求一份AK8975 基于stm32f1系列的驱动
最近想试试软磁条的巡线，找了一款可以修改iic地址的磁场传感器，，网上搜不到stm32的代码，求万能的论坛给一个。。不想自己去写驱动了。代码到时候共享出来免费下载 /** A sensor driver for the magnetometer AK8975.
*
* Magnetic compass sensor driver for monitoring magnetic flux information.
*
* Copyright (c) 2010, NVIDIA Corporation.
*
* 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.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/acpi.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
/*
* Register definitions, as well as various shifts and masks to get at the
* individual fields of the registers.
*/
#define AK8975_REG_WIA 0x00
#define AK8975_DEVICE_ID 0x48
#define AK8975_REG_INFO 0x01
#define AK8975_REG_ST1 0x02
#define AK8975_REG_ST1_DRDY_SHIFT 0
#define AK8975_REG_ST1_DRDY_MASK (1 << AK8975_REG_ST1_DRDY_SHIFT)
#define AK8975_REG_HXL 0x03
#define AK8975_REG_HXH 0x04
#define AK8975_REG_HYL 0x05
#define AK8975_REG_HYH 0x06
#define AK8975_REG_HZL 0x07
#define AK8975_REG_HZH 0x08
#define AK8975_REG_ST2 0x09
#define AK8975_REG_ST2_DERR_SHIFT 2
#define AK8975_REG_ST2_DERR_MASK (1 << AK8975_REG_ST2_DERR_SHIFT)
#define AK8975_REG_ST2_HOFL_SHIFT 3
#define AK8975_REG_ST2_HOFL_MASK (1 << AK8975_REG_ST2_HOFL_SHIFT)
#define AK8975_REG_CNTL 0x0A
#define AK8975_REG_CNTL_MODE_SHIFT 0
#define AK8975_REG_CNTL_MODE_MASK (0xF << AK8975_REG_CNTL_MODE_SHIFT)
#define AK8975_REG_CNTL_MODE_POWER_DOWN 0
#define AK8975_REG_CNTL_MODE_ONCE 1
#define AK8975_REG_CNTL_MODE_SELF_TEST 8
#define AK8975_REG_CNTL_MODE_FUSE_ROM 0xF
#define AK8975_REG_RSVC 0x0B
#define AK8975_REG_ASTC 0x0C
#define AK8975_REG_TS1 0x0D
#define AK8975_REG_TS2 0x0E
#define AK8975_REG_I2CDIS 0x0F
#define AK8975_REG_ASAX 0x10
#define AK8975_REG_ASAY 0x11
#define AK8975_REG_ASAZ 0x12
#define AK8975_MAX_REGS AK8975_REG_ASAZ
/*
* Miscellaneous values.
*/
#define AK8975_MAX_CONVERSION_TIMEOUT 500
#define AK8975_CONVERSION_DONE_POLL_TIME 10
#define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000)
#define RAW_TO_GAUSS_8975(asa) ((((asa) + 128) * 3000) / 256)
#define RAW_TO_GAUSS_8963(asa) ((((asa) + 128) * 6000) / 256)
/* Compatible Asahi Kasei Compass parts */
enum asahi_compass_chipset {
AK8975,
AK8963,
};
/*
* Per-instance context data for the device.
*/
struct ak8975_data {
struct i2c_client *client;
struct attribute_group attrs;
struct mutex lock;
u8 asa;
long raw_to_gauss;
u8 reg_cache;
int eoc_gpio;
int eoc_irq;
wait_queue_head_t data_ready_queue;
unsigned long flags;
enum asahi_compass_chipset chipset;
};
static const int ak8975_index_to_reg[] = {
AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL,
};
/*
* Helper function to write to the I2C device's registers.
