> Hi kernel hackers, > > Here is a patch that adds support to the Linux kernel for Analog > Device's ADXL345 chip. It is an accelerometer that uses I2C and HWMON. > When I looked into the MAINTAINERS file for the appropriate list, the > "Orphan" status of "Hardware Monitoring" confused me as to the proper > list for this patch ... please let me know if I need to forward it > elsewhere. Hi Chris, Just for reference this chip is definitely on my list of ones to support via the Industrial I/O (iio) framework, I just haven't managed to get hold of one as yet! It's particualrly interesting to me because of the fifo buffering functionality as currently I only have access to a VTI chip that does something similar. A new version of the IIO framework will get posted just as soon as I've had a few mins to bring the documentation / demo userspace apps up to date with the current code state. I've been chasing down bugs for the last week. First big question is: What are you actually doing with it? If you aren't doing hardware monitoring then I would expect you aren't going to receive a favourable response on here. (see the original IIO discussion on LKML for why I started writing that in the first place. http://lkml.org/lkml/2008/5/20/135) It's somewhat out of date and incomplete, but there is a white paper draft at http://www-sigproc.eng.cam.ac.uk/~jic23/iio.pdf I'll take a look at the actual code tomorrow. Always good to see another accelerometer driver. Thanks, Jonathan > > ALPHA Warning: THIS CODE COMPILES WITHOUT ERROR, BUT HAS NOT BEEN TESTED > YET. > > I'd appreciate feedback from those who have the time/interest to help! > Code review would be great, someone with hardware for testing would be > excellent. > > Thanks, > Chris > > > --- PATCH BELOW --- > > Signed-off-by: Chris Verges <chrisv at cyberswitching.com> > Index: drivers/hwmon/Makefile > =================================================================== > --- linux-2.6.29.3-orig/drivers/hwmon/Makefile (revision 33) > +++ linux-2.6.29.3/drivers/hwmon/Makefile (revision 49) > @@ -29,6 +29,7 @@ > obj-$(CONFIG_SENSORS_ADT7470) += adt7470.o > obj-$(CONFIG_SENSORS_ADT7473) += adt7473.o > obj-$(CONFIG_SENSORS_ADT7475) += adt7475.o > +obj-$(CONFIG_SENSORS_ADXL345) += adxl345.o > > obj-$(CONFIG_SENSORS_APPLESMC) += applesmc.o > obj-$(CONFIG_SENSORS_AMS) += ams/ > Index: drivers/hwmon/Kconfig > =================================================================== > --- linux-2.6.29.3-orig/drivers/hwmon/Kconfig (revision 33) > +++ linux-2.6.29.3/drivers/hwmon/Kconfig (revision 49) > @@ -199,6 +199,16 @@ > This driver can also be build as a module. If so, the module > will be called adt7475. > > +config SENSORS_ADXL345 > + tristate "Analog Devices ADXL345" > + depends on I2C && EXPERIMENTAL > + help > + If you say yes here, you get support for the Analog Devices > + ADXL345 digital accelerometer chip. > + > + This driver can also be build as a module. If so, the module > + will be called adxl345. > + > config SENSORS_K8TEMP > tristate "AMD Athlon64/FX or Opteron temperature sensor" > depends on X86 && PCI && EXPERIMENTAL > Index: drivers/hwmon/adxl345.c > =================================================================== > --- linux-2.6.29.3-orig/drivers/hwmon/adxl345.c (revision 0) > +++ linux-2.6.29.3/drivers/hwmon/adxl345.c (revision 49) > @@ -0,0 +1,521 @@ > +/* > + * A hwmon driver for the Analog Devices ADXL345 > + * > + * Copyright (c) 2009 Cyber Switching, Inc. > + * Author: Robert Mehranfar <robertme at earthlink.net> > + * > + * 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. > + */ > + > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/slab.h> > +#include <linux/jiffies.h> > +#include <linux/i2c.