drivers/staging/iio/adc/ad799x_ring.c

   1 /*
   2  * Copyright (C) 2010 Michael Hennerich, Analog Devices Inc.
   3  * Copyright (C) 2008-2010 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * ad799x_ring.c
  10  */
  11
  12 #include <linux/interrupt.h>
  13 #include <linux/device.h>
  14 #include <linux/slab.h>
  15 #include <linux/kernel.h>
  16 #include <linux/sysfs.h>
  17 #include <linux/list.h>
  18 #include <linux/i2c.h>
  19 #include <linux/bitops.h>
  20
  21 #include "../iio.h"
  22 #include "../ring_generic.h"
  23 #include "../ring_sw.h"
  24 #include "../trigger.h"
  25 #include "../sysfs.h"
  26
  27 #include "ad799x.h"
  28
  29 int ad799x_single_channel_from_ring(struct ad799x_state *st, long mask)
  30 {
  31         struct iio_ring_buffer *ring = iio_priv_to_dev(st)->ring;
  32         int count = 0, ret;
  33         u16 *ring_data;
  34
  35         if (!(ring->scan_mask & mask)) {
  36                 ret = -EBUSY;
  37                 goto error_ret;
  38         }
  39
  40         ring_data = kmalloc(ring->access->get_bytes_per_datum(ring),
  41                             GFP_KERNEL);
  42         if (ring_data == NULL) {
  43                 ret = -ENOMEM;
  44                 goto error_ret;
  45         }
  46         ret = ring->access->read_last(ring, (u8 *) ring_data);
  47         if (ret)
  48                 goto error_free_ring_data;
  49         /* Need a count of channels prior to this one */
  50         mask >>= 1;
  51         while (mask) {
  52                 if (mask & ring->scan_mask)
  53                         count++;
  54                 mask >>= 1;
  55         }
  56
  57         ret = be16_to_cpu(ring_data[count]);
  58
  59 error_free_ring_data:
  60         kfree(ring_data);
  61 error_ret:
  62         return ret;
  63 }
  64
  65 /**
  66  * ad799x_ring_preenable() setup the parameters of the ring before enabling
  67  *
  68  * The complex nature of the setting of the nuber of bytes per datum is due
  69  * to this driver currently ensuring that the timestamp is stored at an 8
  70  * byte boundary.
  71  **/
  72 static int ad799x_ring_preenable(struct iio_dev *indio_dev)
  73 {
  74         struct iio_ring_buffer *ring = indio_dev->ring;
  75         struct ad799x_state *st = iio_priv(indio_dev);
  76
  77         /*
  78          * Need to figure out the current mode based upon the requested
  79          * scan mask in iio_dev
  80          */
  81
  82         if (st->id == ad7997 || st->id == ad7998)
  83                 ad7997_8_set_scan_mode(st, ring->scan_mask);
  84
  85         st->d_size = ring->scan_count * 2;
  86
  87         if (ring->scan_timestamp) {
  88                 st->d_size += sizeof(s64);
  89
  90                 if (st->d_size % sizeof(s64))
  91                         st->d_size += sizeof(s64) - (st->d_size % sizeof(s64));
  92         }
  93
  94         if (indio_dev->ring->access->set_bytes_per_datum)
  95                 indio_dev->ring->access->set_bytes_per_datum(indio_dev->ring,
  96                                                             st->d_size);
  97
  98         return 0;
  99 }
 100
 101 /**
 102  * ad799x_trigger_handler() bh of trigger launched polling to ring buffer
 103  *
 104  * Currently there is no option in this driver to disable the saving of
 105  * timestamps within the ring.
