310 lines
9.8 KiB
C
310 lines
9.8 KiB
C
/*
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* Copyright (c) 2022 The ZMK Contributors
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*
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* SPDX-License-Identifier: MIT
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*/
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#define DT_DRV_COMPAT maxim_max7318
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/**
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* @file Driver for MAX7318 I2C-based GPIO driver.
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*/
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#include <errno.h>
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#include <kernel.h>
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#include <device.h>
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#include <init.h>
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#include <sys/byteorder.h>
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#include <drivers/gpio.h>
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#include <drivers/i2c.h>
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#include <drivers/ext_power.h>
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#include "gpio_max7318.h"
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#define LOG_LEVEL CONFIG_GPIO_LOG_LEVEL
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#include <logging/log.h>
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LOG_MODULE_REGISTER(gpio_max7318);
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/**
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* @brief Read the value of two consecutive registers
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*
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* Read two consecutive bytes from the register at address `reg` and `reg + 1`,
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* typically reading from registers for port 0 and 1 simultaneously.
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*
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* @param dev The max7318 device.
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* @param reg Register to read (the PORT0 of the pair of registers).
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* @param buf Buffer to read data into.
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*
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* @return 0 if successful, failed otherwise.
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*/
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static int read_registers(const struct device *dev, uint8_t reg, uint16_t *buf) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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uint16_t dev_addr = ((struct max7318_config *)dev->config)->device_addr;
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uint16_t data = 0;
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int ret = i2c_burst_read(drv_data->i2c, dev_addr, reg, (uint8_t *)&data, sizeof(data));
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if (ret) {
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LOG_DBG("i2c_write_read FAIL %d\n", ret);
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return ret;
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}
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*buf = sys_le16_to_cpu(data);
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LOG_DBG("max7318: read: reg[0x%X] = 0x%X, reg[0x%X] = 0x%X", reg, (*buf & 0xFF), (reg + 1),
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(*buf >> 8));
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return 0;
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}
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/**
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* @brief Write the value of two consecutive registers
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*
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* Write two consecutive bytes from the register at address `reg` and `reg + 1`,
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* typically to registers for port 0 and 1 simultaneously.
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*
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* @param dev The max7318 device.
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* @param reg Register to write (usually the register for PORT0).
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* @param value The value to write
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*
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* @return 0 if successful, failed otherwise.
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*/
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static int write_registers(const struct device *dev, uint8_t reg, uint16_t value) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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LOG_DBG("max7318: write: reg[0x%X] = 0x%X, reg[0x%X] = 0x%X", reg, (value & 0xFF), (reg + 1),
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(value >> 8));
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uint16_t data = sys_cpu_to_le16(value);
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uint16_t dev_addr = ((struct max7318_config *)dev->config)->device_addr;
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return i2c_burst_write(drv_data->i2c, dev_addr, reg, (uint8_t *)&data, sizeof(data));
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}
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/**
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* @brief Setup the pin direction (input or output)
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*
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* @param dev The max7318 device.
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* @param pin The pin number.
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* @param flags Flags of pin or port.
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*
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* @return 0 if successful, failed otherwise
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*/
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static int set_pin_direction(const struct device *dev, uint32_t pin, int flags) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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uint16_t *dir = &drv_data->reg_cache.config;
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uint16_t *output = &drv_data->reg_cache.output;
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/*
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The output register is 1=high, 0=low; the direction (config) register
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is 1=input, 0=output.
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*/
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if ((flags & GPIO_OUTPUT) != 0U) {
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if ((flags & GPIO_OUTPUT_INIT_HIGH) != 0U) {
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*output |= BIT(pin);
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} else if ((flags & GPIO_OUTPUT_INIT_LOW) != 0U) {
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*output &= ~BIT(pin);
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}
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*dir &= ~BIT(pin);
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} else {
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*dir |= BIT(pin);
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}
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int ret = write_registers(dev, REG_OUTPUT_PORTA, *output);
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if (ret != 0) {
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return ret;
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}
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return write_registers(dev, REG_CONFIG_PORTA, *dir);
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}
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/**
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* @brief Setup the pin pull up/pull down status. This function doesn't actually set any
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* registers, since the max7318 only supports a pullup, and it can't be controlled.
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*
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* @param dev The max7318 device.
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* @param pin The pin number
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* @param flags Flags of pin or port
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*
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* @return 0 if successful, failed otherwise
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*/
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static int set_pin_pull_direction(const struct device *dev, uint32_t pin, int flags) {
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// actually, this chip only supports pull-up, and it can't be disabled.
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// so, if we try to set anything else, return enotsup; we don't actually
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// need to set any registers.
