1 // Copyright 2024 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 15 #include "pw_digital_io/polarity.h" 16 #include "pw_digital_io_linux/digital_io.h" 17 #include "pw_status/try.h" 18 19 using pw::digital_io::LinuxDigitalIoChip; 20 using pw::digital_io::LinuxOutputConfig; 21 using pw::digital_io::Polarity; 22 using pw::digital_io::State; 23 OutputExample()24pw::Status OutputExample() { 25 // Open handle to chip. 26 PW_TRY_ASSIGN(auto chip, LinuxDigitalIoChip::Open("/dev/gpiochip0")); 27 28 // Configure output line. 29 // Set the polarity to active-low and default state to active. 30 LinuxOutputConfig config( 31 /* gpio_index= */ 4, 32 /* gpio_polarity= */ Polarity::kActiveLow, 33 /* gpio_default_state== */ State::kActive); 34 PW_TRY_ASSIGN(auto output, chip.GetOutputLine(config)); 35 36 // Enable the output pin. This pulls the pin to ground since the 37 // polarity is kActiveLow and the default_state is kActive. 38 PW_TRY(output.Enable()); 39 40 // Set the output pin to inactive. 41 // This pulls pin to Vdd since the polarity is kActiveLow. 42 PW_TRY(output.SetState(State::kInactive)); 43 44 return pw::OkStatus(); 45 } 46