drivers/staging/iio/adc/ad7606_ring.c

   1 /*
   2  * Copyright 2011 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2.
   5  *
   6  */
   7
   8 #include <linux/interrupt.h>
   9 #include <linux/gpio.h>
  10 #include <linux/workqueue.h>
  11 #include <linux/device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysfs.h>
  15
  16 #include "../iio.h"
  17 #include "../ring_generic.h"
  18 #include "../ring_sw.h"
  19 #include "../trigger.h"
  20 #include "../sysfs.h"
  21
  22 #include "ad7606.h"
  23
  24 static IIO_SCAN_EL_C(in0, 0, 0, NULL);
  25 static IIO_SCAN_EL_C(in1, 1, 0, NULL);
  26 static IIO_SCAN_EL_C(in2, 2, 0, NULL);
  27 static IIO_SCAN_EL_C(in3, 3, 0, NULL);
  28 static IIO_SCAN_EL_C(in4, 4, 0, NULL);
  29 static IIO_SCAN_EL_C(in5, 5, 0, NULL);
  30 static IIO_SCAN_EL_C(in6, 6, 0, NULL);
  31 static IIO_SCAN_EL_C(in7, 7, 0, NULL);
  32
  33 static IIO_SCAN_EL_TIMESTAMP(8);
  34 static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64);
  35
  36 static ssize_t ad7606_show_type(struct device *dev,
  37                                 struct device_attribute *attr,
  38                                 char *buf)
  39 {
  40         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
  41         struct iio_dev *indio_dev = ring->indio_dev;
  42         struct ad7606_state *st = indio_dev->dev_data;
  43
  44         return sprintf(buf, "%c%d/%d\n", st->chip_info->sign,
  45                        st->chip_info->bits, st->chip_info->bits);
  46 }
  47 static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7606_show_type, NULL, 0);
  48
  49 static struct attribute *ad7606_scan_el_attrs[] = {
  50         &iio_scan_el_in0.dev_attr.attr,
  51         &iio_const_attr_in0_index.dev_attr.attr,
  52         &iio_scan_el_in1.dev_attr.attr,
  53         &iio_const_attr_in1_index.dev_attr.attr,
  54         &iio_scan_el_in2.dev_attr.attr,
  55         &iio_const_attr_in2_index.dev_attr.attr,
  56         &iio_scan_el_in3.dev_attr.attr,
  57         &iio_const_attr_in3_index.dev_attr.attr,
  58         &iio_scan_el_in4.dev_attr.attr,
  59         &iio_const_attr_in4_index.dev_attr.attr,
  60         &iio_scan_el_in5.dev_attr.attr,
  61         &iio_const_attr_in5_index.dev_attr.attr,
  62         &iio_scan_el_in6.dev_attr.attr,
  63         &iio_const_attr_in6_index.dev_attr.attr,
  64         &iio_scan_el_in7.dev_attr.attr,
  65         &iio_const_attr_in7_index.dev_attr.attr,
  66         &iio_const_attr_timestamp_index.dev_attr.attr,
  67         &iio_scan_el_timestamp.dev_attr.attr,
  68         &iio_const_attr_timestamp_type.dev_attr.attr,
  69         &iio_dev_attr_in_type.dev_attr.attr,
  70         NULL,
  71 };
  72
  73 static mode_t ad7606_scan_el_attr_is_visible(struct kobject *kobj,
  74                                      struct attribute *attr, int n)
  75 {
  76         struct device *dev = container_of(kobj, struct device, kobj);
  77         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
  78         struct iio_dev *indio_dev = ring->indio_dev;
  79         struct ad7606_state *st = indio_dev->dev_data;
  80
  81         mode_t mode = attr->mode;
  82
  83         if (st->chip_info->num_channels <= 6 &&
  84                 (attr == &iio_scan_el_in7.dev_attr.attr ||
  85                 attr == &iio_const_attr_in7_index.dev_attr.attr ||
  86                 attr == &iio_scan_el_in6.dev_attr.attr ||
  87                 attr == &iio_const_attr_in6_index.dev_attr.attr))
  88                 mode = 0;
  89         else if (st->chip_info->num_channels <= 4 &&
  90                 (attr == &iio_scan_el_in5.dev_attr.attr ||
  91                 attr == &iio_const_attr_in5_index.dev_attr.attr ||
  92                 attr == &iio_scan_el_in4.dev_attr.attr ||
  93                 attr == &iio_const_attr_in4_index.dev_attr.attr))
  94                 mode = 0;
  95
  96         return mode;
  97 }
  98
  99 static struct attribute_group ad7606_scan_el_group = {
 100         .name = "scan_elements",
 101         .attrs = ad7606_scan_el_attrs,
 102         .is_visible = ad7606_scan_el_attr_is_visible,
 103 };
 104
 105 int ad7606_scan_from_ring(struct ad7606_state *st, unsigned ch)
 106 {
 107         struct iio_ring_buffer *ring = st->indio_dev->ring;
 108         int ret;
 109         u16 *ring_data;
 110
 111         ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
 112         if (ring_data == NULL) {
 113                 ret = -ENOMEM;
 114                 goto error_ret;
 115         }
 116         ret = ring->access.read_last(ring, (u8 *) ring_data);
 117         if (ret)
 118                 goto error_free_ring_data;
 119
 120         ret = ring_data[ch];
 121
 122 error_free_ring_data:
 123         kfree(ring_data);
 124 error_ret:
 125         return ret;
 126 }
 127
 128 /**
 129  * ad7606_ring_preenable() setup the parameters of the ring before enabling
 130  *
 131  * The complex nature of the setting of the nuber of bytes per datum is due
 132  * to this driver currently ensuring that the timestamp is stored at an 8
 133  * byte boundary.
