/* * STTS751 sensor driver * * Copyright (C) 2016-2017 Istituto Italiano di Tecnologia - RBCS - EDL * Robotics, Brain and Cognitive Sciences department * Electronic Design Laboratory * * Written by Andrea Merello <andrea.merello@gmail.com> * * Based on LM95241 driver and LM90 driver * * 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/interrupt.h> #include <linux/jiffies.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/property.h> #include <linux/slab.h> #include <linux/sysfs.h> #include <linux/util_macros.h> #define DEVNAME "stts751" static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x38, 0x39, /* STTS751-0 */ 0x4A, 0x4B, 0x3A, 0x3B, /* STTS751-1 */ I2C_CLIENT_END }; #define STTS751_REG_TEMP_H 0x00 #define STTS751_REG_STATUS 0x01 #define STTS751_STATUS_TRIPT BIT(0) #define STTS751_STATUS_TRIPL BIT(5) #define STTS751_STATUS_TRIPH BIT(6) #define STTS751_REG_TEMP_L 0x02 #define STTS751_REG_CONF 0x03 #define STTS751_CONF_RES_MASK 0x0C #define STTS751_CONF_RES_SHIFT 2 #define STTS751_CONF_EVENT_DIS BIT(7) #define STTS751_CONF_STOP BIT(6) #define STTS751_REG_RATE 0x04 #define STTS751_REG_HLIM_H 0x05 #define STTS751_REG_HLIM_L 0x06 #define STTS751_REG_LLIM_H 0x07 #define STTS751_REG_LLIM_L 0x08 #define STTS751_REG_TLIM 0x20 #define STTS751_REG_HYST 0x21 #define STTS751_REG_SMBUS_TO 0x22 #define STTS751_REG_PROD_ID 0xFD #define STTS751_REG_MAN_ID 0xFE #define STTS751_REG_REV_ID 0xFF #define STTS751_0_PROD_ID 0x00 #define STTS751_1_PROD_ID 0x01 #define ST_MAN_ID 0x53 /* * Possible update intervals are (in mS): * 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62.5, 31.25 * However we are not going to complicate things too much and we stick to the * approx value in mS. */ static const int stts751_intervals[] = { 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 63, 31 }; static const struct i2c_device_id stts751_id[] = { { "stts751", 0 }, { } }; static const struct of_device_id stts751_of_match[] = { { .compatible = "stts751" }, { }, }; MODULE_DEVICE_TABLE(of, stts751_of_match); struct stts751_priv { struct device *dev; struct i2c_client *client; struct mutex access_lock; u8 interval; int res; int event_max, event_min; int therm; int hyst; bool smbus_timeout; int temp; unsigned long last_update, last_alert_update; u8 config; bool min_alert, max_alert, therm_trip; bool data_valid, alert_valid; bool notify_max, notify_min; }; /* * These functions converts temperature from HW format to integer format and * vice-vers. They are (mostly) taken from lm90 driver. Unit is in mC. */ static int stts751_to_deg(s16 hw_val) { return hw_val * 125 / 32; } static s32 stts751_to_hw(int val) { return DIV_ROUND_CLOSEST(val, 125) * 32; } static int stts751_adjust_resolution(struct stts751_priv *priv) { u8 res; switch (priv->interval) { case 9: /* 10 bits */ res = 0; break; case 8: /* 11 bits */ res = 1; break; default: /* 12 bits */ res = 3; break; } if (priv->res == res) return 0; priv->config &= ~STTS751_CONF_RES_MASK; priv->config |= res << STTS751_CONF_RES_SHIFT; dev_dbg(&priv->client->dev, "setting res %d. config %x", res, priv->config); priv->res = res; return i2c_smbus_write_byte_data(priv->client, STTS751_REG_CONF, priv->config); } static int stts751_update_temp(struct stts751_priv *priv) { s32 integer1, integer2, frac; /* * There is a trick here, like in the lm90 driver. We have to read two * registers to get the sensor temperature, but we have to beware a * conversion could occur between the readings. We could use the * one-shot conversion register, but we don't want to do this (disables * hardware monitoring). So the solution used here is to read the high * byte once, then the low byte, then the high byte again. If the new * high byte matches the old one, then we have a valid reading. Else we * have to read the low byte again, and now we believe we have a correct * reading. */ integer1 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H); if (integer1 < 0) { dev_dbg(&priv->client->dev, "I2C read failed (temp