1/* 2 * Copyright 2010-2011 Analog Devices Inc. 3 * Copyright (C) 2008 Jonathan Cameron 4 * 5 * Licensed under the GPL-2. 6 * 7 * ad7887_ring.c 8 */ 9 10#include <linux/interrupt.h> 11#include <linux/kernel.h> 12#include <linux/slab.h> 13#include <linux/spi/spi.h> 14 15#include "../iio.h" 16#include "../buffer.h" 17#include "../ring_sw.h" 18#include "../trigger_consumer.h" 19 20#include "ad7887.h" 21 22/** 23 * ad7887_ring_preenable() setup the parameters of the ring before enabling 24 * 25 * The complex nature of the setting of the nuber of bytes per datum is due 26 * to this driver currently ensuring that the timestamp is stored at an 8 27 * byte boundary. 28 **/ 29static int ad7887_ring_preenable(struct iio_dev *indio_dev) 30{ 31 struct ad7887_state *st = iio_priv(indio_dev); 32 struct iio_buffer *ring = indio_dev->buffer; 33 34 st->d_size = bitmap_weight(indio_dev->active_scan_mask, 35 indio_dev->masklength) * 36 st->chip_info->channel[0].scan_type.storagebits / 8; 37 38 if (ring->scan_timestamp) { 39 st->d_size += sizeof(s64); 40 41 if (st->d_size % sizeof(s64)) 42 st->d_size += sizeof(s64) - (st->d_size % sizeof(s64)); 43 } 44 45 if (indio_dev->buffer->access->set_bytes_per_datum) 46 indio_dev->buffer->access-> 47 set_bytes_per_datum(indio_dev->buffer, st->d_size); 48 49 /* We know this is a single long so can 'cheat' */ 50 switch (*indio_dev->active_scan_mask) { 51 case (1 << 0): 52 st->ring_msg = &st->msg[AD7887_CH0]; 53 break; 54 case (1 << 1): 55 st->ring_msg = &st->msg[AD7887_CH1]; 56 /* Dummy read: push CH1 setting down to hardware */ 57 spi_sync(st->spi, st->ring_msg); 58 break; 59 case ((1 << 1) | (1 << 0)): 60 st->ring_msg = &st->msg[AD7887_CH0_CH1]; 61 break; 62 } 63 64 return 0; 65} 66 67static int ad7887_ring_postdisable(struct iio_dev *indio_dev) 68{ 69 struct ad7887_state *st = iio_priv(indio_dev); 70 71 /* dummy read: restore default CH0 settin */ 72 return spi_sync(st->spi, &st->msg[AD7887_CH0]); 73} 74 75/** 76 * ad7887_trigger_handler() bh of trigger launched polling to ring buffer 77 * 78 * Currently there is no option in this driver to disable the saving of 79 * timestamps within the ring. 80 **/ 81static irqreturn_t ad7887_trigger_handler(int irq, void *p) 82{ 83 struct iio_poll_func *pf = p; 84 struct iio_dev *indio_dev = pf->indio_dev; 85 struct ad7887_state *st = iio_priv(indio_dev); 86 struct iio_buffer *ring = indio_dev->buffer; 87 s64 time_ns; 88 __u8 *buf; 89 int b_sent; 90 91 unsigned int bytes = bitmap_weight(indio_dev->active_scan_mask, 92 indio_dev->masklength) * 93 st->chip_info->channel[0].scan_type.storagebits / 8; 94 95 buf = kzalloc(st->d_size, GFP_KERNEL); 96 if (buf == NULL) 97 return -ENOMEM; 98 99 b_sent = spi_sync(st->spi, st->ring_msg); 100 if (b_sent) 101 goto done; 102 103 time_ns = iio_get_time_ns(); 104 105 memcpy(buf, st->data, bytes); 106 if (ring->scan_timestamp) 107 memcpy(buf + st->d_size - sizeof(s64), 108 &time_ns, sizeof(time_ns)); 109 110 indio_dev->buffer->access->store_to(indio_dev->buffer, buf, time_ns); 111done: 112 kfree(buf); 113 iio_trigger_notify_done(indio_dev->trig); 114 115 return IRQ_HANDLED; 116} 117 118static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = { 119 .preenable = &ad7887_ring_preenable, 120 .postenable = &iio_triggered_buffer_postenable, 121 .predisable = &iio_triggered_buffer_predisable, 122 .postdisable = &ad7887_ring_postdisable, 123}; 124 125int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev) 126{ 127 int ret; 128 129 indio_dev->buffer = iio_sw_rb_allocate(indio_dev); 130 if (!indio_dev->buffer) { 131 ret = -ENOMEM; 132 goto error_ret; 133 } 134 indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time, 135 &ad7887_trigger_handler, 136 IRQF_ONESHOT, 137 indio_dev, 138 "ad7887_consumer%d", 139 indio_dev->id); 140 if (indio_dev->pollfunc == NULL) { 141 ret = -ENOMEM; 142 goto error_deallocate_sw_rb; 143 } 144 /* Ring buffer functions - here trigger setup related */ 145 indio_dev->setup_ops = &ad7887_ring_setup_ops; 146 147 /* Flag that polled ring buffering is possible */ 148 indio_dev->modes |= INDIO_BUFFER_TRIGGERED; 149 return 0; 150 151error_deallocate_sw_rb: 152 iio_sw_rb_free(indio_dev->buffer); 153error_ret: 154 return ret; 155} 156 157void ad7887_ring_cleanup(struct iio_dev *indio_dev) 158{ 159 iio_dealloc_pollfunc(indio_dev->pollfunc); 160 iio_sw_rb_free(indio_dev->buffer); 161} 162