linux/drivers/iio/adc/ad_sigma_delta.c

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/*
* Support code for Analog Devices Sigma-Delta ADCs
*
* Copyright 2012 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*
* Licensed under the GPL-2.
*/
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/adc/ad_sigma_delta.h>
#include <asm/unaligned.h>
#define AD_SD_COMM_CHAN_MASK 0x3
#define AD_SD_REG_COMM 0x00
#define AD_SD_REG_DATA 0x03
/**
* ad_sd_set_comm() - Set communications register
*
* @sigma_delta: The sigma delta device
* @comm: New value for the communications register
*/
void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
{
/* Some variants use the lower two bits of the communications register
* to select the channel */
sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
}
EXPORT_SYMBOL_GPL(ad_sd_set_comm);
/**
* ad_sd_write_reg() - Write a register
*
* @sigma_delta: The sigma delta device
* @reg: Address of the register
* @size: Size of the register (0-3)
* @val: Value to write to the register
*
* Returns 0 on success, an error code otherwise.
**/
int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
unsigned int size, unsigned int val)
{
uint8_t *data = sigma_delta->data;
struct spi_transfer t = {
.tx_buf = data,
.len = size + 1,
.cs_change = sigma_delta->bus_locked,
};
struct spi_message m;
int ret;
data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
switch (size) {
case 3:
data[1] = val >> 16;
data[2] = val >> 8;
data[3] = val;
break;
case 2:
put_unaligned_be16(val, &data[1]);
break;
case 1:
data[1] = val;
break;
case 0:
break;
default:
return -EINVAL;
}
spi_message_init(&m);
spi_message_add_tail(&t, &m);
if (sigma_delta->bus_locked)
ret = spi_sync_locked(sigma_delta->spi, &m);
else
ret = spi_sync(sigma_delta->spi, &m);
return ret;
}
EXPORT_SYMBOL_GPL(ad_sd_write_reg);
static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
unsigned int reg, unsigned int size, uint8_t *val)
{
uint8_t *data = sigma_delta->data;
int ret;
struct spi_transfer t[] = {
{
.tx_buf = data,
.len = 1,
}, {
.rx_buf = val,
.len = size,
.cs_change = sigma_delta->bus_locked,
},
};
struct spi_message m;
spi_message_init(&m);
if (sigma_delta->info->has_registers) {
data[0] = reg << sigma_delta->info->addr_shift;
data[0] |= sigma_delta->info->read_mask;
spi_message_add_tail(&t[0], &m);
}
spi_message_add_tail(&t[1], &m);
if (sigma_delta->bus_locked)
ret = spi_sync_locked(sigma_delta->spi, &m);
else
ret = spi_sync(sigma_delta->spi, &m);
return ret;
}
/**
* ad_sd_read_reg() - Read a register
*
* @sigma_delta: The sigma delta device
* @reg: Address of the register
* @size: Size of the register (1-4)
* @val: Read value
*
* Returns 0 on success, an error code otherwise.
**/
int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
unsigned int reg, unsigned int size, unsigned int *val)
{
int ret;
ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data);
if (ret < 0)
goto out;
switch (size) {
case 4:
*val = get_unaligned_be32(sigma_delta->data);
break;
case 3:
*val = (sigma_delta->data[0] << 16) |
(sigma_delta->data[1] << 8) |
sigma_delta->data[2];
break;
case 2:
*val = get_unaligned_be16(sigma_delta->data);
break;
case 1:
*val = sigma_delta->data[0];
break;
default:
ret = -EINVAL;
break;
}
out:
return ret;
}
EXPORT_SYMBOL_GPL(ad_sd_read_reg);
/**
* ad_sd_reset() - Reset the serial interface
*
* @sigma_delta: The sigma delta device
* @reset_length: Number of SCLKs with DIN = 1
*
* Returns 0 on success, an error code otherwise.
