diff options
Diffstat (limited to 'drivers/i2c/i2c-slave-testunit.c')
| -rw-r--r-- | drivers/i2c/i2c-slave-testunit.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-slave-testunit.c b/drivers/i2c/i2c-slave-testunit.c new file mode 100644 index 000000000000..c288102de324 --- /dev/null +++ b/drivers/i2c/i2c-slave-testunit.c @@ -0,0 +1,175 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * I2C slave mode testunit + * + * Copyright (C) 2020 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com> + * Copyright (C) 2020 by Renesas Electronics Corporation + */ + +#include <linux/bitops.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/workqueue.h> /* FIXME: is system_long_wq the best choice? */ + +#define TU_CUR_VERSION 0x01 + +enum testunit_cmds { + TU_CMD_READ_BYTES = 1, /* save 0 for ABORT, RESET or similar */ + TU_CMD_HOST_NOTIFY, + TU_NUM_CMDS +}; + +enum testunit_regs { + TU_REG_CMD, + TU_REG_DATAL, + TU_REG_DATAH, + TU_REG_DELAY, + TU_NUM_REGS +}; + +enum testunit_flags { + TU_FLAG_IN_PROCESS, +}; + +struct testunit_data { + unsigned long flags; + u8 regs[TU_NUM_REGS]; + u8 reg_idx; + struct i2c_client *client; + struct delayed_work worker; +}; + +static void i2c_slave_testunit_work(struct work_struct *work) +{ + struct testunit_data *tu = container_of(work, struct testunit_data, worker.work); + struct i2c_msg msg; + u8 msgbuf[256]; + int ret = 0; + + msg.addr = I2C_CLIENT_END; + msg.buf = msgbuf; + + switch (tu->regs[TU_REG_CMD]) { + case TU_CMD_READ_BYTES: + msg.addr = tu->regs[TU_REG_DATAL]; + msg.flags = I2C_M_RD; + msg.len = tu->regs[TU_REG_DATAH]; + break; + + case TU_CMD_HOST_NOTIFY: + msg.addr = 0x08; + msg.flags = 0; + msg.len = 3; + msgbuf[0] = tu->client->addr; + msgbuf[1] = tu->regs[TU_REG_DATAL]; + msgbuf[2] = tu->regs[TU_REG_DATAH]; + break; + + default: + break; + } + + if (msg.addr != I2C_CLIENT_END) { + ret = i2c_transfer(tu->client->adapter, &msg, 1); + /* convert '0 msgs transferred' to errno */ + ret = (ret == 0) ? -EIO : ret; + } + + if (ret < 0) + dev_err(&tu->client->dev, "CMD%02X failed (%d)\n", tu->regs[TU_REG_CMD], ret); + + clear_bit(TU_FLAG_IN_PROCESS, &tu->flags); +} + +static int i2c_slave_testunit_slave_cb(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + struct testunit_data *tu = i2c_get_clientdata(client); + int ret = 0; + + switch (event) { + case I2C_SLAVE_WRITE_RECEIVED: + if (test_bit(TU_FLAG_IN_PROCESS, &tu->flags)) + return -EBUSY; + + if (tu->reg_idx < TU_NUM_REGS) + tu->regs[tu->reg_idx] = *val; + else + ret = -EMSGSIZE; + + if (tu->reg_idx <= TU_NUM_REGS) + tu->reg_idx++; + + /* TU_REG_CMD always written at this point */ + if (tu->regs[TU_REG_CMD] >= TU_NUM_CMDS) + ret = -EINVAL; + + break; + + case I2C_SLAVE_STOP: + if (tu->reg_idx == TU_NUM_REGS) { + set_bit(TU_FLAG_IN_PROCESS, &tu->flags); + queue_delayed_work(system_long_wq, &tu->worker, + msecs_to_jiffies(10 * tu->regs[TU_REG_DELAY])); + } + fallthrough; + + case I2C_SLAVE_WRITE_REQUESTED: + tu->reg_idx = 0; + break; + + case I2C_SLAVE_READ_REQUESTED: + case I2C_SLAVE_READ_PROCESSED: + *val = TU_CUR_VERSION; + break; + } + + return ret; +} + +static int i2c_slave_testunit_probe(struct i2c_client *client) +{ + struct testunit_data *tu; + + tu = devm_kzalloc(&client->dev, sizeof(struct testunit_data), GFP_KERNEL); + if (!tu) + return -ENOMEM; + + tu->client = client; + i2c_set_clientdata(client, tu); + INIT_DELAYED_WORK(&tu->worker, i2c_slave_testunit_work); + + return i2c_slave_register(client, i2c_slave_testunit_slave_cb); +}; + +static int i2c_slave_testunit_remove(struct i2c_client *client) +{ + struct testunit_data *tu = i2c_get_clientdata(client); + + cancel_delayed_work_sync(&tu->worker); + i2c_slave_unregister(client); + return 0; +} + +static const struct i2c_device_id i2c_slave_testunit_id[] = { + { "slave-testunit", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, i2c_slave_testunit_id); + +static struct i2c_driver i2c_slave_testunit_driver = { + .driver = { + .name = "i2c-slave-testunit", + }, + .probe_new = i2c_slave_testunit_probe, + .remove = i2c_slave_testunit_remove, + .id_table = i2c_slave_testunit_id, +}; +module_i2c_driver(i2c_slave_testunit_driver); + +MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>"); +MODULE_DESCRIPTION("I2C slave mode test unit"); +MODULE_LICENSE("GPL v2"); |