1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * kcomedilib/kcomedilib.c 4 * a comedlib interface for kernel modules 5 * 6 * COMEDI - Linux Control and Measurement Device Interface 7 * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org> 8 */ 9 10 #include <linux/module.h> 11 12 #include <linux/errno.h> 13 #include <linux/kernel.h> 14 #include <linux/sched.h> 15 #include <linux/fcntl.h> 16 #include <linux/mm.h> 17 #include <linux/io.h> 18 19 #include <linux/comedi.h> 20 #include <linux/comedi/comedidev.h> 21 #include <linux/comedi/comedilib.h> 22 23 MODULE_AUTHOR("David Schleef <ds@schleef.org>"); 24 MODULE_DESCRIPTION("Comedi kernel library"); 25 MODULE_LICENSE("GPL"); 26 27 struct comedi_device *comedi_open(const char *filename) 28 { 29 struct comedi_device *dev, *retval = NULL; 30 unsigned int minor; 31 32 if (strncmp(filename, "/dev/comedi", 11) != 0) 33 return NULL; 34 35 if (kstrtouint(filename + 11, 0, &minor)) 36 return NULL; 37 38 if (minor >= COMEDI_NUM_BOARD_MINORS) 39 return NULL; 40 41 dev = comedi_dev_get_from_minor(minor); 42 if (!dev) 43 return NULL; 44 45 down_read(&dev->attach_lock); 46 if (dev->attached) 47 retval = dev; 48 else 49 retval = NULL; 50 up_read(&dev->attach_lock); 51 52 if (!retval) 53 comedi_dev_put(dev); 54 55 return retval; 56 } 57 EXPORT_SYMBOL_GPL(comedi_open); 58 59 int comedi_close(struct comedi_device *dev) 60 { 61 comedi_dev_put(dev); 62 return 0; 63 } 64 EXPORT_SYMBOL_GPL(comedi_close); 65 66 static int comedi_do_insn(struct comedi_device *dev, 67 struct comedi_insn *insn, 68 unsigned int *data) 69 { 70 struct comedi_subdevice *s; 71 int ret; 72 73 mutex_lock(&dev->mutex); 74 75 if (!dev->attached) { 76 ret = -EINVAL; 77 goto error; 78 } 79 80 /* a subdevice instruction */ 81 if (insn->subdev >= dev->n_subdevices) { 82 ret = -EINVAL; 83 goto error; 84 } 85 s = &dev->subdevices[insn->subdev]; 86 87 if (s->type == COMEDI_SUBD_UNUSED) { 88 dev_err(dev->class_dev, 89 "%d not usable subdevice\n", insn->subdev); 90 ret = -EIO; 91 goto error; 92 } 93 94 /* XXX check lock */ 95 96 ret = comedi_check_chanlist(s, 1, &insn->chanspec); 97 if (ret < 0) { 98 dev_err(dev->class_dev, "bad chanspec\n"); 99 ret = -EINVAL; 100 goto error; 101 } 102 103 if (s->busy) { 104 ret = -EBUSY; 105 goto error; 106 } 107 s->busy = dev; 108 109 switch (insn->insn) { 110 case INSN_BITS: 111 ret = s->insn_bits(dev, s, insn, data); 112 break; 113 case INSN_CONFIG: 114 /* XXX should check instruction length */ 115 ret = s->insn_config(dev, s, insn, data); 116 break; 117 default: 118 ret = -EINVAL; 119 break; 120 } 121 122 s->busy = NULL; 123 error: 124 125 mutex_unlock(&dev->mutex); 126 return ret; 127 } 128 129 int comedi_dio_get_config(struct comedi_device *dev, unsigned int subdev, 130 unsigned int chan, unsigned int *io) 131 { 132 struct comedi_insn insn; 133 unsigned int data[2]; 134 int ret; 135 136 memset(&insn, 0, sizeof(insn)); 137 insn.insn = INSN_CONFIG; 138 insn.n = 2; 139 insn.subdev = subdev; 140 insn.chanspec = CR_PACK(chan, 0, 0); 141 data[0] = INSN_CONFIG_DIO_QUERY; 142 data[1] = 0; 143 ret = comedi_do_insn(dev, &insn, data); 144 if (ret >= 0) 145 *io = data[1]; 146 return ret; 147 } 148 EXPORT_SYMBOL_GPL(comedi_dio_get_config); 149 150 int comedi_dio_config(struct comedi_device *dev, unsigned int subdev, 151 unsigned int chan, unsigned int io) 152 { 153 struct comedi_insn insn; 154 155 memset(&insn, 0, sizeof(insn)); 156 insn.insn = INSN_CONFIG; 157 insn.n = 1; 158 insn.subdev = subdev; 159 insn.chanspec = CR_PACK(chan, 0, 0); 160 161 return comedi_do_insn(dev, &insn, &io); 162 } 163 EXPORT_SYMBOL_GPL(comedi_dio_config); 164 165 int comedi_dio_bitfield2(struct comedi_device *dev, unsigned int subdev, 166 unsigned int mask, unsigned int *bits, 167 unsigned int base_channel) 168 { 169 struct comedi_insn insn; 170 unsigned int data[2]; 171 unsigned int n_chan; 172 unsigned int shift; 173 int ret; 174 175 base_channel = CR_CHAN(base_channel); 176 n_chan = comedi_get_n_channels(dev, subdev); 177 if (base_channel >= n_chan) 178 return -EINVAL; 179 180 memset(&insn, 0, sizeof(insn)); 181 insn.insn = INSN_BITS; 182 insn.chanspec = base_channel; 183 insn.n = 2; 184 insn.subdev = subdev; 185 186 data[0] = mask; 187 data[1] = *bits; 188 189 /* 190 * Most drivers ignore the base channel in insn->chanspec. 191 * Fix this here if the subdevice has <= 32 channels. 192 */ 193 if (n_chan <= 32) { 194 shift = base_channel; 195 if (shift) { 196 insn.chanspec = 0; 197 data[0] <<= shift; 198 data[1] <<= shift; 199 } 200 } else { 201 shift = 0; 202 } 203 204 ret = comedi_do_insn(dev, &insn, data); 205 *bits = data[1] >> shift; 206 return ret; 207 } 208 EXPORT_SYMBOL_GPL(comedi_dio_bitfield2); 209 210 int comedi_find_subdevice_by_type(struct comedi_device *dev, int type, 211 unsigned int subd) 212 { 213 struct comedi_subdevice *s; 214 int ret = -ENODEV; 215 216 down_read(&dev->attach_lock); 217 if (dev->attached) 218 for (; subd < dev->n_subdevices; subd++) { 219 s = &dev->subdevices[subd]; 220 if (s->type == type) { 221 ret = subd; 222 break; 223 } 224 } 225 up_read(&dev->attach_lock); 226 return ret; 227 } 228 EXPORT_SYMBOL_GPL(comedi_find_subdevice_by_type); 229 230 int comedi_get_n_channels(struct comedi_device *dev, unsigned int subdevice) 231 { 232 int n; 233 234 down_read(&dev->attach_lock); 235 if (!dev->attached || subdevice >= dev->n_subdevices) 236 n = 0; 237 else 238 n = dev->subdevices[subdevice].n_chan; 239 up_read(&dev->attach_lock); 240 241 return n; 242 } 243 EXPORT_SYMBOL_GPL(comedi_get_n_channels); 244 245 static int __init kcomedilib_module_init(void) 246 { 247 return 0; 248 } 249 250 static void __exit kcomedilib_module_exit(void) 251 { 252 } 253 254 module_init(kcomedilib_module_init); 255 module_exit(kcomedilib_module_exit); 256