[PATCHv2 1/3] misc: clean up bmp085 driver

From: Eric Andersson
Date: Tue Mar 06 2012 - 16:06:48 EST

This patch includes various cleaning of the bmp085 driver including:
- Addition of platform_data and header file
- Implement pm functions
- Whitespaces and alignment fixes
- Minor typos
- Consistency fixes

Reviewed-by: Stefan Nilsson <stefan.nilsson@xxxxxxxxxxxxx>
Signed-off-by: Eric Andersson <eric.andersson@xxxxxxxxxxxxx>
---
drivers/misc/bmp085.c | 178 ++++++++++++++++++++++++++++----------------
include/linux/i2c/bmp085.h | 43 +++++++++++
2 files changed, 158 insertions(+), 63 deletions(-)
create mode 100644 include/linux/i2c/bmp085.h

diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c
index b29a2be..5978094 100644
--- a/drivers/misc/bmp085.c
+++ b/drivers/misc/bmp085.c
@@ -1,4 +1,6 @@
/* Copyright (c) 2010 Christoph Mair <christoph.mair@xxxxxxxxx>
+ Copyright (c) 2012 Bosch Sensortec GmbH
+ Copyright (c) 2012 Unixphere AB

This driver supports the bmp085 digital barometric pressure
and temperature sensor from Bosch Sensortec. The datasheet
@@ -42,13 +44,13 @@
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

-
#include <linux/module.h>
+#include <linux/device.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/delay.h>
-
+#include <linux/i2c/bmp085.h>

#define BMP085_I2C_ADDRESS 0x77
#define BMP085_CHIP_ID 0x55
@@ -56,7 +58,6 @@
#define BMP085_CALIBRATION_DATA_START 0xAA
#define BMP085_CALIBRATION_DATA_LENGTH 11 /* 16 bit values */
#define BMP085_CHIP_ID_REG 0xD0
-#define BMP085_VERSION_REG 0xD1
#define BMP085_CTRL_REG 0xF4
#define BMP085_TEMP_MEASUREMENT 0x2E
#define BMP085_PRESSURE_MEASUREMENT 0x34
@@ -65,9 +66,6 @@
#define BMP085_CONVERSION_REGISTER_XLSB 0xF8
#define BMP085_TEMP_CONVERSION_TIME 5

-#define BMP085_CLIENT_NAME "bmp085"
-
-
static const unsigned short normal_i2c[] = { BMP085_I2C_ADDRESS,
I2C_CLIENT_END };

@@ -78,20 +76,18 @@ struct bmp085_calibration_data {
s16 MB, MC, MD;
};

-
-/* Each client has this additional data */
struct bmp085_data {
- struct i2c_client *client;
- struct mutex lock;
- struct bmp085_calibration_data calibration;
- u32 raw_temperature;
- u32 raw_pressure;
- unsigned char oversampling_setting;
- u32 last_temp_measurement;
- s32 b6; /* calculated temperature correction coefficient */
+ struct i2c_client *client;
+ struct mutex lock;
+ struct bmp085_calibration_data calibration;
+ u8 oversampling_setting;
+ u32 raw_temperature;
+ u32 raw_pressure;
+ u32 temp_measurement_period;
+ u32 last_temp_measurement;
+ s32 b6; /* calculated temperature correction coefficient */
};

-
static s32 bmp085_read_calibration_data(struct i2c_client *client)
{
u16 tmp[BMP085_CALIBRATION_DATA_LENGTH];
@@ -99,12 +95,12 @@ static s32 bmp085_read_calibration_data(struct i2c_client *client)
struct bmp085_calibration_data *cali = &(data->calibration);
s32 status = i2c_smbus_read_i2c_block_data(client,
BMP085_CALIBRATION_DATA_START,
- BMP085_CALIBRATION_DATA_LENGTH*sizeof(u16),
+ (BMP085_CALIBRATION_DATA_LENGTH << 1),
(u8 *)tmp);
if (status < 0)
return status;

