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linux/drivers/iio/adc/ti-adc12138.c
Jonathan Cameron 293e809b2e iio:adc:ti-adc12138 Fix alignment issue with timestamp 
One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes).  This is not guaranteed in
this driver which uses an array of smaller elements on the stack.

We move to a suitable structure in the iio_priv() data with alignment
explicitly requested.  This data is allocated with kzalloc so no
data can leak apart from previous readings. Note that previously
no leak at all could occur, but previous readings should never
be a problem.

In this case the timestamp location depends on what other channels
are enabled. As such we can't use a structure without misleading
by suggesting only one possible timestamp location.

Fixes: 50a6edb1b6 ("iio: adc: add ADC12130/ADC12132/ADC12138 ADC driver")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200722155103.979802-26-jic23@kernel.org
2020-09-21 20:01:51 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
*
* Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
*
* Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
*/
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/clk.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/regulator/consumer.h>
#define ADC12138_MODE_AUTO_CAL 0x08
#define ADC12138_MODE_READ_STATUS 0x0c
#define ADC12138_MODE_ACQUISITION_TIME_6 0x0e
#define ADC12138_MODE_ACQUISITION_TIME_10 0x4e
#define ADC12138_MODE_ACQUISITION_TIME_18 0x8e
#define ADC12138_MODE_ACQUISITION_TIME_34 0xce
#define ADC12138_STATUS_CAL BIT(6)
enum {
adc12130,
adc12132,
adc12138,
};
struct adc12138 {
struct spi_device *spi;
unsigned int id;
/* conversion clock */
struct clk *cclk;
/* positive analog voltage reference */
struct regulator *vref_p;
/* negative analog voltage reference */
struct regulator *vref_n;
struct mutex lock;
struct completion complete;
/* The number of cclk periods for the S/H's acquisition time */
unsigned int acquisition_time;
/*
* Maximum size needed: 16x 2 bytes ADC data + 8 bytes timestamp.
* Less may be need if not all channels are enabled, as long as
* the 8 byte alignment of the timestamp is maintained.
*/
__be16 data[20] __aligned(8);
u8 tx_buf[2] ____cacheline_aligned;
u8 rx_buf[2];
};
#define ADC12138_VOLTAGE_CHANNEL(chan) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = 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 = 's', \
.realbits = 13, \
.storagebits = 16, \
.shift = 3, \
.endianness = IIO_BE, \
}, \
}
#define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (chan1), \
.channel2 = (chan2), \
.differential = 1, \
.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 = si, \
.scan_type = { \
.sign = 's', \
.realbits = 13, \
.storagebits = 16, \
.shift = 3, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec adc12132_channels[] = {
ADC12138_VOLTAGE_CHANNEL(0),
ADC12138_VOLTAGE_CHANNEL(1),
ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
IIO_CHAN_SOFT_TIMESTAMP(4),
};
static const struct iio_chan_spec adc12138_channels[] = {
ADC12138_VOLTAGE_CHANNEL(0),
ADC12138_VOLTAGE_CHANNEL(1),
ADC12138_VOLTAGE_CHANNEL(2),
ADC12138_VOLTAGE_CHANNEL(3),
ADC12138_VOLTAGE_CHANNEL(4),
ADC12138_VOLTAGE_CHANNEL(5),
ADC12138_VOLTAGE_CHANNEL(6),
ADC12138_VOLTAGE_CHANNEL(7),
ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
IIO_CHAN_SOFT_TIMESTAMP(16),
};
static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
void *rx_buf, int len)
{
struct spi_transfer xfer = {
.tx_buf = adc->tx_buf,
.rx_buf = adc->rx_buf,
.len = len,
};
int ret;
/* Skip unused bits for ADC12130 and ADC12132 */
if (adc->id != adc12138)
mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
adc->tx_buf[0] = mode;
ret = spi_sync_transfer(adc->spi, &xfer, 1);
if (ret)
return ret;
memcpy(rx_buf, adc->rx_buf, len);
return 0;
}
static int adc12138_read_status(struct adc12138 *adc)
{
u8 rx_buf[2];
int ret;
ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
