/*
 * 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");