/*
* 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* max1027.c
*
* Partial support for max1027 and similar chips.
*/
#include <linux/kernel.h>
#include <linux/module.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)
enum max1027_id {
max1027,
max1029,
max1031,
};
static const struct spi_device_id max1027_id[] = {
{"max1027", max1027},
{"max1029", max1029},
{"max1031", max1031},
{}
};
MODULE_DEVICE_TABLE(spi, max1027_id);
#ifdef CONFIG_OF
static const struct of_device_id max1027_adc_dt_ids[] = {
{ .compatible = "maxim,max1027" },
{ .compatible = "maxim,max1029" },
{ .compatible = "maxim,max1031" },
{},
};
MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
#endif
#define MAX1027_V_CHAN(index) \
{ \
.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 = 10, \
.storagebits = 16, \
.shift = 2, \
.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, \
}, \
}
static const struct iio_chan_spec max1027_channels[] = {
MAX1027_T_CHAN,
MAX1027_V_CHAN(0),
MAX1027_V_CHAN(1),
MAX1027_V_CHAN(2),
MAX1027_V_CHAN(3),
MAX1027_V_CHAN(4),
MAX1027_V_CHAN(5),
MAX1027_V_CHAN(6),
MAX1027_V_CHAN(7)
};
static const struct iio_chan_spec max1029_channels[] = {
MAX1027_T_CHAN,
MAX1027_V_CHAN(0),
MAX1027_V_CHAN(1),
MAX1027_V_CHAN(2),
MAX1027_V_CHAN(3),
MAX1027_V_CHAN(4),
MAX1027_V_CHAN(5),
MAX1027_V_CHAN(6),
MAX1027_V_CHAN(7),
MAX1027_V_CHAN(8),
MAX1027_V_CHAN(9),
MAX1027_V_CHAN(10),
MAX1027_V_CHAN(11)
};
static const struct iio_chan_spec max1031_channels[] = {
MAX1027_T_CHAN,
MAX1027_V_CHAN(0),
MAX1027_V_CHAN(1),
MAX1027_V_CHAN(2),
MAX1027_V_CHAN(3),
MAX1027_V_CHAN(4),
MAX1027_V_CHAN(5),
MAX1027_V_CHAN(6),
MAX1027_V_CHAN(7),
MAX1027_V_CHAN(8),
MAX1027_V_CHAN(9),
MAX1027_V_CHAN(10),
MAX1027_V_CHAN(11),
MAX1027_V_CHAN(12),
MAX1027_V_CHAN(13),
MAX1027_V_CHAN(14),
MAX1027_V_CHAN(15)
};
static const unsigned long max1027_available_scan_masks[] = {
0x000001ff,
0x00000000,
};
static const unsigned long max1029_available_scan_masks[] = {
0x00001fff,
0x00000000,
};
static const unsigned long max1031_available_scan_masks[] = {
0x0001ffff,
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,
},
};
struct max1027_state {
const struct max1027_chip_info *info;
struct spi_device *spi;
struct iio_trigger *trig;
__be16 *buffer;
struct mutex lock;
u8 reg ____cacheline_aligned;
};
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);
if (iio_buffer_enabled(indio_dev)) {
dev_warn(&indio_dev->dev, "trigger mode already enabled");
return -EBUSY;
}
/* Start acquisition on conversion register write */
st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 | MAX1027_CKS_MODE2;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0) {
dev_err(&indio_dev->dev,
"Failed to configure setup register\n");
return ret;
}
/* Configure conversion register with the requested chan */
st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |
MAX1027_NOSCAN | !!(chan->type == IIO_TEMP);
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0) {
dev_err(&indio_dev->dev,
"Failed to configure conversion register\n");
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 1 ms.