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if ((flags & GPIO_PULL_DOWN) != 0U) {
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return -ENOTSUP;
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}
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return 0;
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}
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static int max7318_config(const struct device *dev, gpio_pin_t pin, gpio_flags_t flags) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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/* Can't do I2C bus operations from an ISR */
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if (k_is_in_isr()) {
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return -EWOULDBLOCK;
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}
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k_sem_take(&drv_data->lock, K_FOREVER);
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int ret = 0;
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if ((flags & GPIO_OPEN_DRAIN) != 0U) {
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ret = -ENOTSUP;
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goto done;
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};
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ret = set_pin_direction(dev, pin, flags);
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if (ret != 0) {
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LOG_ERR("error setting pin direction (%d)", ret);
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goto done;
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}
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ret = set_pin_pull_direction(dev, pin, flags);
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if (ret != 0) {
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LOG_ERR("error setting pin pull up/down (%d)", ret);
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goto done;
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}
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done:
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k_sem_give(&drv_data->lock);
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return ret;
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}
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static int max7318_port_get_raw(const struct device *dev, uint32_t *value) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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/* Can't do I2C bus operations from an ISR */
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if (k_is_in_isr()) {
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return -EWOULDBLOCK;
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}
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k_sem_take(&drv_data->lock, K_FOREVER);
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uint16_t buf = 0;
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int ret = read_registers(dev, REG_INPUT_PORTA, &buf);
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if (ret != 0) {
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goto done;
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}
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*value = buf;
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done:
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k_sem_give(&drv_data->lock);
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return ret;
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}
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static int max7318_port_set_masked_raw(const struct device *dev, uint32_t mask, uint32_t value) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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/* Can't do I2C bus operations from an ISR */
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if (k_is_in_isr()) {
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return -EWOULDBLOCK;
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}
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k_sem_take(&drv_data->lock, K_FOREVER);
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uint16_t buf = drv_data->reg_cache.output;
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buf = (buf & ~mask) | (mask & value);
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int ret = write_registers(dev, REG_OUTPUT_PORTA, buf);
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if (ret == 0) {
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drv_data->reg_cache.output = buf;
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}
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k_sem_give(&drv_data->lock);
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return ret;
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}
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static int max7318_port_set_bits_raw(const struct device *dev, uint32_t mask) {
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return max7318_port_set_masked_raw(dev, mask, mask);
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}
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static int max7318_port_clear_bits_raw(const struct device *dev, uint32_t mask) {
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return max7318_port_set_masked_raw(dev, mask, 0);
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}
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static int max7318_port_toggle_bits(const struct device *dev, uint32_t mask) {
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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/* Can't do I2C bus operations from an ISR */
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if (k_is_in_isr()) {
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return -EWOULDBLOCK;
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}
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k_sem_take(&drv_data->lock, K_FOREVER);
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uint16_t buf = drv_data->reg_cache.output;
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buf ^= mask;
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int ret = write_registers(dev, REG_OUTPUT_PORTA, buf);
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if (ret == 0) {
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drv_data->reg_cache.output = buf;
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}
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k_sem_give(&drv_data->lock);
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return ret;
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}
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static int max7318_pin_interrupt_configure(const struct device *dev, gpio_pin_t pin,
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enum gpio_int_mode mode, enum gpio_int_trig trig) {
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return -ENOTSUP;
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}
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static const struct gpio_driver_api api_table = {
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.pin_configure = max7318_config,
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.port_get_raw = max7318_port_get_raw,
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.port_set_masked_raw = max7318_port_set_masked_raw,
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.port_set_bits_raw = max7318_port_set_bits_raw,
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.port_clear_bits_raw = max7318_port_clear_bits_raw,
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.port_toggle_bits = max7318_port_toggle_bits,
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.pin_interrupt_configure = max7318_pin_interrupt_configure,
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};
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/**
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* @brief Initialisation function of MAX7318
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*
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* @param dev Device struct
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* @return 0 if successful, failed otherwise.
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*/
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static int max7318_init(const struct device *dev) {
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const struct max7318_config *const config = dev->config;
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struct max7318_drv_data *const drv_data = (struct max7318_drv_data *const)dev->data;
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drv_data->i2c = device_get_binding((char *)config->i2c_dev_name);
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if (!drv_data->i2c) {
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LOG_DBG("Unable to get i2c device");
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return -ENODEV;
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}
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if (!device_is_ready(drv_data->i2c)) {
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LOG_WRN("i2c bus not ready!");
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return -EINVAL;
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}
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LOG_INF("device initialised at 0x%x (i2c=%s)", config->device_addr, config->i2c_dev_name);
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k_sem_init(&drv_data->lock, 1, 1);
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return 0;
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}
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#define MAX7318_INIT(inst) \
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static struct max7318_config max7318_##inst##_config = { \
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.i2c_dev_name = DT_INST_BUS_LABEL(inst), \
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.device_addr = DT_INST_REG_ADDR(inst), \
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}; \
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\
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static struct max7318_drv_data max7318_##inst##_drvdata = { \
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/* Default for registers according to datasheet */ \
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.reg_cache.ipol = 0x0, \
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.reg_cache.config = 0xFFFF, \
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.reg_cache.output = 0xFFFF, \
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}; \
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\
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DEVICE_DT_INST_DEFINE(inst, max7318_init, NULL, &max7318_##inst##_drvdata, \
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&max7318_##inst##_config, POST_KERNEL, \
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CONFIG_GPIO_MAX7318_INIT_PRIORITY, &api_table);
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DT_INST_FOREACH_STATUS_OKAY(MAX7318_INIT)
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