--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel La Jolla Cove Adapter USB-I2C driver
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/usb/ljca.h>
+
+/* I2C init flags */
+#define LJCA_I2C_INIT_FLAG_MODE BIT(0)
+#define LJCA_I2C_INIT_FLAG_MODE_POLLING FIELD_PREP(LJCA_I2C_INIT_FLAG_MODE, 0)
+#define LJCA_I2C_INIT_FLAG_MODE_INTERRUPT FIELD_PREP(LJCA_I2C_INIT_FLAG_MODE, 1)
+
+#define LJCA_I2C_INIT_FLAG_ADDR_16BIT BIT(0)
+
+#define LJCA_I2C_INIT_FLAG_FREQ GENMASK(2, 1)
+#define LJCA_I2C_INIT_FLAG_FREQ_100K FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 0)
+#define LJCA_I2C_INIT_FLAG_FREQ_400K FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 1)
+#define LJCA_I2C_INIT_FLAG_FREQ_1M FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 2)
+
+#define LJCA_I2C_BUF_SIZE 60u
+#define LJCA_I2C_MAX_XFER_SIZE (LJCA_I2C_BUF_SIZE - sizeof(struct ljca_i2c_rw_packet))
+
+/* I2C commands */
+enum ljca_i2c_cmd {
+ LJCA_I2C_INIT = 1,
+ LJCA_I2C_XFER,
+ LJCA_I2C_START,
+ LJCA_I2C_STOP,
+ LJCA_I2C_READ,
+ LJCA_I2C_WRITE,
+};
+
+enum ljca_xfer_type {
+ LJCA_I2C_WRITE_XFER_TYPE,
+ LJCA_I2C_READ_XFER_TYPE,
+};
+
+/* I2C raw commands: Init/Start/Read/Write/Stop */
+struct ljca_i2c_rw_packet {
+ u8 id;
+ __le16 len;
+ u8 data[] __counted_by(len);
+} __packed;
+
+struct ljca_i2c_dev {
+ struct ljca_client *ljca;
+ struct ljca_i2c_info *i2c_info;
+ struct i2c_adapter adap;
+
+ u8 obuf[LJCA_I2C_BUF_SIZE];
+ u8 ibuf[LJCA_I2C_BUF_SIZE];
+};
+
+static int ljca_i2c_init(struct ljca_i2c_dev *ljca_i2c, u8 id)
+{
+ struct ljca_i2c_rw_packet *w_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
+ int ret;
+
+ w_packet->id = id;
+ w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
+ w_packet->data[0] = LJCA_I2C_INIT_FLAG_FREQ_400K;
+
+ ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_INIT, (u8 *)w_packet,
+ struct_size(w_packet, data, 1), NULL, 0);
+
+ return ret < 0 ? ret : 0;
+}
+
+static int ljca_i2c_start(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr,
+ enum ljca_xfer_type type)
+{
+ struct ljca_i2c_rw_packet *w_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
+ struct ljca_i2c_rw_packet *r_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
+ s16 rp_len;
+ int ret;
+
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
+ w_packet->data[0] = (slave_addr << 1) | type;
+
+ ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_START, (u8 *)w_packet,
+ struct_size(w_packet, data, 1), (u8 *)r_packet,
+ LJCA_I2C_BUF_SIZE);
+ if (ret < 0 || ret < sizeof(*r_packet))
+ return ret < 0 ? ret : -EIO;
+
+ rp_len = le16_to_cpu(r_packet->len);
+ if (rp_len < 0 || r_packet->id != w_packet->id) {
+ dev_dbg(&ljca_i2c->adap.dev,
+ "i2c start failed len: %d id: %d %d\n",
+ rp_len, r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void ljca_i2c_stop(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr)
+{
+ struct ljca_i2c_rw_packet *w_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
+ struct ljca_i2c_rw_packet *r_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
+ s16 rp_len;