*/
mdelay(1);
/* Read result */
ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);
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 = 10;
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 reg, unsigned writeval,
unsigned *readval)
{
struct max1027_state *st = iio_priv(indio_dev);
u8 *val = (u8 *)st->buffer;
if (readval != NULL)
return -EINVAL;
*val = (u8)writeval;
return spi_write(st->spi, val, 1);
}
static int max1027_validate_trigger(struct iio_dev *indio_dev,
struct iio_trigger *trig)
{
struct max1027_state *st = iio_priv(indio_dev);
if (st->trig != trig)
return -EINVAL;
return 0;
}
static int max1027_set_trigger_state(struct iio_trigger *trig, bool state)
{
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
struct max1027_state *st = iio_priv(indio_dev);
int ret;
if (state) {
/* Start acquisition on cnvst */
st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE0 |
MAX1027_REF_MODE2;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0)
return ret;
/* Scan from 0 to max */
st->reg = MAX1027_CONV_REG | MAX1027_CHAN(0) |
MAX1027_SCAN_N_M | MAX1027_TEMP;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0)
return ret;
} else {
/* Start acquisition on conversion register write */
st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE2 |
MAX1027_REF_MODE2;
ret = spi_write(st->spi, &st->reg, 1);
if (ret < 0)
return ret;
}
return 0;
}
static int max1027_validate_device(struct iio_trigger *trig,
struct iio_dev *indio_dev)
{
struct iio_dev *indio = iio_trigger_get_drvdata(trig);
if (indio != indio_dev)
return -EINVAL;
return 0;
}
static irqreturn_t max1027_trigger_handler(int irq, void *private)
{
struct iio_poll_func *pf = (struct iio_poll_func *)private;
struct iio_dev *indio_dev = pf->indio_dev;
struct max1027_state *st = iio_priv(indio_dev);
pr_debug("%s(irq=%d, private=0x%p)\n", __func__, irq, private);
/* fill buffer with all channel */
spi_read(st->spi, st->buffer, indio_dev->masklength * 2);
iio_push_to_buffers(indio_dev, st->buffer);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_trigger_ops max1027_trigger_ops = {
.owner = THIS_MODULE,
.validate_device = &max1027_validate_device,
.set_trigger_state = &max1027_set_trigger_state,
};
static const struct iio_info max1027_info = {
.driver_module = THIS_MODULE,
.read_raw = &max1027_read_raw,
.validate_trigger = &max1027_validate_trigger,
.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;
pr_debug("%s: probe(spi = 0x%p)\n", __func__, spi);
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL) {
pr_err("Can't allocate iio device\n");
return -ENOMEM;
}
spi_set_drvdata(spi, indio_dev);
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);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
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(&indio_dev->dev,
indio_dev->num_channels * 2,
GFP_KERNEL);
if (st->buffer == NULL) {
dev_err(&indio_dev->dev, "Can't allocate buffer\n");
return -ENOMEM;
}
ret = iio_triggered_buffer_setup(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;
}
st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
indio_dev->name);
if (st->trig == NULL) {
ret = -ENOMEM;
dev_err(&indio_dev->dev, "Failed to allocate iio trigger\n");
goto fail_trigger_alloc;
}
st->trig->ops = &max1027_trigger_ops;
st->trig->dev.parent = &spi->dev;
iio_trigger_set_drvdata(st->trig, indio_dev);
iio_trigger_register(st->trig);
ret = devm_request_threaded_irq(&spi->dev, spi->irq,
iio_trigger_generic_data_rdy_poll,
NULL,
IRQF_TRIGGER_FALLING,
spi->dev.driver->name, st->trig);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
goto fail_dev_register;
}
/* 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");
goto fail_dev_register;
}
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed to register iio device\n");
goto fail_dev_register;
}
return 0;
fail_dev_register:
fail_trigger_alloc:
iio_triggered_buffer_cleanup(indio_dev);
return ret;
}
static int max1027_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
pr_debug("%s: remove(spi = 0x%p)\n", __func__, spi);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
return 0;
}
static struct spi_driver max1027_driver = {
.driver = {
.name = "max1027",
.of_match_table = of_match_ptr(max1027_adc_dt_ids),
},
.probe = max1027_probe,
.remove = max1027_remove,
.id_table = max1027_id,
};
module_spi_driver(max1027_driver);
MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");
MODULE_LICENSE("GPL v2");