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linux/drivers/iio/temperature/mcp9600.c
Dimitri Fedrau dea750f801 iio: temperature: mcp9600: add threshold events support 
The device has four programmable temperature alert outputs which can be
used to monitor hot or cold-junction temperatures and detect falling and
rising temperatures. It supports up to 255 degree celsius programmable
hysteresis. Each alert can be individually configured by setting following
options in the associated alert configuration register:
- monitor hot or cold junction temperature
- monitor rising or falling temperature
- set comparator or interrupt mode
- set output polarity
- enable alert

This patch binds alert outputs to iio events:
- alert1: hot junction, rising temperature
- alert2: hot junction, falling temperature
- alert3: cold junction, rising temperature
- alert4: cold junction, falling temperature

All outputs are set in comparator mode and polarity depends on interrupt
configuration.

Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Link: https://lore.kernel.org/r/20240604133639.959682-1-dima.fedrau@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-06-13 19:19:25 +01:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* mcp9600.c - Support for Microchip MCP9600 thermocouple EMF converter
*
* Copyright (c) 2022 Andrew Hepp
* Author: <andrew.hepp@ahepp.dev>
*/
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/math.h>
#include <linux/minmax.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/iio/events.h>
#include <linux/iio/iio.h>
/* MCP9600 registers */
#define MCP9600_HOT_JUNCTION 0x0
#define MCP9600_COLD_JUNCTION 0x2
#define MCP9600_STATUS 0x4
#define MCP9600_STATUS_ALERT(x) BIT(x)
#define MCP9600_ALERT_CFG1 0x8
#define MCP9600_ALERT_CFG(x) (MCP9600_ALERT_CFG1 + (x - 1))
#define MCP9600_ALERT_CFG_ENABLE BIT(0)
#define MCP9600_ALERT_CFG_ACTIVE_HIGH BIT(2)
#define MCP9600_ALERT_CFG_FALLING BIT(3)
#define MCP9600_ALERT_CFG_COLD_JUNCTION BIT(4)
#define MCP9600_ALERT_HYSTERESIS1 0xc
#define MCP9600_ALERT_HYSTERESIS(x) (MCP9600_ALERT_HYSTERESIS1 + (x - 1))
#define MCP9600_ALERT_LIMIT1 0x10
#define MCP9600_ALERT_LIMIT(x) (MCP9600_ALERT_LIMIT1 + (x - 1))
#define MCP9600_ALERT_LIMIT_MASK GENMASK(15, 2)
#define MCP9600_DEVICE_ID 0x20
/* MCP9600 device id value */
#define MCP9600_DEVICE_ID_MCP9600 0x40
#define MCP9600_ALERT_COUNT 4
#define MCP9600_MIN_TEMP_HOT_JUNCTION_MICRO -200000000
#define MCP9600_MAX_TEMP_HOT_JUNCTION_MICRO 1800000000
#define MCP9600_MIN_TEMP_COLD_JUNCTION_MICRO -40000000
#define MCP9600_MAX_TEMP_COLD_JUNCTION_MICRO 125000000
enum mcp9600_alert {
MCP9600_ALERT1,
MCP9600_ALERT2,
MCP9600_ALERT3,
MCP9600_ALERT4
};
static const char * const mcp9600_alert_name[MCP9600_ALERT_COUNT] = {
[MCP9600_ALERT1] = "alert1",
[MCP9600_ALERT2] = "alert2",
[MCP9600_ALERT3] = "alert3",
[MCP9600_ALERT4] = "alert4",
};
static const struct iio_event_spec mcp9600_events[] = {
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_RISING,
.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
BIT(IIO_EV_INFO_VALUE) |
BIT(IIO_EV_INFO_HYSTERESIS),
},
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_FALLING,
.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
BIT(IIO_EV_INFO_VALUE) |
BIT(IIO_EV_INFO_HYSTERESIS),
},
};
#define MCP9600_CHANNELS(hj_num_ev, hj_ev_spec_off, cj_num_ev, cj_ev_spec_off) \
{ \
{ \
.type = IIO_TEMP, \
.address = MCP9600_HOT_JUNCTION, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_SCALE), \
