--- /dev/null
+/*
+ * tc654.c - Linux kernel modules for fan speed controller
+ *
+ * Copyright (C) 2016 Allied Telesis Labs NZ
+ *
+ * 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/bitops.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/util_macros.h>
+
+enum tc654_regs {
+ TC654_REG_RPM1 = 0x00, /* RPM Output 1 */
+ TC654_REG_RPM2 = 0x01, /* RPM Output 2 */
+ TC654_REG_FAN_FAULT1 = 0x02, /* Fan Fault 1 Threshold */
+ TC654_REG_FAN_FAULT2 = 0x03, /* Fan Fault 2 Threshold */
+ TC654_REG_CONFIG = 0x04, /* Configuration */
+ TC654_REG_STATUS = 0x05, /* Status */
+ TC654_REG_DUTY_CYCLE = 0x06, /* Fan Speed Duty Cycle */
+ TC654_REG_MFR_ID = 0x07, /* Manufacturer Identification */
+ TC654_REG_VER_ID = 0x08, /* Version Identification */
+};
+
+/* Macros to easily index the registers */
+#define TC654_REG_RPM(idx) (TC654_REG_RPM1 + (idx))
+#define TC654_REG_FAN_FAULT(idx) (TC654_REG_FAN_FAULT1 + (idx))
+
+/* Config register bits */
+#define TC654_REG_CONFIG_RES BIT(6) /* Resolution Selection */
+#define TC654_REG_CONFIG_DUTYC BIT(5) /* Duty Cycle Control */
+#define TC654_REG_CONFIG_SDM BIT(0) /* Shutdown Mode */
+
+/* Status register bits */
+#define TC654_REG_STATUS_F2F BIT(1) /* Fan 2 Fault */
+#define TC654_REG_STATUS_F1F BIT(0) /* Fan 1 Fault */
+
+/* RPM resolution for RPM Output registers */
+#define TC654_HIGH_RPM_RESOLUTION 25 /* 25 RPM resolution */
+#define TC654_LOW_RPM_RESOLUTION 50 /* 50 RPM resolution */
+
+/* Convert to the fan fault RPM threshold from register value */
+#define TC654_FAN_FAULT_FROM_REG(val) ((val) * 50) /* 50 RPM resolution */
+
+/* Convert to register value from the fan fault RPM threshold */
+#define TC654_FAN_FAULT_TO_REG(val) (((val) / 50) & 0xff)
+
+/* Register data is read (and cached) at most once per second. */
+#define TC654_UPDATE_INTERVAL HZ
+
+struct tc654_data {
+ struct i2c_client *client;
+
+ /* update mutex */
+ struct mutex update_lock;
+
+ /* tc654 register cache */
+ bool valid;
+ unsigned long last_updated; /* in jiffies */
+
+ u8 rpm_output[2]; /* The fan RPM data for fans 1 and 2 is then
+ * written to registers RPM1 and RPM2
+ */
+ u8 fan_fault[2]; /* The Fan Fault Threshold Registers are used to
+ * set the fan fault threshold levels for fan 1
+ * and fan 2
+ */
+ u8 config; /* The Configuration Register is an 8-bit read/
+ * writable multi-function control register
+ * 7: Fan Fault Clear
+ * 1 = Clear Fan Fault
+ * 0 = Normal Operation (default)
+ * 6: Resolution Selection for RPM Output Registers
+ * RPM Output Registers (RPM1 and RPM2) will be
+ * set for
+ * 1 = 25 RPM (9-bit) resolution
+ * 0 = 50 RPM (8-bit) resolution (default)
+ * 5: Duty Cycle Control Method
+ * The V OUT duty cycle will be controlled via
+ * 1 = the SMBus interface.
+ * 0 = via the V IN analog input pin. (default)
+ * 4,3: Fan 2 Pulses Per Rotation
+ * 00 = 1
+ * 01 = 2 (default)
+ * 10 = 4
+ * 11 = 8
+ * 2,1: Fan 1 Pulses Per Rotation
+ * 00 = 1
+ * 01 = 2 (default)
+ * 10 = 4
+ * 11 = 8
+ * 0: Shutdown Mode
+ * 1 = Shutdown mode.
+ * 0 = Normal operation. (default)
+ */
+ u8 status; /* The Status register provides all the information
+ * about what is going on within the TC654/TC655
+ * devices.
+ * 7,6: Unimplemented, Read as '0'
+ * 5: Over-Temperature Fault Condition
+ * 1 = Over-Temperature condition has occurred
+ * 0 = Normal operation. V IN is less than 2.6V
+ * 4: RPM2 Counter Overflow
+ * 1 = Fault condition
+ * 0 = Normal operation
+ * 3: RPM1 Counter Overflow
+ * 1 = Fault condition
+ * 0 = Normal operation
+ * 2: V IN Input Status
+ * 1 = V IN is open
+ * 0 = Normal operation. voltage present at V IN
+ * 1: Fan 2 Fault
+ * 1 = Fault condition
+ * 0 = Normal operation
+ * 0: Fan 1 Fault
+ * 1 = Fault condition
+ * 0 = Normal operation
+ */
+ u8 duty_cycle; /* The DUTY_CYCLE register is a 4-bit read/
+ * writable register used to control the duty
+ * cycle of the V OUT output.
