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kernel/drivers/iio/adc/max1027.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* iio/adc/max1027.c
* Copyright (C) 2014 Philippe Reynes
*
* based on linux/drivers/iio/ad7923.c
* Copyright 2011 Analog Devices Inc (from AD7923 Driver)
* Copyright 2012 CS Systemes d'Information
*
* max1027.c
*
* Partial support for max1027 and similar chips.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#define MAX1027_CONV_REG BIT(7)
#define MAX1027_SETUP_REG BIT(6)
#define MAX1027_AVG_REG BIT(5)
#define MAX1027_RST_REG BIT(4)
/* conversion register */
#define MAX1027_TEMP BIT(0)
#define MAX1027_SCAN_0_N (0x00 << 1)
#define MAX1027_SCAN_N_M (0x01 << 1)
#define MAX1027_SCAN_N (0x02 << 1)
#define MAX1027_NOSCAN (0x03 << 1)
#define MAX1027_CHAN(n) ((n) << 3)
/* setup register */
#define MAX1027_UNIPOLAR 0x02
#define MAX1027_BIPOLAR 0x03
#define MAX1027_REF_MODE0 (0x00 << 2)
#define MAX1027_REF_MODE1 (0x01 << 2)
#define MAX1027_REF_MODE2 (0x02 << 2)
#define MAX1027_REF_MODE3 (0x03 << 2)
#define MAX1027_CKS_MODE0 (0x00 << 4)
#define MAX1027_CKS_MODE1 (0x01 << 4)
#define MAX1027_CKS_MODE2 (0x02 << 4)
#define MAX1027_CKS_MODE3 (0x03 << 4)
/* averaging register */
#define MAX1027_NSCAN_4 0x00
#define MAX1027_NSCAN_8 0x01
#define MAX1027_NSCAN_12 0x02
#define MAX1027_NSCAN_16 0x03
#define MAX1027_NAVG_4 (0x00 << 2)
#define MAX1027_NAVG_8 (0x01 << 2)
#define MAX1027_NAVG_16 (0x02 << 2)
#define MAX1027_NAVG_32 (0x03 << 2)
#define MAX1027_AVG_EN BIT(4)
/* Device can achieve 300ksps so we assume a 3.33us conversion delay */
#define MAX1027_CONVERSION_UDELAY 4
enum max1027_id {
max1027,
max1029,
max1031,
max1227,
max1229,
max1231,
};
static const struct spi_device_id max1027_id[] = {
{"max1027", max1027},
{"max1029", max1029},
{"max1031", max1031},
{"max1227", max1227},
{"max1229", max1229},
{"max1231", max1231},
{}
};
MODULE_DEVICE_TABLE(spi, max1027_id);
static const struct of_device_id max1027_adc_dt_ids[] = {
{ .compatible = "maxim,max1027" },
{ .compatible = "maxim,max1029" },
{ .compatible = "maxim,max1031" },
{ .compatible = "maxim,max1227" },
{ .compatible = "maxim,max1229" },
{ .compatible = "maxim,max1231" },
{},
};
MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
#define MAX1027_V_CHAN(index, depth) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = index, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.scan_index = index + 1, \
.scan_type = { \
.sign = 'u', \
.realbits = depth, \
.storagebits = 16, \
.shift = (depth == 10) ? 2 : 0, \
.endianness = IIO_BE, \
}, \
}
#define MAX1027_T_CHAN \
{ \
.type = IIO_TEMP, \
.channel = 0, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.scan_index = 0, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
.endianness = IIO_BE, \
}, \
}
#define MAX1X27_CHANNELS(depth) \
MAX1027_T_CHAN, \
MAX1027_V_CHAN(0, depth), \
MAX1027_V_CHAN(1, depth), \
MAX1027_V_CHAN(2, depth), \
MAX1027_V_CHAN(3, depth), \
MAX1027_V_CHAN(4, depth), \
MAX1027_V_CHAN(5, depth), \
MAX1027_V_CHAN(6, depth), \
MAX1027_V_CHAN(7, depth)
#define MAX1X29_CHANNELS(depth) \
MAX1X27_CHANNELS(depth), \
MAX1027_V_CHAN(8, depth), \
MAX1027_V_CHAN(9, depth), \
MAX1027_V_CHAN(10, depth), \
MAX1027_V_CHAN(11, depth)
#define MAX1X31_CHANNELS(depth) \
MAX1X29_CHANNELS(depth), \
MAX1027_V_CHAN(12, depth), \
MAX1027_V_CHAN(13, depth), \
MAX1027_V_CHAN(14, depth), \
MAX1027_V_CHAN(15, depth)
static const struct iio_chan_spec max1027_channels[] = {
MAX1X27_CHANNELS(10),
};
static const struct iio_chan_spec max1029_channels[] = {
MAX1X29_CHANNELS(10),
};
static const struct iio_chan_spec max1031_channels[] = {
MAX1X31_CHANNELS(10),
};
static const struct iio_chan_spec max1227_channels[] = {
MAX1X27_CHANNELS(12),
};
static const struct iio_chan_spec max1229_channels[] = {
MAX1X29_CHANNELS(12),
};
static const struct iio_chan_spec max1231_channels[] = {
MAX1X31_CHANNELS(12),
};
/*
* These devices are able to scan from 0 to N, N being the highest voltage
* channel requested by the user. The temperature can be included or not,
* but cannot be retrieved alone. Based on the below
* ->available_scan_masks, the core will select the most appropriate
* ->active_scan_mask and the "minimum" number of channels will be
* scanned and pushed to the buffers.
