/*
* Holt Integrated Circuits HI-8435 threshold detector driver
*
* Copyright (C) 2015 Zodiac Inflight Innovations
* Copyright (C) 2015 Cogent Embedded, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/delay.h>
#include <linux/iio/events.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_event.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/spi/spi.h>
#include <linux/gpio/consumer.h>
#define DRV_NAME "hi8435"
/* Register offsets for HI-8435 */
#define HI8435_CTRL_REG 0x02
#define HI8435_PSEN_REG 0x04
#define HI8435_TMDATA_REG 0x1E
#define HI8435_GOCENHYS_REG 0x3A
#define HI8435_SOCENHYS_REG 0x3C
#define HI8435_SO7_0_REG 0x10
#define HI8435_SO15_8_REG 0x12
#define HI8435_SO23_16_REG 0x14
#define HI8435_SO31_24_REG 0x16
#define HI8435_SO31_0_REG 0x78
#define HI8435_WRITE_OPCODE 0x00
#define HI8435_READ_OPCODE 0x80
/* CTRL register bits */
#define HI8435_CTRL_TEST 0x01
#define HI8435_CTRL_SRST 0x02
struct hi8435_priv {
struct spi_device *spi;
struct mutex lock;
unsigned long event_scan_mask; /* soft mask/unmask channels events */
unsigned int event_prev_val;
unsigned threshold_lo[2]; /* GND-Open and Supply-Open thresholds */
unsigned threshold_hi[2]; /* GND-Open and Supply-Open thresholds */
u8 reg_buffer[3] ____cacheline_aligned;
};
static int hi8435_readb(struct hi8435_priv *priv, u8 reg, u8 *val)
{
reg |= HI8435_READ_OPCODE;
return spi_write_then_read(priv->spi, ®, 1, val, 1);
}
static int hi8435_readw(struct hi8435_priv *priv, u8 reg, u16 *val)
{
int ret;
__be16 be_val;
reg |= HI8435_READ_OPCODE;
ret = spi_write_then_read(priv->spi, ®, 1, &be_val, 2);
*val = be16_to_cpu(be_val);
return ret;
}
static int hi8435_readl(struct hi8435_priv *priv, u8 reg, u32 *val)
{
int ret;
__be32 be_val;
reg |= HI8435_READ_OPCODE;
ret = spi_write_then_read(priv->spi, ®, 1, &be_val, 4);
*val = be32_to_cpu(be_val);
return ret;
}
static int hi8435_writeb(struct hi8435_priv *priv, u8 reg, u8 val)
{
priv->reg_buffer[0] = reg | HI8435_WRITE_OPCODE;
priv->reg_buffer[1] = val;
return spi_write(priv->spi, priv->reg_buffer, 2);
}
static int hi8435_writew(struct hi8435_priv *priv, u8 reg, u16 val)
{
priv->reg_buffer[0] = reg | HI8435_WRITE_OPCODE;
priv->reg_buffer[1] = (val >> 8) & 0xff;
priv->reg_buffer[2] = val & 0xff;
return spi_write(priv->spi, priv->reg_buffer, 3);
}
static int hi8435_read_raw(struct iio_dev *idev,
const struct iio_chan_spec *chan,
int *val, int *val2, long mask)
{
struct hi8435_priv *priv = iio_priv(idev);
u32 tmp;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
if (ret < 0)
return ret;
*val = !!(tmp & BIT(chan->channel));
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int hi8435_read_event_config(struct iio_dev *idev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir)
{
struct hi8435_priv *priv = iio_priv(idev);
return !!(priv->event_scan_mask & BIT(chan->channel));
}
static int hi8435_write_event_config(struct iio_dev *idev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir, int state)
{
struct hi8435_priv *priv = iio_priv(idev);
int ret;
u32 tmp;
if (state) {
ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
if (ret < 0)
return ret;
if (tmp & BIT(chan->channel))
priv->event_prev_val |= BIT(chan->channel);
