/*
   * Hardware monitoring driver for PMBus devices
   *
   * Copyright (c) 2010, 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/mutex.h>
  #include <linux/i2c.h>
  #include "pmbus.h"
  
  /*
   * Find sensor groups and status registers on each page.
   */
  static void pmbus_find_sensor_groups(struct i2c_client *client,
  				     struct pmbus_driver_info *info)
  {
  	int page;
  
  	/* Sensors detected on page 0 only */
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_VIN))
  		info->func[0] |= PMBUS_HAVE_VIN;
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_VCAP))
  		info->func[0] |= PMBUS_HAVE_VCAP;
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_IIN))
  		info->func[0] |= PMBUS_HAVE_IIN;
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_PIN))
  		info->func[0] |= PMBUS_HAVE_PIN;
  	if (info->func[0]
  	    && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
  		info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
  	if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
  	    pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
  		info->func[0] |= PMBUS_HAVE_FAN12;
  		if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
  			info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
  	}
  	if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
  	    pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
  		info->func[0] |= PMBUS_HAVE_FAN34;
  		if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
  			info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
  	}
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_TEMPERATURE_1))
  		info->func[0] |= PMBUS_HAVE_TEMP;
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_TEMPERATURE_2))
  		info->func[0] |= PMBUS_HAVE_TEMP2;
  	if (pmbus_check_word_register(client, 0, PMBUS_READ_TEMPERATURE_3))
  		info->func[0] |= PMBUS_HAVE_TEMP3;
  	if (info->func[0] & (PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
  			     | PMBUS_HAVE_TEMP3)
  	    && pmbus_check_byte_register(client, 0,
  					 PMBUS_STATUS_TEMPERATURE))
  			info->func[0] |= PMBUS_HAVE_STATUS_TEMP;
  
  	/* Sensors detected on all pages */
  	for (page = 0; page < info->pages; page++) {
  		if (pmbus_check_word_register(client, page, PMBUS_READ_VOUT)) {
  			info->func[page] |= PMBUS_HAVE_VOUT;
  			if (pmbus_check_byte_register(client, page,
  						      PMBUS_STATUS_VOUT))
  				info->func[page] |= PMBUS_HAVE_STATUS_VOUT;
  		}
  		if (pmbus_check_word_register(client, page, PMBUS_READ_IOUT)) {
  			info->func[page] |= PMBUS_HAVE_IOUT;
  			if (pmbus_check_byte_register(client, 0,
  						      PMBUS_STATUS_IOUT))
  				info->func[page] |= PMBUS_HAVE_STATUS_IOUT;
  		}
  		if (pmbus_check_word_register(client, page, PMBUS_READ_POUT))
  			info->func[page] |= PMBUS_HAVE_POUT;
  	}
  }
  
  /*
   * Identify chip parameters.
   */
  static int pmbus_identify(struct i2c_client *client,
  			  struct pmbus_driver_info *info)
  {
  	int ret = 0;
  
  	if (!info->pages) {
  		/*
  		 * Check if the PAGE command is supported. If it is,
  		 * keep setting the page number until it fails or until the
  		 * maximum number of pages has been reached. Assume that
  		 * this is the number of pages supported by the chip.
  		 */
  		if (pmbus_check_byte_register(client, 0, PMBUS_PAGE)) {
  			int page;
  
  			for (page = 1; page < PMBUS_PAGES; page++) {
  				if (pmbus_set_page(client, page) < 0)
  					break;
  			}
  			pmbus_set_page(client, 0);
  			info->pages = page;
  		} else {
  			info->pages = 1;
  		}
  	}
  
  	if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE)) {
  		int vout_mode;
  
  		vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);
  		if (vout_mode >= 0 && vout_mode != 0xff) {
  			switch (vout_mode >> 5) {
  			case 0:
  				break;
  			case 1:
  				info->format[PSC_VOLTAGE_OUT] = vid;
  				break;
  			case 2:
  				info->format[PSC_VOLTAGE_OUT] = direct;
  				break;
  			default:
  				ret = -ENODEV;
  				goto abort;
  			}
  		}
  	}
  
  	/*
  	 * We should check if the COEFFICIENTS register is supported.
  	 * If it is, and the chip is configured for direct mode, we can read
  	 * the coefficients from the chip, one set per group of sensor
  	 * registers.
  	 *
  	 * To do this, we will need access to a chip which actually supports the
  	 * COEFFICIENTS command, since the command is too complex to implement
  	 * without testing it. Until then, abort if a chip configured for direct
  	 * mode was detected.
  	 */
  	if (info->format[PSC_VOLTAGE_OUT] == direct) {
  		ret = -ENODEV;
  		goto abort;
  	}
  
  	/* Try to find sensor groups  */
  	pmbus_find_sensor_groups(client, info);
  abort:
  	return ret;
  }
  
  static int pmbus_probe(struct i2c_client *client,
  		       const struct i2c_device_id *id)
  {
  	struct pmbus_driver_info *info;
  
  	info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
  			    GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  
  	info->pages = id->driver_data;
  	info->identify = pmbus_identify;
  
  	return pmbus_do_probe(client, id, info);
  }
  
  /*
   * Use driver_data to set the number of pages supported by the chip.
   */
  static const struct i2c_device_id pmbus_id[] = {
  	{"adp4000", 1},
  	{"bmr453", 1},
  	{"bmr454", 1},
  	{"mdt040", 1},
  	{"ncp4200", 1},
  	{"ncp4208", 1},
  	{"pdt003", 1},
  	{"pdt006", 1},
  	{"pdt012", 1},
  	{"pmbus", 0},
  	{"tps40400", 1},
  	{"tps40422", 2},
  	{"udt020", 1},
  	{}
  };
  
  MODULE_DEVICE_TABLE(i2c, pmbus_id);
  
  /* This is the driver that will be inserted */
  static struct i2c_driver pmbus_driver = {
  	.driver = {
  		   .name = "pmbus",
  		   },
  	.probe = pmbus_probe,
  	.remove = pmbus_do_remove,
  	.id_table = pmbus_id,
  };
  
  module_i2c_driver(pmbus_driver);
  
  MODULE_AUTHOR("Guenter Roeck");
  MODULE_DESCRIPTION("Generic PMBus driver");
  MODULE_LICENSE("GPL");