drivers/iio/imu/adis_buffer.c

   1 /*
   2  * Common library for ADIS16XXX devices
   3  *
   4  * Copyright 2012 Analog Devices Inc.
   5  *   Author: Lars-Peter Clausen <lars@metafoo.de>
   6  *
   7  * Licensed under the GPL-2 or later.
   8  */
   9
  10 #include <linux/export.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/mutex.h>
  13 #include <linux/kernel.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/slab.h>
  16
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/buffer.h>
  19 #include <linux/iio/trigger_consumer.h>
  20 #include <linux/iio/triggered_buffer.h>
  21 #include <linux/iio/imu/adis.h>
  22
  23 int adis_update_scan_mode(struct iio_dev *indio_dev,
  24         const unsigned long *scan_mask)
  25 {
  26         struct adis *adis = iio_device_get_drvdata(indio_dev);
  27         const struct iio_chan_spec *chan;
  28         unsigned int scan_count;
  29         unsigned int i, j;
  30         __be16 *tx, *rx;
  31
  32         kfree(adis->xfer);
  33         kfree(adis->buffer);
  34
  35         scan_count = indio_dev->scan_bytes / 2;
  36
  37         adis->xfer = kcalloc(scan_count + 1, sizeof(*adis->xfer), GFP_KERNEL);
  38         if (!adis->xfer)
  39                 return -ENOMEM;
  40
  41         adis->buffer = kcalloc(indio_dev->scan_bytes, 2, GFP_KERNEL);
  42         if (!adis->buffer)
  43                 return -ENOMEM;
  44
  45         rx = adis->buffer;
  46         tx = rx + scan_count;
  47
  48         spi_message_init(&adis->msg);
  49
  50         for (j = 0; j <= scan_count; j++) {
  51                 adis->xfer[j].bits_per_word = 8;
  52                 if (j != scan_count)
  53                         adis->xfer[j].cs_change = 1;
  54                 adis->xfer[j].len = 2;
  55                 adis->xfer[j].delay_usecs = adis->data->read_delay;
  56                 if (j < scan_count)
  57                         adis->xfer[j].tx_buf = &tx[j];
  58                 if (j >= 1)
  59                         adis->xfer[j].rx_buf = &rx[j - 1];
  60                 spi_message_add_tail(&adis->xfer[j], &adis->msg);
  61         }
  62
  63         chan = indio_dev->channels;
  64         for (i = 0; i < indio_dev->num_channels; i++, chan++) {
  65                 if (!test_bit(chan->scan_index, scan_mask))
  66                         continue;
  67                 if (chan->scan_type.storagebits == 32)
  68                         *tx++ = cpu_to_be16((chan->address + 2) << 8);
  69                 *tx++ = cpu_to_be16(chan->address << 8);
  70         }
  71
  72         return 0;
  73 }
  74 EXPORT_SYMBOL_GPL(adis_update_scan_mode);
  75
  76 static irqreturn_t adis_trigger_handler(int irq, void *p)
  77 {
  78         struct iio_poll_func *pf = p;
  79         struct iio_dev *indio_dev = pf->indio_dev;
  80         struct adis *adis = iio_device_get_drvdata(indio_dev);
  81         int ret;
  82
  83         if (!adis->buffer)
  84                 return -ENOMEM;
  85
  86         if (adis->data->has_paging) {
  87                 mutex_lock(&adis->txrx_lock);
  88                 if (adis->current_page != 0) {
  89                         adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
  90                         adis->tx[1] = 0;
  91                         spi_write(adis->spi, adis->tx, 2);
  92                 }
  93         }
  94
  95         ret = spi_sync(adis->spi, &adis->msg);
  96         if (ret)
  97                 dev_err(&adis->spi->dev, "Failed to read data: %d", ret);
  98
  99
 100         if (adis->data->has_paging) {
 101                 adis->current_page = 0;
 102                 mutex_unlock(&adis->txrx_lock);
 103         }
 104
 105         iio_push_to_buffers_with_timestamp(indio_dev, adis->buffer,
 106                 pf->timestamp);
 107
 108         iio_trigger_notify_done(indio_dev->trig);
 109
 110         return IRQ_HANDLED;
 111 }
 112
 113 /**
 114  * adis_setup_buffer_and_trigger() - Sets up buffer and trigger for the adis device
 115  * @adis: The adis device.
 116  * @indio_dev: The IIO device.
 117  * @trigger_handler: Optional trigger handler, may be NULL.
 118  *
 119  * Returns 0 on success, a negative error code otherwise.
 120  *
 121  * This function sets up the buffer and trigger for a adis devices.  If
 122  * 'trigger_handler' is NULL the default trigger handler will be used. The
 123  * default trigger handler will simply read the registers assigned to the
 124  * currently active channels.
 125  *
 126  * adis_cleanup_buffer_and_trigger() should be called to free the resources
 127  * allocated by this function.
 128  */
 129 int adis_setup_buffer_and_trigger(struct adis *adis, struct iio_dev *indio_dev,
 130         irqreturn_t (*trigger_handler)(int, void *))
 131 {
 132         int ret;
 133
 134         if (!trigger_handler)
 135                 trigger_handler = adis_trigger_handler;
 136
 137         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 138                 trigger_handler, NULL);
 139         if (ret)
 140                 return ret;
 141
 142         if (adis->spi->irq) {
 143                 ret = adis_probe_trigger(adis, indio_dev);
 144                 if (ret)
 145                         goto error_buffer_cleanup;
 146         }
 147         return 0;
 148
 149 error_buffer_cleanup:
 150         iio_triggered_buffer_cleanup(indio_dev);
 151         return ret;
 152 }
 153 EXPORT_SYMBOL_GPL(adis_setup_buffer_and_trigger);
 154
 155 /**
 156  * adis_cleanup_buffer_and_trigger() - Free buffer and trigger resources
 157  * @adis: The adis device.
 158  * @indio_dev: The IIO device.
 159  *
 160  * Frees resources allocated by adis_setup_buffer_and_trigger()
 161  */
 162 void adis_cleanup_buffer_and_trigger(struct adis *adis,
 163         struct iio_dev *indio_dev)
 164 {
 165         if (adis->spi->irq)
 166                 adis_remove_trigger(adis);
 167         kfree(adis->buffer);
 168         kfree(adis->xfer);
 169         iio_triggered_buffer_cleanup(indio_dev);
 170 }
 171 EXPORT_SYMBOL_GPL(adis_cleanup_buffer_and_trigger);