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/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/buffer.h>
  16 #include "../ring_sw.h"
  17 #include <linux/iio/trigger_consumer.h>
  18
  19 #include "ad7606.h"
  20
  21 /**
  22  * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
  23  *
  24  **/
  25 static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
  26 {
  27         struct iio_poll_func *pf = p;
  28         struct ad7606_state *st = iio_priv(pf->indio_dev);
  29
  30         gpio_set_value(st->pdata->gpio_convst, 1);
  31
  32         return IRQ_HANDLED;
  33 }
  34
  35 /**
  36  * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
  37  * @work_s:     the work struct through which this was scheduled
  38  *
  39  * Currently there is no option in this driver to disable the saving of
  40  * timestamps within the ring.
  41  * I think the one copy of this at a time was to avoid problems if the
  42  * trigger was set far too high and the reads then locked up the computer.
  43  **/
  44 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
  45 {
  46         struct ad7606_state *st = container_of(work_s, struct ad7606_state,
  47                                                 poll_work);
  48         struct iio_dev *indio_dev = iio_priv_to_dev(st);
  49         struct iio_buffer *ring = indio_dev->buffer;
  50         s64 time_ns;
  51         __u8 *buf;
  52         int ret;
  53
  54         buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
  55         if (buf == NULL)
  56                 return;
  57
  58         if (gpio_is_valid(st->pdata->gpio_frstdata)) {
  59                 ret = st->bops->read_block(st->dev, 1, buf);
  60                 if (ret)
  61                         goto done;
  62                 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
  63                         /* This should never happen. However
  64                          * some signal glitch caused by bad PCB desgin or
  65                          * electrostatic discharge, could cause an extra read
  66                          * or clock. This allows recovery.
  67                          */
  68                         ad7606_reset(st);
  69                         goto done;
  70                 }
  71                 ret = st->bops->read_block(st->dev,
  72                         st->chip_info->num_channels - 1, buf + 2);
  73                 if (ret)
  74                         goto done;
  75         } else {
  76                 ret = st->bops->read_block(st->dev,
  77                         st->chip_info->num_channels, buf);
  78                 if (ret)
  79                         goto done;
  80         }
  81
  82         time_ns = iio_get_time_ns();
  83
  84         if (indio_dev->scan_timestamp)
  85                 *((s64 *)(buf + indio_dev->scan_bytes - sizeof(s64))) = time_ns;
  86
  87         ring->access->store_to(indio_dev->buffer, buf, time_ns);
  88 done:
  89         gpio_set_value(st->pdata->gpio_convst, 0);
  90         iio_trigger_notify_done(indio_dev->trig);
  91         kfree(buf);
  92 }
  93
  94 static const struct iio_buffer_setup_ops ad7606_ring_setup_ops = {
  95         .preenable = &iio_sw_buffer_preenable,
  96         .postenable = &iio_triggered_buffer_postenable,
  97         .predisable = &iio_triggered_buffer_predisable,
  98 };
  99
 100 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 101 {
 102         struct ad7606_state *st = iio_priv(indio_dev);
 103         int ret;
 104
 105         indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
 106         if (!indio_dev->buffer) {
 107                 ret = -ENOMEM;
 108                 goto error_ret;
 109         }
 110
 111         indio_dev->pollfunc = iio_alloc_pollfunc(&ad7606_trigger_handler_th_bh,
 112                                                  &ad7606_trigger_handler_th_bh,
 113                                                  0,
 114                                                  indio_dev,
 115                                                  "%s_consumer%d",
 116                                                  indio_dev->name,
 117                                                  indio_dev->id);
 118         if (indio_dev->pollfunc == NULL) {
 119                 ret = -ENOMEM;
 120                 goto error_deallocate_sw_rb;
 121         }
 122
 123         /* Ring buffer functions - here trigger setup related */
 124
 125         indio_dev->setup_ops = &ad7606_ring_setup_ops;
 126         indio_dev->buffer->scan_timestamp = true ;
 127
 128         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 129
 130         /* Flag that polled ring buffering is possible */
 131         indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
 132         return 0;
 133
 134 error_deallocate_sw_rb:
 135         iio_sw_rb_free(indio_dev->buffer);
 136 error_ret:
 137         return ret;
 138 }
 139
 140 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 141 {
 142         iio_dealloc_pollfunc(indio_dev->pollfunc);
 143         iio_sw_rb_free(indio_dev->buffer);
 144 }