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![Wolfram Sang](/assets/img/avatar_default.png)
Devices offering SMBus block process calls are rare, so add it to the testunit. This is also a good test case for testing proper I2C_M_RECV_LEN flag handling of I2C bus masters emulating SMBus. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@kernel.org>
183 lines
4.2 KiB
C
183 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* I2C slave mode testunit
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*
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* Copyright (C) 2020 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
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* Copyright (C) 2020 by Renesas Electronics Corporation
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*/
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#include <linux/bitops.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h> /* FIXME: is system_long_wq the best choice? */
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#define TU_CUR_VERSION 0x01
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enum testunit_cmds {
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TU_CMD_READ_BYTES = 1, /* save 0 for ABORT, RESET or similar */
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TU_CMD_HOST_NOTIFY,
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TU_CMD_SMBUS_BLOCK_PROC_CALL,
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TU_NUM_CMDS
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};
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enum testunit_regs {
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TU_REG_CMD,
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TU_REG_DATAL,
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TU_REG_DATAH,
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TU_REG_DELAY,
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TU_NUM_REGS
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};
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enum testunit_flags {
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TU_FLAG_IN_PROCESS,
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};
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struct testunit_data {
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unsigned long flags;
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u8 regs[TU_NUM_REGS];
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u8 reg_idx;
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struct i2c_client *client;
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struct delayed_work worker;
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};
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static void i2c_slave_testunit_work(struct work_struct *work)
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{
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struct testunit_data *tu = container_of(work, struct testunit_data, worker.work);
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struct i2c_msg msg;
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u8 msgbuf[256];
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int ret = 0;
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msg.addr = I2C_CLIENT_END;
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msg.buf = msgbuf;
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switch (tu->regs[TU_REG_CMD]) {
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case TU_CMD_READ_BYTES:
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msg.addr = tu->regs[TU_REG_DATAL];
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msg.flags = I2C_M_RD;
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msg.len = tu->regs[TU_REG_DATAH];
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break;
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case TU_CMD_HOST_NOTIFY:
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msg.addr = 0x08;
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msg.flags = 0;
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msg.len = 3;
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msgbuf[0] = tu->client->addr;
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msgbuf[1] = tu->regs[TU_REG_DATAL];
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msgbuf[2] = tu->regs[TU_REG_DATAH];
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break;
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default:
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break;
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}
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if (msg.addr != I2C_CLIENT_END) {
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ret = i2c_transfer(tu->client->adapter, &msg, 1);
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/* convert '0 msgs transferred' to errno */
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ret = (ret == 0) ? -EIO : ret;
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}
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if (ret < 0)
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dev_err(&tu->client->dev, "CMD%02X failed (%d)\n", tu->regs[TU_REG_CMD], ret);
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clear_bit(TU_FLAG_IN_PROCESS, &tu->flags);
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}
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static int i2c_slave_testunit_slave_cb(struct i2c_client *client,
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enum i2c_slave_event event, u8 *val)
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{
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struct testunit_data *tu = i2c_get_clientdata(client);
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bool is_proc_call = tu->reg_idx == 3 && tu->regs[TU_REG_DATAL] == 1 &&
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tu->regs[TU_REG_CMD] == TU_CMD_SMBUS_BLOCK_PROC_CALL;
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int ret = 0;
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switch (event) {
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case I2C_SLAVE_WRITE_RECEIVED:
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if (test_bit(TU_FLAG_IN_PROCESS, &tu->flags))
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return -EBUSY;
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if (tu->reg_idx < TU_NUM_REGS)
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tu->regs[tu->reg_idx] = *val;
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else
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ret = -EMSGSIZE;
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if (tu->reg_idx <= TU_NUM_REGS)
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tu->reg_idx++;
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/* TU_REG_CMD always written at this point */
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if (tu->regs[TU_REG_CMD] >= TU_NUM_CMDS)
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ret = -EINVAL;
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break;
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case I2C_SLAVE_STOP:
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if (tu->reg_idx == TU_NUM_REGS) {
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set_bit(TU_FLAG_IN_PROCESS, &tu->flags);
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queue_delayed_work(system_long_wq, &tu->worker,
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msecs_to_jiffies(10 * tu->regs[TU_REG_DELAY]));
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}
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fallthrough;
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case I2C_SLAVE_WRITE_REQUESTED:
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memset(tu->regs, 0, TU_NUM_REGS);
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tu->reg_idx = 0;
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break;
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case I2C_SLAVE_READ_PROCESSED:
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if (is_proc_call && tu->regs[TU_REG_DATAH])
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tu->regs[TU_REG_DATAH]--;
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fallthrough;
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case I2C_SLAVE_READ_REQUESTED:
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*val = is_proc_call ? tu->regs[TU_REG_DATAH] : TU_CUR_VERSION;
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break;
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}
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return ret;
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}
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static int i2c_slave_testunit_probe(struct i2c_client *client)
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{
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struct testunit_data *tu;
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tu = devm_kzalloc(&client->dev, sizeof(struct testunit_data), GFP_KERNEL);
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if (!tu)
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return -ENOMEM;
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tu->client = client;
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i2c_set_clientdata(client, tu);
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INIT_DELAYED_WORK(&tu->worker, i2c_slave_testunit_work);
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return i2c_slave_register(client, i2c_slave_testunit_slave_cb);
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};
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static int i2c_slave_testunit_remove(struct i2c_client *client)
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{
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struct testunit_data *tu = i2c_get_clientdata(client);
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cancel_delayed_work_sync(&tu->worker);
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i2c_slave_unregister(client);
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return 0;
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}
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static const struct i2c_device_id i2c_slave_testunit_id[] = {
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{ "slave-testunit", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, i2c_slave_testunit_id);
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static struct i2c_driver i2c_slave_testunit_driver = {
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.driver = {
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.name = "i2c-slave-testunit",
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},
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.probe_new = i2c_slave_testunit_probe,
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.remove = i2c_slave_testunit_remove,
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.id_table = i2c_slave_testunit_id,
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};
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module_i2c_driver(i2c_slave_testunit_driver);
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MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
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MODULE_DESCRIPTION("I2C slave mode test unit");
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MODULE_LICENSE("GPL v2");
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