/*
   * Hardware monitoring driver for ucd9200 series Digital PWM System Controllers
   *
   * Copyright (C) 2011 Ericsson AB.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/slab.h>
  #include <linux/i2c.h>
  #include <linux/i2c/pmbus.h>
  #include "pmbus.h"
  
  #define UCD9200_PHASE_INFO	0xd2
  #define UCD9200_DEVICE_ID	0xfd
  
  enum chips { ucd9200, ucd9220, ucd9222, ucd9224, ucd9240, ucd9244, ucd9246,
  	     ucd9248 };
  
  static const struct i2c_device_id ucd9200_id[] = {
  	{"ucd9200", ucd9200},
  	{"ucd9220", ucd9220},
  	{"ucd9222", ucd9222},
  	{"ucd9224", ucd9224},
  	{"ucd9240", ucd9240},
  	{"ucd9244", ucd9244},
  	{"ucd9246", ucd9246},
  	{"ucd9248", ucd9248},
  	{}
  };
  MODULE_DEVICE_TABLE(i2c, ucd9200_id);
  
  static int ucd9200_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
  	struct pmbus_driver_info *info;
  	const struct i2c_device_id *mid;
  	int i, j, ret;
  
  	if (!i2c_check_functionality(client->adapter,
  				     I2C_FUNC_SMBUS_BYTE_DATA |
  				     I2C_FUNC_SMBUS_BLOCK_DATA))
  		return -ENODEV;
  
  	ret = i2c_smbus_read_block_data(client, UCD9200_DEVICE_ID,
  					block_buffer);
  	if (ret < 0) {
  		dev_err(&client->dev, "Failed to read device ID
  ");
  		return ret;
  	}
  	block_buffer[ret] = '\0';
  	dev_info(&client->dev, "Device ID %s
  ", block_buffer);
  
  	for (mid = ucd9200_id; mid->name[0]; mid++) {
  		if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
  			break;
  	}
  	if (!mid->name[0]) {
  		dev_err(&client->dev, "Unsupported device
  ");
  		return -ENODEV;
  	}
  	if (id->driver_data != ucd9200 && id->driver_data != mid->driver_data)
  		dev_notice(&client->dev,
  			   "Device mismatch: Configured %s, detected %s
  ",
  			   id->name, mid->name);
  
  	info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
  			    GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  
  	ret = i2c_smbus_read_block_data(client, UCD9200_PHASE_INFO,
  					block_buffer);
  	if (ret < 0) {
  		dev_err(&client->dev, "Failed to read phase information
  ");
  		return ret;
  	}
  
  	/*
  	 * Calculate number of configured pages (rails) from PHASE_INFO
  	 * register.
  	 * Rails have to be sequential, so we can abort after finding
  	 * the first unconfigured rail.
  	 */
  	info->pages = 0;
  	for (i = 0; i < ret; i++) {
  		if (!block_buffer[i])
  			break;
  		info->pages++;
  	}
  	if (!info->pages) {
  		dev_err(&client->dev, "No rails configured
  ");
  		return -ENODEV;
  	}
  	dev_info(&client->dev, "%d rails configured
  ", info->pages);
  
  	/*
  	 * Set PHASE registers on all pages to 0xff to ensure that phase
  	 * specific commands will apply to all phases of a given page (rail).
  	 * This only affects the READ_IOUT and READ_TEMPERATURE2 registers.
  	 * READ_IOUT will return the sum of currents of all phases of a rail,
  	 * and READ_TEMPERATURE2 will return the maximum temperature detected
  	 * for the the phases of the rail.
  	 */
  	for (i = 0; i < info->pages; i++) {
  		/*
  		 * Setting PAGE & PHASE fails once in a while for no obvious
  		 * reason, so we need to retry a couple of times.
  		 */
  		for (j = 0; j < 3; j++) {
  			ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
  			if (ret < 0)
  				continue;
  			ret = i2c_smbus_write_byte_data(client, PMBUS_PHASE,
  							0xff);
  			if (ret < 0)
  				continue;
  			break;
  		}
  		if (ret < 0) {
  			dev_err(&client->dev,
  				"Failed to initialize PHASE registers
  ");
  			return ret;
  		}
  	}
  	if (info->pages > 1)
  		i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
  
  	info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
  			PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
  			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
  			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
  			PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP |
  			PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
  
  	for (i = 1; i < info->pages; i++)
  		info->func[i] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
  			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
  			PMBUS_HAVE_POUT |
  			PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
  
  	/* ucd9240 supports a single fan */
  	if (mid->driver_data == ucd9240)
  		info->func[0] |= PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12;
  
  	return pmbus_do_probe(client, mid, info);
  }
  
  /* This is the driver that will be inserted */
  static struct i2c_driver ucd9200_driver = {
  	.driver = {
  		.name = "ucd9200",
  	},
  	.probe = ucd9200_probe,
  	.remove = pmbus_do_remove,
  	.id_table = ucd9200_id,
  };
  
  module_i2c_driver(ucd9200_driver);
  
  MODULE_AUTHOR("Guenter Roeck");
  MODULE_DESCRIPTION("PMBus driver for TI UCD922x, UCD924x");
  MODULE_LICENSE("GPL");