zephyr/drivers/spi/spi_emul.c

143 lines
3.3 KiB
C

/*
* Copyright 2020 Google LLC
*
* SPDX-License-Identifier: Apache-2.0
*
* This driver creates fake SPI buses which can contain emulated devices,
* implemented by a separate emulation driver. The API between this driver and
* its emulators is defined by struct spi_emul_driver_api.
*/
#define DT_DRV_COMPAT zephyr_spi_emul_controller
#define LOG_LEVEL CONFIG_SPI_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_REGISTER(spi_emul_ctlr);
#include <device.h>
#include <emul.h>
#include <drivers/spi.h>
#include <drivers/spi_emul.h>
/** Working data for the device */
struct spi_emul_data {
/* List of struct spi_emul associated with the device */
sys_slist_t emuls;
/* SPI host configuration */
uint32_t config;
};
uint32_t spi_emul_get_config(const struct device *dev)
{
struct spi_emul_data *data = dev->data;
return data->config;
}
/**
* Find an emulator for a SPI bus
*
* At present only a single emulator is supported on the bus, since we do not
* support chip selects, despite there being a chipsel field. It cannot be
* implemented until we have a GPIO emulator.
*
* @param dev SPI emulation controller device
* @param chipsel Chip-select value
* @return emulator to use
* @return NULL if not found
*/
static struct spi_emul *spi_emul_find(const struct device *dev,
unsigned int chipsel)
{
struct spi_emul_data *data = dev->data;
sys_snode_t *node;
SYS_SLIST_FOR_EACH_NODE(&data->emuls, node) {
struct spi_emul *emul;
emul = CONTAINER_OF(node, struct spi_emul, node);
if (emul->chipsel == chipsel) {
return emul;
}
}
return NULL;
}
static int spi_emul_io(const struct device *dev,
const struct spi_config *config,
const struct spi_buf_set *tx_bufs,
const struct spi_buf_set *rx_bufs)
{
struct spi_emul *emul;
const struct spi_emul_api *api;
emul = spi_emul_find(dev, config->slave);
if (!emul) {
return -EIO;
}
api = emul->api;
__ASSERT_NO_MSG(emul->api);
__ASSERT_NO_MSG(emul->api->io);
return api->io(emul, config, tx_bufs, rx_bufs);
}
/**
* Set up a new emulator and add it to the list
*
* @param dev SPI emulation controller device
*/
static int spi_emul_init(const struct device *dev)
{
struct spi_emul_data *data = dev->data;
const struct emul_list_for_bus *list = dev->config;
sys_slist_init(&data->emuls);
return emul_init_for_bus_from_list(dev, list);
}
int spi_emul_register(const struct device *dev, const char *name,
struct spi_emul *emul)
{
struct spi_emul_data *data = dev->data;
sys_slist_append(&data->emuls, &emul->node);
LOG_INF("Register emulator '%s' at cs %u\n", name, emul->chipsel);
return 0;
}
/* Device instantiation */
static struct spi_driver_api spi_emul_api = {
.transceive = spi_emul_io,
};
#define EMUL_LINK_AND_COMMA(node_id) { \
.label = DT_LABEL(node_id), \
},
#define SPI_EMUL_INIT(n) \
static const struct emul_link_for_bus emuls_##n[] = { \
DT_FOREACH_CHILD(DT_DRV_INST(0), EMUL_LINK_AND_COMMA) \
}; \
static struct emul_list_for_bus spi_emul_cfg_##n = { \
.children = emuls_##n, \
.num_children = ARRAY_SIZE(emuls_##n), \
}; \
static struct spi_emul_data spi_emul_data_##n; \
DEVICE_DT_INST_DEFINE(n, \
spi_emul_init, \
device_pm_control_nop, \
&spi_emul_data_##n, \
&spi_emul_cfg_##n, \
POST_KERNEL, \
CONFIG_SPI_INIT_PRIORITY, \
&spi_emul_api);
DT_INST_FOREACH_STATUS_OKAY(SPI_EMUL_INIT)