1 /* 2 * adcxx.c 3 * 4 * The adcxx4s is an AD converter family from National Semiconductor (NS). 5 * 6 * Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch> 7 * 8 * The adcxx4s communicates with a host processor via an SPI/Microwire Bus 9 * interface. This driver supports the whole family of devices with name 10 * ADC<bb><c>S<sss>, where 11 * * bb is the resolution in number of bits (8, 10, 12) 12 * * c is the number of channels (1, 2, 4, 8) 13 * * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS 14 * and 101 for 1 MSPS) 15 * 16 * Complete datasheets are available at National's website here: 17 * http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf 18 * 19 * Handling of 8, 10 and 12 bits converters are the same, the 20 * unavailable bits are 0 :) 21 * 22 * This program is free software; you can redistribute it and/or modify 23 * it under the terms of the GNU General Public License as published by 24 * the Free Software Foundation; either version 2 of the License, or 25 * (at your option) any later version. 26 * 27 * This program is distributed in the hope that it will be useful, 28 * but WITHOUT ANY WARRANTY; without even the implied warranty of 29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 30 * GNU General Public License for more details. 31 * 32 * You should have received a copy of the GNU General Public License 33 * along with this program; if not, write to the Free Software 34 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 35 */ 36 37 #include <linux/init.h> 38 #include <linux/module.h> 39 #include <linux/kernel.h> 40 #include <linux/slab.h> 41 #include <linux/device.h> 42 #include <linux/err.h> 43 #include <linux/sysfs.h> 44 #include <linux/hwmon.h> 45 #include <linux/hwmon-sysfs.h> 46 #include <linux/mutex.h> 47 #include <linux/mod_devicetable.h> 48 #include <linux/spi/spi.h> 49 50 #define DRVNAME "adcxx" 51 52 struct adcxx { 53 struct device *hwmon_dev; 54 struct mutex lock; 55 u32 channels; 56 u32 reference; /* in millivolts */ 57 }; 58 59 /* sysfs hook function */ 60 static ssize_t adcxx_read(struct device *dev, 61 struct device_attribute *devattr, char *buf) 62 { 63 struct spi_device *spi = to_spi_device(dev); 64 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 65 struct adcxx *adc = spi_get_drvdata(spi); 66 u8 tx_buf[2]; 67 u8 rx_buf[2]; 68 int status; 69 u32 value; 70 71 if (mutex_lock_interruptible(&adc->lock)) 72 return -ERESTARTSYS; 73 74 if (adc->channels == 1) { 75 status = spi_read(spi, rx_buf, sizeof(rx_buf)); 76 } else { 77 tx_buf[0] = attr->index << 3; /* other bits are don't care */ 78 status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf), 79 rx_buf, sizeof(rx_buf)); 80 } 81 if (status < 0) { 82 dev_warn(dev, "SPI synch. transfer failed with status %d\n", 83 status); 84 goto out; 85 } 86 87 value = (rx_buf[0] << 8) + rx_buf[1]; 88 dev_dbg(dev, "raw value = 0x%x\n", value); 89 90 value = value * adc->reference >> 12; 91 status = sprintf(buf, "%d\n", value); 92 out: 93 mutex_unlock(&adc->lock); 94 return status; 95 } 96 97 static ssize_t adcxx_show_min(struct device *dev, 98 struct device_attribute *devattr, char *buf) 99 { 100 /* The minimum reference is 0 for this chip family */ 101 return sprintf(buf, "0\n"); 102 } 103 104 static ssize_t adcxx_show_max(struct device *dev, 105 struct device_attribute *devattr, char *buf) 106 { 107 struct spi_device *spi = to_spi_device(dev); 108 struct adcxx *adc = spi_get_drvdata(spi); 109 u32 reference; 110 111 if (mutex_lock_interruptible(&adc->lock)) 112 return -ERESTARTSYS; 113 114 reference = adc->reference; 115 116 mutex_unlock(&adc->lock); 117 118 