Hi, On Thu, Mar 03, 2011 at 11:36:45AM -0500, per.dalen@xxxxxxxxxxxx wrote: > LTC4151 is High Voltage I2C Current and Voltage Monitor from Linear > Technology. > > Signed-off-by: Per Dalen <per.dalen@xxxxxxxxxxxx> > > --- > diff --git a/Documentation/hwmon/ltc4151 b/Documentation/hwmon/ltc4151 > new file mode 100644 > index 0000000..00a564f > --- /dev/null > +++ b/Documentation/hwmon/ltc4151 > @@ -0,0 +1,54 @@ > +Kernel driver ltc4151 > +===================== > + > +Supported chips: > + * Linear Technology LTC4151 > + Prefix: 'ltc4151' > + Addresses scanned: - > + Datasheet: > + http://www.linear.com/docs/Datasheet/4151fc.pdf > + > +Author: Per Dalen <per.dalen@xxxxxxxxxxxx> > + > + > +Description > +----------- > + > +The LTC4151 High Voltage I2C Current and Voltage Monitor > + > + > +Usage Notes > +----------- > + > +This driver does not probe for LTC4151 devices, since there is no register > +which can be safely used to identify the chip. You will have to instantiate > +the devices explicitly. > + > +Example: the following will load the driver for an LTC4261 at address 0x6f LTC4151 > +on I2C bus #1: > +# modprobe ltc4151 > +# echo ltc4151 0x6f > /sys/bus/i2c/devices/i2c-0/new_device That is i2c bus #0, not #1. > + > +The driver assumes 1 mOhm sense resistor is used for the current reading. > +You can change this value in sysfs. > + > +Example: the following will set the sense resistor on LTC4261 to LTC4151 > +20 mOhm (20000 uOhm): > +# echo 20000 > /sys/module/ltc4151/parameters/sense_resistor > + Not a good idea. It sets the value for all instances of the driver, and thus for all LCT4151 chips in the system. If the system supports more than one of the chips, and different sense resistors are used, you are in trouble. Better make a fixed assumption (eg 1 mOhm) and then use sensors3.conf to correct the value. If you really want it to be configurable in the driver, use platform data (and/or device tree information if you are adventurous). > +Sysfs entries > +------------- > + > +Voltage readings provided by this driver are reported as obtained from > the ADIN > +and VIN registers. > + > +Current reading provided by this driver is reported as obtained from the > Current > +Sense register. The reported value assumes that a 1 mOhm sense resistor > is installed. > +If a different sense resistor is installed, change the module param value > sense_resistor > +in uOhm calculate the real current. > + > +in1_input VDIN voltage (mV) > + > +in2_input ADIN voltage (mV) > + > +curr1_input SENSE current (mA) > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 297bc9a..fc1f9a0 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -625,6 +625,17 @@ config SENSORS_LM93 > This driver can also be built as a module. If so, the module > will be called lm93. > > +config SENSORS_LTC4151 > + tristate "Linear Technology LTC4151" > + depends on I2C > + default n > + help > + If you say yes here you get support for Linear Technology LTC4151 > + High Voltage I2C Current and Voltage Monitor interface. > + > + This driver can also be built as a module. If so, the module will > + be called ltc4151. > + > config SENSORS_LTC4215 > tristate "Linear Technology LTC4215" > depends on I2C && EXPERIMENTAL > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index dde02d9..9cf9b12 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -79,6 +79,7 @@ obj-$(CONFIG_SENSORS_LM90) += lm90.o > obj-$(CONFIG_SENSORS_LM92) += lm92.o > obj-$(CONFIG_SENSORS_LM93) += lm93.o > obj-$(CONFIG_SENSORS_LM95241) += lm95241.o > +obj-$(CONFIG_SENSORS_LTC4151) += ltc4151.o > obj-$(CONFIG_SENSORS_LTC4215) += ltc4215.o > obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o > obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o > diff --git a/drivers/hwmon/ltc4151.c b/drivers/hwmon/ltc4151.c > new file mode 100644 > index 0000000..49cc695 > --- /dev/null > +++ b/drivers/hwmon/ltc4151.c > @@ -0,0 +1,270 @@ > +/* > + * Driver for Linear Technology LTC4151 High Voltage I2C Current > + * and Voltage Monitor > + * > + * Copyright (C) 2011 AppearTV AS > + * > + * Derived from: > + * > + * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot > + * Swap Controller > + * Copyright (C) 2010 Ericsson AB. > + * > + * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.