**/
int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
unsigned int reset_length)
{
uint8_t *buf;
unsigned int size;
int ret;
size = DIV_ROUND_UP(reset_length, 8);
buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
if (!buf)
return -ENOMEM;
memset(buf, 0xff, size);
ret = spi_write(sigma_delta->spi, buf, size);
kfree(buf);
return ret;
}
EXPORT_SYMBOL_GPL(ad_sd_reset);
static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
unsigned int mode, unsigned int channel)
{
int ret;
ret = ad_sigma_delta_set_channel(sigma_delta, channel);
if (ret)
return ret;
spi_bus_lock(sigma_delta->spi->master);
sigma_delta->bus_locked = true;
reinit_completion(&sigma_delta->completion);
ret = ad_sigma_delta_set_mode(sigma_delta, mode);
if (ret < 0)
goto out;
sigma_delta->irq_dis = false;
enable_irq(sigma_delta->spi->irq);
ret = wait_for_completion_timeout(&sigma_delta->completion, 2*HZ);
if (ret == 0) {
sigma_delta->irq_dis = true;
disable_irq_nosync(sigma_delta->spi->irq);
ret = -EIO;
} else {
ret = 0;
}
out:
sigma_delta->bus_locked = false;
spi_bus_unlock(sigma_delta->spi->master);
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
return ret;
}
/**
* ad_sd_calibrate_all() - Performs channel calibration
* @sigma_delta: The sigma delta device
* @cb: Array of channels and calibration type to perform
* @n: Number of items in cb
*
* Returns 0 on success, an error code otherwise.
**/
int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
const struct ad_sd_calib_data *cb, unsigned int n)
{
unsigned int i;
int ret;
for (i = 0; i < n; i++) {
ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
/**
* ad_sigma_delta_single_conversion() - Performs a single data conversion
* @indio_dev: The IIO device
* @chan: The conversion is done for this channel
* @val: Pointer to the location where to store the read value
*
* Returns: 0 on success, an error value otherwise.
*/
int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, int *val)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
unsigned int sample, raw_sample;
int ret = 0;
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
mutex_lock(&indio_dev->mlock);
ad_sigma_delta_set_channel(sigma_delta, chan->address);
spi_bus_lock(sigma_delta->spi->master);
sigma_delta->bus_locked = true;
reinit_completion(&sigma_delta->completion);
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
sigma_delta->irq_dis = false;
enable_irq(sigma_delta->spi->irq);
ret = wait_for_completion_interruptible_timeout(
&sigma_delta->completion, HZ);
sigma_delta->bus_locked = false;
spi_bus_unlock(sigma_delta->spi->master);
if (ret == 0)
ret = -EIO;
if (ret < 0)
goto out;
ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
&raw_sample);
out:
if (!sigma_delta->irq_dis) {
disable_irq_nosync(sigma_delta->spi->irq);
sigma_delta->irq_dis = true;
}
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
mutex_unlock(&indio_dev->mlock);
if (ret)
return ret;
sample = raw_sample >> chan->scan_type.shift;
sample &= (1 << chan->scan_type.realbits) - 1;
*val = sample;
ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
if (ret)
return ret;
return IIO_VAL_INT;
}
EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
unsigned int channel;
int ret;
ret = iio_triggered_buffer_postenable(indio_dev);
if (ret < 0)
return ret;
channel = find_first_bit(indio_dev->active_scan_mask,
indio_dev->masklength);
ret = ad_sigma_delta_set_channel(sigma_delta,
indio_dev->channels[channel].address);
if (ret)
goto err_predisable;
spi_bus_lock(sigma_delta->spi->master);
sigma_delta->bus_locked = true;
ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
if (ret)
goto err_unlock;
sigma_delta->irq_dis = false;
enable_irq(sigma_delta->spi->irq);
return 0;
err_unlock:
spi_bus_unlock(sigma_delta->spi->master);
err_predisable:
return ret;
}
static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
reinit_completion(&sigma_delta->completion);
wait_for_completion_timeout(&sigma_delta->completion, HZ);
if (!sigma_delta->irq_dis) {
disable_irq_nosync(sigma_delta->spi->irq);
sigma_delta->irq_dis = true;
}
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
sigma_delta->bus_locked = false;
return spi_bus_unlock(sigma_delta->spi->master);
