[net-next-2.6.git] / drivers / hwmon / ltc4245.c

/*
 * 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/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 device *hwmon_dev;

	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 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);
	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 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);
}

/* 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)

#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 */
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_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);
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_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 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)
{
	struct i2c_adapter *adapter = client->adapter;
	struct ltc4245_data *data;
	int ret;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		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);
	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 = ltc4245_sysfs_create_groups(client);
	if (ret)
		goto out_sysfs_create_groups;

	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:
	ltc4245_sysfs_remove_groups(client);
out_sysfs_create_groups:
	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);
	ltc4245_sysfs_remove_groups(client);
	kfree(data);

	return 0;
}

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,
	.remove		= ltc4245_remove,
	.id_table	= ltc4245_id,
};

static int __init ltc4245_init(void)
{
	return i2c_add_driver(&ltc4245_driver);
}

static void __exit ltc4245_exit(void)
{
	i2c_del_driver(&ltc4245_driver);
}

MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("LTC4245 driver");
MODULE_LICENSE("GPL");

module_init(ltc4245_init);
module_exit(ltc4245_exit);
Commit	Line	Data
6e34b187 IS	1	/*
	2	* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
	3	*
	4	* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; version 2 of the License.
	9	*
	10	* This driver is based on the ds1621 and ina209 drivers.
	11	*
	12	* Datasheet:
	13	* http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
	14	*/
	15
	16	#include <linux/kernel.h>
	17	#include <linux/module.h>
	18	#include <linux/init.h>
	19	#include <linux/err.h>
	20	#include <linux/slab.h>
	21	#include <linux/i2c.h>
	22	#include <linux/hwmon.h>
	23	#include <linux/hwmon-sysfs.h>
5950ec8d	24	#include <linux/i2c/ltc4245.h>
6e34b187	25
6e34b187 IS	26	/* Here are names of the chip's registers (a.k.a. commands) */
	27	enum ltc4245_cmd {
	28	LTC4245_STATUS = 0x00, /* readonly */
	29	LTC4245_ALERT = 0x01,
	30	LTC4245_CONTROL = 0x02,
	31	LTC4245_ON = 0x03,
	32	LTC4245_FAULT1 = 0x04,
	33	LTC4245_FAULT2 = 0x05,
	34	LTC4245_GPIO = 0x06,
	35	LTC4245_ADCADR = 0x07,
	36
	37	LTC4245_12VIN = 0x10,
	38	LTC4245_12VSENSE = 0x11,
	39	LTC4245_12VOUT = 0x12,
	40	LTC4245_5VIN = 0x13,
	41	LTC4245_5VSENSE = 0x14,
	42	LTC4245_5VOUT = 0x15,
	43	LTC4245_3VIN = 0x16,
	44	LTC4245_3VSENSE = 0x17,
	45	LTC4245_3VOUT = 0x18,
	46	LTC4245_VEEIN = 0x19,
	47	LTC4245_VEESENSE = 0x1a,
	48	LTC4245_VEEOUT = 0x1b,
df16dd53	49	LTC4245_GPIOADC = 0x1c,
6e34b187 IS	50	};
	51
	52	struct ltc4245_data {
	53	struct device *hwmon_dev;
	54
	55	struct mutex update_lock;
	56	bool valid;
	57	unsigned long last_updated; /* in jiffies */
	58
	59	/* Control registers */
	60	u8 cregs[0x08];
	61
	62	/* Voltage registers */
df16dd53	63	u8 vregs[0x0d];
5950ec8d IS	64
	65	/* GPIO ADC registers */
