iio_simple_dummy_buffer.c revision 550268ca1111a5b4737f15f7bf646cede9d1f0cd
19ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron/** 29ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Copyright (c) 2011 Jonathan Cameron 39ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 49ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * This program is free software; you can redistribute it and/or modify it 59ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * under the terms of the GNU General Public License version 2 as published by 69ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * the Free Software Foundation. 79ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 89ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Buffer handling elements of industrial I/O reference driver. 99ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Uses the kfifo buffer. 109ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 119ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * To test without hardware use the sysfs trigger. 129ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 139ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 149ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include <linux/kernel.h> 158e336a722bb234f9d7805647e0290f2a397ca04dPaul Gortmaker#include <linux/export.h> 169ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include <linux/slab.h> 179ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include <linux/interrupt.h> 189ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include <linux/irq.h> 199ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include <linux/bitmap.h> 209ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 219ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include "iio.h" 229ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include "trigger_consumer.h" 239ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include "kfifo_buf.h" 249ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 259ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron#include "iio_simple_dummy.h" 269ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 279ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron/* Some fake data */ 289ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 299ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronstatic const s16 fakedata[] = { 309ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron [voltage0] = 7, 319ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron [diffvoltage1m2] = -33, 329ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron [diffvoltage3m4] = -2, 339ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron [accelx] = 344, 349ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron}; 359ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron/** 369ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * iio_simple_dummy_trigger_h() - the trigger handler function 379ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * @irq: the interrupt number 389ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * @p: private data - always a pointer to the poll func. 399ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 409ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * This is the guts of buffered capture. On a trigger event occuring, 419ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * if the pollfunc is attached then this handler is called as a threaded 429ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * interrupt (and hence may sleep). It is responsible for grabbing data 439ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * from the device and pushing it into the associated buffer. 449ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 459ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronstatic irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p) 469ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron{ 479ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron struct iio_poll_func *pf = p; 489ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron struct iio_dev *indio_dev = pf->indio_dev; 499ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron struct iio_buffer *buffer = indio_dev->buffer; 509ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron int len = 0; 519ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 529ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * The datasize is obtained from the buffer. It was stored when 539ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * the preenable setup function was called. 549ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 559ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron size_t datasize = buffer->access->get_bytes_per_datum(buffer); 569ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron u16 *data = kmalloc(datasize, GFP_KERNEL); 579ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron if (data == NULL) 589ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron return -ENOMEM; 599ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 60550268ca1111a5b4737f15f7bf646cede9d1f0cdJonathan Cameron if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) { 619ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 629ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Three common options here: 639ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * hardware scans: certain combinations of channels make 649ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * up a fast read. The capture will consist of all of them. 659ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Hence we just call the grab data function and fill the 669ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * buffer without processing. 679ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * sofware scans: can be considered to be random access 689ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * so efficient reading is just a case of minimal bus 699ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * transactions. 709ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * software culled hardware scans: 719ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * occasionally a driver may process the nearest hardware 729ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * scan to avoid storing elements that are not desired. This 739ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * is the fidliest option by far. 749ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Here lets pretend we have random access. And the values are 759ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * in the constant table fakedata. 769ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 779ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron int i, j; 78550268ca1111a5b4737f15f7bf646cede9d1f0cdJonathan Cameron for (i = 0, j = 0; 79550268ca1111a5b4737f15f7bf646cede9d1f0cdJonathan Cameron i < bitmap_weight(indio_dev->active_scan_mask, 80550268ca1111a5b4737f15f7bf646cede9d1f0cdJonathan Cameron indio_dev->masklength); 81550268ca1111a5b4737f15f7bf646cede9d1f0cdJonathan Cameron i++) { 829ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron j = find_next_bit(buffer->scan_mask, 839ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron indio_dev->masklength, j + 1); 849ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* random access read form the 'device' */ 859ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron data[i] = fakedata[j]; 869ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron len += 2; 879ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron } 889ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron } 899ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* Store a timestampe at an 8 byte boundary */ 909ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron if (buffer->scan_timestamp) 919ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron *(s64 *)(((phys_addr_t)data + len 929ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron + sizeof(s64) - 1) & ~(sizeof(s64) - 1)) 939ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron = iio_get_time_ns(); 949ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron buffer->access->store_to(buffer, (u8 *)data, pf->timestamp); 959ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 969ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron kfree(data); 979ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 989ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 999ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Tell the core we are done with this trigger and ready for the 1009ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * next one. 1019ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1029ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron iio_trigger_notify_done(indio_dev->trig); 1039ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1049ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron return IRQ_HANDLED; 1059ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron} 1069ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1079ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronstatic const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = { 1089ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 1099ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * iio_sw_buffer_preenable: 1109ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Generic function for equal sized ring elements + 64 bit timestamp 1119ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Assumes that any combination of channels can be enabled. 