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-rw-r--r--Documentation/hwmon/ltc424524
-rw-r--r--drivers/hwmon/ltc4245.c177
-rw-r--r--include/linux/i2c/ltc4245.h21
3 files changed, 211 insertions, 11 deletions
diff --git a/Documentation/hwmon/ltc4245 b/Documentation/hwmon/ltc4245
index 86b5880d850..b478b086496 100644
--- a/Documentation/hwmon/ltc4245
+++ b/Documentation/hwmon/ltc4245
@@ -72,9 +72,31 @@ 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 voltage data
+in9_input GPIO voltage data (see note 1)
+in10_input GPIO voltage data (see note 1)
+in11_input GPIO voltage data (see note 1)
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)
+
+
+Note 1
+------
+
+If you have NOT configured the driver to sample all GPIO pins as analog
+voltages, then the in10_input and in11_input sysfs attributes will not be
+created. The driver will sample the GPIO pin that is currently connected to the
+ADC as an analog voltage, and report the value in in9_input.
+
+If you have configured the driver to sample all GPIO pins as analog voltages,
+then they will be sampled in round-robin fashion. If userspace reads too
+slowly, -EAGAIN will be returned when you read the sysfs attribute containing
+the sensor reading.
+
+The LTC4245 chip can be configured to sample all GPIO pins with two methods:
+1) platform data -- see include/linux/i2c/ltc4245.h
+2) OF device tree -- add the "ltc4245,use-extra-gpios" property to each chip
+
+The default mode of operation is to sample a single GPIO pin.
diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
index 21d201befc2..65930832930 100644
--- a/drivers/hwmon/ltc4245.c
+++ b/drivers/hwmon/ltc4245.c
@@ -21,6 +21,7 @@
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
+#include <linux/i2c/ltc4245.h>
/* Here are names of the chip's registers (a.k.a. commands) */
enum ltc4245_cmd {
@@ -60,8 +61,72 @@ struct ltc4245_data {
/* Voltage registers */
u8 vregs[0x0d];
+
+ /* GPIO ADC registers */
+ bool use_extra_gpios;
+ int gpios[3];
};
+/*
+ * Update the readings from the GPIO pins. If the driver has been configured to
+ * sample all GPIO's as analog voltages, a round-robin sampling method is used.
+ * Otherwise, only the configured GPIO pin is sampled.
+ *
+ * LOCKING: must hold data->update_lock
+ */
+static void ltc4245_update_gpios(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct ltc4245_data *data = i2c_get_clientdata(client);
+ u8 gpio_curr, gpio_next, gpio_reg;
+ int i;
+
+ /* no extra gpio support, we're basically done */
+ if (!data->use_extra_gpios) {
+ data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
+ return;
+ }
+
+ /*
+ * If the last reading was too long ago, then we mark all old GPIO
+ * readings as stale by setting them to -EAGAIN
+ */
+ if (time_after(jiffies, data->last_updated + 5 * HZ)) {
+ dev_dbg(&client->dev, "Marking GPIOs invalid\n");
+ for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
+ data->gpios[i] = -EAGAIN;
+ }
+
+ /*
+ * Get the current GPIO pin
+ *
+ * The datasheet calls these GPIO[1-3], but we'll calculate the zero
+ * based array index instead, and call them GPIO[0-2]. This is much
+ * easier to think about.
+ */
+ gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
+ if (gpio_curr > 0)
+ gpio_curr -= 1;
+
+ /* Read the GPIO voltage from the GPIOADC register */
+ data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
+
+ /* Find the next GPIO pin to read */
+ gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
+
+ /*
+ * Calculate the correct setting for the GPIO register so it will
+ * sample the next GPIO pin
+ */
+ gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
+
+ /* Update the GPIO register */
+ i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
+
+ /* Update saved data */
+ data->cregs[LTC4245_GPIO] = gpio_reg;
+}
+
static struct ltc4245_data *ltc4245_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
@@ -93,6 +158,9 @@ static struct ltc4245_data *ltc4245_update_device(struct device *dev)
data->vregs[i] = val;
}
+ /* Update GPIO readings */
+ ltc4245_update_gpios(dev);
+
data->last_updated = jiffies;
data->valid = 1;
}
@@ -233,6 +301,22 @@ static ssize_t ltc4245_show_alarm(struct device *dev,
return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
}
+static ssize_t ltc4245_show_gpio(struct device *dev,
+ struct device_attribute *da,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct ltc4245_data *data = ltc4245_update_device(dev);
+ int val = data->gpios[attr->index];
+
+ /* handle stale GPIO's */
+ if (val < 0)
+ return val;
+
+ /* Convert to millivolts and print */
+ return snprintf(buf, PAGE_SIZE, "%u\n", val * 10);
+}
+
/* 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.