	66	bool use_extra_gpios;
	67	int gpios[3];
6e34b187 IS	68	};
6e34b187 IS	69
5950ec8d IS	70	/*
	71	* Update the readings from the GPIO pins. If the driver has been configured to
	72	* sample all GPIO's as analog voltages, a round-robin sampling method is used.
	73	* Otherwise, only the configured GPIO pin is sampled.
	74	*
	75	* LOCKING: must hold data->update_lock
	76	*/
	77	static void ltc4245_update_gpios(struct device *dev)
	78	{
	79	struct i2c_client *client = to_i2c_client(dev);
	80	struct ltc4245_data *data = i2c_get_clientdata(client);
	81	u8 gpio_curr, gpio_next, gpio_reg;
	82	int i;
	83
	84	/* no extra gpio support, we're basically done */
	85	if (!data->use_extra_gpios) {
	86	data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
	87	return;
	88	}
	89
	90	/*
	91	* If the last reading was too long ago, then we mark all old GPIO
	92	* readings as stale by setting them to -EAGAIN
	93	*/
	94	if (time_after(jiffies, data->last_updated + 5 * HZ)) {
	95	dev_dbg(&client->dev, "Marking GPIOs invalid\n");
	96	for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
	97	data->gpios[i] = -EAGAIN;
	98	}
	99
	100	/*
	101	* Get the current GPIO pin
	102	*
	103	* The datasheet calls these GPIO[1-3], but we'll calculate the zero
	104	* based array index instead, and call them GPIO[0-2]. This is much
	105	* easier to think about.
	106	*/
	107	gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
	108	if (gpio_curr > 0)
	109	gpio_curr -= 1;
	110
	111	/* Read the GPIO voltage from the GPIOADC register */
	112	data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
	113
	114	/* Find the next GPIO pin to read */
	115	gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
	116
	117	/*
	118	* Calculate the correct setting for the GPIO register so it will
	119	* sample the next GPIO pin
	120	*/
	121	gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) \| ((gpio_next + 1) << 6);
	122
	123	/* Update the GPIO register */
	124	i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
	125
	126	/* Update saved data */
	127	data->cregs[LTC4245_GPIO] = gpio_reg;
	128	}
	129
6e34b187 IS	130	static struct ltc4245_data ltc4245_update_device(struct device dev)
	131	{
	132	struct i2c_client *client = to_i2c_client(dev);
	133	struct ltc4245_data *data = i2c_get_clientdata(client);
	134	s32 val;
	135	int i;
	136
	137	mutex_lock(&data->update_lock);
	138
	139	if (time_after(jiffies, data->last_updated + HZ) \|\| !data->valid) {
	140
	141	dev_dbg(&client->dev, "Starting ltc4245 update\n");
	142
	143	/* Read control registers -- 0x00 to 0x07 */
	144	for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
	145	val = i2c_smbus_read_byte_data(client, i);
	146	if (unlikely(val < 0))
	147	data->cregs[i] = 0;
	148	else
	149	data->cregs[i] = val;
	150	}
	151
df16dd53	152	/* Read voltage registers -- 0x10 to 0x1c */
6e34b187 IS	153	for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
	154	val = i2c_smbus_read_byte_data(client, i+0x10);
	155	if (unlikely(val < 0))
	156	data->vregs[i] = 0;
	157	else
	158	data->vregs[i] = val;
	159	}
	160
5950ec8d IS	161	/* Update GPIO readings */
	162	ltc4245_update_gpios(dev);
	163
6e34b187 IS	164	data->last_updated = jiffies;
	165	data->valid = 1;
	166	}
	167
	168	mutex_unlock(&data->update_lock);
	169
	170	return data;
	171	}
	172
	173	/* Return the voltage from the given register in millivolts */
	174	static int ltc4245_get_voltage(struct device *dev, u8 reg)
	175	{
	176	struct ltc4245_data *data = ltc4245_update_device(dev);