+ int ret;
+
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
+ w_packet->data[0] = 0;
+
+ ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_STOP, (u8 *)w_packet,
+ struct_size(w_packet, data, 1), (u8 *)r_packet,
+ LJCA_I2C_BUF_SIZE);
+ if (ret < 0 || ret < sizeof(*r_packet)) {
+ dev_dbg(&ljca_i2c->adap.dev,
+ "i2c stop failed ret: %d id: %d\n",
+ ret, w_packet->id);
+ return;
+ }
+
+ rp_len = le16_to_cpu(r_packet->len);
+ if (rp_len < 0 || r_packet->id != w_packet->id)
+ dev_dbg(&ljca_i2c->adap.dev,
+ "i2c stop failed len: %d id: %d %d\n",
+ rp_len, r_packet->id, w_packet->id);
+}
+
+static int ljca_i2c_pure_read(struct ljca_i2c_dev *ljca_i2c, u8 *data, u8 len)
+{
+ struct ljca_i2c_rw_packet *w_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
+ struct ljca_i2c_rw_packet *r_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
+ s16 rp_len;
+ int ret;
+
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->len = cpu_to_le16(len);
+ w_packet->data[0] = 0;
+
+ ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_READ, (u8 *)w_packet,
+ struct_size(w_packet, data, 1), (u8 *)r_packet,
+ LJCA_I2C_BUF_SIZE);
+ if (ret < 0 || ret < sizeof(*r_packet))
+ return ret < 0 ? ret : -EIO;
+
+ rp_len = le16_to_cpu(r_packet->len);
+ if (rp_len != len || r_packet->id != w_packet->id) {
+ dev_dbg(&ljca_i2c->adap.dev,
+ "i2c raw read failed len: %d id: %d %d\n",
+ rp_len, r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ memcpy(data, r_packet->data, len);
+
+ return 0;
+}
+
+static int ljca_i2c_read(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr, u8 *data,
+ u8 len)
+{
+ int ret;
+
+ ret = ljca_i2c_start(ljca_i2c, slave_addr, LJCA_I2C_READ_XFER_TYPE);
+ if (!ret)
+ ret = ljca_i2c_pure_read(ljca_i2c, data, len);
+
+ ljca_i2c_stop(ljca_i2c, slave_addr);
+
+ return ret;
+}
+
+static int ljca_i2c_pure_write(struct ljca_i2c_dev *ljca_i2c, u8 *data, u8 len)
+{
+ struct ljca_i2c_rw_packet *w_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->obuf;
+ struct ljca_i2c_rw_packet *r_packet =
+ (struct ljca_i2c_rw_packet *)ljca_i2c->ibuf;
+ s16 rplen;
+ int ret;
+
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->len = cpu_to_le16(len);
+ memcpy(w_packet->data, data, len);
+
+ ret = ljca_transfer(ljca_i2c->ljca, LJCA_I2C_WRITE, (u8 *)w_packet,
+ struct_size(w_packet, data, len), (u8 *)r_packet,
+ LJCA_I2C_BUF_SIZE);
+ if (ret < 0 || ret < sizeof(*r_packet))
+ return ret < 0 ? ret : -EIO;
+
+ rplen = le16_to_cpu(r_packet->len);
+ if (rplen != len || r_packet->id != w_packet->id) {
+ dev_dbg(&ljca_i2c->adap.dev,
+ "i2c write failed len: %d id: %d/%d\n",
+ rplen, r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ljca_i2c_write(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr,
+ u8 *data, u8 len)
+{
+ int ret;
+
+ ret = ljca_i2c_start(ljca_i2c, slave_addr, LJCA_I2C_WRITE_XFER_TYPE);
+ if (!ret)
+ ret = ljca_i2c_pure_write(ljca_i2c, data, len);
+
+ ljca_i2c_stop(ljca_i2c, slave_addr);
+
+ return ret;
+}
+
+static int ljca_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msg,
+ int num)
