linux-imx

/*

 * Generic ADC thermal driver

 *

 * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.

 *

 * Author: Laxman Dewangan <ldewangan@nvidia.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include <linux/iio/consumer.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

#include <linux/thermal.h>

​

struct gadc_thermal_info {

    struct device *dev;

    struct thermal_zone_device *tz_dev;

    struct iio_channel *channel;

    s32 *lookup_table;

    int nlookup_table;

};

​

static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)

{

    int temp, temp_hi, temp_lo, adc_hi, adc_lo;

    int i;

​

    for (i = 0; i < gti->nlookup_table; i++) {

        if (val >= gti->lookup_table[2 * i + 1])

            break;

    }

​

    if (i == 0) {

        temp = gti->lookup_table[0];

    } else if (i >= gti->nlookup_table) {

        temp = gti->lookup_table[2 * (gti->nlookup_table - 1)];

    } else {

        adc_hi = gti->lookup_table[2 * i - 1];

        adc_lo = gti->lookup_table[2 * i + 1];

​

        temp_hi = gti->lookup_table[2 * i - 2];

        temp_lo = gti->lookup_table[2 * i];

​

        temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi,

                       adc_lo - adc_hi);

    }

​

    return temp;

}

​

static int gadc_thermal_get_temp(void *data, int *temp)

{

    struct gadc_thermal_info *gti = data;

    int val;

    int ret;

​

    ret = iio_read_channel_processed(gti->channel, &val);

    if (ret < 0) {

        dev_err(gti->dev, "IIO channel read failed %d\n", ret);