1 /*
2 * Copyright 2020 Google LLC
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 *
6 * This driver creates fake SPI buses which can contain emulated devices,
7 * implemented by a separate emulation driver. The API between this driver and
8 * its emulators is defined by struct spi_emul_driver_api.
9 */
10
11 #define DT_DRV_COMPAT zephyr_spi_emul_controller
12
13 #define LOG_LEVEL CONFIG_SPI_LOG_LEVEL
14 #include <zephyr/logging/log.h>
15 LOG_MODULE_REGISTER(spi_emul_ctlr);
16
17 #include <zephyr/device.h>
18 #include <zephyr/drivers/emul.h>
19 #include <zephyr/drivers/spi.h>
20 #include <zephyr/drivers/spi_emul.h>
21
22 /** Working data for the device */
23 struct spi_emul_data {
24 /* List of struct spi_emul associated with the device */
25 sys_slist_t emuls;
26 /* SPI host configuration */
27 uint32_t config;
28 };
29
spi_emul_get_config(const struct device * dev)30 uint32_t spi_emul_get_config(const struct device *dev)
31 {
32 struct spi_emul_data *data = dev->data;
33
34 return data->config;
35 }
36
37 /**
38 * Find an emulator for a SPI bus
39 *
40 * At present only a single emulator is supported on the bus, since we do not
41 * support chip selects, despite there being a chipsel field. It cannot be
42 * implemented until we have a GPIO emulator.
43 *
44 * @param dev SPI emulation controller device
45 * @param chipsel Chip-select value
46 * @return emulator to use
47 * @return NULL if not found
48 */
spi_emul_find(const struct device * dev,unsigned int chipsel)49 static struct spi_emul *spi_emul_find(const struct device *dev, unsigned int chipsel)
50 {
51 struct spi_emul_data *data = dev->data;
52 sys_snode_t *node;
53
54 SYS_SLIST_FOR_EACH_NODE(&data->emuls, node) {
55 struct spi_emul *emul;
56
57 emul = CONTAINER_OF(node, struct spi_emul, node);
58 if (emul->chipsel == chipsel) {
59 return emul;
60 }
61 }
62
63 return NULL;
64 }
65
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)66 static int spi_emul_io(const struct device *dev, const struct spi_config *config,
67 const struct spi_buf_set *tx_bufs, const struct spi_buf_set *rx_bufs)
68 {
69 struct spi_emul *emul;
70 const struct spi_emul_api *api;
71
72 emul = spi_emul_find(dev, config->slave);
73 if (!emul) {
74 return -EIO;
75 }
76
77 api = emul->api;
78 __ASSERT_NO_MSG(emul->api);
79 __ASSERT_NO_MSG(emul->api->io);
80
81 return api->io(emul->target, config, tx_bufs, rx_bufs);
82 }
83
84 /**
85 * Set up a new emulator and add it to the list
86 *
87 * @param dev SPI emulation controller device
88 */
spi_emul_init(const struct device * dev)89 static int spi_emul_init(const struct device *dev)
90 {
91 struct spi_emul_data *data = dev->data;
92
93 sys_slist_init(&data->emuls);
94
95 return emul_init_for_bus(dev);
96 }
97
spi_emul_register(const struct device * dev,struct spi_emul * emul)98 int spi_emul_register(const struct device *dev, struct spi_emul *emul)
99 {
100 struct spi_emul_data *data = dev->data;
101 const char *name = emul->target->dev->name;
102
103 sys_slist_append(&data->emuls, &emul->node);
104
105 LOG_INF("Register emulator '%s' at cs %u\n", name, emul->chipsel);
106
107 return 0;
108 }
109
110 /* Device instantiation */
111
112 static struct spi_driver_api spi_emul_api = {
113 .transceive = spi_emul_io,
114 };
115
116 #define EMUL_LINK_AND_COMMA(node_id) \
117 { \
118 .dev = DEVICE_DT_GET(node_id), \
119 },
120
121 #define SPI_EMUL_INIT(n) \
122 static const struct emul_link_for_bus emuls_##n[] = { DT_FOREACH_CHILD( \
123 DT_DRV_INST(0), EMUL_LINK_AND_COMMA) }; \
124 static struct emul_list_for_bus spi_emul_cfg_##n = { \
125 .children = emuls_##n, \
126 .num_children = ARRAY_SIZE(emuls_##n), \
127 }; \
128 static struct spi_emul_data spi_emul_data_##n; \
129 DEVICE_DT_INST_DEFINE(n, spi_emul_init, NULL, &spi_emul_data_##n, &spi_emul_cfg_##n, \
130 POST_KERNEL, CONFIG_SPI_INIT_PRIORITY, &spi_emul_api);
131
132 DT_INST_FOREACH_STATUS_OKAY(SPI_EMUL_INIT)
133