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/kernel.h> > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/err.h> > +#include <linux/slab.h> > +#include <linux/i2c.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > + > +/* Default sense resistor, 1 mOhm (1000 uOhm) */ > +#define MAX4151_SENSE_RESISTOR 1000 > + > +/* module parameters */ > +static int sense_resistor = MAX4151_SENSE_RESISTOR; > +module_param(sense_resistor, uint, S_IWUSR | S_IRUGO); > +MODULE_PARM_DESC(sense_resistor, "Reference sense resistor in uOhm"); > + > +/* chip registers */ > +#define LTC4151_SENSE_H 0x00 > +#define LTC4151_SENSE_L 0x01 > +#define LTC4151_VIN_H 0x02 > +#define LTC4151_VIN_L 0x03 > +#define LTC4151_ADIN_H 0x04 > +#define LTC4151_ADIN_L 0x05 > + > +struct ltc4151_data { > + struct device *hwmon_dev; > + > + struct mutex update_lock; > + bool valid; > + unsigned long last_updated; /* in jiffies */ > + > + /* Registers */ > + u8 regs[6]; > +}; > + > +static struct ltc4151_data *ltc4151_update_device(struct device *dev) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct ltc4151_data *data = i2c_get_clientdata(client); > + struct ltc4151_data *ret = data; > + > + mutex_lock(&data->update_lock); > + > + /* The chip's A/D updates 8 times per second (Conversion Rate 6 - 9 Hz) */ > + if (time_after(jiffies, data->last_updated + HZ / 8) || !data->valid) { Note that you don't _have_ to match the chip update rate. Reason for choosing a lower update rate is often to be more efficient, especially if the values are not expected to change quickly. > + int i; > + > + dev_dbg(&client->dev, "Starting ltc4151 update\n"); > + > + /* Read all registers */ > + for (i = 0; i < ARRAY_SIZE(data->regs); i++) { > + int val; > + > + val = i2c_smbus_read_byte_data(client, i); > + if (unlikely(val < 0)) { > + dev_dbg(dev, > + "Failed to read ADC value: error %d\n", > + val); > + ret = ERR_PTR(val); > + goto abort; > + } > + data->regs[i] = val; > + } > + data->last_updated = jiffies; > + data->valid = 1; > + } > +abort: > + mutex_unlock(&data->update_lock); > + return ret; > +} > + > +/* Return the voltage from the given register in mV */ > +static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) > +{ > + u32 val; > + > + val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4); > + > + switch (reg) { > + case LTC4151_ADIN_H: > + /* 500uV resolution. Convert to mV. */ > + val = val * 500 / 1000; > + break; > + case LTC4151_SENSE_H: > + /* > + * 20uV resolution. Convert to current as measured with > + * an 1000 uOhm sense resistor, in mA. If a different sense > + * resistor is installed, calculate the actual current by > + * dividing the reported current by the sense_resistor value > + * in uOhm. Description is not really accurate anymore. It was intended for user space correction via sensors3.conf. That correction would still have to be based on mOhm, not uOhm (since the ABI reports a value in mA). As mentioned above, using a module parameter to specify the sense resistor value is not a good idea. > + */ > + val = val * 20 * 1000 / sense_resistor; > + break; > + case LTC4151_VIN_H: > + /* 25 mV per increment */ > + val = val * 25; > + break; > + default: > + /* If we