--- /dev/null
+/*
+ * Driver for Linear Technology LTC4222 Dual Hot Swap controller
+ *
+ * Copyright (c) 2014 Guenter Roeck
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
+#include <linux/regmap.h>
+
+/* chip registers */
+
+#define LTC4222_CONTROL1 0xd0
+#define LTC4222_ALERT1 0xd1
+#define LTC4222_STATUS1 0xd2
+#define LTC4222_FAULT1 0xd3
+#define LTC4222_CONTROL2 0xd4
+#define LTC4222_ALERT2 0xd5
+#define LTC4222_STATUS2 0xd6
+#define LTC4222_FAULT2 0xd7
+#define LTC4222_SOURCE1 0xd8
+#define LTC4222_SOURCE2 0xda
+#define LTC4222_ADIN1 0xdc
+#define LTC4222_ADIN2 0xde
+#define LTC4222_SENSE1 0xe0
+#define LTC4222_SENSE2 0xe2
+#define LTC4222_ADC_CONTROL 0xe4
+
+/*
+ * Fault register bits
+ */
+#define FAULT_OV BIT(0)
+#define FAULT_UV BIT(1)
+#define FAULT_OC BIT(2)
+#define FAULT_POWER_BAD BIT(3)
+#define FAULT_FET_BAD BIT(5)
+
+/* Return the voltage from the given register in mV or mA */
+static int ltc4222_get_value(struct device *dev, u8 reg)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+ unsigned int val;
+ u8 buf[2];
+ int ret;
+
+ ret = regmap_bulk_read(regmap, reg, buf, 2);
+ if (ret < 0)
+ return ret;
+
+ val = ((buf[0] << 8) + buf[1]) >> 6;
+
+ switch (reg) {
+ case LTC4222_ADIN1:
+ case LTC4222_ADIN2:
+ /* 1.25 mV resolution. Convert to mV. */
+ val = DIV_ROUND_CLOSEST(val * 5, 4);
+ break;
+ case LTC4222_SOURCE1:
+ case LTC4222_SOURCE2:
+ /* 31.25 mV resolution. Convert to mV. */
+ val = DIV_ROUND_CLOSEST(val * 125, 4);
+ break;
+ case LTC4222_SENSE1:
+ case LTC4222_SENSE2:
+ /*
+ * 62.5 uV resolution. Convert to current as measured with
+ * an 1 mOhm sense resistor, in mA. If a different sense
+ * resistor is installed, calculate the actual current by
+ * dividing the reported current by the sense resistor value
+ * in mOhm.
+ */
+ val = DIV_ROUND_CLOSEST(val * 125, 2);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return val;
+}
+
+static ssize_t ltc4222_show_value(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ int value;
+
+ value = ltc4222_get_value(dev, attr->index);
+ if (value < 0)
+ return value;
+ return snprintf(buf, PAGE_SIZE, "%d\n", value);
+}
+
+static ssize_t ltc4222_show_bool(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
+ struct regmap *regmap = dev_get_drvdata(dev);
+ unsigned int fault;
+ int ret;
+
+ ret = regmap_read(regmap, attr->nr, &fault);
+ if (ret < 0)
+ return ret;
+ fault &= attr->index;
+ if (fault) /* Clear reported faults in chip register */
+ regmap_update_bits(regmap, attr->nr, attr->index, 0);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
+}
+
+/* Voltages */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL,
+ LTC4222_SOURCE1);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL,
+ LTC4222_ADIN1);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL,
+ LTC4222_SOURCE2);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL,
+ LTC4222_ADIN2);
+
+/*
+ * Voltage alarms
+ * UV/OV faults are associated with the input voltage, and power bad and fet
+ * faults are associated with the output voltage.
+ */
+static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT1, FAULT_UV);
+static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT1, FAULT_OV);
+static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD);
+
+static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT2, FAULT_UV);
+static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT2, FAULT_OV);
+static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD);
+
+/* Current (via sense resistor) */
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL,
+ LTC4222_SENSE1);
+static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL,
+ LTC4222_SENSE2);
+
+/* Overcurrent alarm */
+static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT1, FAULT_OC);
+static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
+ LTC4222_FAULT2, FAULT_OC);
+
+static struct attribute *ltc4222_attrs[] = {
+ &sensor_dev_attr_in1_input.dev_attr.attr,
+ &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
+ &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
+ &sensor_dev_attr_in2_input.dev_attr.attr,
+ &sensor_dev_attr_in2_alarm.dev_attr.attr,
+ &sensor_dev_attr_in3_input.dev_attr.attr,
+ &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
+ &sensor_dev_attr_in3_max_alarm.dev_attr.attr,
+ &sensor_dev_attr_in4_input.dev_attr.attr,
+ &sensor_dev_attr_in4_alarm.dev_attr.attr,
+
+ &sensor_dev_attr_curr1_input.dev_attr.attr,
+ &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
+ &sensor_dev_attr_curr2_input.dev_attr.attr,
+ &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
+
+ NULL,
+};
+ATTRIBUTE_GROUPS(ltc4222);
+
+static const struct regmap_config ltc4222_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = LTC4222_ADC_CONTROL,
+};
+
+static int ltc4222_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct device *hwmon_dev;
+ struct regmap *regmap;
+
+ regmap = devm_regmap_init_i2c(client, <c4222_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(dev, "failed to allocate register map\n");
+ return PTR_ERR(regmap);
+ }
+
+ /* Clear faults */
+ regmap_write(regmap, LTC4222_FAULT1, 0x00);
+ regmap_write(regmap, LTC4222_FAULT2, 0x00);
+
+ hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+ regmap,
+ ltc4222_groups);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ltc4222_id[] = {
+ {"ltc4222", 0},
+ { }
+};
+
+MODULE_DEVICE_TABLE(i2c, ltc4222_id);
+
+static struct i2c_driver ltc4222_driver = {
+ .driver = {
+ .name = "ltc4222",
+ },
+ .probe = ltc4222_probe,
+ .id_table = ltc4222_id,
+};
+
+module_i2c_driver(ltc4222_driver);
+
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("LTC4222 driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff