regulators: Implement i2c_write_bit action
Implement the i2c_write_bit action in the JSON config file. See
i2c_write_bit.md for more information about this action.
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I3e056580da98ab89a13667077cb87cbd063630c9
diff --git a/phosphor-regulators/src/actions/i2c_write_bit_action.cpp b/phosphor-regulators/src/actions/i2c_write_bit_action.cpp
new file mode 100644
index 0000000..ee146ac
--- /dev/null
+++ b/phosphor-regulators/src/actions/i2c_write_bit_action.cpp
@@ -0,0 +1,72 @@
+/**
+ * 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.
+ */
+
+#include "i2c_write_bit_action.hpp"
+
+#include "action_error.hpp"
+#include "i2c_interface.hpp"
+
+#include <exception>
+#include <ios>
+#include <sstream>
+
+namespace phosphor::power::regulators
+{
+
+bool I2CWriteBitAction::execute(ActionEnvironment& environment)
+{
+ try
+ {
+ // Read value of device register
+ uint8_t registerValue{0x00};
+ i2c::I2CInterface& interface = getI2CInterface(environment);
+ interface.read(reg, registerValue);
+
+ // Write bit to register value
+ if (value == 0)
+ {
+ // Clear bit within register value
+ registerValue &= ~(0x01 << position);
+ }
+ else
+ {
+ // Set bit within register value
+ registerValue |= (0x01 << position);
+ }
+
+ // Write modified value to device register
+ interface.write(reg, registerValue);
+ }
+ catch (const i2c::I2CException& e)
+ {
+ // Nest I2CException within an ActionError so caller will have both the
+ // low level I2C error information and the action information
+ std::throw_with_nested(ActionError(*this));
+ }
+ return true;
+}
+
+std::string I2CWriteBitAction::toString() const
+{
+ std::ostringstream ss;
+ ss << "i2c_write_bit: { register: 0x" << std::hex << std::uppercase
+ << static_cast<uint16_t>(reg) << ", position: " << std::dec
+ << static_cast<uint16_t>(position)
+ << ", value: " << static_cast<uint16_t>(value) << " }";
+ return ss.str();
+}
+
+} // namespace phosphor::power::regulators
diff --git a/phosphor-regulators/src/actions/i2c_write_bit_action.hpp b/phosphor-regulators/src/actions/i2c_write_bit_action.hpp
new file mode 100644
index 0000000..dea4ba7
--- /dev/null
+++ b/phosphor-regulators/src/actions/i2c_write_bit_action.hpp
@@ -0,0 +1,153 @@
+/**
+ * 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 I2CWriteBitAction
+ *
+ * Writes a bit to a device register. Communicates with the device directly
+ * using the I2C interface.
+ *
+ * Implements the i2c_write_bit action in the JSON config file.
+ */
+class I2CWriteBitAction : public I2CAction
+{
+ public:
+ // Specify which compiler-generated methods we want
+ I2CWriteBitAction() = delete;
+ I2CWriteBitAction(const I2CWriteBitAction&) = delete;
+ I2CWriteBitAction(I2CWriteBitAction&&) = delete;
+ I2CWriteBitAction& operator=(const I2CWriteBitAction&) = delete;
+ I2CWriteBitAction& operator=(I2CWriteBitAction&&) = delete;
+ virtual ~I2CWriteBitAction() = 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 Bit value to write. Must be 0 or 1.
+ */
+ explicit I2CWriteBitAction(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.
+ *
+ * Writes a bit to a device register 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
+ */
+ 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 bit value to write.
+ *
+ * Value is 0 or 1.
+ *
+ * @return 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};
+
+ /**
+ * Bit value to write. Must be 0 or 1.
+ */
+ const uint8_t value{0};
+};
+
+} // namespace phosphor::power::regulators
diff --git a/phosphor-regulators/src/meson.build b/phosphor-regulators/src/meson.build
index 556c65b..d9734c3 100644
--- a/phosphor-regulators/src/meson.build
+++ b/phosphor-regulators/src/meson.build
@@ -10,6 +10,7 @@
'actions/i2c_compare_bit_action.cpp',
'actions/i2c_compare_byte_action.cpp',
'actions/i2c_compare_bytes_action.cpp',
+ 'actions/i2c_write_bit_action.cpp',
'actions/i2c_write_byte_action.cpp',
'actions/i2c_write_bytes_action.cpp'
]