H). ret: %x\n", integer1); return integer1; } frac = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_L); if (frac < 0) { dev_dbg(&priv->client->dev, "I2C read failed (temp L). ret: %x\n", frac); return frac; } integer2 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H); if (integer2 < 0) { dev_dbg(&priv->client->dev, "I2C 2nd read failed (temp H). ret: %x\n", integer2); return integer2; } if (integer1 != integer2) { frac = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_L); if (frac < 0) { dev_dbg(&priv->client->dev, "I2C 2nd read failed (temp L). ret: %x\n", frac); return frac; } } priv->temp = stts751_to_deg((integer1 << 8) | frac); return 0; } static int stts751_set_temp_reg16(struct stts751_priv *priv, int temp, u8 hreg, u8 lreg) { s32 hwval; int ret; hwval = stts751_to_hw(temp); ret = i2c_smbus_write_byte_data(priv->client, hreg, hwval >> 8); if (ret) return ret; return i2c_smbus_write_byte_data(priv->client, lreg, hwval & 0xff); } static int stts751_set_temp_reg8(struct stts751_priv *priv, int temp, u8 reg) { s32 hwval; hwval = stts751_to_hw(temp); return i2c_smbus_write_byte_data(priv->client, reg, hwval >> 8); } static int stts751_read_reg16(struct stts751_priv *priv, int *temp, u8 hreg, u8 lreg) { int integer, frac; integer = i2c_smbus_read_byte_data(priv->client, hreg); if (integer < 0) return integer; frac = i2c_smbus_read_byte_data(priv->client, lreg); if (frac < 0) return frac; *temp = stts751_to_deg((integer << 8) | frac); return 0; } static int stts751_read_reg8(struct stts751_priv *priv, int *temp, u8 reg) { int integer; integer = i2c_smbus_read_byte_data(priv->client, reg); if (integer < 0) return integer; *temp = stts751_to_deg(integer << 8); return 0; } /* * Update alert flags without waiting for cache to expire. We detects alerts * immediately for the sake of the alert handler; we still need to deal with * caching to workaround the fact that alarm flags int the status register, * despite what the datasheet claims, gets always cleared on read. */ static int stts751_update_alert(struct stts751_priv *priv) { int ret; bool conv_done; int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]); /* * Add another 10% because if we run faster than the HW conversion * rate we will end up in reporting incorrectly alarms. */ cache_time += cache_time / 10; ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_STATUS); if (ret < 0) return ret; dev_dbg(&priv->client->dev, "status reg %x\n", ret); conv_done = ret & (STTS751_STATUS_TRIPH | STTS751_STATUS_TRIPL); /* * Reset the cache if the cache time expired, or if we are sure * we have valid data from a device conversion, or if we know * our cache has been never written. * * Note that when the cache has been never written the point is * to correctly initialize the timestamp, rather than clearing * the cache values. * * Note that updating the cache timestamp when we get an alarm flag * is required, otherwise we could incorrectly report alarms to be zero. */ if (time_after(jiffies, priv->last_alert_update + cache_time) || conv_done || !priv->alert_valid) { priv->max_alert = false; priv->min_alert = false; priv->alert_valid = true; priv->last_alert_update = jiffies; dev_dbg(&priv->client->dev, "invalidating alert cache\n"); } priv->max_alert |= !!(ret & STTS751_STATUS_TRIPH); priv->min_alert |= !!(ret & STTS751_STATUS_TRIPL); priv->therm_trip = !!(ret & STTS751_STATUS_TRIPT); dev_dbg(&priv->client->dev, "max_alert: %d, min_alert: %d, therm_trip: %d\n", priv->max_alert, priv->min_alert, priv->therm_trip); return 0; } static void stts751_alert(struct i2c_client *client, enum i2c_alert_protocol type, unsigned int data) { int ret; struct stts751_priv *priv = i2c_get_clientdata(client); if (type != I2C_PROTOCOL_SMBUS_ALERT) return; dev_dbg(&client->dev, "alert!"); mutex_lock(&priv->access_lock); ret = stts751_update_alert(priv); if (ret < 0) { /* default to worst case */ priv->max_alert = true; priv->min_alert = true; dev_warn(priv->dev, "Alert received, but