	177	const u8 regval = data->vregs[reg - 0x10];
	178	u32 voltage = 0;
	179
	180	switch (reg) {
	181	case LTC4245_12VIN:
	182	case LTC4245_12VOUT:
	183	voltage = regval * 55;
	184	break;
	185	case LTC4245_5VIN:
	186	case LTC4245_5VOUT:
	187	voltage = regval * 22;
	188	break;
	189	case LTC4245_3VIN:
	190	case LTC4245_3VOUT:
	191	voltage = regval * 15;
	192	break;
	193	case LTC4245_VEEIN:
	194	case LTC4245_VEEOUT:
	195	voltage = regval * -55;
	196	break;
df16dd53	197	case LTC4245_GPIOADC:
6e34b187 IS	198	voltage = regval * 10;
	199	break;
	200	default:
	201	/* If we get here, the developer messed up */
	202	WARN_ON_ONCE(1);
	203	break;
	204	}
	205
	206	return voltage;
	207	}
	208
	209	/* Return the current in the given sense register in milliAmperes */
	210	static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
	211	{
	212	struct ltc4245_data *data = ltc4245_update_device(dev);
	213	const u8 regval = data->vregs[reg - 0x10];
	214	unsigned int voltage;
	215	unsigned int curr;
	216
	217	/* The strange looking conversions that follow are fixed-point
	218	* math, since we cannot do floating point in the kernel.
	219	*
	220	* Step 1: convert sense register to microVolts
	221	* Step 2: convert voltage to milliAmperes
	222	*
	223	* If you play around with the V=IR equation, you come up with
	224	* the following: X uV / Y mOhm == Z mA
	225	*
	226	* With the resistors that are fractions of a milliOhm, we multiply
	227	* the voltage and resistance by 10, to shift the decimal point.
	228	* Now we can use the normal division operator again.
	229	*/
	230
	231	switch (reg) {
	232	case LTC4245_12VSENSE:
	233	voltage = regval * 250; /* voltage in uV */
	234	curr = voltage / 50; /* sense resistor 50 mOhm */
	235	break;
	236	case LTC4245_5VSENSE:
	237	voltage = regval * 125; /* voltage in uV */
	238	curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
	239	break;
	240	case LTC4245_3VSENSE:
	241	voltage = regval * 125; /* voltage in uV */
	242	curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
	243	break;
	244	case LTC4245_VEESENSE:
	245	voltage = regval * 250; /* voltage in uV */
	246	curr = voltage / 100; /* sense resistor 100 mOhm */
	247	break;
	248	default:
	249	/* If we get here, the developer messed up */
	250	WARN_ON_ONCE(1);
	251	curr = 0;
	252	break;
	253	}
	254
	255	return curr;
	256	}
	257
	258	static ssize_t ltc4245_show_voltage(struct device *dev,
	259	struct device_attribute *da,
	260	char *buf)
	261	{
262	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
263	const int voltage = ltc4245_get_voltage(dev, attr->index);
264
265	return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
266	}
267
268	static ssize_t ltc4245_show_current(struct device *dev,
269	struct device_attribute *da,
270	char *buf)
271	{
272	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
273	const unsigned int curr = ltc4245_get_current(dev, attr->index);
274
275	return snprintf(buf, PAGE_SIZE, "%u\n", curr);
276	}
277
278	static ssize_t ltc4245_show_power(struct device *dev,
279	struct device_attribute *da,
280	char *buf)
281	{
282	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
283	const unsigned int curr = ltc4245_get_current(dev, attr->index);
284	const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
285
286	/* current in mA * voltage in mV == power in uW */
287	const unsigned int power = abs(output_voltage * curr);
288
289	return snprintf(buf, PAGE_SIZE, "%u\n", power);
290	}