 106  **/
 107
 108 static irqreturn_t ad799x_trigger_handler(int irq, void *p)
 109 {
 110         struct iio_poll_func *pf = p;
 111         struct iio_dev *indio_dev = pf->private_data;
 112         struct ad799x_state *st = iio_priv(indio_dev);
 113         struct iio_ring_buffer *ring = indio_dev->ring;
 114         s64 time_ns;
 115         __u8 *rxbuf;
 116         int b_sent;
 117         u8 cmd;
 118
 119         rxbuf = kmalloc(st->d_size, GFP_KERNEL);
 120         if (rxbuf == NULL)
 121                 goto out;
 122
 123         switch (st->id) {
 124         case ad7991:
 125         case ad7995:
 126         case ad7999:
 127                 cmd = st->config | (ring->scan_mask << AD799X_CHANNEL_SHIFT);
 128                 break;
 129         case ad7992:
 130         case ad7993:
 131         case ad7994:
 132                 cmd = (ring->scan_mask << AD799X_CHANNEL_SHIFT) |
 133                         AD7998_CONV_RES_REG;
 134                 break;
 135         case ad7997:
 136         case ad7998:
 137                 cmd = AD7997_8_READ_SEQUENCE | AD7998_CONV_RES_REG;
 138                 break;
 139         default:
 140                 cmd = 0;
 141         }
 142
 143         b_sent = i2c_smbus_read_i2c_block_data(st->client,
 144                         cmd, ring->scan_count * 2, rxbuf);
 145         if (b_sent < 0)
 146                 goto done;
 147
 148         time_ns = iio_get_time_ns();
 149
 150         if (ring->scan_timestamp)
 151                 memcpy(rxbuf + st->d_size - sizeof(s64),
 152                         &time_ns, sizeof(time_ns));
 153
 154         ring->access->store_to(indio_dev->ring, rxbuf, time_ns);
 155 done:
 156         kfree(rxbuf);
 157         if (b_sent < 0)
 158                 return b_sent;
 159 out:
 160         iio_trigger_notify_done(indio_dev->trig);
 161
 162         return IRQ_HANDLED;
 163 }
 164
 165 static const struct iio_ring_setup_ops ad799x_buf_setup_ops = {
 166         .preenable = &ad799x_ring_preenable,
 167         .postenable = &iio_triggered_ring_postenable,
 168         .predisable = &iio_triggered_ring_predisable,
 169 };
 170
 171 int ad799x_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 172 {
 173         int ret = 0;
 174
 175         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 176         if (!indio_dev->ring) {
 177                 ret = -ENOMEM;
 178                 goto error_ret;
 179         }
 180         /* Effectively select the ring buffer implementation */
 181         indio_dev->ring->access = &ring_sw_access_funcs;
 182         indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
 183                                                  &ad799x_trigger_handler,
 184                                                  IRQF_ONESHOT,
 185                                                  indio_dev,
 186                                                  "%s_consumer%d",
 187                                                  indio_dev->name,
 188                                                  indio_dev->id);
 189         if (indio_dev->pollfunc == NULL) {
 190                 ret = -ENOMEM;
 191                 goto error_deallocate_sw_rb;
 192         }
 193
 194         /* Ring buffer functions - here trigger setup related */
 195         indio_dev->ring->setup_ops = &ad799x_buf_setup_ops;
 196         indio_dev->ring->scan_timestamp = true;
 197
 198         /* Flag that polled ring buffering is possible */
 199         indio_dev->modes |= INDIO_RING_TRIGGERED;
 200         return 0;
 201
 202 error_deallocate_sw_rb:
 203         iio_sw_rb_free(indio_dev->ring);
 204 error_ret:
 205         return ret;
 206 }
 207
 208 void ad799x_ring_cleanup(struct iio_dev *indio_dev)
 209 {
 210         /* ensure that the trigger has been detached */
 211         if (indio_dev->trig) {
 212                 iio_put_trigger(indio_dev->trig);
 213                 iio_trigger_dettach_poll_func(indio_dev->trig,
 214                                               indio_dev->pollfunc);
 215         }
 216         iio_dealloc_pollfunc(indio_dev->pollfunc);
 217         iio_sw_rb_free(indio_dev->ring);
 218 }