linux-zen-desktop/drivers/iio/adc/ad_sigma_delta.c

680 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Support code for Analog Devices Sigma-Delta ADCs
*
* Copyright 2012 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*/
#include <linux/align.h>
#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_NS_GPL(ad_sd_set_comm, IIO_AD_SIGMA_DELTA);
/**
* 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->tx_buf;
struct spi_transfer t = {
.tx_buf = data,
.len = size + 1,
.cs_change = sigma_delta->keep_cs_asserted,
};
struct spi_message m;
int ret;
data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
switch (size) {
case 3:
put_unaligned_be24(val, &data[1]);
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_NS_GPL(ad_sd_write_reg, IIO_AD_SIGMA_DELTA);
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->tx_buf;
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;
data[0] |= sigma_delta->comm;
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->rx_buf);
if (ret < 0)
goto out;
switch (size) {
case 4:
*val = get_unaligned_be32(sigma_delta->rx_buf);
break;
case 3:
*val = get_unaligned_be24(sigma_delta->rx_buf);
break;
case 2:
*val = get_unaligned_be16(sigma_delta->rx_buf);
break;
case 1:
*val = sigma_delta->rx_buf[0];
break;
default:
ret = -EINVAL;
break;
}
out:
return ret;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, IIO_AD_SIGMA_DELTA);
/**
* 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_NS_GPL(ad_sd_reset, IIO_AD_SIGMA_DELTA);
int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
unsigned int mode, unsigned int channel)
{
int ret;
unsigned long timeout;
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;
sigma_delta->keep_cs_asserted = 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);
timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
if (timeout == 0) {
sigma_delta->irq_dis = true;
disable_irq_nosync(sigma_delta->spi->irq);
ret = -EIO;
} else {
ret = 0;
}
out:
sigma_delta->keep_cs_asserted = false;
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
sigma_delta->bus_locked = false;
spi_bus_unlock(sigma_delta->spi->master);
return ret;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, IIO_AD_SIGMA_DELTA);
/**
* 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_NS_GPL(ad_sd_calibrate_all, IIO_AD_SIGMA_DELTA);
/**
* 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;
unsigned int data_reg;
int ret = 0;
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ad_sigma_delta_set_channel(sigma_delta, chan->address);
spi_bus_lock(sigma_delta->spi->master);
sigma_delta->bus_locked = true;
sigma_delta->keep_cs_asserted = 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);
if (ret == 0)
ret = -EIO;
if (ret < 0)
goto out;
if (sigma_delta->info->data_reg != 0)
data_reg = sigma_delta->info->data_reg;
else
data_reg = AD_SD_REG_DATA;
ret = ad_sd_read_reg(sigma_delta, data_reg,
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;
}
sigma_delta->keep_cs_asserted = false;
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
sigma_delta->bus_locked = false;
spi_bus_unlock(sigma_delta->spi->master);
iio_device_release_direct_mode(indio_dev);
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_NS_GPL(ad_sigma_delta_single_conversion, IIO_AD_SIGMA_DELTA);
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 i, slot, samples_buf_size;
unsigned int channel;
uint8_t *samples_buf;
int ret;
if (sigma_delta->num_slots == 1) {
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)
return ret;
slot = 1;
} else {
/*
* At this point update_scan_mode already enabled the required channels.
* For sigma-delta sequencer drivers with multiple slots, an update_scan_mode
* implementation is mandatory.
*/
slot = 0;
for_each_set_bit(i, indio_dev->active_scan_mask, indio_dev->masklength) {
sigma_delta->slots[slot] = indio_dev->channels[i].address;
slot++;
}
}
sigma_delta->active_slots = slot;
sigma_delta->current_slot = 0;
if (sigma_delta->active_slots > 1) {
ret = ad_sigma_delta_append_status(sigma_delta, true);
if (ret)
return ret;
}
samples_buf_size = ALIGN(slot * indio_dev->channels[0].scan_type.storagebits, 8);
samples_buf_size += sizeof(int64_t);
samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf,
samples_buf_size, GFP_KERNEL);
if (!samples_buf)
return -ENOMEM;
sigma_delta->samples_buf = samples_buf;
spi_bus_lock(sigma_delta->spi->master);
sigma_delta->bus_locked = true;
sigma_delta->keep_cs_asserted = 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);
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;
}
sigma_delta->keep_cs_asserted = false;
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
if (sigma_delta->status_appended)
ad_sigma_delta_append_status(sigma_delta, false);
ad_sigma_delta_disable_all(sigma_delta);
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);
uint8_t *data = sigma_delta->rx_buf;
unsigned int transfer_size;
unsigned int sample_size;
unsigned int sample_pos;
unsigned int status_pos;
unsigned int reg_size;
unsigned int data_reg;
reg_size = indio_dev->channels[0].scan_type.realbits +
indio_dev->channels[0].scan_type.shift;
reg_size = DIV_ROUND_UP(reg_size, 8);
if (sigma_delta->info->data_reg != 0)
data_reg = sigma_delta->info->data_reg;
else
data_reg = AD_SD_REG_DATA;
/* Status word will be appended to the sample during transfer */
if (sigma_delta->status_appended)
transfer_size = reg_size + 1;
else
transfer_size = reg_size;
switch (reg_size) {
case 4:
case 2:
case 1:
status_pos = reg_size;
ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[0]);
break;
case 3:
/*
* Data array after transfer will look like (if status is appended):
* data[] = { [0][sample][sample][sample][status] }
* Keeping the first byte 0 shifts the status postion by 1 byte to the right.
