1 // SPDX-License-Identifier: GPL-2.0-only
3 * I2C slave mode testunit
5 * Copyright (C) 2020 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
6 * Copyright (C) 2020 by Renesas Electronics Corporation
9 #include <linux/bitops.h>
10 #include <linux/i2c.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/workqueue.h> /* FIXME: is system_long_wq the best choice? */
17 #define TU_CUR_VERSION 0x01
20 TU_CMD_READ_BYTES = 1, /* save 0 for ABORT, RESET or similar */
37 struct testunit_data {
41 struct i2c_client *client;
42 struct delayed_work worker;
45 static void i2c_slave_testunit_work(struct work_struct *work)
47 struct testunit_data *tu = container_of(work, struct testunit_data, worker.work);
52 msg.addr = I2C_CLIENT_END;
55 switch (tu->regs[TU_REG_CMD]) {
56 case TU_CMD_READ_BYTES:
57 msg.addr = tu->regs[TU_REG_DATAL];
59 msg.len = tu->regs[TU_REG_DATAH];
62 case TU_CMD_HOST_NOTIFY:
66 msgbuf[0] = tu->client->addr;
67 msgbuf[1] = tu->regs[TU_REG_DATAL];
68 msgbuf[2] = tu->regs[TU_REG_DATAH];
75 if (msg.addr != I2C_CLIENT_END) {
76 ret = i2c_transfer(tu->client->adapter, &msg, 1);
77 /* convert '0 msgs transferred' to errno */
78 ret = (ret == 0) ? -EIO : ret;
82 dev_err(&tu->client->dev, "CMD%02X failed (%d)\n", tu->regs[TU_REG_CMD], ret);
84 clear_bit(TU_FLAG_IN_PROCESS, &tu->flags);
87 static int i2c_slave_testunit_slave_cb(struct i2c_client *client,
88 enum i2c_slave_event event, u8 *val)
90 struct testunit_data *tu = i2c_get_clientdata(client);
94 case I2C_SLAVE_WRITE_RECEIVED:
95 if (test_bit(TU_FLAG_IN_PROCESS, &tu->flags))
98 if (tu->reg_idx < TU_NUM_REGS)
99 tu->regs[tu->reg_idx] = *val;
103 if (tu->reg_idx <= TU_NUM_REGS)
106 /* TU_REG_CMD always written at this point */
107 if (tu->regs[TU_REG_CMD] >= TU_NUM_CMDS)
113 if (tu->reg_idx == TU_NUM_REGS) {
114 set_bit(TU_FLAG_IN_PROCESS, &tu->flags);
115 queue_delayed_work(system_long_wq, &tu->worker,
116 msecs_to_jiffies(10 * tu->regs[TU_REG_DELAY]));
120 case I2C_SLAVE_WRITE_REQUESTED:
124 case I2C_SLAVE_READ_REQUESTED:
125 case I2C_SLAVE_READ_PROCESSED:
126 *val = TU_CUR_VERSION;
133 static int i2c_slave_testunit_probe(struct i2c_client *client)
135 struct testunit_data *tu;
137 tu = devm_kzalloc(&client->dev, sizeof(struct testunit_data), GFP_KERNEL);
142 i2c_set_clientdata(client, tu);
143 INIT_DELAYED_WORK(&tu->worker, i2c_slave_testunit_work);
145 return i2c_slave_register(client, i2c_slave_testunit_slave_cb);
148 static int i2c_slave_testunit_remove(struct i2c_client *client)
150 struct testunit_data *tu = i2c_get_clientdata(client);
152 cancel_delayed_work_sync(&tu->worker);
153 i2c_slave_unregister(client);
157 static const struct i2c_device_id i2c_slave_testunit_id[] = {
158 { "slave-testunit", 0 },
161 MODULE_DEVICE_TABLE(i2c, i2c_slave_testunit_id);
163 static struct i2c_driver i2c_slave_testunit_driver = {
165 .name = "i2c-slave-testunit",
167 .probe_new = i2c_slave_testunit_probe,
168 .remove = i2c_slave_testunit_remove,
169 .id_table = i2c_slave_testunit_id,
171 module_i2c_driver(i2c_slave_testunit_driver);
173 MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
174 MODULE_DESCRIPTION("I2C slave mode test unit");
175 MODULE_LICENSE("GPL v2");