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linux/drivers/iio/pressure/hp206c.c
Javier Martinez Canillas cdd469ad9e iio: Export I2C module alias information 
The I2C drivers have an i2c_device_id array but that information isn't
exported to the modules using the MODULE_DEVICE_TABLE() macro. So the
modules autoloading won't work if the I2C device is registered using
OF or legacy board files due missing alias information in the modules.

The issue was found using Kieran Bingham's coccinelle semantic patch:
https://lkml.org/lkml/2016/5/10/520

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2016-05-21 20:08:14 +01:00

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/*
* hp206c.c - HOPERF HP206C precision barometer and altimeter sensor
*
* Copyright (c) 2016, Intel Corporation.
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* (7-bit I2C slave address 0x76)
*
* Datasheet:
* http://www.hoperf.com/upload/sensor/HP206C_DataSheet_EN_V2.0.pdf
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/delay.h>
#include <linux/util_macros.h>
#include <linux/acpi.h>
/* I2C commands: */
#define HP206C_CMD_SOFT_RST 0x06
#define HP206C_CMD_ADC_CVT 0x40
#define HP206C_CMD_ADC_CVT_OSR_4096 0x00
#define HP206C_CMD_ADC_CVT_OSR_2048 0x04
#define HP206C_CMD_ADC_CVT_OSR_1024 0x08
#define HP206C_CMD_ADC_CVT_OSR_512 0x0c
#define HP206C_CMD_ADC_CVT_OSR_256 0x10
#define HP206C_CMD_ADC_CVT_OSR_128 0x14
#define HP206C_CMD_ADC_CVT_CHNL_PT 0x00
#define HP206C_CMD_ADC_CVT_CHNL_T 0x02
#define HP206C_CMD_READ_P 0x30
#define HP206C_CMD_READ_T 0x32
#define HP206C_CMD_READ_REG 0x80
#define HP206C_CMD_WRITE_REG 0xc0
#define HP206C_REG_INT_EN 0x0b
#define HP206C_REG_INT_CFG 0x0c
#define HP206C_REG_INT_SRC 0x0d
#define HP206C_FLAG_DEV_RDY 0x40
#define HP206C_REG_PARA 0x0f
#define HP206C_FLAG_CMPS_EN 0x80
/* Maximum spin for DEV_RDY */
#define HP206C_MAX_DEV_RDY_WAIT_COUNT 20
#define HP206C_DEV_RDY_WAIT_US 20000
struct hp206c_data {
struct mutex mutex;
struct i2c_client *client;
int temp_osr_index;
int pres_osr_index;
};
struct hp206c_osr_setting {
u8 osr_mask;
unsigned int temp_conv_time_us;
unsigned int pres_conv_time_us;
};
/* Data from Table 5 in datasheet. */
static const struct hp206c_osr_setting hp206c_osr_settings[] = {
{ HP206C_CMD_ADC_CVT_OSR_4096, 65600, 131100 },
{ HP206C_CMD_ADC_CVT_OSR_2048, 32800, 65600 },
{ HP206C_CMD_ADC_CVT_OSR_1024, 16400, 32800 },
{ HP206C_CMD_ADC_CVT_OSR_512, 8200, 16400 },
{ HP206C_CMD_ADC_CVT_OSR_256, 4100, 8200 },
{ HP206C_CMD_ADC_CVT_OSR_128, 2100, 4100 },
};
static const int hp206c_osr_rates[] = { 4096, 2048, 1024, 512, 256, 128 };
static const char hp206c_osr_rates_str[] = "4096 2048 1024 512 256 128";
static inline int hp206c_read_reg(struct i2c_client *client, u8 reg)
{
return i2c_smbus_read_byte_data(client, HP206C_CMD_READ_REG | reg);
}
static inline int hp206c_write_reg(struct i2c_client *client, u8 reg, u8 val)
{
return i2c_smbus_write_byte_data(client,
HP206C_CMD_WRITE_REG | reg, val);
}
static int hp206c_read_20bit(struct i2c_client *client, u8 cmd)
{
int ret;
u8 values[3];
ret = i2c_smbus_read_i2c_block_data(client, cmd, 3, values);
if (ret < 0)
