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linux-next/drivers/hwmon/max6697.c
Guenter Roeck 3adc2857bb hwmon: (max6697) Document discrepancy in overtemperature status bit values 
In the MAX6581 datasheet Revision 0 to 3, the local channel overtemperature
status is reported in bit 6 of register 0x45, and the overtemperature
status for remote channel 7 is reported in bit 7. In Revision 4 and later,
the local channel overtemperature status is reported in bit 7, and the
remote channel 7 overtemperature status is reported in bit 6. A real
chip was found to match the functionality documented in Revision 4 and
later.

The code was fixed with commit 1ea3fd1eb9 ("hwmon: (max6697) Fix swapped
temp{1,8} critical alarms"). At that time it looked like this was an
original bug. It only turned out later that the problem was the result of
incorrect information in the chip datasheet.

Document the discrepancy to avoid confusion caused by old versions of the
datasheet.

Cc: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-07-31 10:43:53 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2012 Guenter Roeck <linux@roeck-us.net>
*
* based on max1668.c
* Copyright (c) 2011 David George <david.george@ska.ac.za>
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/slab.h>
enum chips { max6581, max6602, max6622, max6636, max6689, max6693, max6694,
max6697, max6698, max6699 };
/* Report local sensor as temp1 */
static const u8 MAX6697_REG_TEMP[] = {
0x07, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x08 };
static const u8 MAX6697_REG_TEMP_EXT[] = {
0x57, 0x09, 0x52, 0x53, 0x54, 0x55, 0x56, 0 };
static const u8 MAX6697_REG_MAX[] = {
0x17, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x18 };
static const u8 MAX6697_REG_CRIT[] = {
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27 };
#define MAX6697_REG_MIN 0x30
/*
* Map device tree / internal register bit map to chip bit map.
* Applies to alert register and over-temperature register.
*/
#define MAX6697_EXTERNAL_MASK_DT GENMASK(7, 1)
#define MAX6697_LOCAL_MASK_DT BIT(0)
#define MAX6697_EXTERNAL_MASK_CHIP GENMASK(6, 0)
#define MAX6697_LOCAL_MASK_CHIP BIT(7)
/* alert - local channel is in bit 6 */
#define MAX6697_ALERT_MAP_BITS(reg) ((((reg) & 0x7e) >> 1) | \
(((reg) & 0x01) << 6) | ((reg) & 0x80))
/* over-temperature - local channel is in bit 7 */
#define MAX6697_OVERT_MAP_BITS(reg) \
(FIELD_PREP(MAX6697_EXTERNAL_MASK_CHIP, FIELD_GET(MAX6697_EXTERNAL_MASK_DT, reg)) | \
FIELD_PREP(MAX6697_LOCAL_MASK_CHIP, FIELD_GET(MAX6697_LOCAL_MASK_DT, reg)))
#define MAX6697_REG_STAT_ALARM 0x44
#define MAX6697_REG_STAT_CRIT 0x45
#define MAX6697_REG_STAT_FAULT 0x46
#define MAX6697_REG_STAT_MIN_ALARM 0x47
#define MAX6697_REG_CONFIG 0x41
#define MAX6581_CONF_EXTENDED BIT(1)
#define MAX6693_CONF_BETA BIT(2)
#define MAX6697_CONF_RESISTANCE BIT(3)
#define MAX6697_CONF_TIMEOUT BIT(5)
#define MAX6697_REG_ALERT_MASK 0x42
#define MAX6697_REG_OVERT_MASK 0x43
#define MAX6581_REG_RESISTANCE 0x4a
#define MAX6581_REG_IDEALITY 0x4b
#define MAX6581_REG_IDEALITY_SELECT 0x4c
#define MAX6581_REG_OFFSET 0x4d
#define MAX6581_REG_OFFSET_SELECT 0x4e
#define MAX6581_OFFSET_MIN -31750
#define MAX6581_OFFSET_MAX 31750
#define MAX6697_CONV_TIME 156 /* ms per channel, worst case */
struct max6697_chip_data {
int channels;
u32 have_ext;
u32 have_crit;
u32 have_fault;
u8 valid_conf;
};
struct max6697_data {
struct regmap *regmap;
enum chips type;
const struct max6697_chip_data *chip;
int temp_offset; /* in degrees C */
struct mutex update_lock;
#define MAX6697_TEMP_INPUT 0
#define MAX6697_TEMP_EXT 1
#define MAX6697_TEMP_MAX 2
#define MAX6697_TEMP_CRIT 3
u32 alarms;
};
static const struct max6697_chip_data max6697_chip_data[] = {
