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linux-sg2042/drivers/iio/accel/kxsd9.c

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/*
* kxsd9.c simple support for the Kionix KXSD9 3D
* accelerometer.
*
* Copyright (c) 2008-2009 Jonathan Cameron <jic23@kernel.org>
*
* 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.
*
* The i2c interface is very similar, so shouldn't be a problem once
* I have a suitable wire made up.
*
* TODO: Support the motion detector
* Uses register address incrementing so could have a
* heavily optimized ring buffer access function.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define KXSD9_REG_X 0x00
#define KXSD9_REG_Y 0x02
#define KXSD9_REG_Z 0x04
#define KXSD9_REG_AUX 0x06
#define KXSD9_REG_RESET 0x0a
#define KXSD9_REG_CTRL_C 0x0c
#define KXSD9_FS_MASK 0x03
#define KXSD9_REG_CTRL_B 0x0d
#define KXSD9_REG_CTRL_A 0x0e
#define KXSD9_READ(a) (0x80 | (a))
#define KXSD9_WRITE(a) (a)
#define KXSD9_STATE_RX_SIZE 2
#define KXSD9_STATE_TX_SIZE 2
struct kxsd9_transport;
/**
* struct kxsd9_transport - transport adapter for SPI or I2C
* @trdev: transport device such as SPI or I2C
* @write1(): function to write a byte to the device
* @write2(): function to write two consecutive bytes to the device
* @readval(): function to read a 16bit value from the device
* @rx: cache aligned read buffer
* @tx: cache aligned write buffer
*/
struct kxsd9_transport {
void *trdev;
int (*write1) (struct kxsd9_transport *tr, u8 byte);
int (*write2) (struct kxsd9_transport *tr, u8 b1, u8 b2);
int (*readval) (struct kxsd9_transport *tr, u8 address);
u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
u8 tx[KXSD9_STATE_TX_SIZE];
};
/**
* struct kxsd9_state - device related storage
* @transport: transport for the KXSD9
* @buf_lock: protect the rx and tx buffers.
* @us: spi device
**/
struct kxsd9_state {
struct kxsd9_transport *transport;
struct mutex buf_lock;
};
#define KXSD9_SCALE_2G "0.011978"
#define KXSD9_SCALE_4G "0.023927"
#define KXSD9_SCALE_6G "0.035934"
#define KXSD9_SCALE_8G "0.047853"
/* reverse order */
static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 };
static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
{
int ret, i;
struct kxsd9_state *st = iio_priv(indio_dev);
bool foundit = false;
for (i = 0; i < 4; i++)
if (micro == kxsd9_micro_scales[i]) {
foundit = true;
break;
}
if (!foundit)
return -EINVAL;
mutex_lock(&st->buf_lock);
ret = st->transport->write1(st->transport, KXSD9_READ(KXSD9_REG_CTRL_C));
if (ret)
goto error_ret;
ret = st->transport->write2(st->transport,
KXSD9_WRITE(KXSD9_REG_CTRL_C),
(ret & ~KXSD9_FS_MASK) | i);
error_ret:
mutex_unlock(&st->buf_lock);
return ret;
}
static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
{
int ret;
struct kxsd9_state *st = iio_priv(indio_dev);
mutex_lock(&st->buf_lock);
ret = st->transport->readval(st->transport, KXSD9_READ(address));
mutex_unlock(&st->buf_lock);
return ret;
}
static IIO_CONST_ATTR(accel_scale_available,
KXSD9_SCALE_2G " "
KXSD9_SCALE_4G " "
KXSD9_SCALE_6G " "
KXSD9_SCALE_8G);
static struct attribute *kxsd9_attributes[] = {
&iio_const_attr_accel_scale_available.dev_attr.attr,
NULL,
};
static int kxsd9_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
int ret = -EINVAL;
if (mask == IIO_CHAN_INFO_SCALE) {
/* Check no integer component */
if (val)
return -EINVAL;
ret = kxsd9_write_scale(indio_dev, val2);
}
return ret;
}
static int kxsd9_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret = -EINVAL;
struct kxsd9_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = kxsd9_read(indio_dev, chan->address);
if (ret < 0)
goto error_ret;
*val = ret;
ret = IIO_VAL_INT;
break;
