drivers/staging/iio/adc/max1363_ring.c

   1 /*
   2  * Copyright (C) 2008 Jonathan Cameron
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * max1363_ring.c
   9  */
  10
  11 #include <linux/interrupt.h>
  12 #include <linux/slab.h>
  13 #include <linux/kernel.h>
  14 #include <linux/i2c.h>
  15 #include <linux/bitops.h>
  16
  17 #include "../iio.h"
  18 #include "../ring_generic.h"
  19 #include "../ring_sw.h"
  20 #include "../trigger_consumer.h"
  21
  22 #include "max1363.h"
  23
  24 int max1363_single_channel_from_ring(const long *mask, struct max1363_state *st)
  25 {
  26         struct iio_ring_buffer *ring = iio_priv_to_dev(st)->ring;
  27         int count = 0, ret, index;
  28         u8 *ring_data;
  29         index = find_first_bit(mask, MAX1363_MAX_CHANNELS);
  30
  31         if (!(test_bit(index, st->current_mode->modemask))) {
  32                 ret = -EBUSY;
  33                 goto error_ret;
  34         }
  35
  36         ring_data = kmalloc(ring->access->get_bytes_per_datum(ring),
  37                             GFP_KERNEL);
  38         if (ring_data == NULL) {
  39                 ret = -ENOMEM;
  40                 goto error_ret;
  41         }
  42         ret = ring->access->read_last(ring, ring_data);
  43         if (ret)
  44                 goto error_free_ring_data;
  45         /* Need a count of channels prior to this one */
  46
  47         count = bitmap_weight(mask, index - 1);
  48         if (st->chip_info->bits != 8)
  49                 ret = ((int)(ring_data[count*2 + 0] & 0x0F) << 8)
  50                         + (int)(ring_data[count*2 + 1]);
  51         else
  52                 ret = ring_data[count];
  53
  54 error_free_ring_data:
  55         kfree(ring_data);
  56 error_ret:
  57         return ret;
  58 }
  59
  60
  61 /**
  62  * max1363_ring_preenable() - setup the parameters of the ring before enabling
  63  *
  64  * The complex nature of the setting of the nuber of bytes per datum is due
  65  * to this driver currently ensuring that the timestamp is stored at an 8
  66  * byte boundary.
  67  **/
  68 static int max1363_ring_preenable(struct iio_dev *indio_dev)
  69 {
  70         struct max1363_state *st = iio_priv(indio_dev);
  71         struct iio_ring_buffer *ring = indio_dev->ring;
  72         size_t d_size = 0;
  73         unsigned long numvals;
  74
  75         /*
  76          * Need to figure out the current mode based upon the requested
  77          * scan mask in iio_dev
  78          */
  79         st->current_mode = max1363_match_mode(ring->scan_mask,
  80                                         st->chip_info);
  81         if (!st->current_mode)
  82                 return -EINVAL;
  83
  84         max1363_set_scan_mode(st);
  85
  86         numvals = bitmap_weight(st->current_mode->modemask,
  87                                 indio_dev->masklength);
  88         if (ring->access->set_bytes_per_datum) {
  89                 if (ring->scan_timestamp)
  90                         d_size += sizeof(s64);
  91                 if (st->chip_info->bits != 8)
  92                         d_size += numvals*2;
  93                 else
  94                         d_size += numvals;
  95                 if (ring->scan_timestamp && (d_size % 8))
  96                         d_size += 8 - (d_size % 8);
  97                 ring->access->set_bytes_per_datum(ring, d_size);
  98         }
  99
 100         return 0;
 101 }
 102
 103 static irqreturn_t max1363_trigger_handler(int irq, void *p)
 104 {
 105         struct iio_poll_func *pf = p;
 106         struct iio_dev *indio_dev = pf->indio_dev;
 107         struct max1363_state *st = iio_priv(indio_dev);
 108         s64 time_ns;
 109         __u8 *rxbuf;
 110         int b_sent;
 111         size_t d_size;
 112         unsigned long numvals = bitmap_weight(st->current_mode->modemask,
 113                                               MAX1363_MAX_CHANNELS);
 114
 115         /* Ensure the timestamp is 8 byte aligned */
 116         if (st->chip_info->bits != 8)
 117                 d_size = numvals*2 + sizeof(s64);
 118         else
 119                 d_size = numvals + sizeof(s64);
 120         if (d_size % sizeof(s64))
 121                 d_size += sizeof(s64) - (d_size % sizeof(s64));
 122
 123         /* Monitor mode prevents reading. Whilst not currently implemented
 124          * might as well have this test in here in the meantime as it does
 125          * no harm.
 126          */
 127         if (numvals == 0)
 128                 return IRQ_HANDLED;
 129
 130         rxbuf = kmalloc(d_size, GFP_KERNEL);
 131         if (rxbuf == NULL)
 132                 return -ENOMEM;
 133         if (st->chip_info->bits != 8)
 134                 b_sent = i2c_master_recv(st->client, rxbuf, numvals*2);
 135         else
 136                 b_sent = i2c_master_recv(st->client, rxbuf, numvals);
 137         if (b_sent < 0)
 138                 goto done;
 139
 140         time_ns = iio_get_time_ns();
 141
 142         memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
 143
 144         indio_dev->ring->access->store_to(indio_dev->ring, rxbuf, time_ns);
 145 done:
 146         iio_trigger_notify_done(indio_dev->trig);
 147         kfree(rxbuf);
 148
 149         return IRQ_HANDLED;
 150 }
 151
 152 static const struct iio_ring_setup_ops max1363_ring_setup_ops = {
 153         .postenable = &iio_triggered_buffer_postenable,
 154         .preenable = &max1363_ring_preenable,
 155         .predisable = &iio_triggered_buffer_predisable,
 156 };
 157
 158 int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 159 {
 160         struct max1363_state *st = iio_priv(indio_dev);
 161         int ret = 0;
 162
 163         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 164         if (!indio_dev->ring) {
 165                 ret = -ENOMEM;
 166                 goto error_ret;
 167         }
 168         indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
 169                                                  &max1363_trigger_handler,
 170                                                  IRQF_ONESHOT,
 171                                                  indio_dev,
 172                                                  "%s_consumer%d",
 173                                                  st->client->name,
 174                                                  indio_dev->id);
 175         if (indio_dev->pollfunc == NULL) {
 176                 ret = -ENOMEM;
 177                 goto error_deallocate_sw_rb;
 178         }
 179         /* Effectively select the ring buffer implementation */
 180         indio_dev->ring->access = &ring_sw_access_funcs;
 181         /* Ring buffer functions - here trigger setup related */
 182         indio_dev->ring->setup_ops = &max1363_ring_setup_ops;
 183
 184         /* Flag that polled ring buffering is possible */
 185         indio_dev->modes |= INDIO_RING_TRIGGERED;
 186
 187         return 0;
 188
 189 error_deallocate_sw_rb:
 190         iio_sw_rb_free(indio_dev->ring);
 191 error_ret:
 192         return ret;
 193 }
 194
 195 void max1363_ring_cleanup(struct iio_dev *indio_dev)
 196 {
 197         /* ensure that the trigger has been detached */
 198         iio_dealloc_pollfunc(indio_dev->pollfunc);
 199         iio_sw_rb_free(indio_dev->ring);
 200 }