[max6581] = {
.channels = 8,
.have_crit = 0xff,
.have_ext = 0x7f,
.have_fault = 0xfe,
.valid_conf = MAX6581_CONF_EXTENDED | MAX6697_CONF_TIMEOUT,
},
[max6602] = {
.channels = 5,
.have_crit = 0x12,
.have_ext = 0x02,
.have_fault = 0x1e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
[max6622] = {
.channels = 5,
.have_crit = 0x12,
.have_ext = 0x02,
.have_fault = 0x1e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
[max6636] = {
.channels = 7,
.have_crit = 0x72,
.have_ext = 0x02,
.have_fault = 0x7e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
[max6689] = {
.channels = 7,
.have_crit = 0x72,
.have_ext = 0x02,
.have_fault = 0x7e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
[max6693] = {
.channels = 7,
.have_crit = 0x72,
.have_ext = 0x02,
.have_fault = 0x7e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6693_CONF_BETA |
MAX6697_CONF_TIMEOUT,
},
[max6694] = {
.channels = 5,
.have_crit = 0x12,
.have_ext = 0x02,
.have_fault = 0x1e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6693_CONF_BETA |
MAX6697_CONF_TIMEOUT,
},
[max6697] = {
.channels = 7,
.have_crit = 0x72,
.have_ext = 0x02,
.have_fault = 0x7e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
[max6698] = {
.channels = 7,
.have_crit = 0x72,
.have_ext = 0x02,
.have_fault = 0x0e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
[max6699] = {
.channels = 5,
.have_crit = 0x12,
.have_ext = 0x02,
.have_fault = 0x1e,
.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
},
};
static int max6697_alarm_channel_map(int channel)
{
switch (channel) {
case 0:
return 6;
case 7:
return 7;
default:
return channel - 1;
}
}
static int max6697_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
unsigned int offset_regs[2] = { MAX6581_REG_OFFSET_SELECT, MAX6581_REG_OFFSET };
unsigned int temp_regs[2] = { MAX6697_REG_TEMP[channel],
MAX6697_REG_TEMP_EXT[channel] };
struct max6697_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u8 regdata[2] = { };
u32 regval;
int ret;
switch (attr) {
case hwmon_temp_input:
ret = regmap_multi_reg_read(regmap, temp_regs, regdata,
data->chip->have_ext & BIT(channel) ? 2 : 1);
if (ret)
return ret;
*val = (((regdata[0] - data->temp_offset) << 3) | (regdata[1] >> 5)) * 125;
break;
case hwmon_temp_max:
ret = regmap_read(regmap, MAX6697_REG_MAX[channel], &regval);
if (ret)
return ret;
*val = ((int)regval - data->temp_offset) * 1000;
break;
case hwmon_temp_crit:
ret = regmap_read(regmap, MAX6697_REG_CRIT[channel], &regval);
if (ret)
return ret;
*val = ((int)regval - data->temp_offset) * 1000;
break;
case hwmon_temp_min:
ret = regmap_read(regmap, MAX6697_REG_MIN, &regval);
if (ret)
return ret;
*val = ((int)regval - data->temp_offset) * 1000;
break;
case hwmon_temp_offset:
ret = regmap_multi_reg_read(regmap, offset_regs, regdata, 2);
if (ret)
return ret;
if (!(regdata[0] & BIT(channel - 1)))
regdata[1] = 0;
*val = sign_extend32(regdata[1], 7) * 250;
break;
case hwmon_temp_fault:
ret = regmap_read(regmap, MAX6697_REG_STAT_FAULT, &regval);
if (ret)
return ret;
if (data->type == max6581)
*val = !!(regval & BIT(channel - 1));
else
*val = !!(regval & BIT(channel));
break;
case hwmon_temp_crit_alarm:
ret = regmap_read(regmap, MAX6697_REG_STAT_CRIT, &regval);
if (ret)
return ret;
/*
* In the MAX6581 datasheet revision 0 to 3, the local channel
* overtemperature status is reported in bit 6 of register 0x45,
* and the overtemperature status for remote channel 7 is
* reported in bit 7. In Revision 4 and later, the local channel
* overtemperature status is reported in bit 7, and the remote
* channel 7 overtemperature status is reported in bit 6. A real
* chip was found to match the functionality documented in
* Revision 4 and later.