.event_spec = &mcp9600_events[hj_ev_spec_off], \
.num_event_specs = hj_num_ev, \
}, \
{ \
.type = IIO_TEMP, \
.address = MCP9600_COLD_JUNCTION, \
.channel2 = IIO_MOD_TEMP_AMBIENT, \
.modified = 1, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_SCALE), \
.event_spec = &mcp9600_events[cj_ev_spec_off], \
.num_event_specs = cj_num_ev, \
}, \
}
static const struct iio_chan_spec mcp9600_channels[][2] = {
MCP9600_CHANNELS(0, 0, 0, 0), /* Alerts: - - - - */
MCP9600_CHANNELS(1, 0, 0, 0), /* Alerts: 1 - - - */
MCP9600_CHANNELS(1, 1, 0, 0), /* Alerts: - 2 - - */
MCP9600_CHANNELS(2, 0, 0, 0), /* Alerts: 1 2 - - */
MCP9600_CHANNELS(0, 0, 1, 0), /* Alerts: - - 3 - */
MCP9600_CHANNELS(1, 0, 1, 0), /* Alerts: 1 - 3 - */
MCP9600_CHANNELS(1, 1, 1, 0), /* Alerts: - 2 3 - */
MCP9600_CHANNELS(2, 0, 1, 0), /* Alerts: 1 2 3 - */
MCP9600_CHANNELS(0, 0, 1, 1), /* Alerts: - - - 4 */
MCP9600_CHANNELS(1, 0, 1, 1), /* Alerts: 1 - - 4 */
MCP9600_CHANNELS(1, 1, 1, 1), /* Alerts: - 2 - 4 */
MCP9600_CHANNELS(2, 0, 1, 1), /* Alerts: 1 2 - 4 */
MCP9600_CHANNELS(0, 0, 2, 0), /* Alerts: - - 3 4 */
MCP9600_CHANNELS(1, 0, 2, 0), /* Alerts: 1 - 3 4 */
MCP9600_CHANNELS(1, 1, 2, 0), /* Alerts: - 2 3 4 */
MCP9600_CHANNELS(2, 0, 2, 0), /* Alerts: 1 2 3 4 */
};
struct mcp9600_data {
struct i2c_client *client;
};
static int mcp9600_read(struct mcp9600_data *data,
struct iio_chan_spec const *chan, int *val)
{
int ret;
ret = i2c_smbus_read_word_swapped(data->client, chan->address);
if (ret < 0)
return ret;
*val = sign_extend32(ret, 15);
return 0;
}
static int mcp9600_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct mcp9600_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = mcp9600_read(data, chan, val);
if (ret)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 62;
*val2 = 500000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static int mcp9600_get_alert_index(int channel2, enum iio_event_direction dir)
{
if (channel2 == IIO_MOD_TEMP_AMBIENT) {
if (dir == IIO_EV_DIR_RISING)
return MCP9600_ALERT3;
else
return MCP9600_ALERT4;
} else {
if (dir == IIO_EV_DIR_RISING)
return MCP9600_ALERT1;
else
return MCP9600_ALERT2;
}
}
static int mcp9600_read_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir)
{
struct mcp9600_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
int i, ret;
i = mcp9600_get_alert_index(chan->channel2, dir);
ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_CFG(i + 1));
if (ret < 0)
return ret;
return FIELD_GET(MCP9600_ALERT_CFG_ENABLE, ret);
}
static int mcp9600_write_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
int state)
{
struct mcp9600_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
int i, ret;
i = mcp9600_get_alert_index(chan->channel2, dir);
ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_CFG(i + 1));
if (ret < 0)
return ret;
if (state)
ret |= MCP9600_ALERT_CFG_ENABLE;
else
ret &= ~MCP9600_ALERT_CFG_ENABLE;
return i2c_smbus_write_byte_data(client, MCP9600_ALERT_CFG(i + 1), ret);
}
static int mcp9600_read_thresh(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
enum iio_event_info info, int *val, int *val2)
{
struct mcp9600_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
s32 ret;
int i;
i = mcp9600_get_alert_index(chan->channel2, dir);
switch (info) {
case IIO_EV_INFO_VALUE:
ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1));
if (ret < 0)
return ret;
/*
* Temperature is stored in two’s complement format in
* bits(15:2), LSB is 0.25 degree celsius.