 134  **/
 135 static int ad7606_ring_preenable(struct iio_dev *indio_dev)
 136 {
 137         struct ad7606_state *st = indio_dev->dev_data;
 138         struct iio_ring_buffer *ring = indio_dev->ring;
 139         size_t d_size;
 140
 141         d_size = st->chip_info->num_channels *
 142                  st->chip_info->bits / 8;
 143
 144         if (ring->scan_timestamp) {
 145                 d_size += sizeof(s64);
 146
 147                 if (d_size % sizeof(s64))
 148                         d_size += sizeof(s64) - (d_size % sizeof(s64));
 149         }
 150
 151         if (ring->access.set_bytes_per_datum)
 152                 ring->access.set_bytes_per_datum(ring, d_size);
 153
 154         st->d_size = d_size;
 155
 156         return 0;
 157 }
 158
 159 /**
 160  * ad7606_poll_func_th() th of trigger launched polling to ring buffer
 161  *
 162  **/
 163 static void ad7606_poll_func_th(struct iio_dev *indio_dev, s64 time)
 164 {
 165         struct ad7606_state *st = indio_dev->dev_data;
 166         gpio_set_value(st->pdata->gpio_convst, 1);
 167
 168         return;
 169 }
 170 /**
 171  * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
 172  * @work_s:     the work struct through which this was scheduled
 173  *
 174  * Currently there is no option in this driver to disable the saving of
 175  * timestamps within the ring.
 176  * I think the one copy of this at a time was to avoid problems if the
 177  * trigger was set far too high and the reads then locked up the computer.
 178  **/
 179 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
 180 {
 181         struct ad7606_state *st = container_of(work_s, struct ad7606_state,
 182                                                 poll_work);
 183         struct iio_dev *indio_dev = st->indio_dev;
 184         struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
 185         struct iio_ring_buffer *ring = indio_dev->ring;
 186         s64 time_ns;
 187         __u8 *buf;
 188         int ret;
 189
 190         /* Ensure only one copy of this function running at a time */
 191         if (atomic_inc_return(&st->protect_ring) > 1)
 192                 return;
 193
 194         buf = kzalloc(st->d_size, GFP_KERNEL);
 195         if (buf == NULL)
 196                 return;
 197
 198         if (st->have_frstdata) {
 199                 ret = st->bops->read_block(st->dev, 1, buf);
 200                 if (ret)
 201                         goto done;
 202                 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
 203                         /* This should never happen. However
 204                          * some signal glitch caused by bad PCB desgin or
 205                          * electrostatic discharge, could cause an extra read
 206                          * or clock. This allows recovery.
 207                          */
 208                         ad7606_reset(st);
 209                         goto done;
 210                 }
 211                 ret = st->bops->read_block(st->dev,
 212                         st->chip_info->num_channels - 1, buf + 2);
 213                 if (ret)
 214                         goto done;
 215         } else {
 216                 ret = st->bops->read_block(st->dev,
 217                         st->chip_info->num_channels, buf);
 218                 if (ret)
 219                         goto done;
 220         }
 221
 222         time_ns = iio_get_time_ns();
 223
 224         if (ring->scan_timestamp)
 225                 memcpy(buf + st->d_size - sizeof(s64),
 226                         &time_ns, sizeof(time_ns));
 227
 228         ring->access.store_to(&sw_ring->buf, buf, time_ns);
 229 done:
 230         gpio_set_value(st->pdata->gpio_convst, 0);
 231         kfree(buf);
 232         atomic_dec(&st->protect_ring);
 233 }
 234
 235 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 236 {
 237         struct ad7606_state *st = indio_dev->dev_data;
 238         int ret;
 239
 240         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 241         if (!indio_dev->ring) {
 242                 ret = -ENOMEM;
 243                 goto error_ret;
 244         }
 245
 246         /* Effectively select the ring buffer implementation */
 247         iio_ring_sw_register_funcs(&indio_dev->ring->access);
 248         ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7606_poll_func_th);
 249         if (ret)
 250                 goto error_deallocate_sw_rb;
 251
 252         /* Ring buffer functions - here trigger setup related */
 253
 254         indio_dev->ring->preenable = &ad7606_ring_preenable;
 255         indio_dev->ring->postenable = &iio_triggered_ring_postenable;
 256         indio_dev->ring->predisable = &iio_triggered_ring_predisable;
 257         indio_dev->ring->scan_el_attrs = &ad7606_scan_el_group;
 258         indio_dev->ring->scan_timestamp = true ;
 259
 260         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 261
 262         /* Flag that polled ring buffering is possible */
 263         indio_dev->modes |= INDIO_RING_TRIGGERED;
 264         return 0;
 265 error_deallocate_sw_rb:
 266         iio_sw_rb_free(indio_dev->ring);
 267 error_ret:
 268         return ret;
 269 }
 270
 271 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 272 {
 273         if (indio_dev->trig) {
 274                 iio_put_trigger(indio_dev->trig);
 275                 iio_trigger_dettach_poll_func(indio_dev->trig,
 276                                               indio_dev->pollfunc);
 277         }
 278         kfree(indio_dev->pollfunc);
 279         iio_sw_rb_free(indio_dev->ring);
 280 }