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > +#include <linux/hwmon-vid.h> > +#include <linux/err.h> > +#include <linux/mutex.h> > +#include <linux/kernel.h> > + > +#define DRV_NAME "adxl345" > +#define DRV_VERSION "0.1" > + > +#define SIMULATE 1 > + > +/* > + * The ADXL345 registers > + */ > +#define ADXL345_REG_DEV_ID 0x00 > +#define ADXL345_REG_OFS(nr) (0x1E + (nr)) > +#define ADXL345_REG_DATA(nr) (0x32 + (nr)) > +#define ADXL345_REG_DATA_FORMAT 0x31 > + > +/* > + * See ADXL345 specification > + */ > +#define OFFSET_SCALE_FACTOR_WHOLE 15 > +#define OFFSET_SCALE_FACTOR_FRACTIONAL 6 > + > +#define MAX_OFFSET 1988 > +#define MIN_OFFSET -1998 > + > +/* > + * Based on 10-bit resolution +/-16 range set in the DATA FORMAT > register > + */ > +#define DATA_SCALE_FACTOR_WHOLE 15 > +#define DATA_SCALE_FACTOR_FRACTIONAL 6 > +#define NUMBER_OF_AXES 3 > + > +#define X_AXIS 0 > +#define Y_AXIS 1 > +#define Z_AXIS 2 > + > +/* Position in the sysfs attribute array */ > +#define X_AXIS_ATTR 0 > +#define Y_AXIS_ATTR 1 > +#define Z_AXIS_ATTR 2 > +#define DATA_ATTR 3 > + > +/* > + * Functions declaration > + */ > +static void adxl345_init_client(struct i2c_client *client); > +static struct adxl345_data *adxl345_update_device(struct device *dev); > +static void convert_to_fraction(s16 data, u8 whole_scale, u8 > fraction_scale, > + int *decimal, int *fraction); > + > +/* > + * Client data (each client gets its own) > + */ > +struct adxl345_data { > + struct i2c_client client; > + struct device *hwmon_dev; > + struct mutex update_lock; /* lock on the structure > */ > + char valid; /* 0 until below are > valid */ > + unsigned long last_updated; /* in jiffies */ > + > + /* > + * ADXL345 Data > + * In two's complement, data coming in from or going out to > user-space > + * must be converted. > + */ > + u8 offset[NUMBER_OF_AXES]; > + u16 data[NUMBER_OF_AXES]; > +}; > + > + > +/* > + * Converts internal data to a decimal-fraction value. > + * Notes: Must already be converted out of twos complement > + * > + * @param data Data to be converted > + * @param whole_scale Scale factor for whole number part. (Set to 1 for > no scaling). > + * @param fraction_scale Scale factor for fractional number part. (Set > to 1 for no scaling). > + * @param decimal Pointer to location to store decimal part. > + * @param fraction Pointer to location to store fractional part. > + */ > +static void convert_to_fraction(s16 data, u8 whole_scale, u8 > fraction_scale, > + int *decimal, int *fraction) > +{ > + int temp_decimal, temp_fraction, temp; > + int sign = 1; > + > + /* Scale the decimal and fractional parts */ > + temp_decimal = data * whole_scale * 10; > + temp_fraction = data * fraction_scale; > + > + /* get rid of the sign for negative fractions */ > + if (temp_fraction < 0) { > + sign = -1; > + temp_fraction *= sign; > + } > + > + /* If necessary, carry */ > + if (temp_fraction >= 10) { > + /* Add to the decimal part */ > + temp_decimal += sign * temp_fraction; > + > + /* Amount to be subtracted from the fractional part */ > + temp = temp_fraction / 10; > + > + temp_fraction -= temp * 10; > + } > + > + temp_decimal /= 10; > + > + /* > + * If at least 10 still remains in the fractional part, one > + * last carry > + */ > + if (temp_fraction >= 10) { > + temp_decimal += sign; > + temp_fraction -= 10; > + } > + > + /* Pass the values up */ > + *decimal = temp_decimal; > + *fraction = temp_fraction; > +} > + > +/* > + * Called in response to cat ofs(x,y,z) in sysfs > + * > + * @param dev Pointer to device > + * @param attr Pointer to the device attributes > + * @param buf Pointer to string shown in user space > + * @return Number of chars copied to buffer > +*/ > +static ssize_t show_offset(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + int index = to_sensor_dev_attr(attr)->index; > + struct adxl345_data *data = adxl345_update_device(dev); > + int decimal, fraction; > + s8 temp_data; > + > + dev_dbg(dev, "%s\n", __func__); > + > + /* Convert from 2's complement */ > + temp_data = ~(data->offset[index] - 1); > + > + dev_dbg(dev, "temp_data=%d\n", temp_data); > + > + convert_to_fraction(temp_data, > + OFFSET_SCALE_FACTOR_WHOLE, > + OFFSET_SCALE_FACTOR_FRACTIONAL, > + &decimal, > + &fraction); > + > + return snprintf(buf, PAGE_SIZE, > + "%4d.%1d\n", decimal, fraction); > +} > + > +/* > + * Called in response to echoing data to ofs(x,y,z) in sysfs > + * Note: Input range is -1998 to 1998 milli-g's > + * > + * @param dev Pointer to device > + * @param attr Pointer to the device attributes > + * @param buf Pointer to string passed in from user space > + * @param count Number of chars passed in from user space.. > + * @return Number of chars passed in from user space. > + */ > +static ssize_t set_offset(struct device *dev, > + struct device_attribute *attr, > + const char *buf, > + size_t count) > +{ > + int index = to_sensor_dev_attr(attr)->index; > + struct i2c_client *client = to_i2c_client(dev); > + struct adxl345_data *data = i2c_get_clientdata(client); > + long val; > + long temp_val; > + > + dev_dbg(dev, "%s\n", __func__); > + > + if (!strict_strtol(buf, 10, &val)) { > + dev_dbg(dev, "error in converting string '%s' to > long\n", > + buf); > + return 0; > + } > + > + /* If outside offset range, clip to max or min value */ > + if (val < MIN_OFFSET) > + val = MIN_OFFSET; > + else if (val > MAX_OFFSET) > + val = MAX_OFFSET; > + > + temp_val = (val * 100) % > + ((OFFSET_SCALE_FACTOR_WHOLE * 100) + > + (OFFSET_SCALE_FACTOR_FRACTIONAL * 10)); > + if (temp_val < 0) > + temp_val *= -1; > + > + /* Get rid of scale for internal storage */ > + val = (val * 100) / > + ((OFFSET_SCALE_FACTOR_WHOLE * 100) + > + (OFFSET_SCALE_FACTOR_FRACTIONAL * 10)); > + > + if (temp_val > (OFFSET_SCALE_FACTOR_WHOLE * 100) / 2 && val > 0) > + ++val; > + else if (temp_val > (OFFSET_SCALE_FACTOR_WHOLE * 100) / 2 && val > < 0) > + --val; > + > + val = ~val + 1; /* convert to two's complement */ > + > + mutex_lock(&data->update_lock); > + > + data->offset[index] = val; > + > + dev_dbg(dev, "offset[%d]=%d\n", index, data->offset[index]); > + > + /* Write the avlue to the chip via I2C */ > + i2c_smbus_write_byte_data(client, > + ADXL345_REG_OFS(index), > + data->offset[index]); > + > + mutex_unlock(&data->update_lock); > + > + return count; > +} > + > +/* > + * Called in response to cat data in sysfs > + * > + * @param dev Pointer to device > + * @param attr Pointer to the device attributes > + * @param buf Pointer to string shown in user space > + * @return Number of chars copied to buffer > +*/ > +static ssize_t show_data(struct