else
priv->event_prev_val &= ~BIT(chan->channel);
priv->event_scan_mask |= BIT(chan->channel);
} else
priv->event_scan_mask &= ~BIT(chan->channel);
return 0;
}
static int hi8435_read_event_value(struct iio_dev *idev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
enum iio_event_info info,
int *val, int *val2)
{
struct hi8435_priv *priv = iio_priv(idev);
int ret;
u8 mode, psen;
u16 reg;
ret = hi8435_readb(priv, HI8435_PSEN_REG, &psen);
if (ret < 0)
return ret;
/* Supply-Open or GND-Open sensing mode */
mode = !!(psen & BIT(chan->channel / 8));
ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG :
HI8435_GOCENHYS_REG, ®);
if (ret < 0)
return ret;
if (dir == IIO_EV_DIR_FALLING)
*val = ((reg & 0xff) - (reg >> 8)) / 2;
else if (dir == IIO_EV_DIR_RISING)
*val = ((reg & 0xff) + (reg >> 8)) / 2;
return IIO_VAL_INT;
}
static int hi8435_write_event_value(struct iio_dev *idev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
enum iio_event_info info,
int val, int val2)
{
struct hi8435_priv *priv = iio_priv(idev);
int ret;
u8 mode, psen;
u16 reg;
ret = hi8435_readb(priv, HI8435_PSEN_REG, &psen);
if (ret < 0)
return ret;
/* Supply-Open or GND-Open sensing mode */
mode = !!(psen & BIT(chan->channel / 8));
ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG :
HI8435_GOCENHYS_REG, ®);
if (ret < 0)
return ret;
if (dir == IIO_EV_DIR_FALLING) {
/* falling threshold range 2..21V, hysteresis minimum 2V */
if (val < 2 || val > 21 || (val + 2) > priv->threshold_hi[mode])
return -EINVAL;
if (val == priv->threshold_lo[mode])
return 0;
priv->threshold_lo[mode] = val;
/* hysteresis must not be odd */
if ((priv->threshold_hi[mode] - priv->threshold_lo[mode]) % 2)
priv->threshold_hi[mode]--;
} else if (dir == IIO_EV_DIR_RISING) {
/* rising threshold range 3..22V, hysteresis minimum 2V */
if (val < 3 || val > 22 || val < (priv->threshold_lo[mode] + 2))
return -EINVAL;
if (val == priv->threshold_hi[mode])
return 0;
priv->threshold_hi[mode] = val;
/* hysteresis must not be odd */
if ((priv->threshold_hi[mode] - priv->threshold_lo[mode]) % 2)
priv->threshold_lo[mode]++;
}
/* program thresholds */
mutex_lock(&priv->lock);
ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG :
HI8435_GOCENHYS_REG, ®);
if (ret < 0) {
mutex_unlock(&priv->lock);
return ret;
}
/* hysteresis */
reg = priv->threshold_hi[mode] - priv->threshold_lo[mode];
reg <<= 8;
/* threshold center */
reg |= (priv->threshold_hi[mode] + priv->threshold_lo[mode]);
ret = hi8435_writew(priv, mode ? HI8435_SOCENHYS_REG :
HI8435_GOCENHYS_REG, reg);
mutex_unlock(&priv->lock);
return ret;
}
static int hi8435_debugfs_reg_access(struct iio_dev *idev,
unsigned reg, unsigned writeval,
unsigned *readval)
{
struct hi8435_priv *priv = iio_priv(idev);
int ret;
u8 val;
if (readval != NULL) {
ret = hi8435_readb(priv, reg, &val);
*readval = val;
} else {
val = (u8)writeval;
ret = hi8435_writeb(priv, reg, val);
}
return ret;
}
static const struct iio_event_spec hi8435_events[] = {
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_RISING,
.mask_separate = BIT(IIO_EV_INFO_VALUE),
}, {
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_FALLING,
.mask_separate = BIT(IIO_EV_INFO_VALUE),
}, {
