diff options
author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
---|---|---|
committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /drivers/hwmon/ads7828.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
download | FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.gz FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.bz2 FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.zip |
Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'drivers/hwmon/ads7828.c')
-rw-r--r-- | drivers/hwmon/ads7828.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c new file mode 100644 index 00000000..bf3fdf49 --- /dev/null +++ b/drivers/hwmon/ads7828.c @@ -0,0 +1,274 @@ +/* + * ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC + * (C) 2007 EADS Astrium + * + * This driver is based on the lm75 and other lm_sensors/hwmon drivers + * + * Written by Steve Hardy <shardy@redhat.com> + * + * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf + * + * 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/err.h> +#include <linux/mutex.h> + +/* The ADS7828 registers */ +#define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */ +#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */ +#define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */ +#define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */ +#define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */ +#define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */ +#define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */ +#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */ + +/* Addresses to scan */ +static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, + I2C_CLIENT_END }; + +/* Module parameters */ +static bool se_input = 1; /* Default is SE, 0 == diff */ +static bool int_vref = 1; /* Default is internal ref ON */ +static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */ +module_param(se_input, bool, S_IRUGO); +module_param(int_vref, bool, S_IRUGO); +module_param(vref_mv, int, S_IRUGO); + +/* Global Variables */ +static u8 ads7828_cmd_byte; /* cmd byte without channel bits */ +static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */ + +/* Each client has this additional data */ +struct ads7828_data { + struct device *hwmon_dev; + struct mutex update_lock; /* mutex protect updates */ + char valid; /* !=0 if following fields are valid */ + unsigned long last_updated; /* In jiffies */ + u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */ +}; + +/* Function declaration - necessary due to function dependencies */ +static int ads7828_detect(struct i2c_client *client, + struct i2c_board_info *info); +static int ads7828_probe(struct i2c_client *client, + const struct i2c_device_id *id); + +static inline u8 channel_cmd_byte(int ch) +{ + /* cmd byte C2,C1,C0 - see datasheet */ + u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4); + cmd |= ads7828_cmd_byte; + return cmd; +} + +/* Update data for the device (all 8 channels) */ +static struct ads7828_data *ads7828_update_device(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct ads7828_data *data = i2c_get_clientdata(client); + + mutex_lock(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ + HZ / 2) + || !data->valid) { + unsigned int ch; + dev_dbg(&client->dev, "Starting ads7828 update\n"); + + for (ch = 0; ch < ADS7828_NCH; ch++) { + u8 cmd = channel_cmd_byte(ch); + data->adc_input[ch] = + i2c_smbus_read_word_swapped(client, cmd); + } + data->last_updated = jiffies; + data->valid = 1; + } + + mutex_unlock(&data->update_lock); + + return data; +} + +/* sysfs callback function */ +static ssize_t show_in(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); + struct ads7828_data *data = ads7828_update_device(dev); + /* Print value (in mV as specified in sysfs-interface documentation) */ + return sprintf(buf, "%d\n", (data->adc_input[attr->index] * + ads7828_lsb_resol)/1000); +} + +#define in_reg(offset)\ +static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\ + NULL, offset) + +in_reg(0); +in_reg(1); +in_reg(2); +in_reg(3); +in_reg(4); +in_reg(5); +in_reg(6); +in_reg(7); + +static struct attribute *ads7828_attributes[] = { + &sensor_dev_attr_in0_input.dev_attr.attr, + &sensor_dev_attr_in1_input.dev_attr.attr, + &sensor_dev_attr_in2_input.dev_attr.attr, + &sensor_dev_attr_in3_input.dev_attr.attr, + &sensor_dev_attr_in4_input.dev_attr.attr, + &sensor_dev_attr_in5_input.dev_attr.attr, + &sensor_dev_attr_in6_input.dev_attr.attr, + &sensor_dev_attr_in7_input.dev_attr.attr, + NULL +}; + +static const struct attribute_group ads7828_group = { + .attrs = ads7828_attributes, +}; + +static int ads7828_remove(struct i2c_client *client) +{ + struct ads7828_data *data = i2c_get_clientdata(client); + hwmon_device_unregister(data->hwmon_dev); + sysfs_remove_group(&client->dev.kobj, &ads7828_group); + kfree(i2c_get_clientdata(client)); + return 0; +} + +static const struct i2c_device_id ads7828_id[] = { + { "ads7828", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ads7828_id); + +/* This is the driver that will be inserted */ +static struct i2c_driver ads7828_driver = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "ads7828", + }, + .probe = ads7828_probe, + .remove = ads7828_remove, + .id_table = ads7828_id, + .detect = ads7828_detect, + .address_list = normal_i2c, +}; + +/* Return 0 if detection is successful, -ENODEV otherwise */ +static int ads7828_detect(struct i2c_client *client, + struct i2c_board_info *info) +{ + struct i2c_adapter *adapter = client->adapter; + int ch; + + /* Check we have a valid client */ + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) + return -ENODEV; + + /* + * Now, we do the remaining detection. There is no identification + * dedicated register so attempt to sanity check using knowledge of + * the chip + * - Read from the 8 channel addresses + * - Check the top 4 bits of each result are not set (12 data bits) + */ + for (ch = 0; ch < ADS7828_NCH; ch++) { + u16 in_data; + u8 cmd = channel_cmd_byte(ch); + in_data = i2c_smbus_read_word_swapped(client, cmd); + if (in_data & 0xF000) { + pr_debug("%s : Doesn't look like an ads7828 device\n", + __func__); + return -ENODEV; + } + } + + strlcpy(info->type, "ads7828", I2C_NAME_SIZE); + + return 0; +} + +static int ads7828_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct ads7828_data *data; + int err; + + data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL); + if (!data) { + err = -ENOMEM; + goto exit; + } + + i2c_set_clientdata(client, data); + mutex_init(&data->update_lock); + + /* Register sysfs hooks */ + err = sysfs_create_group(&client->dev.kobj, &ads7828_group); + if (err) + goto exit_free; + + data->hwmon_dev = hwmon_device_register(&client->dev); + if (IS_ERR(data->hwmon_dev)) { + err = PTR_ERR(data->hwmon_dev); + goto exit_remove; + } + + return 0; + +exit_remove: + sysfs_remove_group(&client->dev.kobj, &ads7828_group); +exit_free: + kfree(data); +exit: + return err; +} + +static int __init sensors_ads7828_init(void) +{ + /* Initialize the command byte according to module parameters */ + ads7828_cmd_byte = se_input ? + ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF; + ads7828_cmd_byte |= int_vref ? + ADS7828_CMD_PD3 : ADS7828_CMD_PD1; + + /* Calculate the LSB resolution */ + ads7828_lsb_resol = (vref_mv*1000)/4096; + + return i2c_add_driver(&ads7828_driver); +} + +static void __exit sensors_ads7828_exit(void) +{ + i2c_del_driver(&ads7828_driver); +} + +MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); +MODULE_DESCRIPTION("ADS7828 driver"); +MODULE_LICENSE("GPL"); + +module_init(sensors_ads7828_init); +module_exit(sensors_ads7828_exit); |