2 * Copyright (C) 2008 Jonathan Cameron
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.
11 #include <linux/interrupt.h>
12 #include <linux/gpio.h>
13 #include <linux/workqueue.h>
14 #include <linux/device.h>
15 #include <linux/slab.h>
16 #include <linux/kernel.h>
17 #include <linux/sysfs.h>
18 #include <linux/list.h>
19 #include <linux/i2c.h>
20 #include <linux/bitops.h>
23 #include "../ring_generic.h"
24 #include "../ring_sw.h"
25 #include "../trigger.h"
31 int max1363_single_channel_from_ring(long mask, struct max1363_state *st)
33 struct iio_ring_buffer *ring = st->indio_dev->ring;
36 if (!(st->current_mode->modemask & mask)) {
41 ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
42 if (ring_data == NULL) {
46 ret = ring->access.read_last(ring, ring_data);
48 goto error_free_ring_data;
49 /* Need a count of channels prior to this one */
52 if (mask & st->current_mode->modemask)
56 if (st->chip_info->bits != 8)
57 ret = ((int)(ring_data[count*2 + 0] & 0x0F) << 8)
58 + (int)(ring_data[count*2 + 1]);
60 ret = ring_data[count];
69 * max1363_ring_preenable() - setup the parameters of the ring before enabling
71 * The complex nature of the setting of the nuber of bytes per datum is due
72 * to this driver currently ensuring that the timestamp is stored at an 8
75 static int max1363_ring_preenable(struct iio_dev *indio_dev)
77 struct max1363_state *st = indio_dev->dev_data;
78 struct iio_ring_buffer *ring = indio_dev->ring;
80 unsigned long numvals;
83 * Need to figure out the current mode based upon the requested
84 * scan mask in iio_dev
86 st->current_mode = max1363_match_mode(ring->scan_mask,
88 if (!st->current_mode)
91 max1363_set_scan_mode(st);
93 numvals = hweight_long(st->current_mode->modemask);
94 if (ring->access.set_bytes_per_datum) {
95 if (st->chip_info->bits != 8)
96 d_size = numvals*2 + sizeof(s64);
98 d_size = numvals + sizeof(s64);
100 d_size += 8 - (d_size % 8);
101 ring->access.set_bytes_per_datum(ring, d_size);
109 * max1363_poll_func_th() - th of trigger launched polling to ring buffer
111 * As sampling only occurs on i2c comms occurring, leave timestamping until
112 * then. Some triggers will generate their own time stamp. Currently
113 * there is no way of notifying them when no one cares.
115 static void max1363_poll_func_th(struct iio_dev *indio_dev, s64 time)
117 struct max1363_state *st = indio_dev->dev_data;
119 schedule_work(&st->poll_work);
124 * max1363_poll_bh_to_ring() - bh of trigger launched polling to ring buffer
125 * @work_s: the work struct through which this was scheduled
127 * Currently there is no option in this driver to disable the saving of
128 * timestamps within the ring.
129 * I think the one copy of this at a time was to avoid problems if the
130 * trigger was set far too high and the reads then locked up the computer.
132 static void max1363_poll_bh_to_ring(struct work_struct *work_s)
134 struct max1363_state *st = container_of(work_s, struct max1363_state,
136 struct iio_dev *indio_dev = st->indio_dev;
137 struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
142 unsigned long numvals = hweight_long(st->current_mode->modemask);
144 /* Ensure the timestamp is 8 byte aligned */
145 if (st->chip_info->bits != 8)
146 d_size = numvals*2 + sizeof(s64);
148 d_size = numvals + sizeof(s64);
149 if (d_size % sizeof(s64))
150 d_size += sizeof(s64) - (d_size % sizeof(s64));
152 /* Ensure only one copy of this function running at a time */
153 if (atomic_inc_return(&st->protect_ring) > 1)
156 /* Monitor mode prevents reading. Whilst not currently implemented
157 * might as well have this test in here in the meantime as it does
163 rxbuf = kmalloc(d_size, GFP_KERNEL);
166 if (st->chip_info->bits != 8)
167 b_sent = i2c_master_recv(st->client, rxbuf, numvals*2);
169 b_sent = i2c_master_recv(st->client, rxbuf, numvals);
173 time_ns = iio_get_time_ns();
175 memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
177 indio_dev->ring->access.store_to(&sw_ring->buf, rxbuf, time_ns);
180 atomic_dec(&st->protect_ring);
184 int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
186 struct max1363_state *st = indio_dev->dev_data;
189 indio_dev->ring = iio_sw_rb_allocate(indio_dev);
190 if (!indio_dev->ring) {
194 /* Effectively select the ring buffer implementation */
195 iio_ring_sw_register_funcs(&indio_dev->ring->access);
196 ret = iio_alloc_pollfunc(indio_dev, NULL, &max1363_poll_func_th);
198 goto error_deallocate_sw_rb;
200 /* Ring buffer functions - here trigger setup related */
201 indio_dev->ring->scan_el_attrs = st->chip_info->scan_attrs;
202 indio_dev->ring->postenable = &iio_triggered_ring_postenable;
203 indio_dev->ring->preenable = &max1363_ring_preenable;
204 indio_dev->ring->predisable = &iio_triggered_ring_predisable;
205 INIT_WORK(&st->poll_work, &max1363_poll_bh_to_ring);
207 /* Flag that polled ring buffering is possible */
208 indio_dev->modes |= INDIO_RING_TRIGGERED;
210 error_deallocate_sw_rb:
211 iio_sw_rb_free(indio_dev->ring);
216 void max1363_ring_cleanup(struct iio_dev *indio_dev)
218 /* ensure that the trigger has been detached */
219 if (indio_dev->trig) {
220 iio_put_trigger(indio_dev->trig);
221 iio_trigger_dettach_poll_func(indio_dev->trig,
222 indio_dev->pollfunc);
224 kfree(indio_dev->pollfunc);
225 iio_sw_rb_free(indio_dev->ring);