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linux/drivers/iio/temperature/tmp006.c
Alexandru Ardelean c359a80ca2 iio: temperature: tmp006: make sure the chip is powered up in probe 
When the device is probed, there's no guarantee that the device is not in
power-down mode. This can happen if the driver is unregistered and
re-probed.

To make sure this doesn't happen, the value of the TMP006_CONFIG register
(which is read in the probe function and stored in the device's private
data) is being checked to see if the MOD bits have the correct value.

This is a fix for a somewhat-rare corner case. As it stands, this doesn't
look like a high priority to go into the Fixes route.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210624081924.15897-2-aardelean@deviqon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-07-19 09:51:59 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* tmp006.c - Support for TI TMP006 IR thermopile sensor
*
* Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
*
* Driver for the Texas Instruments I2C 16-bit IR thermopile sensor
*
* (7-bit I2C slave address 0x40, changeable via ADR pins)
*
* TODO: data ready irq
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define TMP006_VOBJECT 0x00
#define TMP006_TAMBIENT 0x01
#define TMP006_CONFIG 0x02
#define TMP006_MANUFACTURER_ID 0xfe
#define TMP006_DEVICE_ID 0xff
#define TMP006_TAMBIENT_SHIFT 2
#define TMP006_CONFIG_RESET BIT(15)
#define TMP006_CONFIG_DRDY_EN BIT(8)
#define TMP006_CONFIG_DRDY BIT(7)
#define TMP006_CONFIG_MOD_MASK GENMASK(14, 12)
#define TMP006_CONFIG_CR_MASK GENMASK(11, 9)
#define TMP006_CONFIG_CR_SHIFT 9
#define TMP006_MANUFACTURER_MAGIC 0x5449
#define TMP006_DEVICE_MAGIC 0x0067
struct tmp006_data {
struct i2c_client *client;
u16 config;
};
static int tmp006_read_measurement(struct tmp006_data *data, u8 reg)
{
s32 ret;
int tries = 50;
while (tries-- > 0) {
ret = i2c_smbus_read_word_swapped(data->client,
TMP006_CONFIG);
if (ret < 0)
return ret;
if (ret & TMP006_CONFIG_DRDY)
break;
msleep(100);
}
if (tries < 0)
return -EIO;
return i2c_smbus_read_word_swapped(data->client, reg);
}
static const int tmp006_freqs[5][2] = { {4, 0}, {2, 0}, {1, 0},
{0, 500000}, {0, 250000} };
static int tmp006_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct tmp006_data *data = iio_priv(indio_dev);
s32 ret;
int cr;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (channel->type == IIO_VOLTAGE) {
/* LSB is 156.25 nV */
ret = tmp006_read_measurement(data, TMP006_VOBJECT);
if (ret < 0)
return ret;
*val = sign_extend32(ret, 15);
} else if (channel->type == IIO_TEMP) {
/* LSB is 0.03125 degrees Celsius */
ret = tmp006_read_measurement(data, TMP006_TAMBIENT);
if (ret < 0)
return ret;
*val = sign_extend32(ret, 15) >> TMP006_TAMBIENT_SHIFT;
} else {
break;
}
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
if (channel->type == IIO_VOLTAGE) {
*val = 0;
*val2 = 156250;
} else if (channel->type == IIO_TEMP) {
*val = 31;
*val2 = 250000;
} else {
break;
}
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
cr = (data->config & TMP006_CONFIG_CR_MASK)
>> TMP006_CONFIG_CR_SHIFT;
*val = tmp006_freqs[cr][0];
*val2 = tmp006_freqs[cr][1];
return IIO_VAL_INT_PLUS_MICRO;
default:
break;
}
return -EINVAL;
}
static int tmp006_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
struct tmp006_data *data = iio_priv(indio_dev);
int i;
if (mask != IIO_CHAN_INFO_SAMP_FREQ)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(tmp006_freqs); i++)
if ((val == tmp006_freqs[i][0]) &&
(val2 == tmp006_freqs[i][1])) {
data->config &= ~TMP006_CONFIG_CR_MASK;
data->config |= i << TMP006_CONFIG_CR_SHIFT;
return i2c_smbus_write_word_swapped(data->client,
TMP006_CONFIG,
data->config);
}
return -EINVAL;
}
static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");
static struct attribute *tmp006_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL
};
static const struct attribute_group tmp006_attribute_group = {
.attrs = tmp006_attributes,
};
static const struct iio_chan_spec tmp006_channels[] = {
{
.type = IIO_VOLTAGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
}
};
static const struct iio_info tmp006_info = {
.read_raw = tmp006_read_raw,
.write_raw = tmp006_write_raw,
.attrs = &tmp006_attribute_group,
};
static bool tmp006_check_identification(struct i2c_client *client)
{
int mid, did;
mid = i2c_smbus_read_word_swapped(client, TMP006_MANUFACTURER_ID);
if (mid < 0)
return false;
did = i2c_smbus_read_word_swapped(client, TMP006_DEVICE_ID);
if (did < 0)
return false;
return mid == TMP006_MANUFACTURER_MAGIC && did == TMP006_DEVICE_MAGIC;
}
static int tmp006_power(struct device *dev, bool up)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct tmp006_data *data = iio_priv(indio_dev);
if (up)
data->config |= TMP006_CONFIG_MOD_MASK;
else
data->config &= ~TMP006_CONFIG_MOD_MASK;
return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
data->config);
}
static void tmp006_powerdown_cleanup(void *dev)
{
tmp006_power(dev, false);
}
static int tmp006_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct tmp006_data *data;
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -EOPNOTSUPP;
if (!tmp006_check_identification(client)) {
dev_err(&client->dev, "no TMP006 sensor\n");
return -ENODEV;
}
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
indio_dev->name = dev_name(&client->dev);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &tmp006_info;
indio_dev->channels = tmp006_channels;
indio_dev->num_channels = ARRAY_SIZE(tmp006_channels);
ret = i2c_smbus_read_word_swapped(data->client, TMP006_CONFIG);
if (ret < 0)
return ret;
data->config = ret;
if ((ret & TMP006_CONFIG_MOD_MASK) != TMP006_CONFIG_MOD_MASK) {
ret = tmp006_power(&client->dev, true);
if (ret < 0)
return ret;
}
ret = devm_add_action_or_reset(&client->dev, tmp006_powerdown_cleanup,
&client->dev);
if (ret < 0)
return ret;
return devm_iio_device_register(&client->dev, indio_dev);
}
#ifdef CONFIG_PM_SLEEP
static int tmp006_suspend(struct device *dev)
{
return tmp006_power(dev, false);
}
static int tmp006_resume(struct device *dev)
{
return tmp006_power(dev, true);
}
#endif
static SIMPLE_DEV_PM_OPS(tmp006_pm_ops, tmp006_suspend, tmp006_resume);
static const struct i2c_device_id tmp006_id[] = {
{ "tmp006", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, tmp006_id);
static struct i2c_driver tmp006_driver = {
.driver = {
.name = "tmp006",
.pm = &tmp006_pm_ops,
},
.probe = tmp006_probe,
.id_table = tmp006_id,
};
module_i2c_driver(tmp006_driver);
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("TI TMP006 IR thermopile sensor driver");
MODULE_LICENSE("GPL");
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