291
292	static ssize_t ltc4245_show_alarm(struct device *dev,
293	struct device_attribute *da,
294	char *buf)
295	{
296	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
297	struct ltc4245_data *data = ltc4245_update_device(dev);
298	const u8 reg = data->cregs[attr->index];
299	const u32 mask = attr->nr;
300
301	return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
302	}
303
5950ec8d IS	304	static ssize_t ltc4245_show_gpio(struct device *dev,
	305	struct device_attribute *da,
	306	char *buf)
	307	{
	308	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	309	struct ltc4245_data *data = ltc4245_update_device(dev);
	310	int val = data->gpios[attr->index];
	311
	312	/* handle stale GPIO's */
	313	if (val < 0)
	314	return val;
	315
	316	/* Convert to millivolts and print */
	317	return snprintf(buf, PAGE_SIZE, "%u\n", val * 10);
	318	}
	319
6e34b187 IS	320	/* These macros are used below in constructing device attribute objects
	321	* for use with sysfs_create_group() to make a sysfs device file
	322	* for each register.
	323	*/
	324
	325	#define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
	326	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	327	ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
	328
	329	#define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
	330	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	331	ltc4245_show_current, NULL, ltc4245_cmd_idx)
	332
	333	#define LTC4245_POWER(name, ltc4245_cmd_idx) \
	334	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	335	ltc4245_show_power, NULL, ltc4245_cmd_idx)
	336
	337	#define LTC4245_ALARM(name, mask, reg) \
	338	static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
	339	ltc4245_show_alarm, NULL, (mask), reg)
	340
5950ec8d IS	341	#define LTC4245_GPIO_VOLTAGE(name, gpio_num) \
	342	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	343	ltc4245_show_gpio, NULL, gpio_num)
	344
6e34b187 IS	345	/* Construct a sensor_device_attribute structure for each register */
	346
	347	/* Input voltages */
	348	LTC4245_VOLTAGE(in1_input, LTC4245_12VIN);
	349	LTC4245_VOLTAGE(in2_input, LTC4245_5VIN);
	350	LTC4245_VOLTAGE(in3_input, LTC4245_3VIN);
	351	LTC4245_VOLTAGE(in4_input, LTC4245_VEEIN);
	352
	353	/* Input undervoltage alarms */
	354	LTC4245_ALARM(in1_min_alarm, (1 << 0), LTC4245_FAULT1);
	355	LTC4245_ALARM(in2_min_alarm, (1 << 1), LTC4245_FAULT1);
	356	LTC4245_ALARM(in3_min_alarm, (1 << 2), LTC4245_FAULT1);
	357	LTC4245_ALARM(in4_min_alarm, (1 << 3), LTC4245_FAULT1);
	358
	359	/* Currents (via sense resistor) */
	360	LTC4245_CURRENT(curr1_input, LTC4245_12VSENSE);
	361	LTC4245_CURRENT(curr2_input, LTC4245_5VSENSE);
	362	LTC4245_CURRENT(curr3_input, LTC4245_3VSENSE);
	363	LTC4245_CURRENT(curr4_input, LTC4245_VEESENSE);
	364
	365	/* Overcurrent alarms */
	366	LTC4245_ALARM(curr1_max_alarm, (1 << 4), LTC4245_FAULT1);
	367	LTC4245_ALARM(curr2_max_alarm, (1 << 5), LTC4245_FAULT1);
	368	LTC4245_ALARM(curr3_max_alarm, (1 << 6), LTC4245_FAULT1);
	369	LTC4245_ALARM(curr4_max_alarm, (1 << 7), LTC4245_FAULT1);
	370
	371	/* Output voltages */
	372	LTC4245_VOLTAGE(in5_input, LTC4245_12VOUT);
	373	LTC4245_VOLTAGE(in6_input, LTC4245_5VOUT);
	374	LTC4245_VOLTAGE(in7_input, LTC4245_3VOUT);
	375	LTC4245_VOLTAGE(in8_input, LTC4245_VEEOUT);
	376
	377	/* Power Bad alarms */
	378	LTC4245_ALARM(in5_min_alarm, (1 << 0), LTC4245_FAULT2);
	379	LTC4245_ALARM(in6_min_alarm, (1 << 1), LTC4245_FAULT2);
	380	LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2);
