/* * 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", }, .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");