case IIO_CHAN_INFO_SCALE:
ret = st->transport->write1(st->transport, KXSD9_READ(KXSD9_REG_CTRL_C));
if (ret)
goto error_ret;
*val = 0;
*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
ret = IIO_VAL_INT_PLUS_MICRO;
break;
}
error_ret:
return ret;
};
#define KXSD9_ACCEL_CHAN(axis) \
{ \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.address = KXSD9_REG_##axis, \
}
static const struct iio_chan_spec kxsd9_channels[] = {
KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z),
{
.type = IIO_VOLTAGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.indexed = 1,
.address = KXSD9_REG_AUX,
}
};
static const struct attribute_group kxsd9_attribute_group = {
.attrs = kxsd9_attributes,
};
static int kxsd9_power_up(struct kxsd9_state *st)
{
int ret;
ret = st->transport->write2(st->transport, 0x0d, 0x40);
if (ret)
return ret;
return st->transport->write2(st->transport, 0x0c, 0x9b);
};
static const struct iio_info kxsd9_info = {
.read_raw = &kxsd9_read_raw,
.write_raw = &kxsd9_write_raw,
.attrs = &kxsd9_attribute_group,
.driver_module = THIS_MODULE,
};
static int kxsd9_common_probe(struct device *parent,
struct kxsd9_transport *transport,
const char *name)
{
struct iio_dev *indio_dev;
struct kxsd9_state *st;
int ret;
indio_dev = devm_iio_device_alloc(parent, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->transport = transport;
mutex_init(&st->buf_lock);
indio_dev->channels = kxsd9_channels;
indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
indio_dev->name = name;
indio_dev->dev.parent = parent;
indio_dev->info = &kxsd9_info;
indio_dev->modes = INDIO_DIRECT_MODE;
kxsd9_power_up(st);
ret = iio_device_register(indio_dev);
if (ret)
return ret;
dev_set_drvdata(parent, indio_dev);
return 0;
}
static int kxsd9_common_remove(struct device *parent)
{
struct iio_dev *indio_dev = dev_get_drvdata(parent);
iio_device_unregister(indio_dev);
return 0;
}
static int kxsd9_spi_write1(struct kxsd9_transport *tr, u8 byte)
{
struct spi_device *spi = tr->trdev;
return spi_w8r8(spi, byte);
}
static int kxsd9_spi_write2(struct kxsd9_transport *tr, u8 b1, u8 b2)
{
struct spi_device *spi = tr->trdev;
tr->tx[0] = b1;
tr->tx[1] = b2;
return spi_write(spi, tr->tx, 2);
}
static int kxsd9_spi_readval(struct kxsd9_transport *tr, u8 address)
{
struct spi_device *spi = tr->trdev;
struct spi_transfer xfers[] = {
{
.bits_per_word = 8,
.len = 1,
.delay_usecs = 200,
.tx_buf = tr->tx,
}, {
.bits_per_word = 8,
.len = 2,
.rx_buf = tr->rx,
},
};
int ret;
tr->tx[0] = address;
ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
if (!ret)
ret = (((u16)(tr->rx[0])) << 8) | (tr->rx[1] & 0xF0);
return ret;
}
static int kxsd9_spi_probe(struct spi_device *spi)
{
struct kxsd9_transport *transport;
int ret;
transport = devm_kzalloc(&spi->dev, sizeof(*transport), GFP_KERNEL);
if (!transport)
return -ENOMEM;
transport->trdev = spi;
transport->write1 = kxsd9_spi_write1;
transport->write2 = kxsd9_spi_write2;
transport->readval = kxsd9_spi_readval;
spi->mode = SPI_MODE_0;
spi_setup(spi);
ret = kxsd9_common_probe(&spi->dev,
transport,
spi_get_device_id(spi)->name);
if (ret)
return ret;
return 0;
}
static int kxsd9_spi_remove(struct spi_device *spi)
{
return kxsd9_common_remove(&spi->dev);
}
static const struct spi_device_id kxsd9_spi_id[] = {
{"kxsd9", 0},
{ },
};
MODULE_DEVICE_TABLE(spi, kxsd9_spi_id);
static struct spi_driver kxsd9_spi_driver = {
.driver = {
.name = "kxsd9",
},
.probe = kxsd9_spi_probe,
.remove = kxsd9_spi_remove,
.id_table = kxsd9_spi_id,
};
module_spi_driver(kxsd9_spi_driver);
MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
MODULE_LICENSE("GPL v2");
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