*/
*val = sign_extend32(FIELD_GET(MCP9600_ALERT_LIMIT_MASK, ret), 13);
*val2 = 4;
return IIO_VAL_FRACTIONAL;
case IIO_EV_INFO_HYSTERESIS:
ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_HYSTERESIS(i + 1));
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int mcp9600_write_thresh(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
enum iio_event_info info, int val, int val2)
{
struct mcp9600_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
int s_val, i;
s16 thresh;
u8 hyst;
i = mcp9600_get_alert_index(chan->channel2, dir);
switch (info) {
case IIO_EV_INFO_VALUE:
/* Scale value to include decimal part into calculations */
s_val = (val < 0) ? ((val * 1000000) - val2) :
((val * 1000000) + val2);
if (chan->channel2 == IIO_MOD_TEMP_AMBIENT) {
s_val = max(s_val, MCP9600_MIN_TEMP_COLD_JUNCTION_MICRO);
s_val = min(s_val, MCP9600_MAX_TEMP_COLD_JUNCTION_MICRO);
} else {
s_val = max(s_val, MCP9600_MIN_TEMP_HOT_JUNCTION_MICRO);
s_val = min(s_val, MCP9600_MAX_TEMP_HOT_JUNCTION_MICRO);
}
/*
* Shift length 4 bits = 2(15:2) + 2(0.25 LSB), temperature is
* stored in two’s complement format.
*/
thresh = (s16)(s_val / (1000000 >> 4));
return i2c_smbus_write_word_swapped(client,
MCP9600_ALERT_LIMIT(i + 1),
thresh);
case IIO_EV_INFO_HYSTERESIS:
hyst = min(abs(val), 255);
return i2c_smbus_write_byte_data(client,
MCP9600_ALERT_HYSTERESIS(i + 1),
hyst);
default:
return -EINVAL;
}
}
static const struct iio_info mcp9600_info = {
.read_raw = mcp9600_read_raw,
.read_event_config = mcp9600_read_event_config,
.write_event_config = mcp9600_write_event_config,
.read_event_value = mcp9600_read_thresh,
.write_event_value = mcp9600_write_thresh,
};
static irqreturn_t mcp9600_alert_handler(void *private,
enum mcp9600_alert alert,
enum iio_modifier mod,
enum iio_event_direction dir)
{
struct iio_dev *indio_dev = private;
struct mcp9600_data *data = iio_priv(indio_dev);
int ret;
ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS);
if (ret < 0)
return IRQ_HANDLED;
if (!(ret & MCP9600_STATUS_ALERT(alert)))
return IRQ_NONE;
iio_push_event(indio_dev,
IIO_MOD_EVENT_CODE(IIO_TEMP, 0, mod, IIO_EV_TYPE_THRESH,
dir),
iio_get_time_ns(indio_dev));
return IRQ_HANDLED;
}
static irqreturn_t mcp9600_alert1_handler(int irq, void *private)
{
return mcp9600_alert_handler(private, MCP9600_ALERT1, IIO_NO_MOD,
IIO_EV_DIR_RISING);
}
static irqreturn_t mcp9600_alert2_handler(int irq, void *private)
{
return mcp9600_alert_handler(private, MCP9600_ALERT2, IIO_NO_MOD,
IIO_EV_DIR_FALLING);
}
static irqreturn_t mcp9600_alert3_handler(int irq, void *private)
{
return mcp9600_alert_handler(private, MCP9600_ALERT3,
IIO_MOD_TEMP_AMBIENT, IIO_EV_DIR_RISING);
}
static irqreturn_t mcp9600_alert4_handler(int irq, void *private)
{
return mcp9600_alert_handler(private, MCP9600_ALERT4,
IIO_MOD_TEMP_AMBIENT, IIO_EV_DIR_FALLING);
