Initial import

1 files changed, 533 insertions, 0 deletions

diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
new file mode 100644
index 000000000..681b5b7b3
--- /dev/null
+++ b/drivers/hwmon/ltc4245.c
@@ -0,0 +1,533 @@
+/*
+ * 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>
+#include <linux/jiffies.h>
+#include <linux/i2c/ltc4245.h>
+
+/* 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_GPIOADC			= 0x1c,
+};
+
+struct ltc4245_data {
+	struct i2c_client *client;
+
+	const struct attribute_group *groups[3];
+
+	struct mutex update_lock;
+	bool valid;
+	unsigned long last_updated; /* in jiffies */
+
+	/* Control registers */
+	u8 cregs[0x08];
+
+	/* 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 ltc4245_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->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)) {
+		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 ltc4245_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	s32 val;
+	int i;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+
+		/* 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 0x1c */
+		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;
+		}
+
+		/* Update GPIO readings */
+		ltc4245_update_gpios(dev);
+
+		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_GPIOADC:
+		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);
+}
+
+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);
+}
+
+/* Construct a sensor_device_attribute structure for each register */
+
+/* Input voltages */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_12VIN);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_5VIN);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_3VIN);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_VEEIN);
+
+/* Input undervoltage alarms */
+static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 0, LTC4245_FAULT1);
+static SENSOR_DEVICE_ATTR_2(in2_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 1, LTC4245_FAULT1);
+static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 2, LTC4245_FAULT1);
+static SENSOR_DEVICE_ATTR_2(in4_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 3, LTC4245_FAULT1);
+
+/* Currents (via sense resistor) */
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4245_show_current, NULL,
+			  LTC4245_12VSENSE);
+static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4245_show_current, NULL,
+			  LTC4245_5VSENSE);
+static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO, ltc4245_show_current, NULL,
+			  LTC4245_3VSENSE);
+static SENSOR_DEVICE_ATTR(curr4_input, S_IRUGO, ltc4245_show_current, NULL,
+			  LTC4245_VEESENSE);
+
+/* Overcurrent alarms */
+static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 4, LTC4245_FAULT1);
+static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 5, LTC4245_FAULT1);
+static SENSOR_DEVICE_ATTR_2(curr3_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 6, LTC4245_FAULT1);
+static SENSOR_DEVICE_ATTR_2(curr4_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 7, LTC4245_FAULT1);
+
+/* Output voltages */
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_12VOUT);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_5VOUT);
+static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_3VOUT);
+static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, ltc4245_show_voltage, NULL,
+			  LTC4245_VEEOUT);
+
+/* Power Bad alarms */
+static SENSOR_DEVICE_ATTR_2(in5_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 0, LTC4245_FAULT2);
+static SENSOR_DEVICE_ATTR_2(in6_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 1, LTC4245_FAULT2);
+static SENSOR_DEVICE_ATTR_2(in7_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 2, LTC4245_FAULT2);
+static SENSOR_DEVICE_ATTR_2(in8_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
+			    1 << 3, LTC4245_FAULT2);
+
+/* GPIO voltages */
+static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, ltc4245_show_gpio, NULL, 0);
+static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, ltc4245_show_gpio, NULL, 1);
+static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, ltc4245_show_gpio, NULL, 2);
+
+/* Power Consumption (virtual) */
+static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc4245_show_power, NULL,
+			  LTC4245_12VSENSE);
+static SENSOR_DEVICE_ATTR(power2_input, S_IRUGO, ltc4245_show_power, NULL,
+			  LTC4245_5VSENSE);
+static SENSOR_DEVICE_ATTR(power3_input, S_IRUGO, ltc4245_show_power, NULL,
+			  LTC4245_3VSENSE);
+static SENSOR_DEVICE_ATTR(power4_input, S_IRUGO, ltc4245_show_power, NULL,
+			  LTC4245_VEESENSE);
+
+/*
+ * Finally, construct an array of pointers to members of the above objects,
+ * as required for sysfs_create_group()
+ */
+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,
+	&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_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 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 void ltc4245_sysfs_add_groups(struct ltc4245_data *data)
+{
+	/* standard sysfs attributes */
+	data->groups[0] = &ltc4245_std_group;
+
+	/* if we're using the extra gpio support, register it's attributes */
+	if (data->use_extra_gpios)
+		data->groups[1] = &ltc4245_gpio_group;
+}
+
+static bool ltc4245_use_extra_gpios(struct i2c_client *client)
+{
+	struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct device_node *np = client->dev.of_node;
+
+	/* prefer platform data */
+	if (pdata)
+		return pdata->use_extra_gpios;
+
+	/* fallback on OF */
+	if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
+		return true;
+
+	return false;
+}
+
+static int ltc4245_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct ltc4245_data *data;
+	struct device *hwmon_dev;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	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);
+
+	/* Add sysfs hooks */
+	ltc4245_sysfs_add_groups(data);
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
+							   client->name, data,
+							   data->groups);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ltc4245_id[] = {
+	{ "ltc4245", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4245_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ltc4245_driver = {
+	.driver = {
+		.name	= "ltc4245",
+	},
+	.probe		= ltc4245_probe,
+	.id_table	= ltc4245_id,
+};
+
+module_i2c_driver(ltc4245_driver);
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("LTC4245 driver");
+MODULE_LICENSE("GPL");