	381	LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2);
	382
	383	/* GPIO voltages */
5950ec8d IS	384	LTC4245_GPIO_VOLTAGE(in9_input, 0);
	385	LTC4245_GPIO_VOLTAGE(in10_input, 1);
	386	LTC4245_GPIO_VOLTAGE(in11_input, 2);
6e34b187 IS	387
	388	/* Power Consumption (virtual) */
	389	LTC4245_POWER(power1_input, LTC4245_12VSENSE);
	390	LTC4245_POWER(power2_input, LTC4245_5VSENSE);
	391	LTC4245_POWER(power3_input, LTC4245_3VSENSE);
	392	LTC4245_POWER(power4_input, LTC4245_VEESENSE);
	393
	394	/* Finally, construct an array of pointers to members of the above objects,
	395	* as required for sysfs_create_group()
	396	*/
5950ec8d	397	static struct attribute *ltc4245_std_attributes[] = {
6e34b187 IS	398	&sensor_dev_attr_in1_input.dev_attr.attr,
	399	&sensor_dev_attr_in2_input.dev_attr.attr,
	400	&sensor_dev_attr_in3_input.dev_attr.attr,
	401	&sensor_dev_attr_in4_input.dev_attr.attr,
	402
	403	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	404	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
	405	&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
	406	&sensor_dev_attr_in4_min_alarm.dev_attr.attr,
	407
	408	&sensor_dev_attr_curr1_input.dev_attr.attr,
	409	&sensor_dev_attr_curr2_input.dev_attr.attr,
	410	&sensor_dev_attr_curr3_input.dev_attr.attr,
	411	&sensor_dev_attr_curr4_input.dev_attr.attr,
	412
	413	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
	414	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
	415	&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
	416	&sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
	417
	418	&sensor_dev_attr_in5_input.dev_attr.attr,
	419	&sensor_dev_attr_in6_input.dev_attr.attr,
	420	&sensor_dev_attr_in7_input.dev_attr.attr,
	421	&sensor_dev_attr_in8_input.dev_attr.attr,
	422
	423	&sensor_dev_attr_in5_min_alarm.dev_attr.attr,
	424	&sensor_dev_attr_in6_min_alarm.dev_attr.attr,
	425	&sensor_dev_attr_in7_min_alarm.dev_attr.attr,
	426	&sensor_dev_attr_in8_min_alarm.dev_attr.attr,
	427
	428	&sensor_dev_attr_in9_input.dev_attr.attr,
6e34b187 IS	429
	430	&sensor_dev_attr_power1_input.dev_attr.attr,
	431	&sensor_dev_attr_power2_input.dev_attr.attr,
	432	&sensor_dev_attr_power3_input.dev_attr.attr,
	433	&sensor_dev_attr_power4_input.dev_attr.attr,
	434
	435	NULL,
	436	};
	437
5950ec8d IS	438	static struct attribute *ltc4245_gpio_attributes[] = {
	439	&sensor_dev_attr_in10_input.dev_attr.attr,
	440	&sensor_dev_attr_in11_input.dev_attr.attr,
	441	NULL,
	442	};
	443
	444	static const struct attribute_group ltc4245_std_group = {
	445	.attrs = ltc4245_std_attributes,
	446	};
	447
	448	static const struct attribute_group ltc4245_gpio_group = {
	449	.attrs = ltc4245_gpio_attributes,
6e34b187 IS	450	};
6e34b187 IS	451
5950ec8d IS	452	static int ltc4245_sysfs_create_groups(struct i2c_client *client)
	453	{
	454	struct ltc4245_data *data = i2c_get_clientdata(client);
	455	struct device *dev = &client->dev;
	456	int ret;
	457
	458	/* register the standard sysfs attributes */
	459	ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
	460	if (ret) {
	461	dev_err(dev, "unable to register standard attributes\n");
	462	return ret;
	463	}
	464
	465	/* if we're using the extra gpio support, register it's attributes */
	466	if (data->use_extra_gpios) {
	467	ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
	468	if (ret) {
	469	dev_err(dev, "unable to register gpio attributes\n");
	470	sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