*/
status_pos = reg_size + 1;
/* We store 24 bit samples in a 32 bit word. Keep the upper
* byte set to zero. */
ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[1]);
break;
}
/*
* For devices sampling only one channel at
* once, there is no need for sample number tracking.
*/
if (sigma_delta->active_slots == 1) {
iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
goto irq_handled;
}
if (sigma_delta->status_appended) {
u8 converted_channel;
converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask;
if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) {
/*
* Desync occurred during continuous sampling of multiple channels.
* Drop this incomplete sample and start from first channel again.
*/
sigma_delta->current_slot = 0;
goto irq_handled;
}
}
sample_size = indio_dev->channels[0].scan_type.storagebits / 8;
sample_pos = sample_size * sigma_delta->current_slot;
memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size);
sigma_delta->current_slot++;
if (sigma_delta->current_slot == sigma_delta->active_slots) {
sigma_delta->current_slot = 0;
iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf,
pf->timestamp);
}
irq_handled:
iio_trigger_notify_done(indio_dev->trig);
sigma_delta->irq_dis = false;
enable_irq(sigma_delta->spi->irq);
return IRQ_HANDLED;
}
static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
return bitmap_weight(mask, indio_dev->masklength) <= sigma_delta->num_slots;
}
static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
.postenable = &ad_sd_buffer_postenable,
.postdisable = &ad_sd_buffer_postdisable,
.validate_scan_mask = &ad_sd_validate_scan_mask,
};
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_NS_GPL(ad_sd_validate_trigger, IIO_AD_SIGMA_DELTA);
static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
int ret;
if (dev != &sigma_delta->spi->dev) {
dev_err(dev, "Trigger parent should be '%s', got '%s'\n",
dev_name(dev), dev_name(&sigma_delta->spi->dev));
return -EFAULT;
}
sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
iio_device_id(indio_dev));
if (sigma_delta->trig == NULL)
return -ENOMEM;
init_completion(&sigma_delta->completion);
sigma_delta->irq_dis = true;
/* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
ret = devm_request_irq(dev, sigma_delta->spi->irq,
ad_sd_data_rdy_trig_poll,
sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
indio_dev->name,
sigma_delta);
if (ret)
return ret;
iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
ret = devm_iio_trigger_register(dev, sigma_delta->trig);
if (ret)
return ret;
/* select default trigger */
indio_dev->trig = iio_trigger_get(sigma_delta->trig);
return 0;
}
/**
* devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup
* @dev: Device object to which to bind the life-time of the resources attached
* @indio_dev: The IIO device
*/
int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev)
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
int ret;
sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots,
sizeof(*sigma_delta->slots), GFP_KERNEL);
if (!sigma_delta->slots)
return -ENOMEM;
ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
&iio_pollfunc_store_time,
&ad_sd_trigger_handler,
&ad_sd_buffer_setup_ops);
if (ret)
return ret;
return devm_ad_sd_probe_trigger(dev, indio_dev);
}
EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, IIO_AD_SIGMA_DELTA);
/**
* 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;
/* If the field is unset in ad_sigma_delta_info, asume there can only be 1 slot. */
if (!info->num_slots)
sigma_delta->num_slots = 1;
else
sigma_delta->num_slots = info->num_slots;
if (sigma_delta->num_slots > 1) {
if (!indio_dev->info->update_scan_mode) {
dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n");
return -EINVAL;
}
if (!info->disable_all) {
dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n");
return -EINVAL;
}
}
iio_device_set_drvdata(indio_dev, sigma_delta);
return 0;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_init, IIO_AD_SIGMA_DELTA);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
MODULE_LICENSE("GPL v2");