linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Lochnagar hardware monitoring features

 *

 * Copyright (c) 2016-2019 Cirrus Logic, Inc. and

 *                         Cirrus Logic International Semiconductor Ltd.

 *

 * Author: Lucas Tanure <tanureal@opensource.cirrus.com>

 */

​

#include <linux/delay.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/i2c.h>

#include <linux/math64.h>

#include <linux/mfd/lochnagar.h>

#include <linux/mfd/lochnagar2_regs.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

​

#define LN2_MAX_NSAMPLE 1023

#define LN2_SAMPLE_US   1670

​

#define LN2_CURR_UNITS  1000

#define LN2_VOLT_UNITS  1000

#define LN2_TEMP_UNITS  1000

#define LN2_PWR_UNITS   1000000

​

static const char * const lochnagar_chan_names[] = {

    "DBVDD1",

    "1V8 DSP",

    "1V8 CDC",

    "VDDCORE DSP",

    "AVDD 1V8",

    "SYSVDD",

    "VDDCORE CDC",

    "MICVDD",

};

​

struct lochnagar_hwmon {

    struct regmap *regmap;

​

    long power_nsamples[ARRAY_SIZE(lochnagar_chan_names)];

​

    /* Lock to ensure only a single sensor is read at a time */

    struct mutex sensor_lock;

};

​

enum lochnagar_measure_mode {

    LN2_CURR = 0,

    LN2_VOLT,

    LN2_TEMP,

};

​

/**

 * float_to_long - Convert ieee754 reading from hardware to an integer

 *

 * @data: Value read from the hardware

 * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro

 *

 * Return: Converted integer reading

 *

 * Depending on the measurement type the hardware returns an ieee754

 * floating point value in either volts, amps or celsius. This function

 * will convert that into an integer in a smaller unit such as micro-amps

 * or milli-celsius. The hardware does not return NaN, so consideration of

 * that is not required.

 */

static long float_to_long(u32 data, u32 precision)

{

    u64 man = data & 0x007FFFFF;

    int exp = ((data & 0x7F800000) >> 23) - 127 - 23;

    bool negative = data & 0x80000000;

    long result;

​

    man = (man + (1 << 23)) * precision;

​

    if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)

        result = LONG_MAX;

    else if (exp < 0)

        result = (man + (1ull << (-exp - 1))) >> -exp;

    else

        result = man << exp;

​

    return negative ? -result : result;

}

​

static int do_measurement(struct regmap *regmap, int chan,

              enum lochnagar_measure_mode mode, int nsamples)