+ */
+};
+
+/* helper to grab and cache data, at most one time per second */
+static struct tc654_data *tc654_update_client(struct device *dev)
+{
+ struct tc654_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ int ret = 0;
+
+ mutex_lock(&data->update_lock);
+ if (time_before(jiffies, data->last_updated + TC654_UPDATE_INTERVAL) &&
+ likely(data->valid))
+ goto out;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(0));
+ if (ret < 0)
+ goto out;
+ data->rpm_output[0] = ret;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(1));
+ if (ret < 0)
+ goto out;
+ data->rpm_output[1] = ret;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(0));
+ if (ret < 0)
+ goto out;
+ data->fan_fault[0] = ret;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(1));
+ if (ret < 0)
+ goto out;
+ data->fan_fault[1] = ret;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
+ if (ret < 0)
+ goto out;
+ data->config = ret;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_STATUS);
+ if (ret < 0)
+ goto out;
+ data->status = ret;
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_DUTY_CYCLE);
+ if (ret < 0)
+ goto out;
+ data->duty_cycle = ret & 0x0f;
+
+ data->last_updated = jiffies;
+ data->valid = true;
+out:
+ mutex_unlock(&data->update_lock);
+
+ if (ret < 0) /* upon error, encode it in return value */
+ data = ERR_PTR(ret);
+
+ return data;
+}
+
+/*
+ * sysfs attributes
+ */
+
+static ssize_t show_fan(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ int nr = to_sensor_dev_attr(da)->index;
+ struct tc654_data *data = tc654_update_client(dev);
+ int val;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ if (data->config & TC654_REG_CONFIG_RES)
+ val = data->rpm_output[nr] * TC654_HIGH_RPM_RESOLUTION;
+ else
+ val = data->rpm_output[nr] * TC654_LOW_RPM_RESOLUTION;
+
+ return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t show_fan_min(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ int nr = to_sensor_dev_attr(da)->index;
+ struct tc654_data *data = tc654_update_client(dev);
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ return sprintf(buf, "%d\n",
+ TC654_FAN_FAULT_FROM_REG(data->fan_fault[nr]));
+}
+
+static ssize_t set_fan_min(struct device *dev, struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ int nr = to_sensor_dev_attr(da)->index;
+ struct tc654_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ unsigned long val;
+ int ret;
+
+ if (kstrtoul(buf, 10, &val))
+ return -EINVAL;
+
+ val = clamp_val(val, 0, 12750);
+
+ mutex_lock(&data->update_lock);
+
+ data->fan_fault[nr] = TC654_FAN_FAULT_TO_REG(val);
+ ret = i2c_smbus_write_byte_data(client, TC654_REG_FAN_FAULT(nr),
+ data->fan_fault[nr]);
+
+ mutex_unlock(&data->update_lock);
+ return ret < 0 ? ret : count;
+}
+
+static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ int nr = to_sensor_dev_attr(da)->index;
+ struct tc654_data *data = tc654_update_client(dev);
+ int val;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ if (nr == 0)
+ val = !!(data->status & TC654_REG_STATUS_F1F);
+ else
+ val = !!(data->status & TC654_REG_STATUS_F2F);
+
+ return sprintf(buf, "%d\n", val);
+}
+
+static const u8 TC654_FAN_PULSE_SHIFT[] = { 1, 3 };
+
+static ssize_t show_fan_pulses(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ int nr = to_sensor_dev_attr(da)->index;
+ struct tc654_data *data = tc654_update_client(dev);
+ u8 val;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ val = BIT((data->config >> TC654_FAN_PULSE_SHIFT[nr]) & 0x03);
+ return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t set_fan_pulses(struct device *dev, struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ int nr = to_sensor_dev_attr(da)->index;
+ struct tc654_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ u8 config;
+ unsigned long val;
+ int ret;
+
+ if (kstrtoul(buf, 10, &val))
+ return -EINVAL;
+
+ switch (val) {
+ case 1:
+ config = 0;
+ break;
+ case 2:
+ config = 1;
+ break;
+ case 4:
+ config = 2;
+ break;
+ case 8:
+ config = 3;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ mutex_lock(&data->update_lock);
+
+ data->config &= ~(0x03 << TC654_FAN_PULSE_SHIFT[nr]);
+ data->config |= (config << TC654_FAN_PULSE_SHIFT[nr]);
+ ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
+
+ mutex_unlock(&data->update_lock);
+ return ret < 0 ? ret : count;
+}
+
