Commit 6e34b187 authored by Ira Snyder's avatar Ira Snyder Committed by Jean Delvare
Browse files

hwmon: Add LTC4245 driver



Add Linux support for the Linear Technology LTC4245 Multiple Supply Hot
Swap controller I2C monitoring interface.
Signed-off-by: default avatarIra W. Snyder <iws@ovro.caltech.edu>
Acked-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 2f650631
Kernel driver ltc4245
=====================
Supported chips:
* Linear Technology LTC4245
Prefix: 'ltc4245'
Addresses scanned: 0x20-0x3f
Datasheet:
http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
Author: Ira W. Snyder <iws@ovro.caltech.edu>
Description
-----------
The LTC4245 controller allows a board to be safely inserted and removed
from a live backplane in multiple supply systems such as CompactPCI and
PCI Express.
Usage Notes
-----------
This driver does not probe for LTC4245 devices, due to the fact that some
of the possible addresses are unfriendly to probing. You will need to use
the "force" parameter to tell the driver where to find the device.
Example: the following will load the driver for an LTC4245 at address 0x23
on I2C bus #1:
$ modprobe ltc4245 force=1,0x23
Sysfs entries
-------------
The LTC4245 has built-in limits for over and under current warnings. This
makes it very likely that the reference circuit will be used.
This driver uses the values in the datasheet to change the register values
into the values specified in the sysfs-interface document. The current readings
rely on the sense resistors listed in Table 2: "Sense Resistor Values".
in1_input 12v input voltage (mV)
in2_input 5v input voltage (mV)
in3_input 3v input voltage (mV)
in4_input Vee (-12v) input voltage (mV)
in1_min_alarm 12v input undervoltage alarm
in2_min_alarm 5v input undervoltage alarm
in3_min_alarm 3v input undervoltage alarm
in4_min_alarm Vee (-12v) input undervoltage alarm
curr1_input 12v current (mA)
curr2_input 5v current (mA)
curr3_input 3v current (mA)
curr4_input Vee (-12v) current (mA)
curr1_max_alarm 12v overcurrent alarm
curr2_max_alarm 5v overcurrent alarm
curr3_max_alarm 3v overcurrent alarm
curr4_max_alarm Vee (-12v) overcurrent alarm
in5_input 12v output voltage (mV)
in6_input 5v output voltage (mV)
in7_input 3v output voltage (mV)
in8_input Vee (-12v) output voltage (mV)
in5_min_alarm 12v output undervoltage alarm
in6_min_alarm 5v output undervoltage alarm
in7_min_alarm 3v output undervoltage alarm
in8_min_alarm Vee (-12v) output undervoltage alarm
in9_input GPIO #1 voltage data
in10_input GPIO #2 voltage data
in11_input GPIO #3 voltage data
power1_input 12v power usage (mW)
power2_input 5v power usage (mW)
power3_input 3v power usage (mW)
power4_input Vee (-12v) power usage (mW)
......@@ -549,6 +549,17 @@ config SENSORS_LM93
This driver can also be built as a module. If so, the module
will be called lm93.
config SENSORS_LTC4245
tristate "Linear Technology LTC4245"
depends on I2C && EXPERIMENTAL
default n
help
If you say yes here you get support for Linear Technology LTC4245
Multiple Supply Hot Swap Controller I2C interface.
This driver can also be built as a module. If so, the module will
be called ltc4245.
config SENSORS_MAX1111
tristate "Maxim MAX1111 Multichannel, Serial 8-bit ADC chip"
depends on SPI_MASTER
......
......@@ -62,6 +62,7 @@ obj-$(CONFIG_SENSORS_LM87) += lm87.o
obj-$(CONFIG_SENSORS_LM90) += lm90.o
obj-$(CONFIG_SENSORS_LM92) += lm92.o
obj-$(CONFIG_SENSORS_LM93) += lm93.o
obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o
obj-$(CONFIG_SENSORS_MAX1111) += max1111.o
obj-$(CONFIG_SENSORS_MAX1619) += max1619.o
obj-$(CONFIG_SENSORS_MAX6650) += max6650.o
......
/*
* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
*
* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
*
* 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; version 2 of the License.
*
* This driver is based on the ds1621 and ina209 drivers.
