+ {
+ return position;
+ }
+
+ /**
+ * Returns the expected bit value.
+ *
+ * Value is 0 or 1.
+ *
+ * @return expected bit value
+ */
+ uint8_t getValue() const
+ {
+ return value;
+ }
+
+ /**
+ * Returns a string description of this action.
+ *
+ * @return description of action
+ */
+ virtual std::string toString() const override;
+
+ private:
+ /**
+ * Device register address. Note: named 'reg' because 'register' is a
+ * reserved keyword.
+ */
+ const uint8_t reg{0x00};
+
+ /**
+ * Bit position. Must be in the range 0-7. Bit 0 is the least significant
+ * bit.
+ */
+ const uint8_t position{0};
+
+ /**
+ * Expected bit value. Must be 0 or 1.
+ */
+ const uint8_t value{0};
+};
+
+} // namespace phosphor::power::regulators