path: root/drivers/hwmon/lm95245.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
 *
 * The LM95245 is a sensor chip made by TI / National Semiconductor.
 * It reports up to two temperatures (its own plus an external one).
 *
 * This driver is based on lm95241.c
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/slab.h>

static const unsigned short normal_i2c[] = {
	0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };

/* LM95245 registers */
/* general registers */
#define LM95245_REG_RW_CONFIG1		0x03
#define LM95245_REG_RW_CONVERS_RATE	0x04
#define LM95245_REG_W_ONE_SHOT		0x0F

/* diode configuration */
#define LM95245_REG_RW_CONFIG2		0xBF
#define LM95245_REG_RW_REMOTE_OFFH	0x11
#define LM95245_REG_RW_REMOTE_OFFL	0x12

/* status registers */
#define LM95245_REG_R_STATUS1		0x02
#define LM95245_REG_R_STATUS2		0x33

/* limit registers */
#define LM95245_REG_RW_REMOTE_OS_LIMIT		0x07
#define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT	0x20
#define LM95245_REG_RW_REMOTE_TCRIT_LIMIT	0x19
#define LM95245_REG_RW_COMMON_HYSTERESIS	0x21

/* temperature signed */
#define LM95245_REG_R_LOCAL_TEMPH_S	0x00
#define LM95245_REG_R_LOCAL_TEMPL_S	0x30
#define LM95245_REG_R_REMOTE_TEMPH_S	0x01
#define LM95245_REG_R_REMOTE_TEMPL_S	0x10
/* temperature unsigned */
#define LM95245_REG_R_REMOTE_TEMPH_U	0x31
#define LM95245_REG_R_REMOTE_TEMPL_U	0x32

/* id registers */
#define LM95245_REG_R_MAN_ID		0xFE
#define LM95245_REG_R_CHIP_ID		0xFF

/* LM95245 specific bitfields */
#define CFG_STOP		0x40
#define CFG_REMOTE_TCRIT_MASK	0x10
#define CFG_REMOTE_OS_MASK	0x08
#define CFG_LOCAL_TCRIT_MASK	0x04
#define CFG_LOCAL_OS_MASK	0x02

#define CFG2_OS_A0		0x40
#define CFG2_DIODE_FAULT_OS	0x20
#define CFG2_DIODE_FAULT_TCRIT	0x10
#define CFG2_REMOTE_TT		0x08
#define CFG2_REMOTE_FILTER_DIS	0x00
#define CFG2_REMOTE_FILTER_EN	0x06

/* conversation rate in ms */
#define RATE_CR0063	0x00
#define RATE_CR0364	0x01
#define RATE_CR1000	0x02
#define RATE_CR2500	0x03

#define STATUS1_ROS		0x10
#define STATUS1_DIODE_FAULT	0x04
#define STATUS1_RTCRIT		0x02
#define STATUS1_LOC		0x01

#define MANUFACTURER_ID		0x01
#define LM95235_REVISION	0xB1
#define LM95245_REVISION	0xB3

/* Client data (each client gets its own) */
struct lm95245_data {
	struct regmap *regmap;
	struct mutex update_lock;
	int interval;	/* in msecs */
};

/* Conversions */
static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
{
	return val_h * 1000 + val_l * 1000 / 256;
}

static int temp_from_reg_signed(u8 val_h, u8 val_l)
{
	if (val_h & 0x80)
		return (val_h - 0x100) * 1000;
	return temp_from_reg_unsigned(val_h, val_l);
}

static int lm95245_read_conversion_rate(struct lm95245_data *data)
{
	unsigned int rate;
	int ret;

	ret = regmap_read(data->regmap, LM95245_REG_RW_CONVERS_RATE, &rate);
	if (ret < 0)
		return ret;

	switch (rate) {
	case RATE_CR0063:
		data->interval = 63;
		break;
	case RATE_CR0364:
		data->interval = 364;
		break;
	case RATE_CR1000:
		data->interval = 1000;
		break;
	case RATE_CR2500:
	default:
		data->interval = 2500;
		break;
	}
	return 0;
}

static int lm95245_set_conversion_rate(struct lm95245_data *data, long interval)
{
	int ret, rate;

	if (interval <= 63) {
		interval = 63;
		rate = RATE_CR0063;
	} else if (interval <= 364) {
		interval = 364;
		rate = RATE_CR0364;
	} else if (interval <= 1000) {
		interval = 1000;
		rate = RATE_CR1000;
	} else {
		interval = 2500;
		rate = RATE_CR2500;
	}

	ret = regmap_write(data->regmap, LM95245_REG_RW_CONVERS_RATE, rate);
	if (ret < 0)
		return ret;

	data->interval = interval;
	return 0;
}

static int lm95245_read_temp(struct device *dev, u32 attr, int channel,
			     long *val)
{
	struct lm95245_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	int ret, regl, regh, regvall, regvalh;

	switch (attr) {
	case hwmon_temp_input:
		regl = channel ? LM95245_REG_R_REMOTE_TEMPL_S :
				 LM95245_REG_R_LOCAL_TEMPL_S;
		regh = channel ? LM95245_REG_R_REMOTE_TEMPH_S :
				 LM95245_REG_R_LOCAL_TEMPH_S;
		ret = regmap_read(regmap, regl, &regvall);
		if (ret < 0)
			return ret;
		ret = regmap_read(regmap, regh, &regvalh);
		if (ret < 0)
			return ret;
		/*
		 * Local temp is always signed.
		 * Remote temp has both signed and unsigned data.
		 * Use signed calculation for remote if signed bit is set
		 * or if reported temperature is below signed limit.
		 */
		if (!channel || (regvalh & 0x80) || regvalh < 0x7f) {
			*val = temp_from_reg_signed(regvalh, regvall);
			return 0;
		}
		ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPL_U,
				  &regvall);
		if (ret < 0)
			return ret;
		ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPH_U,
				  &regvalh);
		if (ret < 0)
			return ret;
		*val = temp_from_reg_unsigned(regvalh, regvall);
		return 0;
	case hwmon_temp_max:
		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
				  &regvalh);
		if (ret < 0)
			return ret;
		*val = regvalh * 1000;
		return 0;
	case hwmon_temp_crit:
		regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
				 LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
		ret = regmap_read(regmap, regh, &regvalh);
		if (ret < 0)
			return ret;
		*val = regvalh * 1000;
		return 0;
	case hwmon_temp_max_hyst:
		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
				  &regvalh);
		if (ret < 0)
			return ret;
		ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
				  &regvall);
		if (ret < 0)
			return ret;
		*val = (regvalh - regvall) * 1000;
		return 0;
	case hwmon_temp_crit_hyst:
		regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
				 LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
		ret = regmap_read(regmap, regh, &regvalh);
		if (ret < 0)
			return ret;
		ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
				  &regvall);
		if (ret < 0)
			return ret;
		*val = (regvalh - regvall) * 1000;
		return 0;
	case hwmon_temp_type:
		ret = regmap_read(regmap, LM95245_REG_RW_CONFIG2, &regvalh);
		if (ret < 0)
			return ret;
		*val = (regvalh & CFG2_REMOTE_TT) ? 1 : 2;
		return 0;
	case hwmon_temp_offset:
		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFL,
				  &regvall);
		if (ret < 0)