/* * 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, <c4245_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, <c4245_gpio_group); if (ret) { dev_err(dev, "unable to register gpio attributes\n"); sysfs_remove_group(&dev->kobj, <c4245_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, <c4245_gpio_group); sysfs_remove_group(&dev->kobj, <c4245_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(<c4245_driver); } static void __exit ltc4245_exit(void) { i2c_del_driver(<c4245_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);