diff options
Diffstat (limited to 'drivers/hwmon/ltc4245.c')
| -rw-r--r-- | drivers/hwmon/ltc4245.c | 533 |
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] = <c4245_std_group; + + /* if we're using the extra gpio support, register it's attributes */ + if (data->use_extra_gpios) + data->groups[1] = <c4245_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"); |