@@ -254,6 +338,10 @@ static ssize_t ltc4245_show_alarm(struct device *dev,
static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
ltc4245_show_alarm, NULL, (mask), reg)
+#define LTC4245_GPIO_VOLTAGE(name, gpio_num) \
+ static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
+ ltc4245_show_gpio, NULL, gpio_num)
+
/* Construct a sensor_device_attribute structure for each register */
/* Input voltages */
@@ -293,7 +381,9 @@ 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_GPIOADC);
+LTC4245_GPIO_VOLTAGE(in9_input, 0);
+LTC4245_GPIO_VOLTAGE(in10_input, 1);
+LTC4245_GPIO_VOLTAGE(in11_input, 2);
/* Power Consumption (virtual) */
LTC4245_POWER(power1_input, LTC4245_12VSENSE);
@@ -304,7 +394,7 @@ 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[] = {
+static struct attribute *ltc4245_std_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,
@@ -345,10 +435,77 @@ static struct attribute *ltc4245_attributes[] = {
NULL,
};
-static const struct attribute_group ltc4245_group = {
- .attrs = ltc4245_attributes,
+static struct attribute *ltc4245_gpio_attributes[] = {
+ &sensor_dev_attr_in10_input.dev_attr.attr,
+ &sensor_dev_attr_in11_input.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group ltc4245_std_group = {
+ .attrs = ltc4245_std_attributes,
+};
+
+static const struct attribute_group ltc4245_gpio_group = {
+ .attrs = ltc4245_gpio_attributes,
};
+static int ltc4245_sysfs_create_groups(struct i2c_client *client)
+{
+ struct ltc4245_data *data = i2c_get_clientdata(client);
+ struct device *dev = &client->dev;
+ int ret;
+
+ /* register the standard sysfs attributes */
+ ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
+ if (ret) {
+ dev_err(dev, "unable to register standard attributes\n");
+ return ret;
+ }
+
+ /* if we're using the extra gpio support, register it's attributes */
+ if (data->use_extra_gpios) {
+ ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
+ if (ret) {
+ dev_err(dev, "unable to register gpio attributes\n");
+ sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
+{
+ struct ltc4245_data *data = i2c_get_clientdata(client);
+ struct device *dev = &client->dev;
+
+ if (data->use_extra_gpios)
+ sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
+
+ sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
+}
+
+static bool ltc4245_use_extra_gpios(struct i2c_client *client)
+{
+ struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
+#ifdef CONFIG_OF
+ struct device_node *np = client->dev.of_node;
+#endif
+
+ /* prefer platform data */
+ if (pdata)
+ return pdata->use_extra_gpios;
+
+#ifdef CONFIG_OF
+ /* fallback on OF */
+ if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
+ return true;
+#endif
+
+ return false;
+}
+
static int ltc4245_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -367,15 +524,16 @@ static int ltc4245_probe(struct i2c_client *client,
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
+ data->use_extra_gpios = ltc4245_use_extra_gpios(client);
/* Initialize the LTC4245 chip */
i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
/* Register sysfs hooks */
- ret = sysfs_create_group(&client->dev.kobj, &ltc4245_group);
+ ret = ltc4245_sysfs_create_groups(client);
if (ret)
- goto out_sysfs_create_group;
+ goto out_sysfs_create_groups;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
@@ -386,8 +544,8 @@ static int ltc4245_probe(struct i2c_client *client,
return 0;
out_hwmon_device_register:
- sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
-out_sysfs_create_group:
+ ltc4245_sysfs_remove_groups(client);
+out_sysfs_create_groups:
kfree(data);
out_kzalloc:
return ret;
@@ -398,8 +556,7 @@ 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);
-
+ ltc4245_sysfs_remove_groups(client);
kfree(data);
return 0;
diff --git a/include/linux/i2c/ltc4245.h b/include/linux/i2c/ltc4245.h
new file mode 100644
index 00000000000..56bda4be001
--- /dev/null
+++ b/include/linux/i2c/ltc4245.h
@@ -0,0 +1,21 @@
+/*
+ * Platform Data for LTC4245 hardware monitor chip
+ *
+ * Copyright (c) 2010 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; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#ifndef LINUX_LTC4245_H
+#define LINUX_LTC4245_H
+
+#include <linux/types.h>
+
+struct ltc4245_platform_data {
+ bool use_extra_gpios;
+};
+
+#endif /* LINUX_LTC4245_H */