text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * AD5671R, AD5675R, AD5691R, AD5692R, AD5693, AD5693R,
   * AD5694, AD5694R, AD5695R, AD5696, AD5696R
   * Digital to analog converters driver
   *
   * Copyright 2018 Analog Devices Inc.
   */
  
  #include "ad5686.h"
  
  #include <linux/module.h>
  #include <linux/i2c.h>
  
  static int ad5686_i2c_read(struct ad5686_state *st, u8 addr)
  {
  	struct i2c_client *i2c = to_i2c_client(st->dev);
  	struct i2c_msg msg[2] = {
  		{
  			.addr = i2c->addr,
  			.flags = i2c->flags,
  			.len = 3,
  			.buf = &st->data[0].d8[1],
  		},
  		{
  			.addr = i2c->addr,
  			.flags = i2c->flags | I2C_M_RD,
  			.len = 2,
  			.buf = (char *)&st->data[0].d16,
  		},
  	};
  	int ret;
  
  	st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP) |
  				      AD5686_ADDR(addr) |
  				      0x00);
  
  	ret = i2c_transfer(i2c->adapter, msg, 2);
  	if (ret < 0)
  		return ret;
  
  	return be16_to_cpu(st->data[0].d16);
  }
  
  static int ad5686_i2c_write(struct ad5686_state *st,
  			    u8 cmd, u8 addr, u16 val)
  {
  	struct i2c_client *i2c = to_i2c_client(st->dev);
  	int ret;
  
  	st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) | AD5686_ADDR(addr)
  				      | val);
  
  	ret = i2c_master_send(i2c, &st->data[0].d8[1], 3);
  	if (ret < 0)
  		return ret;
  
  	return (ret != 3) ? -EIO : 0;
  }
  
  static int ad5686_i2c_probe(struct i2c_client *i2c,
  			    const struct i2c_device_id *id)
  {
  	return ad5686_probe(&i2c->dev, id->driver_data, id->name,
  			    ad5686_i2c_write, ad5686_i2c_read);
  }
  
  static int ad5686_i2c_remove(struct i2c_client *i2c)
  {
  	return ad5686_remove(&i2c->dev);
  }
  
  static const struct i2c_device_id ad5686_i2c_id[] = {
  	{"ad5671r", ID_AD5671R},
  	{"ad5675r", ID_AD5675R},
  	{"ad5691r", ID_AD5691R},
  	{"ad5692r", ID_AD5692R},
  	{"ad5693", ID_AD5693},
  	{"ad5693r", ID_AD5693R},
  	{"ad5694", ID_AD5694},
  	{"ad5694r", ID_AD5694R},
  	{"ad5695r", ID_AD5695R},
  	{"ad5696", ID_AD5696},
  	{"ad5696r", ID_AD5696R},
  	{}
  };
  MODULE_DEVICE_TABLE(i2c, ad5686_i2c_id);
  
  static struct i2c_driver ad5686_i2c_driver = {
  	.driver = {
  		.name = "ad5696",
  	},
  	.probe = ad5686_i2c_probe,
  	.remove = ad5686_i2c_remove,
  	.id_table = ad5686_i2c_id,
  };
  
  module_i2c_driver(ad5686_i2c_driver);
  
  MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
  MODULE_DESCRIPTION("Analog Devices AD5686 and similar multi-channel DACs");
  MODULE_LICENSE("GPL v2");
  