Quelle  i2c-ljca.c   Sprache: C

// 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 target_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] = (target_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)
{
 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 target_addr, u8 *data,
    u8 len)
{
 int ret;

 ret = ljca_i2c_start(ljca_i2c, target_addr, LJCA_I2C_READ_XFER_TYPE);
 if (!ret)
  ret = ljca_i2c_pure_read(ljca_i2c, data, len);

 ljca_i2c_stop(ljca_i2c);

 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 target_addr,
     u8 *data, u8 len)
{
 int ret;

 ret = ljca_i2c_start(ljca_i2c, target_addr, LJCA_I2C_WRITE_XFER_TYPE);
 if (!ret)
  ret = ljca_i2c_pure_write(ljca_i2c, data, len);

 ljca_i2c_stop(ljca_i2c);

 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 = {
 .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 ");
MODULE_AUTHOR("Zhifeng Wang ");
MODULE_AUTHOR("Lixu Zhang ");
MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB-I2C driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("LJCA");