- if (status != BMP085_CALIBRATION_DATA_LENGTH*sizeof(u16))
+ if (status != (BMP085_CALIBRATION_DATA_LENGTH << 1))
return -EIO;

cali->AC1 = be16_to_cpu(tmp[0]);
@@ -121,7 +117,6 @@ static s32 bmp085_read_calibration_data(struct i2c_client *client)
return 0;
}

-
static s32 bmp085_update_raw_temperature(struct bmp085_data *data)
{
u16 tmp;
@@ -129,8 +124,8 @@ static s32 bmp085_update_raw_temperature(struct bmp085_data *data)

mutex_lock(&data->lock);
status = i2c_smbus_write_byte_data(data->client, BMP085_CTRL_REG,
- BMP085_TEMP_MEASUREMENT);
- if (status != 0) {
+ BMP085_TEMP_MEASUREMENT);
+ if (status < 0) {
dev_err(&data->client->dev,
"Error while requesting temperature measurement.\n");
goto exit;
@@ -163,8 +158,9 @@ static s32 bmp085_update_raw_pressure(struct bmp085_data *data)

mutex_lock(&data->lock);
status = i2c_smbus_write_byte_data(data->client, BMP085_CTRL_REG,
- BMP085_PRESSURE_MEASUREMENT + (data->oversampling_setting<<6));
- if (status != 0) {
+ BMP085_PRESSURE_MEASUREMENT +
+ (data->oversampling_setting << 6));
+ if (status < 0) {
dev_err(&data->client->dev,
"Error while requesting pressure measurement.\n");
goto exit;
@@ -193,7 +189,6 @@ exit:
return status;
}

-
/*
* This function starts the temperature measurement and returns the value
* in tenth of a degree celsius.
@@ -205,7 +200,7 @@ static s32 bmp085_get_temperature(struct bmp085_data *data, int *temperature)
int status;

status = bmp085_update_raw_temperature(data);
- if (status != 0)
+ if (status < 0)
goto exit;

x1 = ((data->raw_temperature - cali->AC6) * cali->AC5) >> 15;
@@ -222,8 +217,10 @@ exit:
/*
* This function starts the pressure measurement and returns the value
* in millibar. Since the pressure depends on the ambient temperature,
- * a temperature measurement is executed if the last known value is older
- * than one second.
+ * a temperature measurement is executed according to the given temperature
+ * measurememt period (default is 1 sec boundary). This period could vary
+ * and needs to be adjusted according to the sensor environment, i.e. if big
+ * temperature variations then the temperature needs to be read out often.
*/
static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
{
@@ -233,16 +230,17 @@ static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
s32 p;
int status;

- /* alt least every second force an update of the ambient temperature */
- if (data->last_temp_measurement + 1*HZ < jiffies) {
+ /* update the ambient temperature according to the given meas. period */
+ if (data->last_temp_measurement +
+ data->temp_measurement_period < jiffies) {
status = bmp085_get_temperature(data, NULL);
- if (status != 0)
- goto exit;
+ if (status < 0)
+ return status;
}

status = bmp085_update_raw_pressure(data);
- if (status != 0)
- goto exit;
+ if (status < 0)
+ return status;

x1 = (data->b6 * data->b6) >> 12;
x1 *= cali->B2;
@@ -273,15 +271,14 @@ static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)

*pressure = p;

