linux/drivers/hwmon/adcxx.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

233 lines
5.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* adcxx.c
*
* The adcxx4s is an AD converter family from National Semiconductor (NS).
*
* Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>
*
* The adcxx4s communicates with a host processor via an SPI/Microwire Bus
* interface. This driver supports the whole family of devices with name
* ADC<bb><c>S<sss>, where
* * bb is the resolution in number of bits (8, 10, 12)
* * c is the number of channels (1, 2, 4, 8)
* * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
* and 101 for 1 MSPS)
*
* Complete datasheets are available at National's website here:
* http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
*
* Handling of 8, 10 and 12 bits converters are the same, the
* unavailable bits are 0 :)
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/sysfs.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/mutex.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#define DRVNAME "adcxx"
struct adcxx {
struct device *hwmon_dev;
struct mutex lock;
u32 channels;
u32 reference; /* in millivolts */
};
/* sysfs hook function */
static ssize_t adcxx_show(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct spi_device *spi = to_spi_device(dev);
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct adcxx *adc = spi_get_drvdata(spi);
u8 tx_buf[2];
u8 rx_buf[2];
int status;
u32 value;
if (mutex_lock_interruptible(&adc->lock))
return -ERESTARTSYS;
if (adc->channels == 1) {
status = spi_read(spi, rx_buf, sizeof(rx_buf));
} else {
tx_buf[0] = attr->index << 3; /* other bits are don't care */
status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
rx_buf, sizeof(rx_buf));
}
if (status < 0) {
dev_warn(dev, "SPI synch. transfer failed with status %d\n",
status);
goto out;
}
value = (rx_buf[0] << 8) + rx_buf[1];
dev_dbg(dev, "raw value = 0x%x\n", value);
value = value * adc->reference >> 12;
status = sprintf(buf, "%d\n", value);
out:
mutex_unlock(&adc->lock);
return status;
}
static ssize_t adcxx_min_show(struct device *dev,
struct device_attribute *devattr, char *buf)
{
/* The minimum reference is 0 for this chip family */
return sprintf(buf, "0\n");
}
static ssize_t adcxx_max_show(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct spi_device *spi = to_spi_device(dev);
struct adcxx *adc = spi_get_drvdata(spi);
u32 reference;
if (mutex_lock_interruptible(&adc->lock))
return -ERESTARTSYS;
reference = adc->reference;
mutex_unlock(&adc->lock);
return sprintf(buf, "%d\n", reference);
}
static ssize_t adcxx_max_store(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct spi_device *spi = to_spi_device(dev);
struct adcxx *adc = spi_get_drvdata(spi);
unsigned long value;
if (kstrtoul(buf, 10, &value))
return -EINVAL;
if (mutex_lock_interruptible(&adc->lock))
return -ERESTARTSYS;
adc->reference = value;
mutex_unlock(&adc->lock);
return count;
}
static ssize_t adcxx_name_show(struct device *dev,
struct device_attribute *devattr, char *buf)
{
return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
}
static struct sensor_device_attribute ad_input[] = {
SENSOR_ATTR_RO(name, adcxx_name, 0),
SENSOR_ATTR_RO(in_min, adcxx_min, 0),
SENSOR_ATTR_RW(in_max, adcxx_max, 0),
SENSOR_ATTR_RO(in0_input, adcxx, 0),
SENSOR_ATTR_RO(in1_input, adcxx, 1),
SENSOR_ATTR_RO(in2_input, adcxx, 2),
SENSOR_ATTR_RO(in3_input, adcxx, 3),
SENSOR_ATTR_RO(in4_input, adcxx, 4),
SENSOR_ATTR_RO(in5_input, adcxx, 5),
SENSOR_ATTR_RO(in6_input, adcxx, 6),
SENSOR_ATTR_RO(in7_input, adcxx, 7),
};
/*----------------------------------------------------------------------*/
static int adcxx_probe(struct spi_device *spi)
{
int channels = spi_get_device_id(spi)->driver_data;
struct adcxx *adc;
int status;
int i;
adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL);
if (!adc)
return -ENOMEM;
/* set a default value for the reference */
adc->reference = 3300;
adc->channels = channels;
mutex_init(&adc->lock);
mutex_lock(&adc->lock);
spi_set_drvdata(spi, adc);
for (i = 0; i < 3 + adc->channels; i++) {
status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
if (status) {
dev_err(&spi->dev, "device_create_file failed.\n");
goto out_err;
}
}
adc->hwmon_dev = hwmon_device_register(&spi->dev);
if (IS_ERR(adc->hwmon_dev)) {
dev_err(&spi->dev, "hwmon_device_register failed.\n");
status = PTR_ERR(adc->hwmon_dev);
goto out_err;
}
mutex_unlock(&adc->lock);
return 0;
out_err:
for (i--; i >= 0; i--)
device_remove_file(&spi->dev, &ad_input[i].dev_attr);
mutex_unlock(&adc->lock);
return status;
}
static void adcxx_remove(struct spi_device *spi)
{
struct adcxx *adc = spi_get_drvdata(spi);
int i;
mutex_lock(&adc->lock);
hwmon_device_unregister(adc->hwmon_dev);
for (i = 0; i < 3 + adc->channels; i++)
device_remove_file(&spi->dev, &ad_input[i].dev_attr);
mutex_unlock(&adc->lock);
}
static const struct spi_device_id adcxx_ids[] = {
{ "adcxx1s", 1 },
{ "adcxx2s", 2 },
{ "adcxx4s", 4 },
{ "adcxx8s", 8 },
{ },
};
MODULE_DEVICE_TABLE(spi, adcxx_ids);
static struct spi_driver adcxx_driver = {
.driver = {
.name = "adcxx",
},
.id_table = adcxx_ids,
.probe = adcxx_probe,
.remove = adcxx_remove,
};
module_spi_driver(adcxx_driver);
MODULE_AUTHOR("Marc Pignat");
MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
MODULE_LICENSE("GPL");