*
* Datasheet:
* http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
*/
#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>
/* Valid addresses are 0x20 - 0x3f
*
* For now, we do not probe, since some of these addresses
* are known to be unfriendly to probing */
static const unsigned short normal_i2c[] = { I2C_CLIENT_END };
/* Insmod parameters */
I2C_CLIENT_INSMOD_1(ltc4245);
/* Here are names of the chip's registers (a.k.a. commands) */
enum ltc4245_cmd {
LTC4245_STATUS = 0x00, /* readonly */
LTC4245_ALERT = 0x01,
LTC4245_CONTROL = 0x02,
LTC4245_ON = 0x03,
LTC4245_FAULT1 = 0x04,
LTC4245_FAULT2 = 0x05,
LTC4245_GPIO = 0x06,
LTC4245_ADCADR = 0x07,
LTC4245_12VIN = 0x10,
LTC4245_12VSENSE = 0x11,
LTC4245_12VOUT = 0x12,
LTC4245_5VIN = 0x13,
LTC4245_5VSENSE = 0x14,
LTC4245_5VOUT = 0x15,
LTC4245_3VIN = 0x16,
LTC4245_3VSENSE = 0x17,
LTC4245_3VOUT = 0x18,
LTC4245_VEEIN = 0x19,
LTC4245_VEESENSE = 0x1a,
LTC4245_VEEOUT = 0x1b,
LTC4245_GPIOADC1 = 0x1c,
LTC4245_GPIOADC2 = 0x1d,
LTC4245_GPIOADC3 = 0x1e,
};
struct ltc4245_data {
struct device *hwmon_dev;
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
/* Control registers */
u8 cregs[0x08];
/* Voltage registers */
u8 vregs[0x0f];
};
static struct ltc4245_data *ltc4245_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ltc4245_data *data = i2c_get_clientdata(client);
s32 val;
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
dev_dbg(&client->dev, "Starting ltc4245 update\n");
/* Read control registers -- 0x00 to 0x07 */
for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
val = i2c_smbus_read_byte_data(client, i);
if (unlikely(val < 0))
data->cregs[i] = 0;
else
data->cregs[i] = val;
}
/* Read voltage registers -- 0x10 to 0x1f */
for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
val = i2c_smbus_read_byte_data(client, i+0x10);
if (unlikely(val < 0))
data->vregs[i] = 0;
else
data->vregs[i] = val;
}
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
/* Return the voltage from the given register in millivolts */
static int ltc4245_get_voltage(struct device *dev, u8 reg)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
const u8 regval = data->vregs[reg - 0x10];
u32 voltage = 0;
switch (reg) {
case LTC4245_12VIN:
case LTC4245_12VOUT:
voltage = regval * 55;
break;
case LTC4245_5VIN:
case LTC4245_5VOUT:
voltage = regval * 22;
break;
case LTC4245_3VIN:
case LTC4245_3VOUT:
voltage = regval * 15;
break;
case LTC4245_VEEIN:
case LTC4245_VEEOUT:
voltage = regval * -55;
break;
case LTC4245_GPIOADC1:
case LTC4245_GPIOADC2:
case LTC4245_GPIOADC3:
voltage = regval * 10;
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
break;
}
return voltage;
}
/* Return the current in the given sense register in milliAmperes */
static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
const u8 regval = data->vregs[reg - 0x10];
unsigned int voltage;
unsigned int curr;
/* The strange looking conversions that follow are fixed-point
* math, since we cannot do floating point in the kernel.
*
* Step 1: convert sense register to microVolts
* Step 2: convert voltage to milliAmperes
*
* If you play around with the V=IR equation, you come up with
* the following: X uV / Y mOhm == Z mA
*
* With the resistors that are fractions of a milliOhm, we multiply
* the voltage and resistance by 10, to shift the decimal point.
* Now we can use the normal division operator again.