return ret;
if (ret != 3)
return -EIO;
return ((values[0] & 0xF) << 16) | (values[1] << 8) | (values[2]);
}
/* Spin for max 160ms until DEV_RDY is 1, or return error. */
static int hp206c_wait_dev_rdy(struct iio_dev *indio_dev)
{
int ret;
int count = 0;
struct hp206c_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
while (++count <= HP206C_MAX_DEV_RDY_WAIT_COUNT) {
ret = hp206c_read_reg(client, HP206C_REG_INT_SRC);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed READ_REG INT_SRC: %d\n", ret);
return ret;
}
if (ret & HP206C_FLAG_DEV_RDY)
return 0;
usleep_range(HP206C_DEV_RDY_WAIT_US, HP206C_DEV_RDY_WAIT_US * 3 / 2);
}
return -ETIMEDOUT;
}
static int hp206c_set_compensation(struct i2c_client *client, bool enabled)
{
int val;
val = hp206c_read_reg(client, HP206C_REG_PARA);
if (val < 0)
return val;
if (enabled)
val |= HP206C_FLAG_CMPS_EN;
else
val &= ~HP206C_FLAG_CMPS_EN;
return hp206c_write_reg(client, HP206C_REG_PARA, val);
}
/* Do a soft reset */
static int hp206c_soft_reset(struct iio_dev *indio_dev)
{
int ret;
struct hp206c_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
ret = i2c_smbus_write_byte(client, HP206C_CMD_SOFT_RST);
if (ret) {
dev_err(&client->dev, "Failed to reset device: %d\n", ret);
return ret;
}
usleep_range(400, 600);
ret = hp206c_wait_dev_rdy(indio_dev);
if (ret) {
dev_err(&client->dev, "Device not ready after soft reset: %d\n", ret);
return ret;
}
ret = hp206c_set_compensation(client, true);
if (ret)
dev_err(&client->dev, "Failed to enable compensation: %d\n", ret);
return ret;
}
static int hp206c_conv_and_read(struct iio_dev *indio_dev,
u8 conv_cmd, u8 read_cmd,
unsigned int sleep_us)
{
int ret;
struct hp206c_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
ret = hp206c_wait_dev_rdy(indio_dev);
if (ret < 0) {
dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
return ret;
}
ret = i2c_smbus_write_byte(client, conv_cmd);
if (ret < 0) {
dev_err(&indio_dev->dev, "Failed convert: %d\n", ret);
return ret;
}
usleep_range(sleep_us, sleep_us * 3 / 2);
ret = hp206c_wait_dev_rdy(indio_dev);
if (ret < 0) {
dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
return ret;
}
ret = hp206c_read_20bit(client, read_cmd);
if (ret < 0)
dev_err(&indio_dev->dev, "Failed read: %d\n", ret);
return ret;
}
static int hp206c_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
int ret;
struct hp206c_data *data = iio_priv(indio_dev);
const struct hp206c_osr_setting *osr_setting;
u8 conv_cmd;
mutex_lock(&data->mutex);
switch (mask) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
switch (chan->type) {
case IIO_TEMP:
*val = hp206c_osr_rates[data->temp_osr_index];
ret = IIO_VAL_INT;
break;
case IIO_PRESSURE:
*val = hp206c_osr_rates[data->pres_osr_index];
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
}
break;
case IIO_CHAN_INFO_RAW:
switch (chan->type) {
case IIO_TEMP:
osr_setting = &hp206c_osr_settings[data->temp_osr_index];
conv_cmd = HP206C_CMD_ADC_CVT |
osr_setting->osr_mask |
HP206C_CMD_ADC_CVT_CHNL_T;
ret = hp206c_conv_and_read(indio_dev,
conv_cmd,
HP206C_CMD_READ_T,
osr_setting->temp_conv_time_us);
if (ret >= 0) {
/* 20 significant bits are provided.