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_EITHER,
.mask_separate = BIT(IIO_EV_INFO_ENABLE),
},
};
static int hi8435_get_sensing_mode(struct iio_dev *idev,
const struct iio_chan_spec *chan)
{
struct hi8435_priv *priv = iio_priv(idev);
int ret;
u8 reg;
ret = hi8435_readb(priv, HI8435_PSEN_REG, ®);
if (ret < 0)
return ret;
return !!(reg & BIT(chan->channel / 8));
}
static int hi8435_set_sensing_mode(struct iio_dev *idev,
const struct iio_chan_spec *chan,
unsigned int mode)
{
struct hi8435_priv *priv = iio_priv(idev);
int ret;
u8 reg;
mutex_lock(&priv->lock);
ret = hi8435_readb(priv, HI8435_PSEN_REG, ®);
if (ret < 0) {
mutex_unlock(&priv->lock);
return ret;
}
reg &= ~BIT(chan->channel / 8);
if (mode)
reg |= BIT(chan->channel / 8);
ret = hi8435_writeb(priv, HI8435_PSEN_REG, reg);
mutex_unlock(&priv->lock);
return ret;
}
static const char * const hi8435_sensing_modes[] = { "GND-Open",
"Supply-Open" };
static const struct iio_enum hi8435_sensing_mode = {
.items = hi8435_sensing_modes,
.num_items = ARRAY_SIZE(hi8435_sensing_modes),
.get = hi8435_get_sensing_mode,
.set = hi8435_set_sensing_mode,
};
static const struct iio_chan_spec_ext_info hi8435_ext_info[] = {
IIO_ENUM("sensing_mode", IIO_SEPARATE, &hi8435_sensing_mode),
IIO_ENUM_AVAILABLE("sensing_mode", &hi8435_sensing_mode),
{},
};
#define HI8435_VOLTAGE_CHANNEL(num) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = num, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.event_spec = hi8435_events, \
.num_event_specs = ARRAY_SIZE(hi8435_events), \
.ext_info = hi8435_ext_info, \
}
static const struct iio_chan_spec hi8435_channels[] = {
HI8435_VOLTAGE_CHANNEL(0),
HI8435_VOLTAGE_CHANNEL(1),
HI8435_VOLTAGE_CHANNEL(2),
HI8435_VOLTAGE_CHANNEL(3),
HI8435_VOLTAGE_CHANNEL(4),
HI8435_VOLTAGE_CHANNEL(5),
HI8435_VOLTAGE_CHANNEL(6),
HI8435_VOLTAGE_CHANNEL(7),
HI8435_VOLTAGE_CHANNEL(8),
HI8435_VOLTAGE_CHANNEL(9),
HI8435_VOLTAGE_CHANNEL(10),
HI8435_VOLTAGE_CHANNEL(11),
HI8435_VOLTAGE_CHANNEL(12),
HI8435_VOLTAGE_CHANNEL(13),
HI8435_VOLTAGE_CHANNEL(14),
HI8435_VOLTAGE_CHANNEL(15),
HI8435_VOLTAGE_CHANNEL(16),
HI8435_VOLTAGE_CHANNEL(17),
HI8435_VOLTAGE_CHANNEL(18),
HI8435_VOLTAGE_CHANNEL(19),
HI8435_VOLTAGE_CHANNEL(20),
HI8435_VOLTAGE_CHANNEL(21),
HI8435_VOLTAGE_CHANNEL(22),
HI8435_VOLTAGE_CHANNEL(23),
HI8435_VOLTAGE_CHANNEL(24),
HI8435_VOLTAGE_CHANNEL(25),
HI8435_VOLTAGE_CHANNEL(26),
HI8435_VOLTAGE_CHANNEL(27),
HI8435_VOLTAGE_CHANNEL(28),
HI8435_VOLTAGE_CHANNEL(29),
HI8435_VOLTAGE_CHANNEL(30),
HI8435_VOLTAGE_CHANNEL(31),
IIO_CHAN_SOFT_TIMESTAMP(32),
};
static const struct iio_info hi8435_info = {
.read_raw = hi8435_read_raw,
.read_event_config = hi8435_read_event_config,
.write_event_config = hi8435_write_event_config,
.read_event_value = hi8435_read_event_value,
.write_event_value = hi8435_write_event_value,
.debugfs_reg_access = hi8435_debugfs_reg_access,
};
static void hi8435_iio_push_event(struct iio_dev *idev, unsigned int val)
{
struct hi8435_priv *priv = iio_priv(idev);
enum iio_event_direction dir;
unsigned int i;
unsigned int status = priv->event_prev_val ^ val;
if (!status)
return;
for_each_set_bit(i, &priv->event_scan_mask, 32) {
if (status & BIT(i)) {
dir = val & BIT(i) ? IIO_EV_DIR_RISING :