+{
+ struct ljca_i2c_dev *ljca_i2c;
+ struct i2c_msg *cur_msg;
+ int i, ret;
+
+ ljca_i2c = i2c_get_adapdata(adapter);
+ if (!ljca_i2c)
+ return -EINVAL;
+
+ for (i = 0; i < num; i++) {
+ cur_msg = &msg[i];
+ if (cur_msg->flags & I2C_M_RD)
+ ret = ljca_i2c_read(ljca_i2c, cur_msg->addr,
+ cur_msg->buf, cur_msg->len);
+ else
+ ret = ljca_i2c_write(ljca_i2c, cur_msg->addr,
+ cur_msg->buf, cur_msg->len);
+
+ if (ret)
+ return ret;
+ }
+
+ return num;
+}
+
+static u32 ljca_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static const struct i2c_adapter_quirks ljca_i2c_quirks = {
+ .flags = I2C_AQ_NO_ZERO_LEN,
+ .max_read_len = LJCA_I2C_MAX_XFER_SIZE,
+ .max_write_len = LJCA_I2C_MAX_XFER_SIZE,
+};
+
+static const struct i2c_algorithm ljca_i2c_algo = {
+ .master_xfer = ljca_i2c_xfer,
+ .functionality = ljca_i2c_func,
+};
+
+static int ljca_i2c_probe(struct auxiliary_device *auxdev,
+ const struct auxiliary_device_id *aux_dev_id)
+{
+ struct ljca_client *ljca = auxiliary_dev_to_ljca_client(auxdev);
+ struct ljca_i2c_dev *ljca_i2c;
+ int ret;
+
+ ljca_i2c = devm_kzalloc(&auxdev->dev, sizeof(*ljca_i2c), GFP_KERNEL);
+ if (!ljca_i2c)
+ return -ENOMEM;
+
+ ljca_i2c->ljca = ljca;
+ ljca_i2c->i2c_info = dev_get_platdata(&auxdev->dev);
+
+ ljca_i2c->adap.owner = THIS_MODULE;
+ ljca_i2c->adap.class = I2C_CLASS_HWMON;
+ ljca_i2c->adap.algo = &ljca_i2c_algo;
+ ljca_i2c->adap.quirks = &ljca_i2c_quirks;
+ ljca_i2c->adap.dev.parent = &auxdev->dev;
+
+ snprintf(ljca_i2c->adap.name, sizeof(ljca_i2c->adap.name), "%s-%s-%d",
+ dev_name(&auxdev->dev), dev_name(auxdev->dev.parent),
+ ljca_i2c->i2c_info->id);
+
+ device_set_node(&ljca_i2c->adap.dev, dev_fwnode(&auxdev->dev));
+
+ i2c_set_adapdata(&ljca_i2c->adap, ljca_i2c);
+ auxiliary_set_drvdata(auxdev, ljca_i2c);
+
+ ret = ljca_i2c_init(ljca_i2c, ljca_i2c->i2c_info->id);
+ if (ret)
+ return dev_err_probe(&auxdev->dev, -EIO,
+ "i2c init failed id: %d\n",
+ ljca_i2c->i2c_info->id);
+
+ ret = devm_i2c_add_adapter(&auxdev->dev, &ljca_i2c->adap);
+ if (ret)
+ return ret;
+
+ if (has_acpi_companion(&ljca_i2c->adap.dev))
+ acpi_dev_clear_dependencies(ACPI_COMPANION(&ljca_i2c->adap.dev));
+
+ return 0;
+}
+
+static void ljca_i2c_remove(struct auxiliary_device *auxdev)
+{
+ struct ljca_i2c_dev *ljca_i2c = auxiliary_get_drvdata(auxdev);
+
+ i2c_del_adapter(&ljca_i2c->adap);
+}
+
+static const struct auxiliary_device_id ljca_i2c_id_table[] = {
+ { "usb_ljca.ljca-i2c", 0 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(auxiliary, ljca_i2c_id_table);
+
+static struct auxiliary_driver ljca_i2c_driver = {
+ .probe = ljca_i2c_probe,
+ .remove = ljca_i2c_remove,
+ .id_table = ljca_i2c_id_table,
+};
+module_auxiliary_driver(ljca_i2c_driver);
+
+MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
+MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
+MODULE_AUTHOR("Lixu Zhang <lixu.zhang@intel.com>");
+MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB-I2C driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(LJCA);
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