* Extend sign over the rest.
*/
*val = sign_extend32(ret, 19);
ret = IIO_VAL_INT;
}
break;
case IIO_PRESSURE:
osr_setting = &hp206c_osr_settings[data->pres_osr_index];
conv_cmd = HP206C_CMD_ADC_CVT |
osr_setting->osr_mask |
HP206C_CMD_ADC_CVT_CHNL_PT;
ret = hp206c_conv_and_read(indio_dev,
conv_cmd,
HP206C_CMD_READ_P,
osr_setting->pres_conv_time_us);
if (ret >= 0) {
*val = ret;
ret = IIO_VAL_INT;
}
break;
default:
ret = -EINVAL;
}
break;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_TEMP:
*val = 0;
*val2 = 10000;
ret = IIO_VAL_INT_PLUS_MICRO;
break;
case IIO_PRESSURE:
*val = 0;
*val2 = 1000;
ret = IIO_VAL_INT_PLUS_MICRO;
break;
default:
ret = -EINVAL;
}
break;
default:
ret = -EINVAL;
}
mutex_unlock(&data->mutex);
return ret;
}
static int hp206c_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
int ret = 0;
struct hp206c_data *data = iio_priv(indio_dev);
if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
return -EINVAL;
mutex_lock(&data->mutex);
switch (chan->type) {
case IIO_TEMP:
data->temp_osr_index = find_closest_descending(val,
hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
break;
case IIO_PRESSURE:
data->pres_osr_index = find_closest_descending(val,
hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
break;
default:
ret = -EINVAL;
}
mutex_unlock(&data->mutex);
return ret;
}
static const struct iio_chan_spec hp206c_channels[] = {
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
},
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
}
};
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(hp206c_osr_rates_str);
static struct attribute *hp206c_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL,
};
static const struct attribute_group hp206c_attribute_group = {
.attrs = hp206c_attributes,
};
static const struct iio_info hp206c_info = {
.attrs = &hp206c_attribute_group,
.read_raw = hp206c_read_raw,
.write_raw = hp206c_write_raw,
.driver_module = THIS_MODULE,
};
static int hp206c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct hp206c_data *data;
int ret;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
dev_err(&client->dev, "Adapter does not support "
"all required i2c functionality\n");
return -ENODEV;
}
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->client = client;
mutex_init(&data->mutex);
indio_dev->info = &hp206c_info;
indio_dev->name = id->name;
indio_dev->dev.parent = &client->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = hp206c_channels;
indio_dev->num_channels = ARRAY_SIZE(hp206c_channels);
i2c_set_clientdata(client, indio_dev);
/* Do a soft reset on probe */
ret = hp206c_soft_reset(indio_dev);
if (ret) {
dev_err(&client->dev, "Failed to reset on startup: %d\n", ret);
return -ENODEV;
}
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id hp206c_id[] = {
{"hp206c"},
{}
};
MODULE_DEVICE_TABLE(i2c, hp206c_id);
#ifdef CONFIG_ACPI
static const struct acpi_device_id hp206c_acpi_match[] = {
{"HOP206C", 0},
{ },
};
MODULE_DEVICE_TABLE(acpi, hp206c_acpi_match);
#endif
static struct i2c_driver hp206c_driver = {
.probe = hp206c_probe,
.id_table = hp206c_id,
.driver = {
.name = "hp206c",
.acpi_match_table = ACPI_PTR(hp206c_acpi_match),
},
};
module_i2c_driver(hp206c_driver);
MODULE_DESCRIPTION("HOPERF HP206C precision barometer and altimeter sensor");
MODULE_AUTHOR("Leonard Crestez <leonard.crestez@intel.com>");
MODULE_LICENSE("GPL v2");
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