+static ssize_t show_pwm_mode(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct tc654_data *data = tc654_update_client(dev);
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ return sprintf(buf, "%d\n", !!(data->config & TC654_REG_CONFIG_DUTYC));
+}
+
+static ssize_t set_pwm_mode(struct device *dev,
+ struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct tc654_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ unsigned long val;
+ int ret;
+
+ if (kstrtoul(buf, 10, &val))
+ return -EINVAL;
+
+ if (val != 0 && val != 1)
+ return -EINVAL;
+
+ mutex_lock(&data->update_lock);
+
+ if (val)
+ data->config |= TC654_REG_CONFIG_DUTYC;
+ else
+ data->config &= ~TC654_REG_CONFIG_DUTYC;
+
+ ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
+
+ mutex_unlock(&data->update_lock);
+ return ret < 0 ? ret : count;
+}
+
+static const int tc654_pwm_map[16] = { 77, 88, 102, 112, 124, 136, 148, 160,
+ 172, 184, 196, 207, 219, 231, 243, 255};
+
+static ssize_t show_pwm(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct tc654_data *data = tc654_update_client(dev);
+ int pwm;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ if (data->config & TC654_REG_CONFIG_SDM)
+ pwm = 0;
+ else
+ pwm = tc654_pwm_map[data->duty_cycle];
+
+ return sprintf(buf, "%d\n", pwm);
+}
+
+static ssize_t set_pwm(struct device *dev, struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct tc654_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ unsigned long val;
+ int ret;
+
+ if (kstrtoul(buf, 10, &val))
+ return -EINVAL;
+ if (val > 255)
+ return -EINVAL;
+
+ mutex_lock(&data->update_lock);
+
+ if (val == 0)
+ data->config |= TC654_REG_CONFIG_SDM;
+ else
+ data->config &= ~TC654_REG_CONFIG_SDM;
+
+ data->duty_cycle = find_closest(val, tc654_pwm_map,
+ ARRAY_SIZE(tc654_pwm_map));
+
+ ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
+ if (ret < 0)
+ goto out;
+
+ ret = i2c_smbus_write_byte_data(client, TC654_REG_DUTY_CYCLE,
+ data->duty_cycle);
+
+out:
+ mutex_unlock(&data->update_lock);
+ return ret < 0 ? ret : count;
+}
+
+static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan1_min, S_IWUSR | S_IRUGO, show_fan_min,
+ set_fan_min, 0);
+static SENSOR_DEVICE_ATTR(fan2_min, S_IWUSR | S_IRUGO, show_fan_min,
+ set_fan_min, 1);
+static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_fan_alarm, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan1_pulses, S_IWUSR | S_IRUGO, show_fan_pulses,
+ set_fan_pulses, 0);
+static SENSOR_DEVICE_ATTR(fan2_pulses, S_IWUSR | S_IRUGO, show_fan_pulses,
+ set_fan_pulses, 1);
+static SENSOR_DEVICE_ATTR(pwm1_mode, S_IWUSR | S_IRUGO,
+ show_pwm_mode, set_pwm_mode, 0);
+static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, show_pwm,
+ set_pwm, 0);
+
+/* Driver data */
+static struct attribute *tc654_attrs[] = {
+ &sensor_dev_attr_fan1_input.dev_attr.attr,
+ &sensor_dev_attr_fan2_input.dev_attr.attr,
+ &sensor_dev_attr_fan1_min.dev_attr.attr,
+ &sensor_dev_attr_fan2_min.dev_attr.attr,
+ &sensor_dev_attr_fan1_alarm.dev_attr.attr,
+ &sensor_dev_attr_fan2_alarm.dev_attr.attr,
+ &sensor_dev_attr_fan1_pulses.dev_attr.attr,
+ &sensor_dev_attr_fan2_pulses.dev_attr.attr,
+ &sensor_dev_attr_pwm1_mode.dev_attr.attr,
+ &sensor_dev_attr_pwm1.dev_attr.attr,
+ NULL
+};
+
+ATTRIBUTE_GROUPS(tc654);
+
+/*
+ * device probe and removal
+ */
+
+static int tc654_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct tc654_data *data;
+ struct device *hwmon_dev;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+ return -ENODEV;
+
+ data = devm_kzalloc(dev, sizeof(struct tc654_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = client;
+ mutex_init(&data->update_lock);
+
+ ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
+ if (ret < 0)
+ return ret;
+
+ data->config = ret;
+
+ hwmon_dev =
+ devm_hwmon_device_register_with_groups(dev, client->name, data,
+ tc654_groups);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id tc654_id[] = {
+ {"tc654", 0},
+ {"tc655", 0},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, tc654_id);
+
+static struct i2c_driver tc654_driver = {
+ .driver = {
+ .name = "tc654",
+ },
+ .probe = tc654_probe,
+ .id_table = tc654_id,
+};
+
+module_i2c_driver(tc654_driver);
+
+MODULE_AUTHOR("Allied Telesis Labs");
+MODULE_DESCRIPTION("Microchip TC654/TC655 driver");
+MODULE_LICENSE("GPL");
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