From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754835AbZHNLFm (ORCPT ); Fri, 14 Aug 2009 07:05:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754573AbZHNLFl (ORCPT ); Fri, 14 Aug 2009 07:05:41 -0400 Received: from wa-out-1112.google.com ([209.85.146.180]:14852 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753807AbZHNLFk convert rfc822-to-8bit (ORCPT ); Fri, 14 Aug 2009 07:05:40 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=r8+P9LtySuILn3oPAr1J+wcwsfWIfzu5X9TkTLMgYBbOgtLsidb93oMXzSm9XGMrqG f1n1cKoCYsvBkq61/tJHn3tT7n+x/Ctwvinevii894rbsSJV6WTYU9a3Z1lnlHWAkm6N mOLKgyH+fmIf4uel5DXGREd6Ff4whKLApDOFg= MIME-Version: 1.0 In-Reply-To: <68FBE0F3CE97264395875AC1C468F22C152BE8@mail03.cyberswitching.local> References: <68FBE0F3CE97264395875AC1C468F22C152BE8@mail03.cyberswitching.local> From: XingChao Wang Date: Fri, 14 Aug 2009 19:05:26 +0800 Message-ID: Subject: Re: [PATCH] adxl345 accelerometer hwmon driver To: Chris Verges Cc: linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2009/7/2 Chris Verges > > 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. > > 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 > 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 > + * > + * 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#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); > + it doesn't need convertion if data->data[i] with bit16==0. --wxc200 > +               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 "); > +MODULE_DESCRIPTION("Analog Devices ADXL345 driver"); > +MODULE_LICENSE("GPL"); > +MODULE_VERSION(DRV_VERSION); > + > +module_init(adxl345_init); > +module_exit(adxl345_exit);