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-rw-r--r--drivers/i2c/i2c-slave-testunit.c182
1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-slave-testunit.c b/drivers/i2c/i2c-slave-testunit.c
new file mode 100644
index 000000000..75ee7ebdb
--- /dev/null
+++ b/drivers/i2c/i2c-slave-testunit.c
@@ -0,0 +1,182 @@
+// 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_CMD_SMBUS_BLOCK_PROC_CALL,
+ 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);
+ bool is_proc_call = tu->reg_idx == 3 && tu->regs[TU_REG_DATAL] == 1 &&
+ tu->regs[TU_REG_CMD] == TU_CMD_SMBUS_BLOCK_PROC_CALL;
+ 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:
+ memset(tu->regs, 0, TU_NUM_REGS);
+ tu->reg_idx = 0;
+ break;
+
+ case I2C_SLAVE_READ_PROCESSED:
+ if (is_proc_call && tu->regs[TU_REG_DATAH])
+ tu->regs[TU_REG_DATAH]--;
+ fallthrough;
+
+ case I2C_SLAVE_READ_REQUESTED:
+ *val = is_proc_call ? tu->regs[TU_REG_DATAH] : 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 void 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);
+}
+
+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");