linux/drivers/iio/imu/adis_buffer.c
Lars-Peter Clausen 484a0bf091 iio:imu:adis: Add paging support
Some of the newer generation devices from the ADIS16XXX series have more
registers than what can be supported with the current register addressing
scheme. These devices implement register paging to support a larger register
range. Each page is 128 registers large and the currently active page can be
selected via register 0x00 in each page. This patch implements transparent
paging inside the common adis library. The register read/write interface stays
the same and when a register is accessed the library automatically switches to
the correct page if it is not already selected. The page number is encoded in
the upper bits of the register number, e.g. register 0x5 of page 1 is 0x85.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-11-20 21:26:37 +00:00

177 lines
4.4 KiB
C

/*
* Common library for ADIS16XXX devices
*
* Copyright 2012 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*
* Licensed under the GPL-2 or later.
*/
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/imu/adis.h>
int adis_update_scan_mode(struct iio_dev *indio_dev,
const unsigned long *scan_mask)
{
struct adis *adis = iio_device_get_drvdata(indio_dev);
const struct iio_chan_spec *chan;
unsigned int scan_count;
unsigned int i, j;
__be16 *tx, *rx;
kfree(adis->xfer);
kfree(adis->buffer);
scan_count = indio_dev->scan_bytes / 2;
adis->xfer = kcalloc(scan_count + 1, sizeof(*adis->xfer), GFP_KERNEL);
if (!adis->xfer)
return -ENOMEM;
adis->buffer = kzalloc(indio_dev->scan_bytes * 2, GFP_KERNEL);
if (!adis->buffer)
return -ENOMEM;
rx = adis->buffer;
tx = rx + indio_dev->scan_bytes;
spi_message_init(&adis->msg);
for (j = 0; j <= scan_count; j++) {
adis->xfer[j].bits_per_word = 8;
if (j != scan_count)
adis->xfer[j].cs_change = 1;
adis->xfer[j].len = 2;
adis->xfer[j].delay_usecs = adis->data->read_delay;
if (j < scan_count)
adis->xfer[j].tx_buf = &tx[j];
if (j >= 1)
adis->xfer[j].rx_buf = &rx[j - 1];
spi_message_add_tail(&adis->xfer[j], &adis->msg);
}
chan = indio_dev->channels;
for (i = 0; i < indio_dev->num_channels; i++, chan++) {
if (!test_bit(chan->scan_index, scan_mask))
continue;
if (chan->scan_type.storagebits == 32)
*tx++ = cpu_to_be16((chan->address + 2) << 8);
*tx++ = cpu_to_be16(chan->address << 8);
}
return 0;
}
EXPORT_SYMBOL_GPL(adis_update_scan_mode);
static irqreturn_t adis_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct adis *adis = iio_device_get_drvdata(indio_dev);
int ret;
if (!adis->buffer)
return -ENOMEM;
if (adis->data->has_paging) {
mutex_lock(&adis->txrx_lock);
if (adis->current_page != 0) {
adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
adis->tx[1] = 0;
spi_write(adis->spi, adis->tx, 2);
}
}
ret = spi_sync(adis->spi, &adis->msg);
if (ret)
dev_err(&adis->spi->dev, "Failed to read data: %d", ret);
if (adis->data->has_paging) {
adis->current_page = 0;
mutex_unlock(&adis->txrx_lock);
}
/* Guaranteed to be aligned with 8 byte boundary */
if (indio_dev->scan_timestamp) {
void *b = adis->buffer + indio_dev->scan_bytes - sizeof(s64);
*(s64 *)b = pf->timestamp;
}
iio_push_to_buffers(indio_dev, adis->buffer);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
/**
* adis_setup_buffer_and_trigger() - Sets up buffer and trigger for the adis device
* @adis: The adis device.
* @indio_dev: The IIO device.
* @trigger_handler: Optional trigger handler, may be NULL.
*
* Returns 0 on success, a negative error code otherwise.
*
* This function sets up the buffer and trigger for a adis devices. If
* 'trigger_handler' is NULL the default trigger handler will be used. The
* default trigger handler will simply read the registers assigned to the
* currently active channels.
*
* adis_cleanup_buffer_and_trigger() should be called to free the resources
* allocated by this function.
*/
int adis_setup_buffer_and_trigger(struct adis *adis, struct iio_dev *indio_dev,
irqreturn_t (*trigger_handler)(int, void *))
{
int ret;
if (!trigger_handler)
trigger_handler = adis_trigger_handler;
ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
trigger_handler, NULL);
if (ret)
return ret;
if (adis->spi->irq) {
ret = adis_probe_trigger(adis, indio_dev);
if (ret)
goto error_buffer_cleanup;
}
return 0;
error_buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
return ret;
}
EXPORT_SYMBOL_GPL(adis_setup_buffer_and_trigger);
/**
* adis_cleanup_buffer_and_trigger() - Free buffer and trigger resources
* @adis: The adis device.
* @indio_dev: The IIO device.
*
* Frees resources allocated by adis_setup_buffer_and_trigger()
*/
void adis_cleanup_buffer_and_trigger(struct adis *adis,
struct iio_dev *indio_dev)
{
if (adis->spi->irq)
adis_remove_trigger(adis);
kfree(adis->buffer);
kfree(adis->xfer);
iio_triggered_buffer_cleanup(indio_dev);
}
EXPORT_SYMBOL_GPL(adis_cleanup_buffer_and_trigger);