IIO_EV_DIR_FALLING;
iio_push_event(idev,
IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
IIO_EV_TYPE_THRESH, dir),
iio_get_time_ns(idev));
}
}
priv->event_prev_val = val;
}
static irqreturn_t hi8435_trigger_handler(int irq, void *private)
{
struct iio_poll_func *pf = private;
struct iio_dev *idev = pf->indio_dev;
struct hi8435_priv *priv = iio_priv(idev);
u32 val;
int ret;
ret = hi8435_readl(priv, HI8435_SO31_0_REG, &val);
if (ret < 0)
goto err_read;
hi8435_iio_push_event(idev, val);
err_read:
iio_trigger_notify_done(idev->trig);
return IRQ_HANDLED;
}
static int hi8435_probe(struct spi_device *spi)
{
struct iio_dev *idev;
struct hi8435_priv *priv;
struct gpio_desc *reset_gpio;
int ret;
idev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
if (!idev)
return -ENOMEM;
priv = iio_priv(idev);
priv->spi = spi;
reset_gpio = devm_gpiod_get(&spi->dev, NULL, GPIOD_OUT_LOW);
if (IS_ERR(reset_gpio)) {
/* chip s/w reset if h/w reset failed */
hi8435_writeb(priv, HI8435_CTRL_REG, HI8435_CTRL_SRST);
hi8435_writeb(priv, HI8435_CTRL_REG, 0);
} else {
udelay(5);
gpiod_set_value(reset_gpio, 1);
}
spi_set_drvdata(spi, idev);
mutex_init(&priv->lock);
idev->dev.parent = &spi->dev;
idev->dev.of_node = spi->dev.of_node;
idev->name = spi_get_device_id(spi)->name;
idev->modes = INDIO_DIRECT_MODE;
idev->info = &hi8435_info;
idev->channels = hi8435_channels;
idev->num_channels = ARRAY_SIZE(hi8435_channels);
/* unmask all events */
priv->event_scan_mask = ~(0);
/*
* There is a restriction in the chip - the hysteresis can not be odd.
* If the hysteresis is set to odd value then chip gets into lock state
* and not functional anymore.
* After chip reset the thresholds are in undefined state, so we need to
* initialize thresholds to some initial values and then prevent
* userspace setting odd hysteresis.
*
* Set threshold low voltage to 2V, threshold high voltage to 4V
* for both GND-Open and Supply-Open sensing modes.
*/
priv->threshold_lo[0] = priv->threshold_lo[1] = 2;
priv->threshold_hi[0] = priv->threshold_hi[1] = 4;
hi8435_writew(priv, HI8435_GOCENHYS_REG, 0x206);
hi8435_writew(priv, HI8435_SOCENHYS_REG, 0x206);
ret = iio_triggered_event_setup(idev, NULL, hi8435_trigger_handler);
if (ret)
return ret;
ret = iio_device_register(idev);
if (ret < 0) {
dev_err(&spi->dev, "unable to register device\n");
goto unregister_triggered_event;
}
return 0;
unregister_triggered_event:
iio_triggered_event_cleanup(idev);
return ret;
}
static int hi8435_remove(struct spi_device *spi)
{
struct iio_dev *idev = spi_get_drvdata(spi);
iio_device_unregister(idev);
iio_triggered_event_cleanup(idev);
return 0;
}
static const struct of_device_id hi8435_dt_ids[] = {
{ .compatible = "holt,hi8435" },
{},
};
MODULE_DEVICE_TABLE(of, hi8435_dt_ids);
static const struct spi_device_id hi8435_id[] = {
{ "hi8435", 0},
{ }
};
MODULE_DEVICE_TABLE(spi, hi8435_id);
static struct spi_driver hi8435_driver = {
.driver = {
.name = DRV_NAME,
.of_match_table = of_match_ptr(hi8435_dt_ids),
},
.probe = hi8435_probe,
.remove = hi8435_remove,
.id_table = hi8435_id,
};
module_spi_driver(hi8435_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vladimir Barinov");
MODULE_DESCRIPTION("HI-8435 threshold detector");