| // Copyright 2021 The Pigweed Authors |
| // |
| // 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 |
| // |
| // https://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 "pw_bytes/span.h" |
| #include "pw_chrono/system_clock.h" |
| #include "pw_i2c/address.h" |
| #include "pw_i2c/initiator.h" |
| #include "pw_status/status.h" |
| |
| namespace pw { |
| namespace i2c { |
| |
| // Device is used to write/read arbitrary chunks of data over a bus to a device. |
| // This object essentially just wrap the Initiator API with a fixed I2C device |
| // address. |
| class Device { |
| public: |
| constexpr Device(Initiator& initiator, Address device_address) |
| : initiator_(initiator), device_address_(device_address) {} |
| |
| Device(const Device&) = delete; |
| ~Device() = default; |
| |
| // Write bytes and then read bytes as either one atomic or two independent I2C |
| // transaction. |
| // The signal on the bus should appear as follows: |
| // 1) Write Only: |
| // START + I2C Address + WRITE(0) + TX_BUFFER_BYTES + STOP |
| // 2) Read Only: |
| // START + I2C Address + READ(1) + RX_BUFFER_BYTES + STOP |
| // 3A) Write + Read (atomic): |
| // START + I2C Address + WRITE(0) + TX_BUFFER_BYTES + |
| // START + I2C Address + READ(1) + RX_BUFFER_BYTES + STOP |
| // 3B) Write + Read (separate): |
| // START + I2C Address + WRITE(0) + TX_BUFFER_BYTES + STOP |
| // START + I2C Address + READ(1) + RX_BUFFER_BYTES + STOP |
| // |
| // The timeout defines the minimum duration one may block waiting for both |
| // exclusive bus access and the completion of the I2C transaction. |
| // |
| // Preconditions: |
| // The Address must be supported by the Initiator, i.e. do not use a 10 |
| // address if the Initiator only supports 7 bit. This will assert. |
| // |
| // Returns: |
| // Ok - Success. |
| // InvalidArgument - device_address is larger than the 10 bit address space. |
| // DeadlineExceeded - Was unable to acquire exclusive Initiator access |
| // and complete the I2C transaction in time. |
| // Unavailable - NACK condition occurred, meaning the addressed device did |
| // not respond or was unable to process the request. |
| // FailedPrecondition - The interface is not currently initialized and/or |
| // enabled. |
| Status WriteReadFor(ConstByteSpan tx_buffer, |
| ByteSpan rx_buffer, |
| chrono::SystemClock::duration for_at_least) { |
| return initiator_.WriteReadFor( |
| device_address_, tx_buffer, rx_buffer, for_at_least); |
| } |
| Status WriteReadFor(const void* tx_buffer, |
| size_t tx_size_bytes, |
| void* rx_buffer, |
| size_t rx_size_bytes, |
| chrono::SystemClock::duration for_at_least) { |
| return initiator_.WriteReadFor(device_address_, |
| tx_buffer, |
| tx_size_bytes, |
| rx_buffer, |
| rx_size_bytes, |
| for_at_least); |
| } |
| |
| // Write bytes. The signal on the bus should appear as follows: |
| // START + I2C Address + WRITE(0) + TX_BUFFER_BYTES + STOP |
| // |
| // The timeout defines the minimum duration one may block waiting for both |
| // exclusive bus access and the completion of the I2C transaction. |
| // |
| // Preconditions: |
| // The Address must be supported by the Initiator, i.e. do not use a 10 |
| // address if the Initiator only supports 7 bit. This will assert. |
| // |
| // Returns: |
| // Ok - Success. |
| // InvalidArgument - device_address is larger than the 10 bit address space. |
| // DeadlineExceeded - Was unable to acquire exclusive Initiator access |
| // and complete the I2C transaction in time. |
| // Unavailable - NACK condition occurred, meaning the addressed device did |
| // not respond or was unable to process the request. |
| // FailedPrecondition - The interface is not currently initialized and/or |
| // enabled. |
| Status WriteFor(ConstByteSpan tx_buffer, |
| chrono::SystemClock::duration for_at_least) { |
| return initiator_.WriteFor(device_address_, tx_buffer, for_at_least); |
| } |
| Status WriteFor(const void* tx_buffer, |
| size_t tx_size_bytes, |
| chrono::SystemClock::duration for_at_least) { |
| return initiator_.WriteFor( |
| device_address_, tx_buffer, tx_size_bytes, for_at_least); |
| } |
| |
| // Read bytes. The signal on the bus should appear as follows: |
| // START + I2C Address + READ(1) + RX_BUFFER_BYTES + STOP |
| // |
| // The timeout defines the minimum duration one may block waiting for both |
| // exclusive bus access and the completion of the I2C transaction. |
| // |
| // Preconditions: |
| // The Address must be supported by the Initiator, i.e. do not use a 10 |
| // address if the Initiator only supports 7 bit. This will assert. |
| // |
| // Returns: |
| // Ok - Success. |
| // InvalidArgument - device_address is larger than the 10 bit address space. |
| // DeadlineExceeded - Was unable to acquire exclusive Initiator access |
| // and complete the I2C transaction in time. |
| // Unavailable - NACK condition occurred, meaning the addressed device did |
| // not respond or was unable to process the request. |
| // FailedPrecondition - The interface is not currently initialized and/or |
| // enabled. |
| Status ReadFor(ByteSpan rx_buffer, |
| chrono::SystemClock::duration for_at_least) { |
| return initiator_.ReadFor(device_address_, rx_buffer, for_at_least); |
| } |
| Status ReadFor(void* rx_buffer, |
| size_t rx_size_bytes, |
| chrono::SystemClock::duration for_at_least) { |
| return initiator_.ReadFor( |
| device_address_, rx_buffer, rx_size_bytes, for_at_least); |
| } |
| |
| // Probes the device for an I2C ACK after only writing the address. |
| // This is done by attempting to read a single byte from the specified device. |
| // |
| // The timeout defines the minimum duration one may block waiting for both |
| // exclusive bus access and the completion of the I2C transaction. |
| // |
| // Preconditions: |
| // The Address must be supported by the Initiator, i.e. do not use a 10 |
| // address if the Initiator only supports 7 bit. This will assert. |
| // |
| // Returns: |
| // Ok - Success. |
| // InvalidArgument - device_address is larger than the 10 bit address space. |
| // DeadlineExceeded - Was unable to acquire exclusive Initiator access |
| // and complete the I2C transaction in time. |
| // Unavailable - NACK condition occurred, meaning the addressed device did |
| // not respond or was unable to process the request. |
| // FailedPrecondition - The interface is not currently initialized and/or |
| // enabled. |
| Status ProbeFor(chrono::SystemClock::duration for_at_least) { |
| return initiator_.ProbeDeviceFor(device_address_, for_at_least); |
| } |
| |
| private: |
| Initiator& initiator_; |
| const Address device_address_; |
| }; |
| |
| } // namespace i2c |
| } // namespace pw |