*/
static int ak8975_write_data(struct i2c_client *client,
u8 reg, u8 val, u8 mask, u8 shift)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ak8975_data *data = iio_priv(indio_dev);
u8 regval;
int ret;
regval = (data->reg_cache & ~mask) | (val << shift);
ret = i2c_smbus_write_byte_data(client, reg, regval);
if (ret < 0) {
dev_err(&client->dev, "Write to device fails status %x\n", ret);
return ret;
}
data->reg_cache = regval;
return 0;
}
/*
* Handle data ready irq
*/
static irqreturn_t ak8975_irq_handler(int irq, void *data)
{
struct ak8975_data *ak8975 = data;
set_bit(0, &ak8975->flags);
wake_up(&ak8975->data_ready_queue);
return IRQ_HANDLED;
}
/*
* Install data ready interrupt handler
*/
static int ak8975_setup_irq(struct ak8975_data *data)
{
struct i2c_client *client = data->client;
int rc;
int irq;
if (client->irq)
irq = client->irq;
else
irq = gpio_to_irq(data->eoc_gpio);
rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
dev_name(&client->dev), data);
if (rc < 0) {
dev_err(&client->dev,
"irq %d request failed, (gpio %d): %d\n",
irq, data->eoc_gpio, rc);
return rc;
}
init_waitqueue_head(&data->data_ready_queue);
clear_bit(0, &data->flags);
data->eoc_irq = irq;
return rc;
}
/*
* Perform some start-of-day setup, including reading the asa calibration
* values and caching them.
*/
static int ak8975_setup(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ak8975_data *data = iio_priv(indio_dev);
u8 device_id;
int ret;
/* Confirm that the device we're talking to is really an AK8975. */
ret = i2c_smbus_read_byte_data(client, AK8975_REG_WIA);
if (ret < 0) {
dev_err(&client->dev, "Error reading WIA\n");
return ret;
}
device_id = ret;
if (device_id != AK8975_DEVICE_ID) {
dev_err(&client->dev, "Device ak8975 not found\n");
return -ENODEV;
}
/* Write the fused rom access mode. */
ret = ak8975_write_data(client,
AK8975_REG_CNTL,
AK8975_REG_CNTL_MODE_FUSE_ROM,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
if (ret < 0) {
dev_err(&client->dev, "Error in setting fuse access mode\n");
return ret;
}
/* Get asa data and store in the device data. */
ret = i2c_smbus_read_i2c_block_data(client, AK8975_REG_ASAX,
3, data->asa);
if (ret < 0) {
dev_err(&client->dev, "Not able to read asa data\n");
return ret;
}
/* After reading fuse ROM data set power-down mode */
ret = ak8975_write_data(client,
AK8975_REG_CNTL,
AK8975_REG_CNTL_MODE_POWER_DOWN,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
if (data->eoc_gpio > 0 || client->irq) {
ret = ak8975_setup_irq(data);
if (ret < 0) {
dev_err(&client->dev,
"Error setting data ready interrupt\n");
return ret;
}
}
if (ret < 0) {
dev_err(&client->dev, "Error in setting power-down mode\n");
return ret;
}
/*
* Precalculate scale factor (in Gauss units) for each axis and
* store in the device data.
*
* This scale factor is axis-dependent, and is derived from 3 calibration
* factors ASA(x), ASA(y), and ASA(z).
*
* These ASA values are read from the sensor device at start of day, and
* cached in the device context struct.
*
* Adjusting the flux value with the sensitivity adjustment value should be
* done via the following formula:
*
* Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
*
* where H is the raw value, ASA is the sensitivity adjustment, and Hadj
* is the resultant adjusted value.
*
* We reduce the formula to:
*
* Hadj = H * (ASA + 128) / 256
*
* H is in the range of -4096 to 4095.The magnetometer has a range of
* +-1229uT.To go from the raw value to uT is:
*
* HuT = H * 1229/4096, or roughly, 3/10.
*
* Since 1uT = 0.01 gauss, our final scale factor becomes:
*
* Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100
* Hadj = H * ((ASA + 128) * 0.003) / 256
*
* Since ASA doesn't change, we cache the resultant scale factor into the
* device context in ak8975_setup().
*/
if (data->chipset == AK8963) {
/*
* H range is +-8190 and magnetometer range is +-4912.
* So HuT using the above explanation for 8975,
* 4912/8190 = ~ 6/10.
* So the Hadj should use 6/10 instead of 3/10.
