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linux/drivers/iio/adc/ad7266.c
Jonathan Cameron b990cdfe75 iio: adc: ad7266: Fix alignment for DMA safety 
____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_DMA_MINALIGN definition.

Update the comment to reflect that DMA safety 'may' require separate
cachelines.

Fixes: 54e018da31 ("iio:ad7266: Mark transfer buffer as __be16")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-10-jic23@kernel.org
2022-06-14 11:53:12 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* AD7266/65 SPI ADC driver
*
* Copyright 2012 Analog Devices Inc.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/interrupt.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/platform_data/ad7266.h>
struct ad7266_state {
struct spi_device *spi;
struct regulator *reg;
unsigned long vref_mv;
struct spi_transfer single_xfer[3];
struct spi_message single_msg;
enum ad7266_range range;
enum ad7266_mode mode;
bool fixed_addr;
struct gpio_desc *gpios[3];
/*
* DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
* The buffer needs to be large enough to hold two samples (4 bytes) and
* the naturally aligned timestamp (8 bytes).
*/
struct {
__be16 sample[2];
s64 timestamp;
} data __aligned(IIO_DMA_MINALIGN);
};
static int ad7266_wakeup(struct ad7266_state *st)
{
/* Any read with >= 2 bytes will wake the device */
return spi_read(st->spi, &st->data.sample[0], 2);
}
static int ad7266_powerdown(struct ad7266_state *st)
{
/* Any read with < 2 bytes will powerdown the device */
return spi_read(st->spi, &st->data.sample[0], 1);
}
static int ad7266_preenable(struct iio_dev *indio_dev)
{
struct ad7266_state *st = iio_priv(indio_dev);
return ad7266_wakeup(st);
}
static int ad7266_postdisable(struct iio_dev *indio_dev)
{
struct ad7266_state *st = iio_priv(indio_dev);
return ad7266_powerdown(st);
}
static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
.preenable = &ad7266_preenable,
.postdisable = &ad7266_postdisable,
};
static irqreturn_t ad7266_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7266_state *st = iio_priv(indio_dev);
int ret;
ret = spi_read(st->spi, st->data.sample, 4);
if (ret == 0) {
iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
pf->timestamp);
}
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
{
unsigned int i;
if (st->fixed_addr)
return;
switch (st->mode) {
case AD7266_MODE_SINGLE_ENDED:
nr >>= 1;
break;
case AD7266_MODE_PSEUDO_DIFF:
nr |= 1;
break;
case AD7266_MODE_DIFF:
nr &= ~1;
break;
}
for (i = 0; i < 3; ++i)
gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
}
static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
const unsigned long *scan_mask)
{
struct ad7266_state *st = iio_priv(indio_dev);
unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
ad7266_select_input(st, nr);
return 0;
}
static int ad7266_read_single(struct ad7266_state *st, int *val,
unsigned int address)
{
int ret;
ad7266_select_input(st, address);
ret = spi_sync(st->spi, &st->single_msg);
*val = be16_to_cpu(st->data.sample[address % 2]);
return ret;
}
static int ad7266_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val, int *val2, long m)
{
struct ad7266_state *st = iio_priv(indio_dev);
unsigned long scale_mv;
int ret;
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ret = ad7266_read_single(st, val, chan->address);
iio_device_release_direct_mode(indio_dev);
*val = (*val >> 2) & 0xfff;
if (chan->scan_type.sign == 's')
*val = sign_extend32(*val,
chan->scan_type.realbits - 1);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
scale_mv = st->vref_mv;
if (st->mode == AD7266_MODE_DIFF)
scale_mv *= 2;
if (st->range == AD7266_RANGE_2VREF)
scale_mv *= 2;