get here, the developer messed up */ > + WARN_ON_ONCE(1); > + val = 0; > + break; > + } > + > + return val; > +} > + > +static ssize_t ltc4151_show_value(struct device *dev, > + struct device_attribute *da, char *buf) > +{ > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); > + struct ltc4151_data *data = ltc4151_update_device(dev); > + int value; > + > + if (IS_ERR(data)) > + return PTR_ERR(data); > + > + value = ltc4151_get_value(data, attr->index); > + return snprintf(buf, PAGE_SIZE, "%d\n", value); > +} > + > +/* These macros are used below in constructing device attribute objects > + * for use with sysfs_create_group() to make a sysfs device file > + * for each register. > + */ > + > +#define LTC4151_VALUE(name, ltc4151_cmd_idx) \ > + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ > + ltc4151_show_value, NULL, ltc4151_cmd_idx) > + > +/* > + * Input voltages. > + */ > +LTC4151_VALUE(in1_input, LTC4151_VIN_H); > +LTC4151_VALUE(in2_input, LTC4151_ADIN_H); > + > +/* Currents (via sense resistor) */ > +LTC4151_VALUE(curr1_input, LTC4151_SENSE_H); > + > +/* Finally, construct an array of pointers to members of the above objects, > + * as required for sysfs_create_group() > + */ > +static struct attribute *ltc4151_attributes[] = { > + &sensor_dev_attr_in1_input.dev_attr.attr, > + &sensor_dev_attr_in2_input.dev_attr.attr, > + > + &sensor_dev_attr_curr1_input.dev_attr.attr, > + > + NULL, > +}; > + > +static const struct attribute_group ltc4151_group = { > + .attrs = ltc4151_attributes, > +}; > + > +static int ltc4151_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct i2c_adapter *adapter = client->adapter; > + struct ltc4151_data *data; > + int ret; > + > + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) > + return -ENODEV; > + > + data = kzalloc(sizeof(*data), GFP_KERNEL); > + if (!data) { > + ret = -ENOMEM; > + goto out_kzalloc; > + } > + > + i2c_set_clientdata(client, data); > + mutex_init(&data->update_lock); > + > + /* Register sysfs hooks */ > + ret = sysfs_create_group(&client->dev.kobj, <c4151_group); > + if (ret) > + goto out_sysfs_create_group; > + > + data->hwmon_dev = hwmon_device_register(&client->dev); > + if (IS_ERR(data->hwmon_dev)) { > + ret = PTR_ERR(data->hwmon_dev); > + goto out_hwmon_device_register; > + } > + > + return 0; > + > +out_hwmon_device_register: > + sysfs_remove_group(&client->dev.kobj, <c4151_group); > +out_sysfs_create_group: > + kfree(data); > +out_kzalloc: > + return ret; > +} > + > +static int ltc4151_remove(struct i2c_client *client) > +{ > + struct ltc4151_data *data = i2c_get_clientdata(client); > + > + hwmon_device_unregister(data->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, <c4151_group); > + > + kfree(data); > + > + return 0; > +} > + > +static const struct i2c_device_id ltc4151_id[] = { > + { "ltc4151", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, ltc4151_id); > + > +/* This is the driver that will be inserted */ > +static struct i2c_driver ltc4151_driver = { > + .driver = { > + .name = "ltc4151", > + }, > + .probe = ltc4151_probe, > + .remove = ltc4151_remove, > + .id_table = ltc4151_id, > +}; > + > +static int __init ltc4151_init(void) > +{ > + return i2c_add_driver(<c4151_driver); > +} > + > +static void __exit ltc4151_exit(void) > +{ > + i2c_del_driver(<c4151_driver); > +} > + > +MODULE_AUTHOR("Per Dalen <per.dalen@xxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("LTC4151 driver"); > +MODULE_LICENSE("GPL"); > + > +module_init(ltc4151_init); > +module_exit(ltc4151_exit); > > > > _______________________________________________ > lm-sensors mailing list > lm-sensors@xxxxxxxxxxxxxx > http://lists.lm-sensors.org/mailman/listinfo/lm-sensors _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