1129ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Typically replaced to implement restrictions on what combinations 1139ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * can be captured (hardware scan modes). 1149ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1159ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron .preenable = &iio_sw_buffer_preenable, 1169ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 1179ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * iio_triggered_buffer_postenable: 1189ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Generic function that simply attaches the pollfunc to the trigger. 1199ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Replace this to mess with hardware state before we attach the 1209ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * trigger. 1219ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1229ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron .postenable = &iio_triggered_buffer_postenable, 1239ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 1249ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * iio_triggered_buffer_predisable: 1259ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Generic function that simple detaches the pollfunc from the trigger. 1269ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Replace this to put hardware state back again after the trigger is 1279ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * detached but before userspace knows we have disabled the ring. 1289ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1299ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron .predisable = &iio_triggered_buffer_predisable, 1309ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron}; 1319ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1329ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronint iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev) 1339ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron{ 1349ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron int ret; 1359ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron struct iio_buffer *buffer; 1369ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1379ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* Allocate a buffer to use - here a kfifo */ 1389ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron buffer = iio_kfifo_allocate(indio_dev); 1399ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron if (buffer == NULL) { 1409ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron ret = -ENOMEM; 1419ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron goto error_ret; 1429ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron } 1439ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1449ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron indio_dev->buffer = buffer; 1459ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* Tell the core how to access the buffer */ 1469ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron buffer->access = &kfifo_access_funcs; 1479ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1489ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* Enable timestamps by default */ 1499ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron buffer->scan_timestamp = true; 1509ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1519ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 1529ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Tell the core what device type specific functions should 1539ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * be run on either side of buffer capture enable / disable. 1549ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1551612244f8a70dae6a7f266e78c5ba22a3db75780Jonathan Cameron indio_dev->setup_ops = &iio_simple_dummy_buffer_setup_ops; 1569ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron buffer->owner = THIS_MODULE; 1579ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1589ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 1599ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Configure a polling function. 1609ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * When a trigger event with this polling function connected 1619ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * occurs, this function is run. Typically this grabs data 1629ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * from the device. 1639ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 1649ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * NULL for the top half. This is normally implemented only if we 1659ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * either want to ping a capture now pin (no sleeping) or grab 1669ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * a timestamp as close as possible to a data ready trigger firing. 1679ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 1689ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * IRQF_ONESHOT ensures irqs are masked such that only one instance 1699ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * of the handler can run at a time. 1709ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * 1719ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * "iio_simple_dummy_consumer%d" formatting string for the irq 'name' 1729ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * as seen under /proc/interrupts. Remaining parameters as per printk. 1739ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1749ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron indio_dev->pollfunc = iio_alloc_pollfunc(NULL, 1759ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron &iio_simple_dummy_trigger_h, 1769ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron IRQF_ONESHOT, 1779ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron indio_dev, 1789ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron "iio_simple_dummy_consumer%d", 1799ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron indio_dev->id); 1809ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1819ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron if (indio_dev->pollfunc == NULL) { 1829ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron ret = -ENOMEM; 1839ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron goto error_free_buffer; 1849ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron } 1859ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1869ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron /* 1879ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * Notify the core that this device is capable of buffered capture 1889ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * driven by a trigger. 1899ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 1909ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron indio_dev->modes |= INDIO_BUFFER_TRIGGERED; 1919ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron return 0; 1929ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1939ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronerror_free_buffer: 1949ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron iio_kfifo_free(indio_dev->buffer); 1959ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronerror_ret: 1969ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron return ret; 1979ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 1989ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron} 1999ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron 2009ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron/** 2019ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * iio_simple_dummy_unconfigure_buffer() - release buffer resources 2029ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron * @indo_dev: device instance state 2039ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron */ 2049ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameronvoid iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev) 2059ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron{ 2069ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron iio_dealloc_pollfunc(indio_dev->pollfunc); 2079ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron iio_kfifo_free(indio_dev->buffer); 2089ad2e2e1d6506252f31a142a9b04121992af25e3Jonathan Cameron} 209