*
* For example, if the user wants channels 1, 4 and 5, all channels from
* 0 to 5 will be scanned and pushed to the IIO buffers. The core will then
* filter out the unneeded samples based on the ->active_scan_mask that has
* been selected and only channels 1, 4 and 5 will be available to the user
* in the shared buffer.
*/
#define MAX1X27_SCAN_MASK_TEMP BIT(0)
#define MAX1X27_SCAN_MASKS(temp) \
GENMASK(1, 1 - (temp)), GENMASK(2, 1 - (temp)), \
GENMASK(3, 1 - (temp)), GENMASK(4, 1 - (temp)), \
GENMASK(5, 1 - (temp)), GENMASK(6, 1 - (temp)), \
GENMASK(7, 1 - (temp)), GENMASK(8, 1 - (temp))
#define MAX1X29_SCAN_MASKS(temp) \
MAX1X27_SCAN_MASKS(temp), \
GENMASK(9, 1 - (temp)), GENMASK(10, 1 - (temp)), \
GENMASK(11, 1 - (temp)), GENMASK(12, 1 - (temp))
#define MAX1X31_SCAN_MASKS(temp) \
MAX1X29_SCAN_MASKS(temp), \
GENMASK(13, 1 - (temp)), GENMASK(14, 1 - (temp)), \
GENMASK(15, 1 - (temp)), GENMASK(16, 1 - (temp))
static const unsigned long max1027_available_scan_masks[] = {
MAX1X27_SCAN_MASKS(0),
MAX1X27_SCAN_MASKS(1),
0x00000000,
};
static const unsigned long max1029_available_scan_masks[] = {
MAX1X29_SCAN_MASKS(0),
MAX1X29_SCAN_MASKS(1),
0x00000000,
};
static const unsigned long max1031_available_scan_masks[] = {
MAX1X31_SCAN_MASKS(0),
MAX1X31_SCAN_MASKS(1),
0x00000000,
};
struct max1027_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
const unsigned long *available_scan_masks;
};
static const struct max1027_chip_info max1027_chip_info_tbl[] = {
[max1027] = {
.channels = max1027_channels,
.num_channels = ARRAY_SIZE(max1027_channels),
.available_scan_masks = max1027_available_scan_masks,
},
[max1029] = {
.channels = max1029_channels,
.num_channels = ARRAY_SIZE(max1029_channels),
.available_scan_masks = max1029_available_scan_masks,
},
[max1031] = {
.channels = max1031_channels,
.num_channels = ARRAY_SIZE(max1031_channels),
.available_scan_masks = max1031_available_scan_masks,
},
[max1227] = {
.channels = max1227_channels,
.num_channels = ARRAY_SIZE(max1227_channels),
.available_scan_masks = max1027_available_scan_masks,
},
[max1229] = {
.channels = max1229_channels,
.num_channels = ARRAY_SIZE(max1229_channels),
.available_scan_masks = max1029_available_scan_masks,
},
[max1231] = {
.channels = max1231_channels,
.num_channels = ARRAY_SIZE(max1231_channels),
.available_scan_masks = max1031_available_scan_masks,
},
};
struct max1027_state {
const struct max1027_chip_info *info;
struct spi_device *spi;
struct iio_trigger *trig;
__be16 *buffer;
struct mutex lock;
struct completion complete;
u8 reg ____cacheline_aligned;
};
static int max1027_wait_eoc(struct iio_dev *indio_dev)
{
struct max1027_state *st = iio_priv(indio_dev);
unsigned int conversion_time = MAX1027_CONVERSION_UDELAY;
int ret;
if (st->spi->irq) {
ret = wait_for_completion_timeout(&st->complete,
msecs_to_jiffies(1000));
reinit_completion(&st->complete);
if (!ret)
return -ETIMEDOUT;
} else {
if (indio_dev->active_scan_mask)
conversion_time *= hweight32(*indio_dev->active_scan_mask);
usleep_range(conversion_time, conversion_time * 2);
}
return 0;
}
/* Scan from chan 0 to the highest requested channel. Include temperature on demand. */
static int max1027_configure_chans_and_start(struct iio_dev *indio_dev)
{
struct max1027_state *st = iio_priv(indio_dev);
st->reg = MAX1027_CONV_REG | MAX1027_SCAN_0_N;
st->reg |= MAX1027_CHAN(fls(*indio_dev->active_scan_mask) - 2);
if (*indio_dev->active_scan_mask & MAX1X27_SCAN_MASK_TEMP)
st->reg |= MAX1027_TEMP;
return spi_write(st->spi, &st->reg, 1);
}
static int max1027_enable_trigger(struct iio_dev *indio_dev, bool enable)
{
