linux/drivers/hwmon/max31722.c
Uwe Kleine-König a0386bba70
spi: make remove callback a void function
The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09 13:00:45 +00:00

156 lines
3.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI
* digital thermometer and thermostats.
*
* Copyright (c) 2016, Intel Corporation.
*/
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spi/spi.h>
#define MAX31722_REG_CFG 0x00
#define MAX31722_REG_TEMP_LSB 0x01
#define MAX31722_MODE_CONTINUOUS 0x00
#define MAX31722_MODE_STANDBY 0x01
#define MAX31722_MODE_MASK 0xFE
#define MAX31722_RESOLUTION_12BIT 0x06
#define MAX31722_WRITE_MASK 0x80
struct max31722_data {
struct device *hwmon_dev;
struct spi_device *spi_device;
u8 mode;
};
static int max31722_set_mode(struct max31722_data *data, u8 mode)
{
int ret;
struct spi_device *spi = data->spi_device;
u8 buf[2] = {
MAX31722_REG_CFG | MAX31722_WRITE_MASK,
(data->mode & MAX31722_MODE_MASK) | mode
};
ret = spi_write(spi, &buf, sizeof(buf));
if (ret < 0) {
dev_err(&spi->dev, "failed to set sensor mode.\n");
return ret;
}
data->mode = (data->mode & MAX31722_MODE_MASK) | mode;
return 0;
}
static ssize_t max31722_temp_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
ssize_t ret;
struct max31722_data *data = dev_get_drvdata(dev);
ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB);
if (ret < 0)
return ret;
/* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */
return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32);
}
static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0);
static struct attribute *max31722_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(max31722);
static int max31722_probe(struct spi_device *spi)
{
int ret;
struct max31722_data *data;
data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
spi_set_drvdata(spi, data);
data->spi_device = spi;
/*
* Set SD bit to 0 so we can have continuous measurements.
* Set resolution to 12 bits for maximum precision.
*/
data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT;
ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
if (ret < 0)
return ret;
data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev,
spi->modalias,
data,
max31722_groups);
if (IS_ERR(data->hwmon_dev)) {
max31722_set_mode(data, MAX31722_MODE_STANDBY);
return PTR_ERR(data->hwmon_dev);
}
return 0;
}
static void max31722_remove(struct spi_device *spi)
{
struct max31722_data *data = spi_get_drvdata(spi);
int ret;
hwmon_device_unregister(data->hwmon_dev);
ret = max31722_set_mode(data, MAX31722_MODE_STANDBY);
if (ret)
/* There is nothing we can do about this ... */
dev_warn(&spi->dev, "Failed to put device in stand-by mode\n");
}
static int __maybe_unused max31722_suspend(struct device *dev)
{
struct spi_device *spi_device = to_spi_device(dev);
struct max31722_data *data = spi_get_drvdata(spi_device);
return max31722_set_mode(data, MAX31722_MODE_STANDBY);
}
static int __maybe_unused max31722_resume(struct device *dev)
{
struct spi_device *spi_device = to_spi_device(dev);
struct max31722_data *data = spi_get_drvdata(spi_device);
return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
}
static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume);
static const struct spi_device_id max31722_spi_id[] = {
{"max31722", 0},
{"max31723", 0},
{}
};
MODULE_DEVICE_TABLE(spi, max31722_spi_id);
static struct spi_driver max31722_driver = {
.driver = {
.name = "max31722",
.pm = &max31722_pm_ops,
},
.probe = max31722_probe,
.remove = max31722_remove,
.id_table = max31722_spi_id,
};
module_spi_driver(max31722_driver);
MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
MODULE_DESCRIPTION("max31722 sensor driver");
MODULE_LICENSE("GPL v2");