diff options
Diffstat (limited to 'kernel/drivers/hwmon/adcxx.c')
| -rw-r--r-- | kernel/drivers/hwmon/adcxx.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/kernel/drivers/hwmon/adcxx.c b/kernel/drivers/hwmon/adcxx.c new file mode 100644 index 000000000..04c08c2f7 --- /dev/null +++ b/kernel/drivers/hwmon/adcxx.c @@ -0,0 +1,248 @@ +/* + * 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 :) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#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_read(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_show_min(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_show_max(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_set_max(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_show_name(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(name, S_IRUGO, adcxx_show_name, NULL, 0), + SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0), + SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max, + adcxx_set_max, 0), + SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0), + SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1), + SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2), + SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3), + SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4), + SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5), + SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6), + SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 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 int 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); + + return 0; +} + +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", + .owner = THIS_MODULE, + }, + .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"); |