Driver for PCF8574 (8-bit I2C GPIO expander)

extras/pcf8574/pcf8574.h

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+/*
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+/**
+ * \file Driver for PCF8574 compartible remote 8-bit I/O expanders for I2C-bus
+ */
+#ifndef PCF8574_PCF8574_H_
+#define PCF8574_PCF8574_H_
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/**
+ * \brief Read GPIO port value
+ * \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
+ * \return 8-bit GPIO port value
+ */
+uint8_t pcf8574_port_read(uint8_t addr);
+
+/**
+ * \brief Continiously read GPIO port values to buffer
+ * @param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
+ * @param buf Target buffer
+ * @param len Buffer length
+ * @return Number of bytes read
+ */
+size_t pcf8574_port_read_buf(uint8_t addr, void *buf, size_t len);
+
+/**
+ * \brief Write value to GPIO port
+ * \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
+ * \param value GPIO port value
+ */
+void pcf8574_port_write(uint8_t addr, uint8_t value);
+
+/**
+ * \brief Continiously write GPIO values to GPIO port
+ * \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
+ * @param buf Buffer with values
+ * @param len Buffer length
+ * @return Number of bytes written
+ */
+size_t pcf8574_port_write_buf(uint8_t addr, void *buf, size_t len);
+
+/**
+ * \brief Read input value of a GPIO pin
+ * \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
+ * \param num pin number (0..7)
+ * \return GPIO pin value
+ */
+bool pcf8574_gpio_read(uint8_t addr, uint8_t num);
+
+/**
+ * \brief Set GPIO pin output
+ * Note it's READ - MODIFY - WRITE operation! Please read PCF8574
+ * datasheet first.
+ * \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
+ * \param num pin number (0..7)
+ * \param value true for high level
+ */
+void pcf8574_gpio_write(uint8_t addr, uint8_t num, bool value);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PCF8574_PCF8574_H_ */