233 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * adcxx.c4 *5 * The adcxx4s is an AD converter family from National Semiconductor (NS).6 *7 * Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>8 *9 * The adcxx4s communicates with a host processor via an SPI/Microwire Bus10 * interface. This driver supports the whole family of devices with name11 * ADC<bb><c>S<sss>, where12 * * bb is the resolution in number of bits (8, 10, 12)13 * * c is the number of channels (1, 2, 4, 8)14 * * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS15 * and 101 for 1 MSPS)16 *17 * Complete datasheets are available at National's website here:18 * http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf19 *20 * Handling of 8, 10 and 12 bits converters are the same, the21 * unavailable bits are 0 :)22 */23 24#include <linux/init.h>25#include <linux/module.h>26#include <linux/kernel.h>27#include <linux/slab.h>28#include <linux/device.h>29#include <linux/err.h>30#include <linux/sysfs.h>31#include <linux/hwmon.h>32#include <linux/hwmon-sysfs.h>33#include <linux/mutex.h>34#include <linux/mod_devicetable.h>35#include <linux/spi/spi.h>36 37#define DRVNAME "adcxx"38 39struct adcxx {40 struct device *hwmon_dev;41 struct mutex lock;42 u32 channels;43 u32 reference; /* in millivolts */44};45 46/* sysfs hook function */47static ssize_t adcxx_show(struct device *dev,48 struct device_attribute *devattr, char *buf)49{50 struct spi_device *spi = to_spi_device(dev);51 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);52 struct adcxx *adc = spi_get_drvdata(spi);53 u8 tx_buf[2];54 u8 rx_buf[2];55 int status;56 u32 value;57 58 if (mutex_lock_interruptible(&adc->lock))59 return -ERESTARTSYS;60 61 if (adc->channels == 1) {62 status = spi_read(spi, rx_buf, sizeof(rx_buf));63 } else {64 tx_buf[0] = attr->index << 3; /* other bits are don't care */65 status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),66 rx_buf, sizeof(rx_buf));67 }68 if (status < 0) {69 dev_warn(dev, "SPI synch. transfer failed with status %d\n",70 status);71 goto out;72 }73 74 value = (rx_buf[0] << 8) + rx_buf[1];75 dev_dbg(dev, "raw value = 0x%x\n", value);76 77 value = value * adc->reference >> 12;78 status = sprintf(buf, "%d\n", value);79out:80 mutex_unlock(&adc->lock);81 return status;82}83 84static ssize_t adcxx_min_show(struct device *dev,85 struct device_attribute *devattr, char *buf)86{87 /* The minimum reference is 0 for this chip family */88 return sprintf(buf, "0\n");89}90 91static ssize_t adcxx_max_show(struct device *dev,92 struct device_attribute *devattr, char *buf)93{94 struct spi_device *spi = to_spi_device(dev);95 struct adcxx *adc = spi_get_drvdata(spi);96 u32 reference;97 98 if (mutex_lock_interruptible(&adc->lock))99 return -ERESTARTSYS;100 101 reference = adc->reference;102 103 mutex_unlock(&adc->lock);104 105 return sprintf(buf, "%d\n", reference);106}107 108static ssize_t adcxx_max_store(struct device *dev,109 struct device_attribute *devattr,110 const char *buf, size_t count)111{112 struct spi_device *spi = to_spi_device(dev);113 struct adcxx *adc = spi_get_drvdata(spi);114 unsigned long value;115 116 if (kstrtoul(buf, 10, &value))117 return -EINVAL;118 119 if (mutex_lock_interruptible(&adc->lock))120 return -ERESTARTSYS;121 122 adc->reference = value;123 124 mutex_unlock(&adc->lock);125 126 return count;127}128 129static ssize_t adcxx_name_show(struct device *dev,130 struct device_attribute *devattr, char *buf)131{132 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);133}134 135static struct sensor_device_attribute ad_input[] = {136 SENSOR_ATTR_RO(name, adcxx_name, 0),137 SENSOR_ATTR_RO(in_min, adcxx_min, 0),138 SENSOR_ATTR_RW(in_max, adcxx_max, 0),139 SENSOR_ATTR_RO(in0_input, adcxx, 0),140 SENSOR_ATTR_RO(in1_input, adcxx, 1),141 SENSOR_ATTR_RO(in2_input, adcxx, 2),142 SENSOR_ATTR_RO(in3_input, adcxx, 3),143 SENSOR_ATTR_RO(in4_input, adcxx, 4),144 SENSOR_ATTR_RO(in5_input, adcxx, 5),145 SENSOR_ATTR_RO(in6_input, adcxx, 6),146 SENSOR_ATTR_RO(in7_input, adcxx, 7),147};148 149/*----------------------------------------------------------------------*/150 151static int adcxx_probe(struct spi_device *spi)152{153 int channels = spi_get_device_id(spi)->driver_data;154 struct adcxx *adc;155 int status;156 int i;157 158 adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL);159 if (!adc)160 return -ENOMEM;161 162 /* set a default value for the reference */163 adc->reference = 3300;164 adc->channels = channels;165 mutex_init(&adc->lock);166 167 mutex_lock(&adc->lock);168 169 spi_set_drvdata(spi, adc);170 171 for (i = 0; i < 3 + adc->channels; i++) {172 status = device_create_file(&spi->dev, &ad_input[i].dev_attr);173 if (status) {174 dev_err(&spi->dev, "device_create_file failed.\n");175 goto out_err;176 }177 }178 179 adc->hwmon_dev = hwmon_device_register(&spi->dev);180 if (IS_ERR(adc->hwmon_dev)) {181 dev_err(&spi->dev, "hwmon_device_register failed.\n");182 status = PTR_ERR(adc->hwmon_dev);183 goto out_err;184 }185 186 mutex_unlock(&adc->lock);187 return 0;188 189out_err:190 for (i--; i >= 0; i--)191 device_remove_file(&spi->dev, &ad_input[i].dev_attr);192 193 mutex_unlock(&adc->lock);194 return status;195}196 197static void adcxx_remove(struct spi_device *spi)198{199 struct adcxx *adc = spi_get_drvdata(spi);200 int i;201 202 mutex_lock(&adc->lock);203 hwmon_device_unregister(adc->hwmon_dev);204 for (i = 0; i < 3 + adc->channels; i++)205 device_remove_file(&spi->dev, &ad_input[i].dev_attr);206 207 mutex_unlock(&adc->lock);208}209 210static const struct spi_device_id adcxx_ids[] = {211 { "adcxx1s", 1 },212 { "adcxx2s", 2 },213 { "adcxx4s", 4 },214 { "adcxx8s", 8 },215 { },216};217MODULE_DEVICE_TABLE(spi, adcxx_ids);218 219static struct spi_driver adcxx_driver = {220 .driver = {221 .name = "adcxx",222 },223 .id_table = adcxx_ids,224 .probe = adcxx_probe,225 .remove = adcxx_remove,226};227 228module_spi_driver(adcxx_driver);229 230MODULE_AUTHOR("Marc Pignat");231MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");232MODULE_LICENSE("GPL");233