path: root/drivers/hwmon/ntc_thermistor.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ntc_thermistor.c - NTC Thermistors
 *
 *  Copyright (C) 2010 Samsung Electronics
 *  MyungJoo Ham <myungjoo.ham@samsung.com>
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/math64.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/err.h>
#include <linux/fixp-arith.h>
#include <linux/iio/consumer.h>
#include <linux/hwmon.h>

enum ntc_thermistor_type {
	TYPE_B57330V2103,
	TYPE_B57891S0103,
	TYPE_NCPXXWB473,
	TYPE_NCPXXWF104,
	TYPE_NCPXXWL333,
	TYPE_NCPXXXH103,
	TYPE_NCPXXWM474,
};

struct ntc_compensation {
	int		temp_c;
	unsigned int	ohm;
};

/*
 * Used as index in a zero-terminated array, holes not allowed so
 * that NTC_LAST is the first empty array entry.
 */
enum {
	NTC_B57330V2103,
	NTC_B57891S0103,
	NTC_NCP03WB473,
	NTC_NCP03WF104,
	NTC_NCP15WB473,
	NTC_NCP15WL333,
	NTC_NCP15XH103,
	NTC_NCP18WB473,
	NTC_NCP21WB473,
	NTC_SSG1404001221,
	NTC_NCP18WM474,
	NTC_LAST,
};

static const struct platform_device_id ntc_thermistor_id[] = {
	[NTC_B57330V2103]     = { "b57330v2103",     TYPE_B57330V2103 },
	[NTC_B57891S0103]     = { "b57891s0103",     TYPE_B57891S0103 },
	[NTC_NCP03WB473]      = { "ncp03wb473",      TYPE_NCPXXWB473 },
	[NTC_NCP03WF104]      = { "ncp03wf104",      TYPE_NCPXXWF104 },
	[NTC_NCP15WB473]      = { "ncp15wb473",      TYPE_NCPXXWB473 },
	[NTC_NCP15WL333]      = { "ncp15wl333",      TYPE_NCPXXWL333 },
	[NTC_NCP15XH103]      = { "ncp15xh103",      TYPE_NCPXXXH103 },
	[NTC_NCP18WB473]      = { "ncp18wb473",      TYPE_NCPXXWB473 },
	[NTC_NCP21WB473]      = { "ncp21wb473",      TYPE_NCPXXWB473 },
	[NTC_SSG1404001221]   = { "ssg1404_001221",  TYPE_NCPXXWB473 },
	[NTC_NCP18WM474]      = { "ncp18wm474",      TYPE_NCPXXWM474 },
	[NTC_LAST]            = { },
};
MODULE_DEVICE_TABLE(platform, ntc_thermistor_id);

/*
 * A compensation table should be sorted by the values of .ohm
 * in descending order.
 * The following compensation tables are from the specification of Murata NTC
 * Thermistors Datasheet
 */
static const struct ntc_compensation ncpXXwb473[] = {
	{ .temp_c	= -40, .ohm	= 1747920 },
	{ .temp_c	= -35, .ohm	= 1245428 },
	{ .temp_c	= -30, .ohm	= 898485 },
	{ .temp_c	= -25, .ohm	= 655802 },
	{ .temp_c	= -20, .ohm	= 483954 },
	{ .temp_c	= -15, .ohm	= 360850 },
	{ .temp_c	= -10, .ohm	= 271697 },
	{ .temp_c	= -5, .ohm	= 206463 },
	{ .temp_c	= 0, .ohm	= 158214 },
	{ .temp_c	= 5, .ohm	= 122259 },
	{ .temp_c	= 10, .ohm	= 95227 },
	{ .temp_c	= 15, .ohm	= 74730 },
	{ .temp_c	= 20, .ohm	= 59065 },
	{ .temp_c	= 25, .ohm	= 47000 },
	{ .temp_c	= 30, .ohm	= 37643 },
	{ .temp_c	= 35, .ohm	= 30334 },
	{ .temp_c	= 40, .ohm	= 24591 },
	{ .temp_c	= 45, .ohm	= 20048 },
	{ .temp_c	= 50, .ohm	= 16433 },
	{ .temp_c	= 55, .ohm	= 13539 },
	{ .temp_c	= 60, .ohm	= 11209 },
	{ .temp_c	= 65, .ohm	= 9328 },
	{ .temp_c	= 70, .ohm	= 7798 },
	{ .temp_c	= 75, .ohm	= 6544 },
	{ .temp_c	= 80, .ohm	= 5518 },
	{ .temp_c	= 85, .ohm	= 4674 },
	{ .temp_c	= 90, .ohm	= 3972 },
	{ .temp_c	= 95, .ohm	= 3388 },
	{ .temp_c	= 100, .ohm	= 2902 },
	{ .temp_c	= 105, .ohm	= 2494 },
	{ .temp_c	= 110, .ohm	= 2150 },
	{ .temp_c	= 115, .ohm	= 1860 },
	{ .temp_c	= 120, .ohm	= 1615 },
	{ .temp_c	= 125, .ohm	= 1406 },
};
static const struct ntc_compensation ncpXXwl333[] = {
	{ .temp_c	= -40, .ohm	= 1610154 },
	{ .temp_c	= -35, .ohm	= 1130850 },
	{ .temp_c	= -30, .ohm	= 802609 },
	{ .temp_c	= -25, .ohm	= 575385 },
	{ .temp_c	= -20, .ohm	= 416464 },
	{ .temp_c	= -15, .ohm	= 304219 },
	{ .temp_c	= -10, .ohm	= 224193 },
	{ .temp_c	= -5, .ohm	= 166623 },
	{ .temp_c	= 0, .ohm