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/device.h> 41 #include <linux/err.h> 42 #include <linux/sysfs.h> 43 #include <linux/hwmon.h> 44 #include <linux/hwmon-sysfs.h> 45 #include <linux/mutex.h> 46 #include <linux/mod_devicetable.h> 47 #include <linux/spi/spi.h> 48 49 #define DRVNAME "adcxx" 50 51 struct adcxx { 52 struct device *hwmon_dev; 53 struct mutex lock; 54 u32 channels; 55 u32 reference; /* in millivolts */ 56 }; 57 58 /* sysfs hook function */ 59 static ssize_t adcxx_read(struct device *dev, 60 struct device_attribute *devattr, char *buf) 61 { 62 struct spi_device *spi = to_spi_device(dev); 63 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 64 struct adcxx *adc = dev_get_drvdata(&spi->dev); 65 u8 tx_buf[2] = { attr->index << 3 }; /* other bits are don't care */ 66 u8 rx_buf[2]; 67 int status; 68 int value; 69 70 if (mutex_lock_interruptible(&adc->lock)) 71 return -ERESTARTSYS; 72 73 status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf), 74 rx_buf, sizeof(rx_buf)); 75 if (status < 0) { 76 dev_warn(dev, "spi_write_then_read failed with status %d\n", 77 status); 78 goto out; 79 } 80 81 value = (rx_buf[0] << 8) + rx_buf[1]; 82 dev_dbg(dev, "raw value = 0x%x\n", value); 83 84 value = value * adc->reference >> 12; 85 status = sprintf(buf, "%d\n", value); 86 out: 87 mutex_unlock(&adc->lock); 88 return status; 89 } 90 91 static ssize_t adcxx_show_min(struct device *dev, 92 struct device_attribute *devattr, char *buf) 93 { 94 /* The minimum reference is 0 for this chip family */ 95 return sprintf(buf, "0\n"); 96 } 97 98 static ssize_t adcxx_show_max(struct device *dev, 99 struct device_attribute *devattr, char *buf) 100 { 101 struct spi_device *spi = to_spi_device(dev); 102 struct adcxx *adc = dev_get_drvdata(&spi->dev); 103 u32 reference; 104 105 if (mutex_lock_interruptible(&adc->lock)) 106 return -ERESTARTSYS; 107 108 reference = adc->reference; 109 110 mutex_unlock(&adc->lock); 111 112 return sprintf(buf, "%d\n", reference); 113 } 114 115 static ssize_t adcxx_set_max(struct device *dev, 116 struct device_attribute *devattr, const char *buf, size_t count) 117 { 118 struct spi_device *spi = to_spi_device(dev); 119 struct adcxx *adc = dev_get_drvdata(&spi->dev); 120 unsigned long value; 121 122 if (strict_strtoul(buf, 10, &value)) 123 return -EINVAL; 124 125 if (mutex_lock_interruptible(&adc->lock)) 126 return -ERESTARTSYS; 127 128 adc->reference = value; 129 130 mutex_unlock(&adc->lock); 131 132 return count; 133 } 134 135 static ssize_t adcxx_show_name(struct device *dev, struct device_attribute 136 *devattr, char *buf) 137 { 138 struct spi_device *spi = to_spi_device(dev); 139 struct adcxx *adc = dev_get_drvdata(&spi->dev); 140 141 return sprintf(buf, "adcxx%ds\n", adc->channels); 142 } 143 144 static struct sensor_device_attribute ad_input[] = { 145 SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0), 146 SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0), 147 SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max, 148 adcxx_set_max, 0), 149 SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0), 150 SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1), 151 SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2), 152 SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3), 153 SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4), 154 SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5), 155 SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6), 156 SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7), 157 }; 158 159 /*----------------------------------------------------------------------*/ 160 161 static int __devinit adcxx_probe(struct spi_device *spi) 162 { 163 int channels = spi_get_device_id(spi)->driver_data; 164 struct adcxx *adc; 165 int status; 166 int i; 167 168 adc = kzalloc(sizeof *adc, GFP_KERNEL); 169 if (!adc) 170 return -ENOMEM; 171 172 /* set a default value for the reference */ 173 adc->reference = 3300; 174 adc->channels = channels; 175 mutex_init(&adc->lock); 176 177 mutex_lock(&adc->lock); 178 179 dev_set_drvdata(&spi->dev, adc); 180 181 for (i = 0; i < 3 + adc->channels; i++) { 182 status = device_create_file(&spi->dev, &ad_input[i].dev_attr); 183 if (status) { 184 dev_err(&spi->dev, "device_create_file failed.\n"); 185 goto out_err; 186 } 187 } 188 189 adc->hwmon_dev = hwmon_device_register(&spi->dev); 190 if (IS_ERR(adc->hwmon_dev)) { 191 dev_err(&spi->dev, "hwmon_device_register failed.\n"); 192 status = PTR_ERR(adc->hwmon_dev); 193 goto out_err; 194 } 195 196 mutex_unlock(&adc->lock); 197 return 0; 198 199 out_err: 200 for (i--; i >= 0; i--) 201 device_remove_file(&spi->dev, &ad_input[i].dev_attr); 202 203 dev_set_drvdata(&spi->dev, NULL); 204 mutex_unlock(&adc->lock); 205 kfree(adc); 206 return status; 207 } 208 209 static int __devexit adcxx_remove(struct spi_device *spi) 210 { 211 struct adcxx *adc = dev_get_drvdata(&spi->dev); 212 int i; 213 214 mutex_lock(&adc->lock); 215 hwmon_device_unregister(adc->hwmon_dev); 216 for (i = 0; i < 3 + adc->channels; i++) 217 device_remove_file(&spi->dev, &ad_input[i].dev_attr); 218 219 dev_set_drvdata(&spi->dev, NULL); 220 mutex_unlock(&adc->lock); 221 kfree(adc); 222 223 return 0; 224 } 225 226 static const struct spi_device_id adcxx_ids[] = { 227 { "adcxx1s", 1 }, 228 { "adcxx2s", 2 }, 229 { "adcxx4s", 4 }, 230 { "adcxx8s", 8 }, 231 { }, 232 }; 233 MODULE_DEVICE_TABLE(spi, adcxx_ids); 234 235 static struct spi_driver adcxx_driver = { 236 .driver = { 237 .name = "adcxx", 238 .owner = THIS_MODULE, 239 }, 240 .id_table = adcxx_ids, 241 .probe = adcxx_probe, 242 .remove = __devexit_p(adcxx_remove), 243 }; 244 245 static int __init init_adcxx(void) 246 { 247 return spi_register_driver(&adcxx_driver); 248 } 249 250 static void __exit exit_adcxx(void) 251 { 252 spi_unregister_driver(&adcxx_driver); 253 } 254 255 module_init(init_adcxx); 256 module_exit(exit_adcxx); 257 258 MODULE_AUTHOR("Marc Pignat"); 259 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver"); 260 MODULE_LICENSE("GPL"); 261