*/
data->raw_to_gauss = RAW_TO_GAUSS_8963(data->asa);
data->raw_to_gauss = RAW_TO_GAUSS_8963(data->asa);
data->raw_to_gauss = RAW_TO_GAUSS_8963(data->asa);
} else {
data->raw_to_gauss = RAW_TO_GAUSS_8975(data->asa);
data->raw_to_gauss = RAW_TO_GAUSS_8975(data->asa);
data->raw_to_gauss = RAW_TO_GAUSS_8975(data->asa);
}
return 0;
}
static int wait_conversion_complete_gpio(struct ak8975_data *data)
{
struct i2c_client *client = data->client;
u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
int ret;
/* Wait for the conversion to complete. */
while (timeout_ms) {
msleep(AK8975_CONVERSION_DONE_POLL_TIME);
if (gpio_get_value(data->eoc_gpio))
break;
timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
}
if (!timeout_ms) {
dev_err(&client->dev, "Conversion timeout happened\n");
return -EINVAL;
}
ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1);
if (ret < 0)
dev_err(&client->dev, "Error in reading ST1\n");
return ret;
}
static int wait_conversion_complete_polled(struct ak8975_data *data)
{
struct i2c_client *client = data->client;
u8 read_status;
u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
int ret;
/* Wait for the conversion to complete. */
while (timeout_ms) {
msleep(AK8975_CONVERSION_DONE_POLL_TIME);
ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1);
if (ret < 0) {
dev_err(&client->dev, "Error in reading ST1\n");
return ret;
}
read_status = ret;
if (read_status)
break;
timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
}
if (!timeout_ms) {
dev_err(&client->dev, "Conversion timeout happened\n");
return -EINVAL;
}
return read_status;
}
/* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
static int wait_conversion_complete_interrupt(struct ak8975_data *data)
{
int ret;
ret = wait_event_timeout(data->data_ready_queue,
test_bit(0, &data->flags),
AK8975_DATA_READY_TIMEOUT);
clear_bit(0, &data->flags);
return ret > 0 ? 0 : -ETIME;
}
/*
* Emits the raw flux value for the x, y, or z axis.
*/
static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
{
struct ak8975_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
int ret;
mutex_lock(&data->lock);
/* Set up the device for taking a sample. */
ret = ak8975_write_data(client,
AK8975_REG_CNTL,
AK8975_REG_CNTL_MODE_ONCE,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
if (ret < 0) {
dev_err(&client->dev, "Error in setting operating mode\n");
goto exit;
}
/* Wait for the conversion to complete. */
if (data->eoc_irq)
ret = wait_conversion_complete_interrupt(data);
else if (gpio_is_valid(data->eoc_gpio))
ret = wait_conversion_complete_gpio(data);
else
ret = wait_conversion_complete_polled(data);
if (ret < 0)
goto exit;
/* This will be executed only for non-interrupt based waiting case */
if (ret & AK8975_REG_ST1_DRDY_MASK) {
ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2);
if (ret < 0) {
dev_err(&client->dev, "Error in reading ST2\n");
goto exit;
}
if (ret & (AK8975_REG_ST2_DERR_MASK |
AK8975_REG_ST2_HOFL_MASK)) {
dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
ret = -EINVAL;
goto exit;
}
}
/* Read the flux value from the appropriate register
(the register is specified in the iio device attributes). */
ret = i2c_smbus_read_word_data(client, ak8975_index_to_reg);
if (ret < 0) {
dev_err(&client->dev, "Read axis data fails\n");
goto exit;
}
mutex_unlock(&data->lock);
/* Clamp to valid range. */
*val = clamp_t(s16, ret, -4096, 4095);
return IIO_VAL_INT;
exit:
mutex_unlock(&data->lock);
return ret;
}
static int ak8975_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2,
long mask)
{
struct ak8975_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
return ak8975_read_axis(indio_dev, chan->address, val);
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = data->raw_to_gauss;
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
#define AK8975_CHANNEL(axis, index) \
{ \
.type = IIO_MAGN, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_SCALE), \
.address = index, \
}
static const struct iio_chan_spec ak8975_channels[] = {
AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
};
static const struct iio_info ak8975_info = {
