tps65911-comparator.c

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/*
 * tps65910.c  --  TI TPS6591x
 *
 * Copyright 2010 Texas Instruments Inc.
 *
 * Author: Jorge Eduardo Candelaria <[email protected]>
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/debugfs.h>
#include <linux/gpio.h>
#include <linux/mfd/tps65910.h>

#define COMP                    0
#define COMP1                   1
#define COMP2                   2

/* Comparator 1 voltage selection table in millivolts */
static const u16 COMP_VSEL_TABLE[] = {
    0, 2500, 2500, 2500, 2500, 2550, 2600, 2650,
    2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050,
    3100, 3150, 3200, 3250, 3300, 3350, 3400, 3450,
    3500,
};

struct comparator {
    const char *name;
    int reg;
    int uV_max;
    const u16 *vsel_table;
};

static struct comparator tps_comparators[] = {
    {
        .name = "COMP1",
        .reg = TPS65911_VMBCH,
        .uV_max = 3500,
        .vsel_table = COMP_VSEL_TABLE,
    },
    {
        .name = "COMP2",
        .reg = TPS65911_VMBCH2,
        .uV_max = 3500,
        .vsel_table = COMP_VSEL_TABLE,
    },
};

static int comp_threshold_set(struct tps65910 *tps65910, int id, int voltage)
{
    struct comparator tps_comp = tps_comparators[id];
    int curr_voltage = 0;
    int ret;
    u8 index = 0, val;

    if (id == COMP)
        return 0;

    while (curr_voltage < tps_comp.uV_max) {
        curr_voltage = tps_comp.vsel_table[index];
        if (curr_voltage >= voltage)
            break;
        else if (curr_voltage < voltage)
            index ++;
    }

    if (curr_voltage > tps_comp.uV_max)
        return -EINVAL;

    val = index << 1;
    ret = tps65910->write(tps65910, tps_comp.reg, 1, &val);

    return ret;
}

static int comp_threshold_get(struct tps65910 *tps65910, int id)
{
    struct comparator tps_comp = tps_comparators[id];
    int ret;
    u8 val;

    if (id == COMP)
        return 0;

    ret = tps65910->read(tps65910, tps_comp.reg, 1, &val);
    if (ret < 0)
        return ret;

    val >>= 1;
    return tps_comp.vsel_table[val];
}

static ssize_t comp_threshold_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct tps65910 *tps65910 = dev_get_drvdata(dev->parent);
    struct attribute comp_attr = attr->attr;
    int id, uVolt;

    if (!strcmp(comp_attr.name, "comp1_threshold"))
        id = COMP1;
    else if (!strcmp(comp_attr.name, "comp2_threshold"))
        id = COMP2;
    else
        return -EINVAL;

    uVolt = comp_threshold_get(tps65910, id);

    return sprintf(buf, "%d\n", uVolt);
}

static DEVICE_ATTR(comp1_threshold, S_IRUGO, comp_threshold_show, NULL);
static DEVICE_ATTR(comp2_threshold, S_IRUGO, comp_threshold_show, NULL);

static __devinit int tps65911_comparator_probe(struct platform_device *pdev)
{
    struct tps65910 *tps65910 = dev_get_drvdata(pdev->dev.parent);
    struct tps65910_board *pdata = dev_get_platdata(tps65910->dev);
    int ret;

    ret = comp_threshold_set(tps65910, COMP1,  pdata->vmbch_threshold);
    if (ret < 0) {
        dev_err(&pdev->dev, "cannot set COMP1 threshold\n");
        return ret;
    }

    ret = comp_threshold_set(tps65910, COMP2, pdata->vmbch2_threshold);
    if (ret < 0) {
        dev_err(&pdev->dev, "cannot set COMP2 threshold\n");
        return ret;
    }

    /* Create sysfs entry */
    ret = device_create_file(&pdev->dev, &dev_attr_comp1_threshold);
    if (ret < 0)
        dev_err(&pdev->dev, "failed to add COMP1 sysfs file\n");

    ret = device_create_file(&pdev->dev, &dev_attr_comp2_threshold);
    if (ret < 0)
        dev_err(&pdev->dev, "failed to add COMP2 sysfs file\n");

    return ret;
}

static __devexit int tps65911_comparator_remove(struct platform_device *pdev)
{
    struct tps65910 *tps65910;

    tps65910 = dev_get_drvdata(pdev->dev.parent);
    device_remove_file(&pdev->dev, &dev_attr_comp2_threshold);
    device_remove_file(&pdev->dev, &dev_attr_comp1_threshold);

    return 0;
}

static struct platform_driver tps65911_comparator_driver = {
    .driver = {
        .name = "tps65911-comparator",
        .owner = THIS_MODULE,
    },
    .probe = tps65911_comparator_probe,
    .remove = __devexit_p(tps65911_comparator_remove),
};

static int __init tps65911_comparator_init(void)
{
    return platform_driver_register(&tps65911_comparator_driver);
}
subsys_initcall(tps65911_comparator_init);

static void __exit tps65911_comparator_exit(void)
{
    platform_driver_unregister(&tps65911_comparator_driver);
}
module_exit(tps65911_comparator_exit);

MODULE_AUTHOR("Jorge Eduardo Candelaria <[email protected]>");
MODULE_DESCRIPTION("TPS65911 comparator driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:tps65911-comparator");