On Fri, 17 Sep 2010 21:32:41 -0700, Guenter Roeck wrote: > This driver adds support for Linear Technology LTC4261 I2C Negative > Voltage Hot Swap Controller. > > Signed-off-by: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> Ira, you are familiar with Linear Technology hardware monitoring devices, would you mind reviewing this driver? Thanks. > --- > v2 changes: > - Report voltage alarms on both voltage sensor channels > - Merged patchset into a single patch > - Updated MAINTAINERS > - Replaced curr1_max_alarm with curr1_alarm > - Fixed code to clear faults > > Documentation/hwmon/ltc4261 | 63 +++++++++ > MAINTAINERS | 7 + > drivers/hwmon/Kconfig | 11 ++ > drivers/hwmon/Makefile | 1 + > drivers/hwmon/ltc4261.c | 315 +++++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 397 insertions(+), 0 deletions(-) > create mode 100644 Documentation/hwmon/ltc4261 > create mode 100644 drivers/hwmon/ltc4261.c > > diff --git a/Documentation/hwmon/ltc4261 b/Documentation/hwmon/ltc4261 > new file mode 100644 > index 0000000..01d85b5 > --- /dev/null > +++ b/Documentation/hwmon/ltc4261 > @@ -0,0 +1,63 @@ > +Kernel driver ltc4261 > +===================== > + > +Supported chips: > + * Linear Technology LTC4261 > + Prefix: 'ltc4261' > + Addresses scanned: - > + Datasheet: > + http://cds.linear.com/docs/Datasheet/42612fb.pdf > + > +Author: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> > + > + > +Description > +----------- > + > +The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board > +to be safely inserted and removed from a live backplane. > + > + > +Usage Notes > +----------- > + > +This driver does not probe for LTC4261 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 0x10 > +on I2C bus #1: > +$ modprobe ltc4261 > +$ echo ltc4261 0x10 > /sys/bus/i2c/devices/i2c-1/new_device > + > + > +Sysfs entries > +------------- > + > +Voltage readings provided by this driver are reported as obtained from the ADC > +registers. If a set of voltage divider resistors is installed, calculate the > +real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the > +value of the divider resistor against the measured voltage and R2 is the value > +of the divider resistor against Ground. > + > +Current reading provided by this driver is reported as obtained from the ADC > +Current Sense register. The reported value assumes that a 1 mOhm sense resistor > +is installed. If a different sense resistor is installed, calculate the real > +current by dividing the reported value by the sense resistor value in mOhm. > + > +The chip has two voltage sensors, but only one set of voltage alarm status bits. > +In many many designs, those alarms are associated with the ADIN2 sensor, due to > +the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available > +on all chip variants. To ensure that the alarm condition is reported to the user, > +report it with both voltage sensors. > + > +in1_input ADIN2 voltage (mV) > +in1_min_alarm ADIN/ADIN2 Undervoltage alarm > +in1_max_alarm ADIN/ADIN2 Overvoltage alarm > + > +in2_input ADIN voltage (mV) > +in2_min_alarm ADIN/ADIN2 Undervoltage alarm > +in2_max_alarm ADIN/ADIN2 Overvoltage alarm > + > +curr1_input SENSE current (mA) > +curr1_alarm SENSE overcurrent alarm > diff --git a/MAINTAINERS b/MAINTAINERS > index e7c528f..f585a98 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -3666,6 +3666,13 @@ L: linux-scsi@xxxxxxxxxxxxxxx > S: Maintained > F: drivers/scsi/sym53c8xx_2/ > > +LTC4261 HARDWARE MONITOR DRIVER > +M: Guenter Roeck <linux@xxxxxxxxxxxx> > +L: lm-sensors@xxxxxxxxxxxxxx > +S: Maintained > +F: Documentation/hwmon/ltc4261 > +F: drivers/hwmon/ltc4261.c > + > LTP (Linux Test Project) > M: Rishikesh K Rajak <risrajak@xxxxxxxxxxxxxxxxxx> > M: Garrett Cooper <yanegomi@xxxxxxxxx> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 4d4d09b..71434bd 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -654,6 +654,17 @@ config SENSORS_LTC4245 > This driver can also be built as a module. If so, the module will > be called ltc4245. > > +config SENSORS_LTC4261 > + tristate "Linear Technology LTC4261" > + depends on I2C && EXPERIMENTAL > + default n > + help > + If you say yes here you get support for Linear Technology LTC4261 > + Negative Voltage Hot Swap Controller I2C interface. > + > + This driver can also be built as a module. If so, the module will > + be called ltc4261. > + > config SENSORS_LM95241 > tristate "National Semiconductor LM95241 sensor chip" > depends on I2C > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index e3c2484..2d445ad 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -80,6 +80,7 @@ obj-$(CONFIG_SENSORS_LM93) += lm93.o > obj-$(CONFIG_SENSORS_LM95241) += lm95241.o > obj-$(CONFIG_SENSORS_LTC4215) += ltc4215.o > obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o > +obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o > obj-$(CONFIG_SENSORS_MAX1111) += max1111.o > obj-$(CONFIG_SENSORS_MAX1619) += max1619.o > obj-$(CONFIG_SENSORS_MAX6650) += max6650.o > diff --git a/drivers/hwmon/ltc4261.c b/drivers/hwmon/ltc4261.c > new file mode 100644 > index 0000000..1a8bbf0 > --- /dev/null > +++ b/drivers/hwmon/ltc4261.c > @@ -0,0 +1,315 @@ > +/* > + * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller > + * > + * Copyright (C) 2010 Ericsson AB. > + * > + * Derived from: > + * > + * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller > + * Copyright (C) 2008 Ira W. Snyder <iws@xxxxxxxxxxxxxxxx> > + * > + * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.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> > + > +/* chip registers */ > +#define LTC4261_STATUS 0x00 /* readonly */ > +#define LTC4261_FAULT 0x01 > +#define LTC4261_ALERT 0x02 > +#define LTC4261_CONTROL 0x03 > +#define LTC4261_SENSE_H 0x04 > +#define LTC4261_SENSE_L 0x05 > +#define LTC4261_ADIN2_H 0x06 > +#define LTC4261_ADIN2_L 0x07 > +#define LTC4261_ADIN_H 0x08 > +#define LTC4261_ADIN_L 0x09 > + > +/* > + * Fault register bits > + */ > +#define FAULT_OV (1<<0) > +#define FAULT_UV (1<<1) > +#define FAULT_OC (1<<2) > + > +struct ltc4261_data { > + struct device *hwmon_dev; > + > + struct mutex update_lock; > + bool valid; > + unsigned long last_updated; /* in jiffies */ > + > + /* Registers */ > + u8 regs[10]; > +}; > + > +static struct ltc4261_data *ltc4261_update_device(struct device *dev) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct ltc4261_data *data = i2c_get_clientdata(client); > + struct ltc4261_data *ret = data; > + > + mutex_lock(&data->update_lock); > + > + if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { > + int i; > + > + /* Read registers -- 0x00 to 0x09 */ > + 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", > + 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 or mA */ > +static int ltc4261_get_value(struct ltc4261_data *data, u8 reg) > +{ > + u32 val; > + > + val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6); > + > + switch (reg) { > + case LTC4261_ADIN_H: > + case LTC4261_ADIN2_H: > + /* 2.5mV resolution. Convert to mV. */ > + val = val * 25 / 10; > + break; > + case LTC4261_SENSE_H: > + /* > + * 62.5uV resolution. Convert to current as measured with > + * an 1 mOhm 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 mOhm. > + */ > + val = val * 625 / 10; > + break; > + default: > + /* If we get here, the developer messed up */ > + WARN_ON_ONCE(1); > + val = 0; > + break; > + } > + > + return val; > +} > + > +static ssize_t ltc4261_show_value(struct device *dev, > + struct device_attribute *da, char *buf) > +{ > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); > + struct ltc4261_data *data = ltc4261_update_device(dev); > + int value; > + > + if (IS_ERR(data)) > + return PTR_ERR(data); > + > + value = ltc4261_get_value(data, attr->index); > + return snprintf(buf, PAGE_SIZE, "%d\n", value); > +} > + > +static ssize_t ltc4261_show_bool(struct device *dev, > + struct device_attribute *da, char *buf) > +{ > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); > + struct i2c_client *client = to_i2c_client(dev); > + struct ltc4261_data *data = ltc4261_update_device(dev); > + u8 fault; > + > + if (IS_ERR(data)) > + return PTR_ERR(data); > + > + fault = data->regs[LTC4261_FAULT] & attr->index; > + if (fault) /* Clear reported faults in chip register */ > + i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault); > + > + return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0); > +} > + > +/* > + * 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 LTC4261_VALUE(name, ltc4261_cmd_idx) \ > + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ > + ltc4261_show_value, NULL, ltc4261_cmd_idx) > + > +#define LTC4261_BOOL(name, mask) \ > + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ > + ltc4261_show_bool, NULL, (mask)) > + > +/* > + * Input voltages. > + */ > +LTC4261_VALUE(in1_input, LTC4261_ADIN_H); > +LTC4261_VALUE(in2_input, LTC4261_ADIN2_H); > + > +/* > + * Voltage alarms. The chip has only one set of voltage alarm status bits, > + * triggered by input voltage alarms. In many designs, those alarms are > + * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin > + * to the OV pin. ADIN2 is, however, not available on all chip variants. > + * To ensure that the alarm condition is reported to the user, report it > + * with both voltage sensors. > + */ > +LTC4261_BOOL(in1_min_alarm, FAULT_UV); > +LTC4261_BOOL(in1_max_alarm, FAULT_OV); > +LTC4261_BOOL(in2_min_alarm, FAULT_UV); > +LTC4261_BOOL(in2_max_alarm, FAULT_OV); > + > +/* Currents (via sense resistor) */ > +LTC4261_VALUE(curr1_input, LTC4261_SENSE_H); > + > +/* Overcurrent alarm */ > +LTC4261_BOOL(curr1_max_alarm, FAULT_OC); > + > +static struct attribute *ltc4261_attributes[] = { > + &sensor_dev_attr_in1_input.dev_attr.attr, > + &sensor_dev_attr_in1_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in1_max_alarm.dev_attr.attr, > + &sensor_dev_attr_in2_input.dev_attr.attr, > + &sensor_dev_attr_in2_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in2_max_alarm.dev_attr.attr, > + > + &sensor_dev_attr_curr1_input.dev_attr.attr, > + &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, > + > + NULL, > +}; > + > +static const struct attribute_group ltc4261_group = { > + .attrs = ltc4261_attributes, > +}; > + > +static int ltc4261_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct i2c_adapter *adapter = client->adapter; > + struct ltc4261_data *data; > + int ret; > + > + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) > + return -ENODEV; > + > + if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) { > + dev_err(&client->dev, "Failed to read register %d:%02x:%02x\n", > + adapter->id, client->addr, LTC4261_STATUS); > + 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); > + > + /* Clear faults */ > + i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00); > + > + /* Register sysfs hooks */ > + ret = sysfs_create_group(&client->dev.kobj, <c4261_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, <c4261_group); > +out_sysfs_create_group: > + kfree(data); > +out_kzalloc: > + return ret; > +} > + > +static int ltc4261_remove(struct i2c_client *client) > +{ > + struct ltc4261_data *data = i2c_get_clientdata(client); > + > + hwmon_device_unregister(data->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, <c4261_group); > + > + kfree(data); > + > + return 0; > +} > + > +static const struct i2c_device_id ltc4261_id[] = { > + {"ltc4261", 0}, > + {} > +}; > + > +MODULE_DEVICE_TABLE(i2c, ltc4261_id); > + > +/* This is the driver that will be inserted */ > +static struct i2c_driver ltc4261_driver = { > + .driver = { > + .name = "ltc4261", > + }, > + .probe = ltc4261_probe, > + .remove = ltc4261_remove, > + .id_table = ltc4261_id, > +}; > + > +static int __init ltc4261_init(void) > +{ > + return i2c_add_driver(<c4261_driver); > +} > + > +static void __exit ltc4261_exit(void) > +{ > + i2c_del_driver(<c4261_driver); > +} > + > +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("LTC4261 driver"); > +MODULE_LICENSE("GPL"); > + > +module_init(ltc4261_init); > +module_exit(ltc4261_exit); -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