}
static irqreturn_t (*mcp9600_alert_handler_func[MCP9600_ALERT_COUNT]) (int, void *) = {
mcp9600_alert1_handler,
mcp9600_alert2_handler,
mcp9600_alert3_handler,
mcp9600_alert4_handler,
};
static int mcp9600_probe_alerts(struct iio_dev *indio_dev)
{
struct mcp9600_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
struct device *dev = &client->dev;
struct fwnode_handle *fwnode = dev_fwnode(dev);
unsigned int irq_type;
int ret, irq, i;
u8 val, ch_sel;
/*
* alert1: hot junction, rising temperature
* alert2: hot junction, falling temperature
* alert3: cold junction, rising temperature
* alert4: cold junction, falling temperature
*/
ch_sel = 0;
for (i = 0; i < MCP9600_ALERT_COUNT; i++) {
irq = fwnode_irq_get_byname(fwnode, mcp9600_alert_name[i]);
if (irq <= 0)
continue;
val = 0;
irq_type = irq_get_trigger_type(irq);
if (irq_type == IRQ_TYPE_EDGE_RISING)
val |= MCP9600_ALERT_CFG_ACTIVE_HIGH;
if (i == MCP9600_ALERT2 || i == MCP9600_ALERT4)
val |= MCP9600_ALERT_CFG_FALLING;
if (i == MCP9600_ALERT3 || i == MCP9600_ALERT4)
val |= MCP9600_ALERT_CFG_COLD_JUNCTION;
ret = i2c_smbus_write_byte_data(client,
MCP9600_ALERT_CFG(i + 1),
val);
if (ret < 0)
return ret;
ret = devm_request_threaded_irq(dev, irq, NULL,
mcp9600_alert_handler_func[i],
IRQF_ONESHOT, "mcp9600",
indio_dev);
if (ret)
return ret;
ch_sel |= BIT(i);
}
return ch_sel;
}
static int mcp9600_probe(struct i2c_client *client)
{
struct iio_dev *indio_dev;
struct mcp9600_data *data;
int ret, ch_sel;
ret = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);
if (ret < 0)
return dev_err_probe(&client->dev, ret, "Failed to read device ID\n");
if (ret != MCP9600_DEVICE_ID_MCP9600)
dev_warn(&client->dev, "Expected ID %x, got %x\n",
MCP9600_DEVICE_ID_MCP9600, ret);
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->client = client;
ch_sel = mcp9600_probe_alerts(indio_dev);
if (ch_sel < 0)
return ch_sel;
indio_dev->info = &mcp9600_info;
indio_dev->name = "mcp9600";
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = mcp9600_channels[ch_sel];
indio_dev->num_channels = ARRAY_SIZE(mcp9600_channels[ch_sel]);
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id mcp9600_id[] = {
{ "mcp9600" },
{}
};
MODULE_DEVICE_TABLE(i2c, mcp9600_id);
static const struct of_device_id mcp9600_of_match[] = {
{ .compatible = "microchip,mcp9600" },
{}
};
MODULE_DEVICE_TABLE(of, mcp9600_of_match);
static struct i2c_driver mcp9600_driver = {
.driver = {
.name = "mcp9600",
.of_match_table = mcp9600_of_match,
},
.probe = mcp9600_probe,
.id_table = mcp9600_id
};
module_i2c_driver(mcp9600_driver);
MODULE_AUTHOR("Dimitri Fedrau <dima.fedrau@gmail.com>");
MODULE_AUTHOR("Andrew Hepp <andrew.hepp@ahepp.dev>");
MODULE_DESCRIPTION("Microchip MCP9600 thermocouple EMF converter driver");
MODULE_LICENSE("GPL");
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