*/
switch (reg) {
case LTC4245_12VSENSE:
voltage = regval * 250; /* voltage in uV */
curr = voltage / 50; /* sense resistor 50 mOhm */
break;
case LTC4245_5VSENSE:
voltage = regval * 125; /* voltage in uV */
curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
break;
case LTC4245_3VSENSE:
voltage = regval * 125; /* voltage in uV */
curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
break;
case LTC4245_VEESENSE:
voltage = regval * 250; /* voltage in uV */
curr = voltage / 100; /* sense resistor 100 mOhm */
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
curr = 0;
break;
}
return curr;
}
static ssize_t ltc4245_show_voltage(struct device *dev,
struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
const int voltage = ltc4245_get_voltage(dev, attr->index);
return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
}
static ssize_t ltc4245_show_current(struct device *dev,
struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
const unsigned int curr = ltc4245_get_current(dev, attr->index);
return snprintf(buf, PAGE_SIZE, "%u\n", curr);
}
static ssize_t ltc4245_show_power(struct device *dev,
struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
const unsigned int curr = ltc4245_get_current(dev, attr->index);
const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
/* current in mA * voltage in mV == power in uW */
const unsigned int power = abs(output_voltage * curr);
return snprintf(buf, PAGE_SIZE, "%u\n", power);
}
static ssize_t ltc4245_show_alarm(struct device *dev,
struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
struct ltc4245_data *data = ltc4245_update_device(dev);
const u8 reg = data->cregs[attr->index];
const u32 mask = attr->nr;
return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 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 LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
#define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
ltc4245_show_current, NULL, ltc4245_cmd_idx)
#define LTC4245_POWER(name, ltc4245_cmd_idx) \
static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
ltc4245_show_power, NULL, ltc4245_cmd_idx)
#define LTC4245_ALARM(name, mask, reg) \
static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
ltc4245_show_alarm, NULL, (mask), reg)
/* Construct a sensor_device_attribute structure for each register */
/* Input voltages */
LTC4245_VOLTAGE(in1_input, LTC4245_12VIN);
LTC4245_VOLTAGE(in2_input, LTC4245_5VIN);
LTC4245_VOLTAGE(in3_input, LTC4245_3VIN);
LTC4245_VOLTAGE(in4_input, LTC4245_VEEIN);
/* Input undervoltage alarms */
LTC4245_ALARM(in1_min_alarm, (1 << 0), LTC4245_FAULT1);
LTC4245_ALARM(in2_min_alarm, (1 << 1), LTC4245_FAULT1);
LTC4245_ALARM(in3_min_alarm, (1 << 2), LTC4245_FAULT1);
LTC4245_ALARM(in4_min_alarm, (1 << 3), LTC4245_FAULT1);
/* Currents (via sense resistor) */
LTC4245_CURRENT(curr1_input, LTC4245_12VSENSE);
LTC4245_CURRENT(curr2_input, LTC4245_5VSENSE);
LTC4245_CURRENT(curr3_input, LTC4245_3VSENSE);
LTC4245_CURRENT(curr4_input, LTC4245_VEESENSE);
/* Overcurrent alarms */
LTC4245_ALARM(curr1_max_alarm, (1 << 4), LTC4245_FAULT1);
LTC4245_ALARM(curr2_max_alarm, (1 << 5), LTC4245_FAULT1);
LTC4245_ALARM(curr3_max_alarm, (1 << 6), LTC4245_FAULT1);
LTC4245_ALARM(curr4_max_alarm, (1 << 7), LTC4245_FAULT1);
/* Output voltages */
LTC4245_VOLTAGE(in5_input, LTC4245_12VOUT);
LTC4245_VOLTAGE(in6_input, LTC4245_5VOUT);
LTC4245_VOLTAGE(in7_input, LTC4245_3VOUT);
LTC4245_VOLTAGE(in8_input, LTC4245_VEEOUT);
/* Power Bad alarms */
LTC4245_ALARM(in5_min_alarm, (1 << 0), LTC4245_FAULT2);
LTC4245_ALARM(in6_min_alarm, (1 << 1), LTC4245_FAULT2);
LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2);
LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2);
/* GPIO voltages */
LTC4245_VOLTAGE(in9_input, LTC4245_GPIOADC1);
LTC4245_VOLTAGE(in10_input, LTC4245_GPIOADC2);
LTC4245_VOLTAGE(in11_input, LTC4245_GPIOADC3);
/* Power Consumption (virtual) */
LTC4245_POWER(power1_input, LTC4245_12VSENSE);
LTC4245_POWER(power2_input, LTC4245_5VSENSE);
LTC4245_POWER(power3_input, LTC4245_3VSENSE);
LTC4245_POWER(power4_input, LTC4245_VEESENSE);
/* Finally, construct an array of pointers to members of the above objects,
* as required for sysfs_create_group()
*/
static struct attribute *ltc4245_attributes[] = {