}
static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
unsigned int reg_size;
uint8_t data[16];
int ret;
memset(data, 0x00, 16);
reg_size = indio_dev->channels[0].scan_type.realbits +
indio_dev->channels[0].scan_type.shift;
reg_size = DIV_ROUND_UP(reg_size, 8);
switch (reg_size) {
case 4:
case 2:
case 1:
ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
reg_size, &data[0]);
break;
case 3:
/* We store 24 bit samples in a 32 bit word. Keep the upper
* byte set to zero. */
ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
reg_size, &data[1]);
break;
}
iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
iio_trigger_notify_done(indio_dev->trig);
sigma_delta->irq_dis = false;
enable_irq(sigma_delta->spi->irq);
return IRQ_HANDLED;
}
static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
.postenable = &ad_sd_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
.postdisable = &ad_sd_buffer_postdisable,
.validate_scan_mask = &iio_validate_scan_mask_onehot,
};
static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
{
struct ad_sigma_delta *sigma_delta = private;
complete(&sigma_delta->completion);
disable_irq_nosync(irq);
sigma_delta->irq_dis = true;
iio_trigger_poll(sigma_delta->trig);
return IRQ_HANDLED;
}
/**
* ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
* @indio_dev: The IIO device
* @trig: The new trigger
*
* Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
* device, -EINVAL otherwise.
*/
int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
if (sigma_delta->trig != trig)
return -EINVAL;
return 0;
}
EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
static const struct iio_trigger_ops ad_sd_trigger_ops = {
};
static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
int ret;
sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
indio_dev->id);
if (sigma_delta->trig == NULL) {
ret = -ENOMEM;
goto error_ret;
}
sigma_delta->trig->ops = &ad_sd_trigger_ops;
init_completion(&sigma_delta->completion);
ret = request_irq(sigma_delta->spi->irq,
ad_sd_data_rdy_trig_poll,
IRQF_TRIGGER_LOW,
indio_dev->name,
sigma_delta);
if (ret)
goto error_free_trig;
if (!sigma_delta->irq_dis) {
sigma_delta->irq_dis = true;
disable_irq_nosync(sigma_delta->spi->irq);
}
sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
ret = iio_trigger_register(sigma_delta->trig);
if (ret)
goto error_free_irq;
/* select default trigger */
indio_dev->trig = iio_trigger_get(sigma_delta->trig);
return 0;
error_free_irq:
free_irq(sigma_delta->spi->irq, sigma_delta);
error_free_trig:
iio_trigger_free(sigma_delta->trig);
error_ret:
return ret;
}
static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
iio_trigger_unregister(sigma_delta->trig);
free_irq(sigma_delta->spi->irq, sigma_delta);
iio_trigger_free(sigma_delta->trig);
}
/**
* ad_sd_setup_buffer_and_trigger() -
* @indio_dev: The IIO device
*/
int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
{
int ret;
ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
&ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
if (ret)
return ret;
ret = ad_sd_probe_trigger(indio_dev);
if (ret) {
iio_triggered_buffer_cleanup(indio_dev);
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
/**
* ad_sd_cleanup_buffer_and_trigger() -
* @indio_dev: The IIO device
*/
void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
{
ad_sd_remove_trigger(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
}
EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
/**
* ad_sd_init() - Initializes a ad_sigma_delta struct
* @sigma_delta: The ad_sigma_delta device
* @indio_dev: The IIO device which the Sigma Delta device is used for
* @spi: The SPI device for the ad_sigma_delta device
* @info: Device specific callbacks and options
*
* This function needs to be called before any other operations are performed on
* the ad_sigma_delta struct.
*/
int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
struct spi_device *spi, const struct ad_sigma_delta_info *info)
{
sigma_delta->spi = spi;
sigma_delta->info = info;
iio_device_set_drvdata(indio_dev, sigma_delta);
return 0;
}
EXPORT_SYMBOL_GPL(ad_sd_init);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
MODULE_LICENSE("GPL v2");