---

yaml
---
r: 209419
b: refs/heads/master
c: 5950ec8
h: refs/heads/master
i:
  209417: 63d16ad
  209415: 61a02fe
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b9783dcebe952bf73449fe70a19ee4814adc81a0
+refs/heads/master: 5950ec8d3e47a08ec0b678a0e0ba5d1b9b62dd8e

trunk/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.

trunk/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;

trunk/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 */