*val = scale_mv;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
if (st->range == AD7266_RANGE_2VREF &&
st->mode != AD7266_MODE_DIFF)
*val = 2048;
else
*val = 0;
return IIO_VAL_INT;
}
return -EINVAL;
}
#define AD7266_CHAN(_chan, _sign) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_chan), \
.address = (_chan), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
| BIT(IIO_CHAN_INFO_OFFSET), \
.scan_index = (_chan), \
.scan_type = { \
.sign = (_sign), \
.realbits = 12, \
.storagebits = 16, \
.shift = 2, \
.endianness = IIO_BE, \
}, \
}
#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
const struct iio_chan_spec ad7266_channels_##_name[] = { \
AD7266_CHAN(0, (_sign)), \
AD7266_CHAN(1, (_sign)), \
AD7266_CHAN(2, (_sign)), \
AD7266_CHAN(3, (_sign)), \
AD7266_CHAN(4, (_sign)), \
AD7266_CHAN(5, (_sign)), \
AD7266_CHAN(6, (_sign)), \
AD7266_CHAN(7, (_sign)), \
AD7266_CHAN(8, (_sign)), \
AD7266_CHAN(9, (_sign)), \
AD7266_CHAN(10, (_sign)), \
AD7266_CHAN(11, (_sign)), \
IIO_CHAN_SOFT_TIMESTAMP(13), \
}
#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
AD7266_CHAN(0, (_sign)), \
AD7266_CHAN(1, (_sign)), \
IIO_CHAN_SOFT_TIMESTAMP(2), \
}
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
#define AD7266_CHAN_DIFF(_chan, _sign) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_chan) * 2, \
.channel2 = (_chan) * 2 + 1, \
.address = (_chan), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
| BIT(IIO_CHAN_INFO_OFFSET), \
.scan_index = (_chan), \
.scan_type = { \
.sign = _sign, \
.realbits = 12, \
.storagebits = 16, \
.shift = 2, \
.endianness = IIO_BE, \
}, \
.differential = 1, \
}
#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
AD7266_CHAN_DIFF(0, (_sign)), \
AD7266_CHAN_DIFF(1, (_sign)), \
AD7266_CHAN_DIFF(2, (_sign)), \
AD7266_CHAN_DIFF(3, (_sign)), \
AD7266_CHAN_DIFF(4, (_sign)), \
AD7266_CHAN_DIFF(5, (_sign)), \
IIO_CHAN_SOFT_TIMESTAMP(6), \
}
static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
AD7266_CHAN_DIFF(0, (_sign)), \
AD7266_CHAN_DIFF(1, (_sign)), \
IIO_CHAN_SOFT_TIMESTAMP(2), \
}
static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
static const struct iio_info ad7266_info = {
.read_raw = &ad7266_read_raw,
.update_scan_mode = &ad7266_update_scan_mode,
};
static const unsigned long ad7266_available_scan_masks[] = {
0x003,
0x00c,
0x030,
0x0c0,
0x300,
0xc00,
0x000,
};
static const unsigned long ad7266_available_scan_masks_diff[] = {
0x003,
0x00c,
0x030,
0x000,
};
static const unsigned long ad7266_available_scan_masks_fixed[] = {
0x003,
0x000,
};
struct ad7266_chan_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
const unsigned long *scan_masks;
};
#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
(((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
static const struct ad7266_chan_info ad7266_chan_infos[] = {
[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
.channels = ad7266_channels_u,
.num_channels = ARRAY_SIZE(ad7266_channels_u),
.scan_masks = ad7266_available_scan_masks,
},
[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
.channels = ad7266_channels_u_fixed,
.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
.scan_masks = ad7266_available_scan_masks_fixed,
},
[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
.channels = ad7266_channels_s,
.num_channels = ARRAY_SIZE(ad7266_channels_s),
.scan_masks = ad7266_available_scan_masks,
},
[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
.channels = ad7266_channels_s_fixed,
.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
.scan_masks = ad7266_available_scan_masks_fixed,
},
[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
.channels = ad7266_channels_diff_u,
.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
.scan_masks = ad7266_available_scan_masks_diff,
},
[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
.channels = ad7266_channels_diff_fixed_u,
.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
.scan_masks = ad7266_available_scan_masks_fixed,
},
[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
.channels = ad7266_channels_diff_s,
.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
.scan_masks = ad7266_available_scan_masks_diff,
},
[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
.channels = ad7266_channels_diff_fixed_s,
.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
.scan_masks = ad7266_available_scan_masks_fixed,
},
};
static void ad7266_init_channels(struct iio_dev *indio_dev)
{
struct ad7266_state *st = iio_priv(indio_dev);
bool is_differential, is_signed;
const struct ad7266_chan_info *chan_info;
int i;
is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
is_signed = (st->range == AD7266_RANGE_2VREF) |
(st->mode == AD7266_MODE_DIFF);
i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
chan_info = &ad7266_chan_infos[i];
indio_dev->channels = chan_info->channels;
indio_dev->num_channels = chan_info->num_channels;
indio_dev->available_scan_masks = chan_info->scan_masks;
indio_dev->masklength = chan_info->num_channels - 1;
}
static const char * const ad7266_gpio_labels[] = {
"ad0", "ad1", "ad2",
};
static void ad7266_reg_disable(void *reg)
{
regulator_disable(reg);
}
static int ad7266_probe(struct spi_device *spi)
{
struct ad7266_platform_data *pdata = spi->dev.platform_data;
struct iio_dev *indio_dev;
struct ad7266_state *st;
unsigned int i;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
st->reg = devm_regulator_get_optional(&spi->dev, "vref");
if (!IS_ERR(st->reg)) {
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = devm_add_action_or_reset(&spi->dev, ad7266_reg_disable, st->reg);
if (ret)
return ret;
ret = regulator_get_voltage(st->reg);
if (ret < 0)
return ret;
st->vref_mv = ret / 1000;
} else {
/* Any other error indicates that the regulator does exist */
if (PTR_ERR(st->reg) != -ENODEV)
return PTR_ERR(st->reg);
/* Use internal reference */
st->vref_mv = 2500;
}
if (pdata) {
st->fixed_addr = pdata->fixed_addr;
st->mode = pdata->mode;
st->range = pdata->range;
if (!st->fixed_addr) {
for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
st->gpios[i] = devm_gpiod_get(&spi->dev,
ad7266_gpio_labels[i],
GPIOD_OUT_LOW);
if (IS_ERR(st->gpios[i])) {
ret = PTR_ERR(st->gpios[i]);
return ret;
}
}
}
} else {
st->fixed_addr = true;
st->range = AD7266_RANGE_VREF;
st->mode = AD7266_MODE_DIFF;
}
st->spi = spi;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &ad7266_info;
ad7266_init_channels(indio_dev);
/* wakeup */
st->single_xfer[0].rx_buf = &st->data.sample[0];
st->single_xfer[0].len = 2;
st->single_xfer[0].cs_change = 1;
/* conversion */
st->single_xfer[1].rx_buf = st->data.sample;
st->single_xfer[1].len = 4;
st->single_xfer[1].cs_change = 1;
/* powerdown */
st->single_xfer[2].tx_buf = &st->data.sample[0];
st->single_xfer[2].len = 1;
spi_message_init(&st->single_msg);
spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, &iio_pollfunc_store_time,
&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
if (ret)
return ret;
return devm_iio_device_register(&spi->dev, indio_dev);
}
static const struct spi_device_id ad7266_id[] = {
{"ad7265", 0},
{"ad7266", 0},
{ }
};
MODULE_DEVICE_TABLE(spi, ad7266_id);
static struct spi_driver ad7266_driver = {
.driver = {
.name = "ad7266",
},
.probe = ad7266_probe,
.id_table = ad7266_id,
};
module_spi_driver(ad7266_driver);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
MODULE_LICENSE("GPL v2");
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