*/
*val = !!(regval & BIT(channel ? channel - 1 : 7));
break;
case hwmon_temp_max_alarm:
ret = regmap_read(regmap, MAX6697_REG_STAT_ALARM, &regval);
if (ret)
return ret;
*val = !!(regval & BIT(max6697_alarm_channel_map(channel)));
break;
case hwmon_temp_min_alarm:
ret = regmap_read(regmap, MAX6697_REG_STAT_MIN_ALARM, &regval);
if (ret)
return ret;
*val = !!(regval & BIT(max6697_alarm_channel_map(channel)));
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int max6697_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct max6697_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
int ret;
switch (attr) {
case hwmon_temp_max:
val = clamp_val(val, -1000000, 1000000); /* prevent underflow */
val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
val = clamp_val(val, 0, data->type == max6581 ? 255 : 127);
return regmap_write(regmap, MAX6697_REG_MAX[channel], val);
case hwmon_temp_crit:
val = clamp_val(val, -1000000, 1000000); /* prevent underflow */
val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
val = clamp_val(val, 0, data->type == max6581 ? 255 : 127);
return regmap_write(regmap, MAX6697_REG_CRIT[channel], val);
case hwmon_temp_min:
val = clamp_val(val, -1000000, 1000000); /* prevent underflow */
val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
val = clamp_val(val, 0, 255);
return regmap_write(regmap, MAX6697_REG_MIN, val);
case hwmon_temp_offset:
mutex_lock(&data->update_lock);
val = clamp_val(val, MAX6581_OFFSET_MIN, MAX6581_OFFSET_MAX);
val = DIV_ROUND_CLOSEST(val, 250);
if (!val) { /* disable this (and only this) channel */
ret = regmap_clear_bits(regmap, MAX6581_REG_OFFSET_SELECT,
BIT(channel - 1));
} else {
/* enable channel and update offset */
ret = regmap_set_bits(regmap, MAX6581_REG_OFFSET_SELECT,
BIT(channel - 1));
if (ret)
goto unlock;
ret = regmap_write(regmap, MAX6581_REG_OFFSET, val);
}
unlock:
mutex_unlock(&data->update_lock);
return ret;
default:
return -EOPNOTSUPP;
}
}
static umode_t max6697_is_visible(const void *_data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
const struct max6697_data *data = _data;
const struct max6697_chip_data *chip = data->chip;
if (channel >= chip->channels)
return 0;
switch (attr) {
case hwmon_temp_max:
return 0644;
case hwmon_temp_input:
case hwmon_temp_max_alarm:
return 0444;
case hwmon_temp_min:
if (data->type == max6581)
return channel ? 0444 : 0644;
break;
case hwmon_temp_min_alarm:
if (data->type == max6581)
return 0444;
break;
case hwmon_temp_crit:
if (chip->have_crit & BIT(channel))
return 0644;
break;
case hwmon_temp_crit_alarm:
if (chip->have_crit & BIT(channel))
return 0444;
break;
case hwmon_temp_fault:
if (chip->have_fault & BIT(channel))
return 0444;
break;
case hwmon_temp_offset:
if (data->type == max6581 && channel)
return 0644;
break;
default:
break;
}
return 0;
}
/* Return 0 if detection is successful, -ENODEV otherwise */
static const struct hwmon_channel_info * const max6697_info[] = {
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
HWMON_T_MIN | HWMON_T_MIN_ALARM |
HWMON_T_FAULT | HWMON_T_OFFSET),
NULL
};
static const struct hwmon_ops max6697_hwmon_ops = {
.is_visible = max6697_is_visible,
.read = max6697_read,
.write = max6697_write,
};
static const struct hwmon_chip_info max6697_chip_info = {
.ops = &max6697_hwmon_ops,
.info = max6697_info,
};
static int max6697_config_of(struct device_node *node, struct max6697_data *data)
{
const struct max6697_chip_data *chip = data->chip;
struct regmap *regmap = data->regmap;
int ret, confreg;
u32 vals[2];
confreg = 0;
if (of_property_read_bool(node, "smbus-timeout-disable") &&
(chip->valid_conf & MAX6697_CONF_TIMEOUT)) {
confreg |= MAX6697_CONF_TIMEOUT;
}
if (of_property_read_bool(node, "extended-range-enable") &&
(chip->valid_conf & MAX6581_CONF_EXTENDED)) {
confreg |= MAX6581_CONF_EXTENDED;
data->temp_offset = 64;
}
if (of_property_read_bool(node, "beta-compensation-enable") &&
(chip->valid_conf & MAX6693_CONF_BETA)) {
confreg |= MAX6693_CONF_BETA;
}
if (of_property_read_u32(node, "alert-mask", vals))
vals[0] = 0;
ret = regmap_write(regmap, MAX6697_REG_ALERT_MASK,
MAX6697_ALERT_MAP_BITS(vals[0]));
if (ret)
return ret;
if (of_property_read_u32(node, "over-temperature-mask", vals))
vals[0] = 0;
ret = regmap_write(regmap, MAX6697_REG_OVERT_MASK,
MAX6697_OVERT_MAP_BITS(vals[0]));
if (ret)
return ret;
if (data->type != max6581) {
if (of_property_read_bool(node, "resistance-cancellation") &&
chip->valid_conf & MAX6697_CONF_RESISTANCE) {
confreg |= MAX6697_CONF_RESISTANCE;
}
} else {
if (of_property_read_u32(node, "resistance-cancellation", &vals[0])) {
if (of_property_read_bool(node, "resistance-cancellation"))
vals[0] = 0xfe;
else
vals[0] = 0;
}
vals[0] &= 0xfe;
ret = regmap_write(regmap, MAX6581_REG_RESISTANCE, vals[0] >> 1);
if (ret < 0)
return ret;
if (of_property_read_u32_array(node, "transistor-ideality", vals, 2)) {
vals[0] = 0;
vals[1] = 0;
}
ret = regmap_write(regmap, MAX6581_REG_IDEALITY, vals[1]);
if (ret < 0)
return ret;
ret = regmap_write(regmap, MAX6581_REG_IDEALITY_SELECT,
(vals[0] & 0xfe) >> 1);
if (ret < 0)
return ret;
}
return regmap_write(regmap, MAX6697_REG_CONFIG, confreg);
}
static int max6697_init_chip(struct device_node *np, struct max6697_data *data)
{
unsigned int reg;
int ret;
/*
* Don't touch configuration if there is no devicetree configuration.
