/*
 * ntc_thermistor.c - NTC Thermistors
 *
 *  Copyright (C) 2010 Samsung Electronics
 *  MyungJoo Ham <myungjoo.ham@samsung.com>
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/math64.h>
#include <linux/platform_device.h>
#include <linux/err.h>

#include <linux/platform_data/ntc_thermistor.h>

#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>

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

/*
 * 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
 */
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 },
};
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	= 124850 },
	{ .temp_C	= 5, .ohm	= 94287 },
	{ .temp_C	= 10, .ohm	= 71747 },
	{ .temp_C	= 15, .ohm	= 54996 },
	{ .temp_C	= 20, .ohm	= 42455 },
	{ .temp_C	= 25, .ohm	= 33000 },
	{ .temp_C	= 30, .ohm	= 25822 },
	{ .temp_C	= 35, .ohm	= 20335 },
	{ .temp_C	= 40, .ohm	= 16115 },
	{ .temp_C	= 45, .ohm	= 12849 },
	{ .temp_C	= 50, .ohm	= 10306 },
	{ .temp_C	= 55, .ohm	= 8314 },
	{ .temp_C	= 60, .ohm	= 6746 },
	{ .temp_C	= 65, .ohm	= 5503 },
	{ .temp_C	= 70, .ohm	= 4513 },
	{ .temp_C	= 75, .ohm	= 3721 },
	{ .temp_C	= 80, .ohm	= 3084 },
	{ .temp_C	= 85, .ohm	= 2569 },
	{ .temp_C	= 90, .ohm	= 2151 },
	{ .temp_C	= 95, .ohm	= 1809 },
	{ .temp_C	= 100, .ohm	= 1529 },
	{ .temp_C	= 105, .ohm	= 1299 },
	{ .temp_C	= 110, .ohm	= 1108 },
	{ .temp_C	= 115, .ohm	= 949 },
	{ .temp_C	= 120, .ohm	= 817 },
	{ .temp_C	= 125, .ohm	= 707 },
};

struct ntc_data {
	struct device *hwmon_dev;
	struct ntc_thermistor_platform_data *pdata;
	const struct ntc_compensation *comp;
	struct device *dev;
	int n_comp;
	char name[PLATFORM_NAME_SIZE];
};

static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
{
	if (divisor == 0 && dividend == 0)
		return 0;
	if (divisor == 0)
		return UINT_MAX;
	return div64_u64(dividend, divisor);
}

static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uV)
{
	struct ntc_thermistor_platform_data *pdata = data->pdata;
	u64 mV = uV / 1000;
	u64 pmV = pdata->pullup_uV / 1000;
	u64 N, puO, pdO;
	puO = pdata->pullup_ohm;
	pdO = pdata->pulldown_ohm;

	if (mV == 0) {
		if (pdata->connect == NTC_CONNECTED_POSITIVE)
			return INT_MAX;
		return