-exit:
- return status;
+ return 0;
}

/*
* This function sets the chip-internal oversampling. Valid values are 0..3.
* The chip will use 2^oversampling samples for internal averaging.
* This influences the measurement time and the accuracy; larger values
- * increase both. The datasheet gives on overview on how measurement time,
+ * increase both. The datasheet gives an overview on how measurement time,
* accuracy and noise correlate.
*/
static void bmp085_set_oversampling(struct bmp085_data *data,
@@ -308,12 +305,16 @@ static ssize_t set_oversampling(struct device *dev,
struct i2c_client *client = to_i2c_client(dev);
struct bmp085_data *data = i2c_get_clientdata(client);
unsigned long oversampling;
- int success = strict_strtoul(buf, 10, &oversampling);
- if (success == 0) {
+ int err = kstrtoul(buf, 10, &oversampling);
+
+ if (err == 0) {
+ mutex_lock(&data->lock);
bmp085_set_oversampling(data, oversampling);
+ mutex_unlock(&data->lock);
return count;
}
- return success;
+
+ return err;
}

static ssize_t show_oversampling(struct device *dev,
@@ -321,6 +322,7 @@ static ssize_t show_oversampling(struct device *dev,
{
struct i2c_client *client = to_i2c_client(dev);
struct bmp085_data *data = i2c_get_clientdata(client);
+
return sprintf(buf, "%u\n", bmp085_get_oversampling(data));
}
static DEVICE_ATTR(oversampling, S_IWUSR | S_IRUGO,
@@ -336,7 +338,7 @@ static ssize_t show_temperature(struct device *dev,
struct bmp085_data *data = i2c_get_clientdata(client);

status = bmp085_get_temperature(data, &temperature);
- if (status != 0)
+ if (status < 0)
return status;
else
return sprintf(buf, "%d\n", temperature);
@@ -353,7 +355,7 @@ static ssize_t show_pressure(struct device *dev,
struct bmp085_data *data = i2c_get_clientdata(client);

status = bmp085_get_pressure(data, &pressure);
- if (status != 0)
+ if (status < 0)
return status;
else
return sprintf(buf, "%d\n", pressure);
@@ -385,43 +387,58 @@ static int bmp085_detect(struct i2c_client *client, struct i2c_board_info *info)

static int bmp085_init_client(struct i2c_client *client)
{
- unsigned char version;
- int status;
struct bmp085_data *data = i2c_get_clientdata(client);
+ struct bmp085_platform_data *pdata = client->dev.platform_data;
+ int status = bmp085_read_calibration_data(client);
+
+ if (status < 0)
+ return status;
+
data->client = client;
- status = bmp085_read_calibration_data(client);
- if (status != 0)
- goto exit;
- version = i2c_smbus_read_byte_data(client, BMP085_VERSION_REG);
data->last_temp_measurement = 0;
- data->oversampling_setting = 3;
+ data->temp_measurement_period =
+ pdata ? (pdata->temp_measurement_period/1000)*HZ : 1*HZ;
+ data->oversampling_setting = pdata ? pdata->default_oversampling : 3;
mutex_init(&data->lock);
- dev_info(&data->client->dev, "BMP085 ver. %d.%d found.\n",
- (version & 0x0F), (version & 0xF0) >> 4);
-exit:
- return status;
+
+ return 0;
}

static int __devinit bmp085_probe(struct i2c_client *client,
- const struct i2c_device_id *id)
+ const struct i2c_device_id *id)
{
struct bmp085_data *data;
+ struct bmp085_platform_data *pdata = client->dev.platform_data;
+ u8 chip_id = (pdata && pdata->chip_id) ? pdata->chip_id :
+ BMP085_CHIP_ID;
int err = 0;

+ if (pdata && pdata->init_hw) {
+ err = pdata->init_hw(&client->dev);
+ if (err) {
+ dev_err(&client->dev, "%s: init_hw failed!\n",
+ BMP085_NAME);
+ return err;
+ }
+ }
+
data = kzalloc(sizeof(struct bmp085_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}

- /* default settings after POR */
- data->oversampling_setting = 0x00;
-
i2c_set_clientdata(client, data);