return sprintf(buf, "%d\n", reference); 119 } 120 121 static ssize_t adcxx_set_max(struct device *dev, 122 struct device_attribute *devattr, const char *buf, size_t count) 123 { 124 struct spi_device *spi = to_spi_device(dev); 125 struct adcxx *adc = spi_get_drvdata(spi); 126 unsigned long value; 127 128 if (kstrtoul(buf, 10, &value)) 129 return -EINVAL; 130 131 if (mutex_lock_interruptible(&adc->lock)) 132 return -ERESTARTSYS; 133 134 adc->reference = value; 135 136 mutex_unlock(&adc->lock); 137 138 return count; 139 } 140 141 static ssize_t adcxx_show_name(struct device *dev, struct device_attribute 142 *devattr, char *buf) 143 { 144 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias); 145 } 146 147 static struct sensor_device_attribute ad_input[] = { 148 SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0), 149 SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0), 150 SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max, 151 adcxx_set_max, 0), 152 SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0), 153 SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1), 154 SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2), 155 SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3), 156 SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4), 157 SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5), 158 SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6), 159 SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7), 160 }; 161 162 /*----------------------------------------------------------------------*/ 163 164 static int adcxx_probe(struct spi_device *spi) 165 { 166 int channels = spi_get_device_id(spi)->driver_data; 167 struct adcxx *adc; 168 int status; 169 int i; 170 171 adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL); 172 if (!adc) 173 return -ENOMEM; 174 175 /* set a default value for the reference */ 176 adc->reference = 3300; 177 adc->channels = channels; 178 mutex_init(&adc->lock); 179 180 mutex_lock(&adc->lock); 181 182 spi_set_drvdata(spi, adc); 183 184 for (i = 0; i < 3 + adc->channels; i++) { 185 status = device_create_file(&spi->dev, &ad_input[i].dev_attr); 186 if (status) { 187 dev_err(&spi->dev, "device_create_file failed.\n"); 188 goto out_err; 189 } 190 } 191 192 adc->hwmon_dev = hwmon_device_register(&spi->dev); 193 if (IS_ERR(adc->hwmon_dev)) { 194 dev_err(&spi->dev, "hwmon_device_register failed.\n"); 195 status = PTR_ERR(adc->hwmon_dev); 196 goto out_err; 197 } 198 199 mutex_unlock(&adc->lock); 200 return 0; 201 202 out_err: 203 for (i--; i >= 0; i--) 204 device_remove_file(&spi->dev, &ad_input[i].dev_attr); 205 206 mutex_unlock(&adc->lock); 207 return status; 208 } 209 210 static int adcxx_remove(struct spi_device *spi) 211 { 212 struct adcxx *adc = spi_get_drvdata(spi); 213 int i; 214 215 mutex_lock(&adc->lock); 216 hwmon_device_unregister(adc->hwmon_dev); 217 for (i = 0; i < 3 + adc->channels; i++) 218 device_remove_file(&spi->dev, &ad_input[i].dev_attr); 219 220 mutex_unlock(&adc->lock); 221 222 return 0; 223 } 224 225 static const struct spi_device_id adcxx_ids[] = { 226 { "adcxx1s", 1 }, 227 { "adcxx2s", 2 }, 228 { "adcxx4s", 4 }, 229 { "adcxx8s", 8 }, 230 { }, 231 }; 232 MODULE_DEVICE_TABLE(spi, adcxx_ids); 233 234 static struct spi_driver adcxx_driver = { 235 .driver = { 236 .name = "adcxx", 237 .owner = THIS_MODULE, 238 }, 239 .id_table = adcxx_ids, 240 .probe = adcxx_probe, 241 .remove = adcxx_remove, 242 }; 243 244 module_spi_driver(adcxx_driver); 245 246 MODULE_AUTHOR("Marc Pignat"); 247 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver"); 248 MODULE_LICENSE("GPL"); 249