struct max1027_state *st = iio_priv(indio_dev);
st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2;
/*
* Start acquisition on:
* MODE0: external hardware trigger wired to the cnvst input pin
* MODE2: conversion register write
*/
if (enable)
st->reg |= MAX1027_CKS_MODE0;
else
st->reg |= MAX1027_CKS_MODE2;
return spi_write(st->spi, &st->reg, 1);
}
static int max1027_read_single_value(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val)
{
int ret;
struct max1027_state *st = iio_priv(indio_dev);
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
/* Configure conversion register with the requested chan */
st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |
MAX1027_NOSCAN;
if (chan->type == IIO_TEMP)
st->reg |= MAX1027_TEMP;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0) {
dev_err(&indio_dev->dev,
"Failed to configure conversion register\n");
iio_device_release_direct_mode(indio_dev);
return ret;
}
/*
* For an unknown reason, when we use the mode "10" (write
* conversion register), the interrupt doesn't occur every time.
* So we just wait the maximum conversion time and deliver the value.
*/
ret = max1027_wait_eoc(indio_dev);
if (ret)
return ret;
/* Read result */
ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);
iio_device_release_direct_mode(indio_dev);
if (ret < 0)
return ret;
*val = be16_to_cpu(st->buffer[0]);
return IIO_VAL_INT;
}
static int max1027_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret = 0;
struct max1027_state *st = iio_priv(indio_dev);
mutex_lock(&st->lock);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = max1027_read_single_value(indio_dev, chan, val);
break;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_TEMP:
*val = 1;
*val2 = 8;
ret = IIO_VAL_FRACTIONAL;
break;
case IIO_VOLTAGE:
*val = 2500;
*val2 = chan->scan_type.realbits;
ret = IIO_VAL_FRACTIONAL_LOG2;
break;
default:
ret = -EINVAL;
break;
}
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&st->lock);
return ret;
}
static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,
unsigned int reg, unsigned int writeval,
unsigned int *readval)
{
struct max1027_state *st = iio_priv(indio_dev);
u8 *val = (u8 *)st->buffer;
if (readval) {
int ret = spi_read(st->spi, val, 2);
*readval = be16_to_cpu(st->buffer[0]);
return ret;
}
*val = (u8)writeval;
return spi_write(st->spi, val, 1);
}
static int max1027_set_cnvst_trigger_state(struct iio_trigger *trig, bool state)
{
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
int ret;
/*
* In order to disable the convst trigger, start acquisition on
* conversion register write, which basically disables triggering
* conversions upon cnvst changes and thus has the effect of disabling
* the external hardware trigger.
*/
ret = max1027_enable_trigger(indio_dev, state);
if (ret)
return ret;
if (state) {
ret = max1027_configure_chans_and_start(indio_dev);
if (ret)
return ret;
}
return 0;
}
static int max1027_read_scan(struct iio_dev *indio_dev)
{
struct max1027_state *st = iio_priv(indio_dev);
unsigned int scanned_chans;
int ret;
scanned_chans = fls(*indio_dev->active_scan_mask) - 1;
if (*indio_dev->active_scan_mask & MAX1X27_SCAN_MASK_TEMP)
scanned_chans++;
/* fill buffer with all channel */
ret = spi_read(st->spi, st->buffer, scanned_chans * 2);
if (ret < 0)
return ret;
iio_push_to_buffers(indio_dev, st->buffer);
return 0;
}
static irqreturn_t max1027_handler(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct max1027_state *st = iio_priv(indio_dev);
/*
* If buffers are disabled (raw read) or when using external triggers,
* we just need to unlock the waiters which will then handle the data.