device *dev, struct device_attribute > *attr, > + char *buf) > +{ > + int i; > + s16 temp_data; > + int decimal[NUMBER_OF_AXES], fraction[NUMBER_OF_AXES]; > + > + struct adxl345_data *data = adxl345_update_device(dev); > + > + /* Convert x,y,z values */ > + for (i = 0; i < NUMBER_OF_AXES; i++) { > + /* Convert from 2's complement */ > + temp_data = ~(data->data[i] - 1); > + > + convert_to_fraction(temp_data, > + DATA_SCALE_FACTOR_WHOLE, > + DATA_SCALE_FACTOR_FRACTIONAL, > + &decimal[i], > + &fraction[i]); > + } > + > + return snprintf(buf, PAGE_SIZE, > + "x:%5d.%1d y:%5d.%1d z:%5d.%1d\n", > + decimal[X_AXIS], fraction[X_AXIS], > + decimal[Y_AXIS], fraction[Y_AXIS], > + decimal[Z_AXIS], fraction[Z_AXIS]); > +} > + > +/* Attributes of the sysfs entries */ > +static SENSOR_DEVICE_ATTR(ofsx, S_IWUSR | S_IRUGO, > + show_offset, set_offset, X_AXIS_ATTR); > +static SENSOR_DEVICE_ATTR(ofsy, S_IWUSR | S_IRUGO, > + show_offset, set_offset, Y_AXIS_ATTR); > +static SENSOR_DEVICE_ATTR(ofsz, S_IWUSR | S_IRUGO, > + show_offset, set_offset, Z_AXIS_ATTR); > +static SENSOR_DEVICE_ATTR(data, S_IRUGO, > + show_data, NULL, DATA_ATTR); > + > +static struct attribute *adxl345_attributes[] = { > + &sensor_dev_attr_ofsx.dev_attr.attr, > + &sensor_dev_attr_ofsy.dev_attr.attr, > + &sensor_dev_attr_ofsz.dev_attr.attr, > + &sensor_dev_attr_data.dev_attr.attr, > + NULL > +}; > + > +static const struct attribute_group adxl345_group = { > + .attrs = adxl345_attributes, > +}; > + > +/* > + * Initialize the chip > + * > + * @param client Pointer to the client structure > + */ > +static void adxl345_init_client(struct i2c_client *client) > +{ > + dev_dbg(&client->dev, "%s\n", __func__); > + > + /* > + * Set up the device, No self test, Dont care about SPI or > + * interrupt, 10 bit resoltion, +/- 16g range > + */ > + i2c_smbus_write_byte_data(client, ADXL345_REG_DATA_FORMAT, > 0x03); > +} > + > +/* > + * Does more than just detection. If detection succeeds, it also > + * registers the new chip. > + * > + * @param adapter Pointer to the adapter > + * @param address I2C address > + * @return Zero, upon success > + */ > +static int adxl345_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct adxl345_data *data; > + int err = 0; > + u8 dev_id; > + > + dev_dbg(&client->dev, "%s\n", __func__); > + > + if (!i2c_check_functionality(client->adapter, > I2C_FUNC_SMBUS_BYTE_DATA)) > + return -ENODEV; > + > + data = kzalloc(sizeof(struct adxl345_data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + i2c_set_clientdata(client, data); > + > + #ifdef SIMULATE > + dev_id = 0xE5; /* Spoof the Analog Devices device ID */ > + dev_dbg(&client->dev, "Simulating ADXL345 device\n"); > + #else > + dev_id = i2c_smbus_read_byte_data(client, ADXL345_REG_DEV_ID); > + #endif > + > + /* If the chip is not from Analog Devices, report an error */ > + if (dev_id != 0xE5) { > + dev_err(&client->dev, "Unsupported chip > (dev_id=0x%02X)\n", > + dev_id); > + err = -EINVAL; > + goto err_free_mem; > + } > + > + dev_info(&client->dev, "chip found, driver version " > + DRV_VERSION "\n"); > + > + /* We can fill in the remaining client fields */ > + mutex_init(&data->update_lock); > + > + /* Initialize the ADXL345 chip */ > + adxl345_init_client(client); > + > + /* Register sysfs hooks */ > + err = sysfs_create_group(&client->dev.kobj, &adxl345_group); > + if (err) > + goto err_free_mem; > + > + data->hwmon_dev = hwmon_device_register(&client->dev); > + if (IS_ERR(data->hwmon_dev)) { > + err = PTR_ERR(data->hwmon_dev); > + goto err_remove; > + } > + > + return 0; > + > +err_remove: > + sysfs_remove_group(&client->dev.kobj, &adxl345_group); > +err_free_mem: > + kfree(data); > + > + return err; > +} > + > +/* > + * Unregister device, remove the sysfs entries, and detach the client > + * from I2C bus. > + * > + * @param client Pointer to the client structure > + * @return Zero, upon success. > + */ > +static int adxl345_remove(struct i2c_client *client) > +{ > + struct adxl345_data *data = i2c_get_clientdata(client); > + > + hwmon_device_unregister(data->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, &adxl345_group); > + > + i2c_unregister_device(client); > + > + kfree(data); > + > + return 0; > +} > + > +/* > + * Gets the data from the chip. > + * > + * @param client Pointer to the device > + * @return Pointer to structure containing the data > + */ > +static struct adxl345_data *adxl345_update_device(struct device *dev) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct adxl345_data *data = i2c_get_clientdata(client); > + int i; > + > + dev_dbg(dev, "%s\n", __func__); > + > + mutex_lock(&data->update_lock); > + > + /* > + * This delay is 500ms, based on a default value of 100 for HZ > + * in ARM kernels > + */ > + if (time_after(jiffies, data->last_updated + HZ * 50) || > + !data->valid) { > + for (i = 0; i < NUMBER_OF_AXES; i++) { > + data->offset[i] = > i2c_smbus_read_byte_data(client, > + ADXL345_REG_OFS(i)); > + dev_dbg(dev, "offset[%d]=%d\n", i, > data->offset[i]); > + } > + > + /* > + * Concatenate the data from each register pair > + * Indexing logic is needed as per ADXL345 spec, LSB is > first > + * INDEX(reg) LSB MSB > + * 0 0 1 > + * 1 2 3 > + * 2 4 5 > + */ > + for (i = 0; i < NUMBER_OF_AXES; i++) { > + /* Get the MSB, shift by 8, and then get the LSB > */ > + data->data[i] = i2c_smbus_read_byte_data(client, > + ADXL345_REG_DATA(i*2+1)) > << 8; > + data->data[i] |= > i2c_smbus_read_byte_data(client, > + ADXL345_REG_DATA(i*2)); > + > + dev_dbg(dev, "data[%d]=%d\n", i, data->data[i]); > + } > + > + data->last_updated = jiffies; > + data->valid = 1; > + } > + > + mutex_unlock(&data->update_lock); > + > + return data; > +} > + > +/* > + * Driver data (common to all clients) > + */ > + > +static const struct i2c_device_id adxl345_id[] = { > + { "adxl345", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, adxl345_id); > + > +static struct i2c_driver adxl345_driver = { > + .driver = { > + .name = DRV_NAME, > + }, > + .probe = adxl345_probe, > + .remove = adxl345_remove, > + .id_table = adxl345_id, > +}; > + > +/* > + * Initialize the module > + * > + * @return Zero, upon success > + */ > +static int __init adxl345_init(void) > +{ > + return i2c_add_driver(&adxl345_driver); > +} > + > +/* > + * Remove the module > + */ > +static void __exit adxl345_exit(void) > +{ > + i2c_del_driver(&adxl345_driver); > +} > + > +MODULE_AUTHOR("Robert Mehranfar <robertme at earthlink.net>"); > +MODULE_DESCRIPTION("Analog Devices ADXL345 driver"); > +MODULE_LICENSE("GPL"); > +MODULE_VERSION(DRV_VERSION); > + > +module_init(adxl345_init); > +module_exit(adxl345_exit); > > > ------------------------------------------------------------------------ > > _______________________________________________ > lm-sensors mailing list > lm-sensors at lm-sensors.org > http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