&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_in1_min_alarm.dev_attr.attr,
&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
&sensor_dev_attr_in4_min_alarm.dev_attr.attr,
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_curr2_input.dev_attr.attr,
&sensor_dev_attr_curr3_input.dev_attr.attr,
&sensor_dev_attr_curr4_input.dev_attr.attr,
&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
&sensor_dev_attr_curr4_max_alarm.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,
&sensor_dev_attr_in8_input.dev_attr.attr,
&sensor_dev_attr_in5_min_alarm.dev_attr.attr,
&sensor_dev_attr_in6_min_alarm.dev_attr.attr,
&sensor_dev_attr_in7_min_alarm.dev_attr.attr,
&sensor_dev_attr_in8_min_alarm.dev_attr.attr,
&sensor_dev_attr_in9_input.dev_attr.attr,
&sensor_dev_attr_in10_input.dev_attr.attr,
&sensor_dev_attr_in11_input.dev_attr.attr,
&sensor_dev_attr_power1_input.dev_attr.attr,
&sensor_dev_attr_power2_input.dev_attr.attr,
&sensor_dev_attr_power3_input.dev_attr.attr,
&sensor_dev_attr_power4_input.dev_attr.attr,
NULL,
};
static const struct attribute_group ltc4245_group = {
.attrs = ltc4245_attributes,
};
static int ltc4245_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ltc4245_data *data;
int ret;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data) {
ret = -ENOMEM;
goto out_kzalloc;
}
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
/* Initialize the LTC4245 chip */
/* TODO */
/* Register sysfs hooks */
ret = sysfs_create_group(&client->dev.kobj, &ltc4245_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, &ltc4245_group);
out_sysfs_create_group:
kfree(data);
out_kzalloc:
return ret;
}
static int ltc4245_remove(struct i2c_client *client)
{
struct ltc4245_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
kfree(data);
return 0;
}
/* Check that some bits in a control register appear at all possible
* locations without changing value
*
* @client: the i2c client to use
* @reg: the register to read
* @bits: the bits to check (0xff checks all bits,
* 0x03 checks only the last two bits)
*
* return -ERRNO if the register read failed
* return -ENODEV if the register value doesn't stay constant at all
* possible addresses
*
* return 0 for success
*/
static int ltc4245_check_control_reg(struct i2c_client *client, u8 reg, u8 bits)
{
int i;
s32 v, voff1, voff2;
/* Read register and check for error */
v = i2c_smbus_read_byte_data(client, reg);
if (v < 0)
return v;
v &= bits;
for (i = 0x00; i < 0xff; i += 0x20) {
voff1 = i2c_smbus_read_byte_data(client, reg + i);
if (voff1 < 0)
return voff1;
voff2 = i2c_smbus_read_byte_data(client, reg + i + 0x08);
if (voff2 < 0)
return voff2;
voff1 &= bits;
voff2 &= bits;
if (v != voff1 || v != voff2)
return -ENODEV;
}
return 0;
}
static int ltc4245_detect(struct i2c_client *client,
int kind,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
if (kind < 0) { /* probed detection - check the chip type */
s32 v; /* 8 bits from the chip, or -ERRNO */
/* Chip registers 0x00-0x07 are control registers
* Chip registers 0x10-0x1f are data registers
*
* Address bits b7-b5 are ignored. This makes the chip "repeat"
* in steps of 0x20. Any control registers should appear with
* the same values across all duplicated addresses.
*
* Register 0x02 bit b2 is reserved, expect 0
* Register 0x07 bits b7 to b4 are reserved, expect 0
*
* Registers 0x01, 0x02 are control registers and should not
* change on their own.
*
* Register 0x06 bits b6 and b7 are control bits, and should
* not change on their own.
*
* Register 0x07 bits b3 to b0 are control bits, and should
* not change on their own.
*/
/* read register 0x02 reserved bit, expect 0 */
v = i2c_smbus_read_byte_data(client, LTC4245_CONTROL);
if (v < 0 || (v & 0x04) != 0)
return -ENODEV;
/* read register 0x07 reserved bits, expect 0 */
v = i2c_smbus_read_byte_data(client, LTC4245_ADCADR);
if (v < 0 || (v & 0xf0) != 0)
return -ENODEV;
/* check that the alert register appears at all locations */
if (ltc4245_check_control_reg(client, LTC4245_ALERT, 0xff))
return -ENODEV;
/* check that the control register appears at all locations */
if (ltc4245_check_control_reg(client, LTC4245_CONTROL, 0xff))
return -ENODEV;
/* check that register 0x06 bits b6 and b7 stay constant */
if (ltc4245_check_control_reg(client, LTC4245_GPIO, 0xc0))
return -ENODEV;