*
* When using the internal trigger, we must hand-off the choice of the
* handler to the core which will then lookup through the interrupt tree
* for the right handler registered with iio_triggered_buffer_setup()
* to execute, as this trigger might very well be used in conjunction
* with another device. The core will then call the relevant handler to
* perform the data processing step.
*/
if (!iio_buffer_enabled(indio_dev))
complete(&st->complete);
else
iio_trigger_poll(indio_dev->trig);
return IRQ_HANDLED;
}
static irqreturn_t max1027_trigger_handler(int irq, void *private)
{
struct iio_poll_func *pf = private;
struct iio_dev *indio_dev = pf->indio_dev;
int ret;
if (!iio_trigger_using_own(indio_dev)) {
ret = max1027_configure_chans_and_start(indio_dev);
if (ret)
goto out;
/* This is a threaded handler, it is fine to wait for an IRQ */
ret = max1027_wait_eoc(indio_dev);
if (ret)
goto out;
}
ret = max1027_read_scan(indio_dev);
out:
if (ret)
dev_err(&indio_dev->dev,
"Cannot read scanned values (%d)\n", ret);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_trigger_ops max1027_trigger_ops = {
.validate_device = &iio_trigger_validate_own_device,
.set_trigger_state = &max1027_set_cnvst_trigger_state,
};
static const struct iio_info max1027_info = {
.read_raw = &max1027_read_raw,
.debugfs_reg_access = &max1027_debugfs_reg_access,
};
static int max1027_probe(struct spi_device *spi)
{
int ret;
struct iio_dev *indio_dev;
struct max1027_state *st;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev) {
pr_err("Can't allocate iio device\n");
return -ENOMEM;
}
st = iio_priv(indio_dev);
st->spi = spi;
st->info = &max1027_chip_info_tbl[spi_get_device_id(spi)->driver_data];
mutex_init(&st->lock);
init_completion(&st->complete);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->info = &max1027_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = st->info->channels;
indio_dev->num_channels = st->info->num_channels;
indio_dev->available_scan_masks = st->info->available_scan_masks;
st->buffer = devm_kmalloc_array(&indio_dev->dev,
indio_dev->num_channels, 2,
GFP_KERNEL);
if (!st->buffer)
return -ENOMEM;
/* Enable triggered buffers */
ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
&iio_pollfunc_store_time,
&max1027_trigger_handler,
NULL);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed to setup buffer\n");
return ret;
}
/* If there is an EOC interrupt, register the cnvst hardware trigger */
if (spi->irq) {
st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
indio_dev->name);
if (!st->trig) {
ret = -ENOMEM;
dev_err(&indio_dev->dev,
"Failed to allocate iio trigger\n");
return ret;
}
st->trig->ops = &max1027_trigger_ops;
iio_trigger_set_drvdata(st->trig, indio_dev);
ret = devm_iio_trigger_register(&indio_dev->dev,
st->trig);
if (ret < 0) {
dev_err(&indio_dev->dev,
"Failed to register iio trigger\n");
return ret;
}
ret = devm_request_irq(&spi->dev, spi->irq, max1027_handler,
IRQF_TRIGGER_FALLING,
spi->dev.driver->name, indio_dev);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
return ret;
}
}
/* Internal reset */
st->reg = MAX1027_RST_REG;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed to reset the ADC\n");
return ret;
}
/* Disable averaging */
st->reg = MAX1027_AVG_REG;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed to configure averaging register\n");
return ret;
}
/* Assume conversion on register write for now */
ret = max1027_enable_trigger(indio_dev, false);
if (ret)
return ret;
return devm_iio_device_register(&spi->dev, indio_dev);
}
static struct spi_driver max1027_driver = {
.driver = {
.name = "max1027",
.of_match_table = max1027_adc_dt_ids,
},
.probe = max1027_probe,
.id_table = max1027_id,
};
module_spi_driver(max1027_driver);
MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
MODULE_DESCRIPTION("MAX1X27/MAX1X29/MAX1X31 ADC");
MODULE_LICENSE("GPL v2");
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