can't communicate to the device. Triggering all alarms!"); } if (priv->max_alert) { if (priv->notify_max) dev_notice(priv->dev, "got alert for HIGH temperature"); priv->notify_max = false; /* unblock alert poll */ sysfs_notify(&priv->dev->kobj, NULL, "temp1_max_alarm"); } if (priv->min_alert) { if (priv->notify_min) dev_notice(priv->dev, "got alert for LOW temperature"); priv->notify_min = false; /* unblock alert poll */ sysfs_notify(&priv->dev->kobj, NULL, "temp1_min_alarm"); } if (priv->min_alert || priv->max_alert) kobject_uevent(&priv->dev->kobj, KOBJ_CHANGE); mutex_unlock(&priv->access_lock); } static int stts751_update(struct stts751_priv *priv) { int ret; int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]); if (time_after(jiffies, priv->last_update + cache_time) || !priv->data_valid) { ret = stts751_update_temp(priv); if (ret) return ret; ret = stts751_update_alert(priv); if (ret) return ret; priv->data_valid = true; priv->last_update = jiffies; } return 0; } static ssize_t show_max_alarm(struct device *dev, struct device_attribute *attr, char *buf) { int ret; struct stts751_priv *priv = dev_get_drvdata(dev); mutex_lock(&priv->access_lock); ret = stts751_update(priv); if (!ret) priv->notify_max = true; mutex_unlock(&priv->access_lock); if (ret < 0) return ret; return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->max_alert); } static ssize_t show_min_alarm(struct device *dev, struct device_attribute *attr, char *buf) { int ret; struct stts751_priv *priv = dev_get_drvdata(dev); mutex_lock(&priv->access_lock); ret = stts751_update(priv); if (!ret) priv->notify_min = true; mutex_unlock(&priv->access_lock); if (ret < 0) return ret; return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->min_alert); } static ssize_t show_input(struct device *dev, struct device_attribute *attr, char *buf) { int ret; struct stts751_priv *priv = dev_get_drvdata(dev); mutex_lock(&priv->access_lock); ret = stts751_update(priv); mutex_unlock(&priv->access_lock); if (ret < 0) return ret; return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->temp); } static ssize_t show_therm(struct device *dev, struct device_attribute *attr, char *buf) { struct stts751_priv *priv = dev_get_drvdata(dev); return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->therm); } static ssize_t set_therm(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int ret; long temp; struct stts751_priv *priv = dev_get_drvdata(dev); if (kstrtol(buf, 10, &temp) < 0) return -EINVAL; /* HW works in range -64C to +127.937C */ temp = clamp_val(temp, -64000, 127937); mutex_lock(&priv->access_lock); ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_TLIM); if (ret) goto exit; dev_dbg(&priv->client->dev, "setting therm %ld", temp); /* * hysteresis reg is relative to therm, so the HW does not need to be * adjusted, we need to update our local copy only. */ priv->hyst = temp - (priv->therm - priv->hyst); priv->therm = temp; exit: mutex_unlock(&priv->access_lock); if (ret) return ret; return count; } static ssize_t show_hyst(struct device *dev, struct device_attribute *attr, char *buf) { struct stts751_priv *priv = dev_get_drvdata(dev); return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->hyst); } static ssize_t set_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int ret; long temp; struct stts751_priv *priv = dev_get_drvdata(dev); if (kstrtol(buf, 10, &temp) < 0) return -EINVAL; mutex_lock(&priv->access_lock); /* HW works in range -64C to +127.937C */ temp = clamp_val(temp, -64000, priv->therm); priv->hyst = temp; dev_dbg(&priv->client->dev, "setting hyst %ld", temp); temp = priv->therm - temp; ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_HYST); mutex_unlock(&priv->access_lock); if (ret) return ret; return count; } static ssize_t show_therm_trip(struct device *dev, struct device_attribute *attr, char *buf) { int ret; struct stts751_priv *priv = dev_get_drvdata(dev); mutex_lock(&priv->access_lock); ret = stts751_update(priv); mutex_unlock(&priv->access_lock); if (ret < 0) return ret; return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->therm_trip); } static ssize_t show_max(struct device *dev, struct device_attribute *attr, char *buf) { struct stts751_priv *priv = dev_get_drvdata(dev); return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->event_max); } static ssize_t set_max(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int ret; long temp; struct stts751_priv *priv = dev_get_drvdata(dev); if (kstrtol(buf, 10, &temp) < 0) return -EINVAL; mutex_lock(&priv->access_lock); /* HW works in range -64C to +127.937C */ temp = clamp_val(temp, priv->event_min, 127937); ret = stts751_set_temp_reg16(priv, temp, STTS751_REG_HLIM_H, STTS751_REG_HLIM_L); if (ret) goto exit; dev_dbg(&priv->client->dev, "setting event max %ld", temp); priv->event_max = temp; ret = count; exit: mutex_unlock(&priv->access_lock); return ret; } static ssize_t show_min(struct device *dev, struct device_attribute *attr, char *buf) { struct stts751_priv *priv = dev_get_drvdata(dev); return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->event_min); } static ssize_t set_min(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int ret; long temp; struct stts751_priv *priv = dev_get_drvdata(dev); if (kstrtol(buf, 10, &temp) < 0) return -EINVAL; mutex_lock(&priv->access_lock); /* HW works in range -64C to +127.937C */ temp = clamp_val(temp, -64000, priv->event_max); ret = stts751_set_temp_reg16(priv, temp, STTS751_REG_LLIM_H, STTS751_REG_LLIM_L); if (ret) goto exit; dev_dbg(&priv->client->dev, "setting event min %ld", temp); priv->event_min = temp; ret = count; exit: mutex_unlock(&priv->access_lock); return ret; } static ssize_t show_interval(struct device *dev, struct device_attribute *attr, char *buf) { struct stts751_priv *priv = dev_get_drvdata(dev); return snprintf(buf, PAGE_SIZE - 1, "%d\n", stts751_intervals[priv->interval]); } static ssize_t set_interval(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { unsigned long val; int idx; int ret = count; struct stts751_priv *priv = dev_get_drvdata(dev); if (kstrtoul(buf, 10, &val) < 0) return -EINVAL; idx = find_closest_descending(val, stts751_intervals, ARRAY_SIZE(stts751_intervals)); dev_dbg(&priv->client->dev, "setting interval. req:%lu, idx: %d, val: %d", val, idx, stts751_intervals[idx]); mutex_lock(&priv->access_lock); if (priv->interval == idx) goto exit; /* * In early development stages I've become suspicious about the chip * starting to misbehave if I ever set, even briefly, an invalid * configuration. While I'm not sure this is really needed, be * conservative and set rate/resolution in such an order that avoids * passing through an invalid configuration. */ /* speed up: lower the resolution, then modify convrate */ if (priv->interval < idx) { dev_dbg(&priv->client->dev, "lower resolution, then modify convrate"); priv->interval = idx; ret = stts751_adjust_resolution(priv); if (ret) goto exit; } ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_RATE, idx); if (ret) goto exit; /* slow down: modify convrate, then raise resolution */ if (priv->interval != idx) { dev_dbg(&priv->client->dev, "modify convrate, then raise resolution"); priv->interval = idx; ret = stts751_adjust_resolution(priv); if (ret) goto exit; } ret = count; exit: mutex_unlock(&priv->access_lock); return ret; } static int stts751_detect(struct i2c_client *new_client, struct i2c_board_info *info) { struct i2c_adapter *adapter = new_client->adapter; const char *name; int tmp; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) return -ENODEV; tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_MAN_ID); if (tmp != ST_MAN_ID) return -ENODEV; /* lower temperaure registers always have bits 0-3 set to zero */ tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_TEMP_L); if (tmp & 0xf) return -ENODEV; tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_HLIM_L); if (tmp & 0xf) return -ENODEV; tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_LLIM_L); if (tmp & 0xf) return -ENODEV; /* smbus timeout register always have bits 0-7 set to zero */ tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_SMBUS_TO); if (tmp & 0x7f) return -ENODEV; tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_PROD_ID); switch (tmp) { case STTS751_0_PROD_ID: name = "STTS751-0"; break; case STTS751_1_PROD_ID: name = "STTS751-1"; break; default: return -ENODEV; } dev_dbg(&new_client->dev, "Chip %s detected", name); strlcpy(info->type, stts751_id[0].name, I2C_NAME_SIZE); return 0; } static int stts751_read_chip_config(struct stts751_priv *priv) { int ret; int tmp; ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_CONF); if (ret < 0) return ret; priv->config = ret; priv->res = (ret & STTS751_CONF_RES_MASK) >> STTS751_CONF_RES_SHIFT; ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_RATE); if (ret < 0) return ret; priv->interval = ret; ret = stts751_read_reg16(priv, &priv->event_max, STTS751_REG_HLIM_H, STTS751_REG_HLIM_L); if (ret) return ret; ret = stts751_read_reg16(priv, &priv->event_min, STTS751_REG_LLIM_H, STTS751_REG_LLIM_L); if (ret) return ret; ret = stts751_read_reg8(priv, &priv->therm, STTS751_REG_TLIM); if (ret) return ret; ret = stts751_read_reg8(priv, &tmp, STTS751_REG_HYST); if (ret) return ret; priv->hyst = priv->therm - tmp; return 0; } static SENSOR_DEVICE_ATTR(temp1_input, 0444, show_input, NULL, 0); static SENSOR_DEVICE_ATTR(temp1_min, 0644, show_min, set_min, 0); static SENSOR_DEVICE_ATTR(temp1_max, 0644, show_max, set_max, 0); static SENSOR_DEVICE_ATTR(temp1_min_alarm, 0444, show_min_alarm, NULL, 0); static SENSOR_DEVICE_ATTR(temp1_max_alarm, 0444, show_max_alarm, NULL, 0); static SENSOR_DEVICE_ATTR(temp1_crit, 0644, show_therm, set_therm, 0); static SENSOR_DEVICE_ATTR(temp1_crit_hyst, 0644, show_hyst, set_hyst, 0); static SENSOR_DEVICE_ATTR(temp1_crit_alarm, 0444, show_therm_trip, NULL, 0); static SENSOR_DEVICE_ATTR(update_interval, 0644, show_interval, set_interval, 0); static struct attribute *stts751_attrs[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_temp1_min.dev_attr.attr, &sensor_dev_attr_temp1_max.dev_attr.attr, &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, &sensor_dev_attr_temp1_crit.dev_attr.attr, &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, &sensor_dev_attr_update_interval.dev_attr.attr, NULL }; ATTRIBUTE_GROUPS(stts751); static int stts751_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct stts751_priv *priv; int ret; bool smbus_nto; int rev_id; priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->client = client; priv->notify_max = true; priv->notify_min = true; i2c_set_clientdata(client, priv); mutex_init(&priv->access_lock); if (device_property_present(&client->dev, "smbus-timeout-disable")) { smbus_nto = device_property_read_bool(&client->dev, "smbus-timeout-disable"); ret = i2c_smbus_write_byte_data(client, STTS751_REG_SMBUS_TO, smbus_nto ? 0 : 0x80); if (ret) return ret; } rev_id = i2c_smbus_read_byte_data(client, STTS751_REG_REV_ID); if (rev_id < 0) return -ENODEV; if (rev_id != 0x1) { dev_dbg(&client->dev, "Chip revision 0x%x is untested\n", rev_id); } ret = stts751_read_chip_config(priv); if (ret) return ret; priv->config &= ~(STTS751_CONF_STOP | STTS751_CONF_EVENT_DIS); ret = i2c_smbus_write_byte_data(client, STTS751_REG_CONF, priv->config); if (ret) return ret; priv->dev = devm_hwmon_device_register_with_groups(&client->dev, client->name, priv, stts751_groups); return PTR_ERR_OR_ZERO(priv->dev); } MODULE_DEVICE_TABLE(i2c, stts751_id); static struct i2c_driver stts751_driver = { .class = I2C_CLASS_HWMON, .driver = { .name = DEVNAME, .of_match_table = of_match_ptr(stts751_of_match), }, .probe = stts751_probe, .id_table = stts751_id, .detect = stts751_detect, .alert = stts751_alert, .address_list = normal_i2c, }; module_i2c_driver(stts751_driver); MODULE_AUTHOR("Andrea Merello <andrea.merello@gmail.com>"); MODULE_DESCRIPTION("STTS751 sensor driver"); MODULE_LICENSE("GPL");