Pca gpio expander (#127)

* init pca9539

* get rid of super bad enums lol

* make it way simpler and no bools

* get rid of extra shifts

* misc fixes

* fix buf

* misc fixes needed

* reverse the bits

* no reverse bits

---------

Co-authored-by: Scott A <[email protected]>

general/include/pca9539.h

@@ -0,0 +1,61 @@
+#ifndef PCA9539_H
+#define PCA9539_H
+
+#include "stm32f4xx_hal.h"
+#include <stdint.h>
+
+/*
+PCA 9539 16 bit GPIO expander.  Datasheet: https://www.ti.com/lit/ds/symlink/pca9539.pdf?ts=1716785085909
+*/
+
+/// Possible I2C addresses, see comment below
+///                            A0  A1
+///    PCA_I2C_ADDR_0 0x74,    L   L
+///    PCA_I2C_ADDR_1 0x75,    L   H
+///    PCA_I2C_ADDR_2 0x76,    H   L
+///    PCA_I2C_ADDR_3 0x77,    H   H
+#define PCA_I2C_ADDR_0 0x74
+#define PCA_I2C_ADDR_1 0x75
+#define PCA_I2C_ADDR_2 0x76
+#define PCA_I2C_ADDR_3 0x77
+
+/// What to write/read to/from
+/// 0 is for pins 0X, 1 is for pins 1X
+/// INPUT: The incoming logic level (read only) Result: 1=H 0=L
+/// OUTPUT: The outgoing logic level (write only) Set: 1=H 0=L
+/// POLARITY: Inversion state, 1=Inverted 0=Uninverted
+/// DIRECTION: Input/Output selection 1=Input 0=Output
+
+#define PCA_INPUT_0_REG 0x00
+#define PCA_INPUT_1_REG 0x01
+#define PCA_OUTPUT_0_REG 0x02
+#define PCA_OUTPUT_1_REG 0x03
+#define PCA_POLARITY_0_REG 0x04
+#define PCA_POLARITY_1_REG 0x05
+#define PCA_DIRECTION_0_REG 0x06
+#define PCA_DIRECTION_1_REG 0x07
+
+typedef struct
+{
+	I2C_HandleTypeDef *i2c_handle;
+	uint16_t dev_addr;
+} pca9539_t;
+
+/// Init PCA9539, a 16 bit I2C GPIO expander
+void pca9539_init(pca9539_t *pca, I2C_HandleTypeDef *i2c_handle, uint8_t dev_addr);
+
+/// @brief Read all pins on a bus, for example using reg_type input to get incoming logic level
+HAL_StatusTypeDef pca9539_read_reg(pca9539_t *pca, uint8_t reg_type,
+								   uint8_t *buf);
+/// @brief Read a specific pin on a bus, do not iterate over this, use read_pins instead
+HAL_StatusTypeDef pca9539_read_pin(pca9539_t *pca, uint8_t reg_type,
+								   uint8_t pin, uint8_t *buf);
+
+/// @brief Write all pins on a bus, for example using reg_type OUTPUT to set logic level or DIRECTION to set as
+/// output
+HAL_StatusTypeDef pca9539_write_reg(pca9539_t *pca, uint8_t reg_type, uint8_t buf);
+/// @brief Write a specific pin on a bus, do not iterate over this, use write_pins instead
+HAL_StatusTypeDef pca9539_write_pin(pca9539_t *pca, uint8_t reg_type, uint8_t pin,
+									uint8_t buf);
+
+#endif

general/src/pca9539.c

@@ -0,0 +1,71 @@
+#include "pca9539.h"
+
+#include "../../middleware/include/c_utils.h"
+
+#define REG_SIZE_BITS 8
+
+HAL_StatusTypeDef pca_write_reg(pca9539_t* pca, uint16_t address, uint8_t* data)
+{
+	// ensure shifting left one, HAL adds the write bit
+	return HAL_I2C_Mem_Write(pca->i2c_handle, pca->dev_addr, address, I2C_MEMADD_SIZE_8BIT, data, 1,
+							 HAL_MAX_DELAY);
+}
+
+HAL_StatusTypeDef pca_read_reg(pca9539_t* pca, uint16_t address, uint8_t* data)
+{
+
+	return HAL_I2C_Mem_Read(pca->i2c_handle, pca->dev_addr, address, I2C_MEMADD_SIZE_8BIT, data, 1,
+							HAL_MAX_DELAY);
+}
+
+void pca9539_init(pca9539_t* pca, I2C_HandleTypeDef* i2c_handle, uint8_t dev_addr)
+{
+	pca->i2c_handle = i2c_handle;
+	pca->dev_addr	= dev_addr << 1u; /* shifted one to the left cuz STM says so */
+}
+
+HAL_StatusTypeDef pca9539_read_reg(pca9539_t* pca, uint8_t reg_type, uint8_t* buf)
+{
+
+	HAL_StatusTypeDef status = pca_read_reg(pca, reg_type, buf);
+	if (status) {
+		return status;
+	}
+
+	return status;
+}
+
+HAL_StatusTypeDef pca9539_read_pin(pca9539_t* pca, uint8_t reg_type, uint8_t pin, uint8_t* buf)
+{
+	uint8_t data;
+	HAL_StatusTypeDef status = pca_read_reg(pca, reg_type, &data);
+	if (status) {
+		return status;
+	}
+
+	*buf = (data & (1 << pin)) > 0;
+
+	return status;
+}
+
+HAL_StatusTypeDef pca9539_write_reg(pca9539_t* pca, uint8_t reg_type, uint8_t buf)
+{
+
+	return pca_write_reg(pca, reg_type, &buf);
+}
+
+HAL_StatusTypeDef pca9539_write_pin(pca9539_t* pca, uint8_t reg_type, uint8_t pin, uint8_t buf)
+{
+
+	uint8_t data;
+	uint8_t data_new;
+
+	HAL_StatusTypeDef status = pca_read_reg(pca, reg_type, &data);
+	if (status) {
+		return status;
+	}
+
+	data_new = (data & ~(1u << pin)) | (buf << pin);
+
+	return pca_write_reg(pca, reg_type, &data_new);
+}