.read_raw = &ak8975_read_raw,
.driver_module = THIS_MODULE,
};
static const struct acpi_device_id ak_acpi_match[] = {
{"AK8975", AK8975},
{"AK8963", AK8963},
{"INVN6500", AK8963},
{ },
};
MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
static const char *ak8975_match_acpi_device(struct device *dev,
enum asahi_compass_chipset *chipset)
{
const struct acpi_device_id *id;
id = acpi_match_device(dev->driver->acpi_match_table, dev);
if (!id)
return NULL;
*chipset = (int)id->driver_data;
return dev_name(dev);
}
static int ak8975_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ak8975_data *data;
struct iio_dev *indio_dev;
int eoc_gpio;
int err;
const char *name = NULL;
/* Grab and set up the supplied GPIO. */
if (client->dev.platform_data)
eoc_gpio = *(int *)(client->dev.platform_data);
else if (client->dev.of_node)
eoc_gpio = of_get_gpio(client->dev.of_node, 0);
else
eoc_gpio = -1;
if (eoc_gpio == -EPROBE_DEFER)
return -EPROBE_DEFER;
/* We may not have a GPIO based IRQ to scan, that is fine, we will
poll if so */
if (gpio_is_valid(eoc_gpio)) {
err = devm_gpio_request_one(&client->dev, eoc_gpio,
GPIOF_IN, "ak_8975");
if (err < 0) {
dev_err(&client->dev,
"failed to request GPIO %d, error %d\n",
eoc_gpio, err);
return err;
}
}
/* Register with IIO */
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (indio_dev == NULL)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->eoc_gpio = eoc_gpio;
data->eoc_irq = 0;
/* id will be NULL when enumerated via ACPI */
if (id) {
data->chipset =
(enum asahi_compass_chipset)(id->driver_data);
name = id->name;
} else if (ACPI_HANDLE(&client->dev))
name = ak8975_match_acpi_device(&client->dev, &data->chipset);
else
return -ENOSYS;
dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
/* Perform some basic start-of-day setup of the device. */
err = ak8975_setup(client);
if (err < 0) {
dev_err(&client->dev, "AK8975 initialization fails\n");
return err;
}
data->client = client;
mutex_init(&data->lock);
data->eoc_gpio = eoc_gpio;
indio_dev->dev.parent = &client->dev;
indio_dev->channels = ak8975_channels;
indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
indio_dev->info = &ak8975_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->name = name;
err = devm_iio_device_register(&client->dev, indio_dev);
if (err < 0)
return err;
return 0;
}
static const struct i2c_device_id ak8975_id[] = {
{"ak8975", AK8975},
{"ak8963", AK8963},
{}
};
MODULE_DEVICE_TABLE(i2c, ak8975_id);
static const struct of_device_id ak8975_of_match[] = {
{ .compatible = "asahi-kasei,ak8975", },
{ .compatible = "ak8975", },
{ }
};
MODULE_DEVICE_TABLE(of, ak8975_of_match);
static struct i2c_driver ak8975_driver = {
.driver = {
.name = "ak8975",
.of_match_table = ak8975_of_match,
.acpi_match_table = ACPI_PTR(ak_acpi_match),
},
.probe = ak8975_probe,
.id_table = ak8975_id,
};
module_i2c_driver(ak8975_driver);
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_DESCRIPTION("AK8975 magnetometer driver");
MODULE_LICENSE("GPL"); 最后自己搞了一下，可以读了贴出来
unsigned char aa=0, bb, data;
int x,y,z;
float xx,yy,zz;
int jj;
int f( int x)
{
if ( x > 0x0fff )
return (x-0xf000-4096);
else
return x;
}
void Key_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/*开启按键端口（PB0）的时钟*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(GPIOB, &GPIO_InitStructure);
}
void scan()
{
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_0) == 0)
__nop();//低电平等待
}
int main(void)
{
Key_GPIO_Config();
I2c_Init();
aa = Single_Read(0x18,0x00);
while(1)
{
//scan();
bb = Single_Write(0x18,0x0a,1);
scan();
data = Single_Read(0x18,0x03);
data = Single_Read(0x18,0x04);
data = Single_Read(0x18,0x05);
data = Single_Read(0x18,0x06);
data = Single_Read(0x18,0x07);
data = Single_Read(0x18,0x08);
x = (int)data << 8 | (int)data;
y = (int)data << 8 | (int)data;
z = (int)data << 8 | (int)data;
x = f(x);
y = f(y);
z = f(z);
xx = (float)x * 0.3;
yy = (float)y * 0.3;
zz = (float)z * 0.3;
// for(jj = 0; jj<65530; jj++);
}
// add your code here ^_^。
} 3DA502 发表于 2015-3-22 13:26
感谢分享linux驱动 本帖最后由 熵之矢 于 2015-3-31 10:56 编辑
这是我最后修改的驱动，分享之。
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