rx_buf, 2);
if (ret)
return ret;
return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
}
static int __adc12138_start_conv(struct adc12138 *adc,
struct iio_chan_spec const *channel,
void *data, int len)
{
static const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
u8 mode = (ch_to_mux[channel->channel] << 4) |
(channel->differential ? 0 : 0x80);
return adc12138_mode_programming(adc, mode, data, len);
}
static int adc12138_start_conv(struct adc12138 *adc,
struct iio_chan_spec const *channel)
{
u8 trash;
return __adc12138_start_conv(adc, channel, &trash, 1);
}
static int adc12138_start_and_read_conv(struct adc12138 *adc,
struct iio_chan_spec const *channel,
__be16 *data)
{
return __adc12138_start_conv(adc, channel, data, 2);
}
static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
{
/* Issue a read status instruction and read previous conversion data */
return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
value, sizeof(*value));
}
static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
{
if (!wait_for_completion_timeout(&adc->complete, timeout))
return -ETIMEDOUT;
return 0;
}
static int adc12138_adc_conversion(struct adc12138 *adc,
struct iio_chan_spec const *channel,
__be16 *value)
{
int ret;
reinit_completion(&adc->complete);
ret = adc12138_start_conv(adc, channel);
if (ret)
return ret;
ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
if (ret)
return ret;
return adc12138_read_conv_data(adc, value);
}
static int adc12138_read_raw(struct iio_dev *iio,
struct iio_chan_spec const *channel, int *value,
int *shift, long mask)
{
struct adc12138 *adc = iio_priv(iio);
int ret;
__be16 data;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&adc->lock);
ret = adc12138_adc_conversion(adc, channel, &data);
mutex_unlock(&adc->lock);
if (ret)
return ret;
*value = sign_extend32(be16_to_cpu(data) >> 3, 12);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(adc->vref_p);
if (ret < 0)
return ret;
*value = ret;
if (!IS_ERR(adc->vref_n)) {
ret = regulator_get_voltage(adc->vref_n);
if (ret < 0)
return ret;
*value -= ret;
}
/* convert regulator output voltage to mV */
*value /= 1000;
*shift = channel->scan_type.realbits - 1;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
if (!IS_ERR(adc->vref_n)) {
*value = regulator_get_voltage(adc->vref_n);
if (*value < 0)
return *value;
} else {
*value = 0;
}
/* convert regulator output voltage to mV */
*value /= 1000;
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct iio_info adc12138_info = {
.read_raw = adc12138_read_raw,
};
static int adc12138_init(struct adc12138 *adc)
{
int ret;
int status;
u8 mode;
u8 trash;
reinit_completion(&adc->complete);
ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
if (ret)
return ret;
/* data output at this time has no significance */
status = adc12138_read_status(adc);
if (status < 0)
return status;
adc12138_wait_eoc(adc, msecs_to_jiffies(100));
status = adc12138_read_status(adc);
if (status & ADC12138_STATUS_CAL) {
dev_warn(&adc->spi->dev,
"Auto Cal sequence is still in progress: %#x\n",
status);
return -EIO;
}
switch (adc->acquisition_time) {
case 6:
mode = ADC12138_MODE_ACQUISITION_TIME_6;
break;
case 10:
mode = ADC12138_MODE_ACQUISITION_TIME_10;
break;
case 18:
mode = ADC12138_MODE_ACQUISITION_TIME_18;
break;
case 34:
mode = ADC12138_MODE_ACQUISITION_TIME_34;
break;
default:
return -EINVAL;
}
return adc12138_mode_programming(adc, mode, &trash, 1);
}
static irqreturn_t adc12138_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct adc12138 *adc = iio_priv(indio_dev);
__be16 trash;
int ret;
int scan_index;
int i = 0;
mutex_lock(&adc->lock);
for_each_set_bit(scan_index, indio_dev->active_scan_mask,
indio_dev->masklength) {
const struct iio_chan_spec *scan_chan =
&indio_dev->channels[scan_index];
reinit_completion(&adc->complete);
ret = adc12138_start_and_read_conv(adc, scan_chan,
i ? &adc->data[i - 1] : &trash);
if (ret) {
dev_warn(&adc->spi->dev,
"failed to start conversion\n");
goto out;
}
ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
if (ret) {
dev_warn(&adc->spi->dev, "wait eoc timeout\n");
goto out;
}
i++;
}
if (i) {
ret = adc12138_read_conv_data(adc, &adc->data[i - 1]);
if (ret) {
dev_warn(&adc->spi->dev,
"failed to get conversion data\n");
goto out;
}
}
iio_push_to_buffers_with_timestamp(indio_dev, adc->data,
iio_get_time_ns(indio_dev));
out:
mutex_unlock(&adc->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static irqreturn_t adc12138_eoc_handler(int irq, void *p)
{
struct iio_dev *indio_dev = p;
struct adc12138 *adc = iio_priv(indio_dev);
complete(&adc->complete);
return IRQ_HANDLED;
}
static int adc12138_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct adc12138 *adc;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev)
return -ENOMEM;
adc = iio_priv(indio_dev);
adc->spi = spi;
adc->id = spi_get_device_id(spi)->driver_data;
mutex_init(&adc->lock);
init_completion(&adc->complete);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->info = &adc12138_info;
indio_dev->modes = INDIO_DIRECT_MODE;
switch (adc->id) {
case adc12130:
case adc12132:
indio_dev->channels = adc12132_channels;
indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
break;
case adc12138:
indio_dev->channels = adc12138_channels;
indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
break;
default:
return -EINVAL;
}
ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
&adc->acquisition_time);
if (ret)
adc->acquisition_time = 10;
adc->cclk = devm_clk_get(&spi->dev, NULL);
if (IS_ERR(adc->cclk))
return PTR_ERR(adc->cclk);
adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
if (IS_ERR(adc->vref_p))
return PTR_ERR(adc->vref_p);
adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
if (IS_ERR(adc->vref_n)) {
/*
* Assume vref_n is 0V if an optional regulator is not
* specified, otherwise return the error code.
*/
ret = PTR_ERR(adc->vref_n);
if (ret != -ENODEV)
return ret;
}
ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
if (ret)
return ret;
ret = clk_prepare_enable(adc->cclk);
if (ret)
return ret;
ret = regulator_enable(adc->vref_p);
if (ret)
goto err_clk_disable;
if (!IS_ERR(adc->vref_n)) {
ret = regulator_enable(adc->vref_n);
if (ret)
goto err_vref_p_disable;
}
ret = adc12138_init(adc);
if (ret)
goto err_vref_n_disable;
spi_set_drvdata(spi, indio_dev);
ret = iio_triggered_buffer_setup(indio_dev, NULL,
adc12138_trigger_handler, NULL);
if (ret)
goto err_vref_n_disable;
ret = iio_device_register(indio_dev);
if (ret)
goto err_buffer_cleanup;
return 0;
err_buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
err_vref_n_disable:
if (!IS_ERR(adc->vref_n))
regulator_disable(adc->vref_n);
err_vref_p_disable:
regulator_disable(adc->vref_p);
err_clk_disable:
clk_disable_unprepare(adc->cclk);
return ret;
}
static int adc12138_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct adc12138 *adc = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (!IS_ERR(adc->vref_n))
regulator_disable(adc->vref_n);
regulator_disable(adc->vref_p);
clk_disable_unprepare(adc->cclk);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id adc12138_dt_ids[] = {
{ .compatible = "ti,adc12130", },
{ .compatible = "ti,adc12132", },
{ .compatible = "ti,adc12138", },
{}
};
MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
#endif
static const struct spi_device_id adc12138_id[] = {
{ "adc12130", adc12130 },
{ "adc12132", adc12132 },
{ "adc12138", adc12138 },
{}
};
MODULE_DEVICE_TABLE(spi, adc12138_id);
static struct spi_driver adc12138_driver = {
.driver = {
.name = "adc12138",
.of_match_table = of_match_ptr(adc12138_dt_ids),
},
.probe = adc12138_probe,
.remove = adc12138_remove,
.id_table = adc12138_id,
};
module_spi_driver(adc12138_driver);
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver");
MODULE_LICENSE("GPL v2");
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