+ if (i2c_smbus_read_byte_data(client, BMP085_CHIP_ID_REG) != chip_id) {
+ dev_err(&client->dev, "%s: chip_id failed!\n", BMP085_NAME);
+ err = -ENODEV;
+ goto exit_free;
+ }
+
/* Initialize the BMP085 chip */
err = bmp085_init_client(client);
- if (err != 0)
+ if (err < 0)
goto exit_free;

/* Register sysfs hooks */
@@ -429,22 +446,57 @@ static int __devinit bmp085_probe(struct i2c_client *client,
if (err)
goto exit_free;

- dev_info(&data->client->dev, "Successfully initialized bmp085!\n");
- goto exit;
+ dev_info(&client->dev, "Succesfully initialized bmp085!\n");
+ return 0;

exit_free:
kfree(data);
exit:
+ if (pdata && pdata->deinit_hw)
+ pdata->deinit_hw(&client->dev);
return err;
}

static int __devexit bmp085_remove(struct i2c_client *client)
{
+ struct bmp085_data *data = i2c_get_clientdata(client);
+ struct bmp085_platform_data *pdata = client->dev.platform_data;
+
sysfs_remove_group(&client->dev.kobj, &bmp085_attr_group);
- kfree(i2c_get_clientdata(client));
+
+ if (pdata && pdata->deinit_hw)
+ pdata->deinit_hw(&client->dev);
+
+ kfree(data);
+
return 0;
}

+#ifdef CONFIG_PM
+static int bmp085_suspend(struct device *dev)
+{
+ struct bmp085_platform_data *pdata = dev->platform_data;
+
+ if (pdata && pdata->deinit_hw)
+ pdata->deinit_hw(dev);
+
+ return 0;
+}
+
+static int bmp085_resume(struct device *dev)
+{
+ struct bmp085_platform_data *pdata = dev->platform_data;
+
+ if (pdata && pdata->init_hw)
+ return pdata->init_hw(dev);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(bmp085_pm_ops, bmp085_suspend,
+ bmp085_resume);
+
static const struct i2c_device_id bmp085_id[] = {
{ "bmp085", 0 },
{ }
@@ -454,7 +506,8 @@ MODULE_DEVICE_TABLE(i2c, bmp085_id);
static struct i2c_driver bmp085_driver = {
.driver = {
.owner = THIS_MODULE,
- .name = "bmp085"
+ .name = "bmp085",
+ .pm = &bmp085_pm_ops,
},
.id_table = bmp085_id,
.probe = bmp085_probe,
@@ -474,7 +527,6 @@ static void __exit bmp085_exit(void)
i2c_del_driver(&bmp085_driver);
}

-
MODULE_AUTHOR("Christoph Mair <christoph.mair@xxxxxxxxx");
MODULE_DESCRIPTION("BMP085 driver");
MODULE_LICENSE("GPL");
diff --git a/include/linux/i2c/bmp085.h b/include/linux/i2c/bmp085.h
new file mode 100644
index 0000000..e6fc752
--- /dev/null
+++ b/include/linux/i2c/bmp085.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2012 Bosch Sensortec GmbH
+ * Copyright (c) 2012 Unixphere AB
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _BMP085_H
+#define _BMP085_H
+
+#define BMP085_NAME "bmp085"
+
+/**
+ * struct bmp085_platform_data - represents platform data for the bmp085 driver
+ * @chip_id: Configurable chip id for non-default chip revisions
+ * @default_oversampling: Default oversampling value to be used at startup,
+ * value range is 0-3 with rising sensitivity.
+ * @temp_measurement_period: Temperature measurement period (milliseconds), set
+ * to zero if unsure.
+ * @init_hw: Callback for hw specific startup
+ * @deinit_hw: Callback for hw specific shutdown
+ */
+struct bmp085_platform_data {
+ u8 chip_id;
+ u8 default_oversampling;
+ u32 temp_measurement_period;
+ int (*init_hw)(struct device *dev);
+ void (*deinit_hw)(struct device *dev);
+};
+
+#endif
--
1.7.3.4

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