* If that is the case, use the current chip configuration.
*/
if (!np) {
struct regmap *regmap = data->regmap;
ret = regmap_read(regmap, MAX6697_REG_CONFIG, &reg);
if (ret < 0)
return ret;
if (data->type == max6581) {
if (reg & MAX6581_CONF_EXTENDED)
data->temp_offset = 64;
ret = regmap_read(regmap, MAX6581_REG_RESISTANCE, &reg);
}
} else {
ret = max6697_config_of(np, data);
}
return ret;
}
static bool max6697_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case 0x00 ... 0x09: /* temperature high bytes */
case 0x44 ... 0x47: /* status */
case 0x51 ... 0x58: /* temperature low bytes */
return true;
default:
return false;
}
}
static bool max6697_writeable_reg(struct device *dev, unsigned int reg)
{
return reg != 0x0a && reg != 0x0f && !max6697_volatile_reg(dev, reg);
}
static const struct regmap_config max6697_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = 0x58,
.writeable_reg = max6697_writeable_reg,
.volatile_reg = max6697_volatile_reg,
.cache_type = REGCACHE_MAPLE,
};
static int max6697_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct max6697_data *data;
struct device *hwmon_dev;
struct regmap *regmap;
int err;
regmap = regmap_init_i2c(client, &max6697_regmap_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
data = devm_kzalloc(dev, sizeof(struct max6697_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->regmap = regmap;
data->type = (uintptr_t)i2c_get_match_data(client);
data->chip = &max6697_chip_data[data->type];
mutex_init(&data->update_lock);
err = max6697_init_chip(client->dev.of_node, data);
if (err)
return err;
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
&max6697_chip_info, NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id max6697_id[] = {
{ "max6581", max6581 },
{ "max6602", max6602 },
{ "max6622", max6622 },
{ "max6636", max6636 },
{ "max6689", max6689 },
{ "max6693", max6693 },
{ "max6694", max6694 },
{ "max6697", max6697 },
{ "max6698", max6698 },
{ "max6699", max6699 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max6697_id);
static const struct of_device_id __maybe_unused max6697_of_match[] = {
{
.compatible = "maxim,max6581",
.data = (void *)max6581
},
{
.compatible = "maxim,max6602",
.data = (void *)max6602
},
{
.compatible = "maxim,max6622",
.data = (void *)max6622
},
{
.compatible = "maxim,max6636",
.data = (void *)max6636
},
{
.compatible = "maxim,max6689",
.data = (void *)max6689
},
{
.compatible = "maxim,max6693",
.data = (void *)max6693
},
{
.compatible = "maxim,max6694",
.data = (void *)max6694
},
{
.compatible = "maxim,max6697",
.data = (void *)max6697
},
{
.compatible = "maxim,max6698",
.data = (void *)max6698
},
{
.compatible = "maxim,max6699",
.data = (void *)max6699
},
{ },
};
MODULE_DEVICE_TABLE(of, max6697_of_match);
static struct i2c_driver max6697_driver = {
.driver = {
.name = "max6697",
.of_match_table = of_match_ptr(max6697_of_match),
},
.probe = max6697_probe,
.id_table = max6697_id,
};
module_i2c_driver(max6697_driver);
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("MAX6697 temperature sensor driver");
MODULE_LICENSE("GPL");
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