blob: 91033c02b4ac86dbc06a5689cbe314f846118e94 [file] [log] [blame]
/*
* Copyright 2020 Google LLC
* Copyright (c) 2020 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT atmel_at24
#define LOG_LEVEL CONFIG_I2C_LOG_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(atmel_at24);
#include <zephyr/device.h>
#include <zephyr/drivers/emul.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/drivers/i2c_emul.h>
/** Run-time data used by the emulator */
struct at24_emul_data {
/** I2C emulator detail */
struct i2c_emul emul;
/** AT24 device being emulated */
const struct device *i2c;
/** Current register to read (address) */
uint32_t cur_reg;
};
/** Static configuration for the emulator */
struct at24_emul_cfg {
/** EEPROM data contents */
uint8_t *buf;
/** Size of EEPROM in bytes */
uint32_t size;
/** Address of EEPROM on i2c bus */
uint16_t addr;
/** Address width for EEPROM in bits (only 8 is supported at present) */
uint8_t addr_width;
};
/**
* Emulator an I2C transfer to an AT24 chip
*
* This handles simple reads and writes
*
* @param emul I2C emulation information
* @param msgs List of messages to process. For 'read' messages, this function
* updates the 'buf' member with the data that was read
* @param num_msgs Number of messages to process
* @param addr Address of the I2C target device. This is assumed to be correct,
* due to the
* @retval 0 If successful
* @retval -EIO General input / output error
*/
static int at24_emul_transfer(const struct emul *target, struct i2c_msg *msgs,
int num_msgs, int addr)
{
struct at24_emul_data *data;
const struct at24_emul_cfg *cfg;
unsigned int len;
bool too_fast;
uint32_t i2c_cfg;
data = target->data;
cfg = target->cfg;
if (cfg->addr != addr) {
LOG_ERR("Address mismatch, expected %02x, got %02x", cfg->addr,
addr);
return -EIO;
}
if (i2c_get_config(data->i2c, &i2c_cfg)) {
LOG_ERR("i2c_get_config failed");
return -EIO;
}
/* For testing purposes, fail if the bus speed is above standard */
too_fast = (I2C_SPEED_GET(i2c_cfg) > I2C_SPEED_STANDARD);
if (too_fast) {
LOG_ERR("Speed too high");
return -EIO;
}
i2c_dump_msgs_rw(target->dev, msgs, num_msgs, addr, false);
switch (num_msgs) {
case 1:
if (msgs->flags & I2C_MSG_READ) {
/* handle read */
break;
}
data->cur_reg = msgs->buf[0];
len = MIN(msgs->len - 1, cfg->size - data->cur_reg);
memcpy(&cfg->buf[data->cur_reg], &msgs->buf[1], len);
return 0;
case 2:
if (msgs->flags & I2C_MSG_READ) {
LOG_ERR("Unexpected read");
return -EIO;
}
data->cur_reg = msgs->buf[0];
/* Now process the 'read' part of the message */
msgs++;
if (!(msgs->flags & I2C_MSG_READ)) {
LOG_ERR("Unexpected write");
return -EIO;
}
break;
default:
LOG_ERR("Invalid number of messages");
return -EIO;
}
/* Read data from the EEPROM into the buffer */
len = MIN(msgs->len, cfg->size - data->cur_reg);
memcpy(msgs->buf, &cfg->buf[data->cur_reg], len);
data->cur_reg += len;
return 0;
}
/* Device instantiation */
static struct i2c_emul_api bus_api = {
.transfer = at24_emul_transfer,
};
/**
* Set up a new AT24 emulator
*
* This should be called for each AT24 device that needs to be emulated. It
* registers it with the I2C emulation controller.
*
* @param target Emulation information
* @param parent Device to emulate (must use AT24 driver)
* @return 0 indicating success (always)
*/
static int emul_atmel_at24_init(const struct emul *target, const struct device *parent)
{
const struct at24_emul_cfg *cfg = target->cfg;
struct at24_emul_data *data = target->data;
data->emul.api = &bus_api;
data->emul.addr = cfg->addr;
data->emul.target = target;
data->i2c = parent;
data->cur_reg = 0;
/* Start with an erased EEPROM, assuming all 0xff */
memset(cfg->buf, 0xff, cfg->size);
return 0;
}
#define EEPROM_AT24_EMUL(n) \
static uint8_t at24_emul_buf_##n[DT_INST_PROP(n, size)]; \
static struct at24_emul_data at24_emul_data_##n; \
static const struct at24_emul_cfg at24_emul_cfg_##n = { \
.buf = at24_emul_buf_##n, \
.size = DT_INST_PROP(n, size), \
.addr = DT_INST_REG_ADDR(n), \
.addr_width = 8, \
}; \
EMUL_DT_INST_DEFINE(n, emul_atmel_at24_init, &at24_emul_data_##n, &at24_emul_cfg_##n, \
&bus_api, NULL)
DT_INST_FOREACH_STATUS_OKAY(EEPROM_AT24_EMUL)