zl6100.c

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/*
 * Hardware monitoring driver for ZL6100 and compatibles
 *
 * 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/ktime.h>
#include <linux/delay.h>
#include "pmbus.h"

enum chips { zl2004, zl2005, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105,
         zl9101, zl9117 };

struct zl6100_data {
    int id;
    ktime_t access;     /* chip access time */
    int delay;      /* Delay between chip accesses in uS */
    struct pmbus_driver_info info;
};

#define to_zl6100_data(x)  container_of(x, struct zl6100_data, info)

#define ZL6100_MFR_CONFIG       0xd0
#define ZL6100_DEVICE_ID        0xe4

#define ZL6100_MFR_XTEMP_ENABLE     (1 << 7)

#define ZL6100_WAIT_TIME        1000    /* uS   */

static ushort delay = ZL6100_WAIT_TIME;
module_param(delay, ushort, 0644);
MODULE_PARM_DESC(delay, "Delay between chip accesses in uS");

/* Some chips need a delay between accesses */
static inline void zl6100_wait(const struct zl6100_data *data)
{
    if (data->delay) {
        s64 delta = ktime_us_delta(ktime_get(), data->access);
        if (delta < data->delay)
            udelay(data->delay - delta);
    }
}

static int zl6100_read_word_data(struct i2c_client *client, int page, int reg)
{
    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
    struct zl6100_data *data = to_zl6100_data(info);
    int ret;

    if (page || reg >= PMBUS_VIRT_BASE)
        return -ENXIO;

    if (data->id == zl2005) {
        /*
         * Limit register detection is not reliable on ZL2005.
         * Make sure registers are not erroneously detected.
         */
        switch (reg) {
        case PMBUS_VOUT_OV_WARN_LIMIT:
        case PMBUS_VOUT_UV_WARN_LIMIT:
        case PMBUS_IOUT_OC_WARN_LIMIT:
            return -ENXIO;
        }
    }

    zl6100_wait(data);
    ret = pmbus_read_word_data(client, page, reg);
    data->access = ktime_get();

    return ret;
}

static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
{
    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
    struct zl6100_data *data = to_zl6100_data(info);
    int ret;

    if (page > 0)
        return -ENXIO;

    zl6100_wait(data);
    ret = pmbus_read_byte_data(client, page, reg);
    data->access = ktime_get();

    return ret;
}

static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
                  u16 word)
{
    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
    struct zl6100_data *data = to_zl6100_data(info);
    int ret;

    if (page || reg >= PMBUS_VIRT_BASE)
        return -ENXIO;

    zl6100_wait(data);
    ret = pmbus_write_word_data(client, page, reg, word);
    data->access = ktime_get();

    return ret;
}

static int zl6100_write_byte(struct i2c_client *client, int page, u8 value)
{
    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
    struct zl6100_data *data = to_zl6100_data(info);
    int ret;

    if (page > 0)
        return -ENXIO;

    zl6100_wait(data);
    ret = pmbus_write_byte(client, page, value);
    data->access = ktime_get();

    return ret;
}

static const struct i2c_device_id zl6100_id[] = {
    {"bmr450", zl2005},
    {"bmr451", zl2005},
    {"bmr462", zl2008},
    {"bmr463", zl2008},
    {"bmr464", zl2008},
    {"zl2004", zl2004},
    {"zl2005", zl2005},
    {"zl2006", zl2006},
    {"zl2008", zl2008},
    {"zl2105", zl2105},
    {"zl2106", zl2106},
    {"zl6100", zl6100},
    {"zl6105", zl6105},
    {"zl9101", zl9101},
    {"zl9117", zl9117},
    { }
};
MODULE_DEVICE_TABLE(i2c, zl6100_id);

static int zl6100_probe(struct i2c_client *client,
            const struct i2c_device_id *id)
{
    int ret;
    struct zl6100_data *data;
    struct pmbus_driver_info *info;
    u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
    const struct i2c_device_id *mid;

    if (!i2c_check_functionality(client->adapter,
                     I2C_FUNC_SMBUS_READ_WORD_DATA
                     | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
        return -ENODEV;

    ret = i2c_smbus_read_block_data(client, ZL6100_DEVICE_ID,
                    device_id);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to read device ID\n");
        return ret;
    }
    device_id[ret] = '\0';
    dev_info(&client->dev, "Device ID %s\n", device_id);

    mid = NULL;
    for (mid = zl6100_id; mid->name[0]; mid++) {
        if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
            break;
    }
    if (!mid->name[0]) {
        dev_err(&client->dev, "Unsupported device\n");
        return -ENODEV;
    }
    if (id->driver_data != mid->driver_data)
        dev_notice(&client->dev,
               "Device mismatch: Configured %s, detected %s\n",
               id->name, mid->name);

    data = devm_kzalloc(&client->dev, sizeof(struct zl6100_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    data->id = mid->driver_data;

    /*
     * According to information from the chip vendor, all currently
     * supported chips are known to require a wait time between I2C
     * accesses.
     */
    data->delay = delay;

    /*
     * Since there was a direct I2C device access above, wait before
     * accessing the chip again.
     */
    data->access = ktime_get();
    zl6100_wait(data);

    info = &data->info;

    info->pages = 1;
    info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
      | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
      | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
      | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;

    ret = i2c_smbus_read_word_data(client, ZL6100_MFR_CONFIG);
    if (ret < 0)
        return ret;

    if (ret & ZL6100_MFR_XTEMP_ENABLE)
        info->func[0] |= PMBUS_HAVE_TEMP2;

    data->access = ktime_get();
    zl6100_wait(data);

    info->read_word_data = zl6100_read_word_data;
    info->read_byte_data = zl6100_read_byte_data;
    info->write_word_data = zl6100_write_word_data;
    info->write_byte = zl6100_write_byte;

    return pmbus_do_probe(client, mid, info);
}

static struct i2c_driver zl6100_driver = {
    .driver = {
           .name = "zl6100",
           },
    .probe = zl6100_probe,
    .remove = pmbus_do_remove,
    .id_table = zl6100_id,
};

module_i2c_driver(zl6100_driver);

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for ZL6100 and compatibles");
MODULE_LICENSE("GPL");