	471	return ret;
	472	}
	473	}
	474
	475	return 0;
	476	}
	477
	478	static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
	479	{
	480	struct ltc4245_data *data = i2c_get_clientdata(client);
	481	struct device *dev = &client->dev;
	482
	483	if (data->use_extra_gpios)
	484	sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
	485
	486	sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
	487	}
	488
	489	static bool ltc4245_use_extra_gpios(struct i2c_client *client)
	490	{
	491	struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
	492	#ifdef CONFIG_OF
	493	struct device_node *np = client->dev.of_node;
	494	#endif
	495
	496	/* prefer platform data */
	497	if (pdata)
	498	return pdata->use_extra_gpios;
	499
	500	#ifdef CONFIG_OF
	501	/* fallback on OF */
	502	if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
	503	return true;
	504	#endif
	505
	506	return false;
	507	}
	508
6e34b187 IS	509	static int ltc4245_probe(struct i2c_client *client,
	510	const struct i2c_device_id *id)
	511	{
2d2a7cff	512	struct i2c_adapter *adapter = client->adapter;
6e34b187 IS	513	struct ltc4245_data *data;
	514	int ret;
	515
2d2a7cff JD	516	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
	517	return -ENODEV;
	518
6e34b187 IS	519	data = kzalloc(sizeof(*data), GFP_KERNEL);
	520	if (!data) {
	521	ret = -ENOMEM;
	522	goto out_kzalloc;
	523	}
	524
	525	i2c_set_clientdata(client, data);
	526	mutex_init(&data->update_lock);
5950ec8d	527	data->use_extra_gpios = ltc4245_use_extra_gpios(client);
6e34b187 IS	528
6e34b187 IS	529	/* Initialize the LTC4245 chip */
58f055e5 IS	530	i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
58f055e5 IS	531	i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
6e34b187 IS	532
6e34b187 IS	533	/* Register sysfs hooks */
5950ec8d	534	ret = ltc4245_sysfs_create_groups(client);
6e34b187	535	if (ret)
5950ec8d	536	goto out_sysfs_create_groups;
6e34b187 IS	537
	538	data->hwmon_dev = hwmon_device_register(&client->dev);
	539	if (IS_ERR(data->hwmon_dev)) {
	540	ret = PTR_ERR(data->hwmon_dev);
	541	goto out_hwmon_device_register;
	542	}
	543
	544	return 0;
	545
	546	out_hwmon_device_register:
5950ec8d IS	547	ltc4245_sysfs_remove_groups(client);
5950ec8d IS	548	out_sysfs_create_groups:
6e34b187 IS	549	kfree(data);
	550	out_kzalloc:
	551	return ret;
	552	}
	553
	554	static int ltc4245_remove(struct i2c_client *client)
	555	{
	556	struct ltc4245_data *data = i2c_get_clientdata(client);
	557
	558	hwmon_device_unregister(data->hwmon_dev);
5950ec8d	559	ltc4245_sysfs_remove_groups(client);
6e34b187 IS	560	kfree(data);
	561
	562	return 0;
	563	}
	564
6e34b187	565	static const struct i2c_device_id ltc4245_id[] = {
2d2a7cff	566	{ "ltc4245", 0 },
6e34b187 IS	567	{ }
	568	};
	569	MODULE_DEVICE_TABLE(i2c, ltc4245_id);
	570
	571	/* This is the driver that will be inserted */
	572	static struct i2c_driver ltc4245_driver = {
6e34b187 IS	573	.driver = {
	574	.name = "ltc4245",
	575	},
	576	.probe = ltc4245_probe,
	577	.remove = ltc4245_remove,
	578	.id_table = ltc4245_id,
6e34b187 IS	579	};
	580
	581	static int __init ltc4245_init(void)
	582	{
	583	return i2c_add_driver(&ltc4245_driver);
	584	}
	585
	586	static void __exit ltc4245_exit(void)
	587	{
	588	i2c_del_driver(&ltc4245_driver);
	589	}
	590
	591	MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
	592	MODULE_DESCRIPTION("LTC4245 driver");
	593	MODULE_LICENSE("GPL");
	594
	595	module_init(ltc4245_init);
	596	module_exit(ltc4245_exit);