On Sun, Jan 29, 2017 at 7:13 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On 01/26/2017 06:17 AM, Andrea Merello wrote: >> >> This patch adds a HWMON driver for ST Microelectronics STTS751 >> temperature sensors. >> >> Changes since V3: >> - fix sysfs_notify() filename >> - simplify error exit path in stts751_update_temp(): kill useless goto >> - fix set function were racy due to lock incorrectly placed >> - use msecs_to_jiffies instead of manual calculation >> - fix jiffies and msecs were mixed up >> - don't mark cache as good unless reads really succeded to fill up it >> - when updating therm, hyst keeps relative value rather than abs value >> - don't should in dev_dbg when chip is detected >> - don't ever generate two uevents >> - clarify clear-on-read behaviour of status reg alarm flags >> - simplify mDEG to HW conversion function >> - fix chip stops due to incorrect resolution configuration >> - fix incorrectly reading negative numbers from HW >> >> Thanks-to: LABBE Corentin [for suggestions] >> Signed-off-by: Andrea Merello <andrea.merello@xxxxxxxxx> >> Cc: LABBE Corentin <clabbe.montjoie@xxxxxxxxx> >> Cc: Guenter Roeck <linux@xxxxxxxxxxxx> >> Cc: Jean Delvare <jdelvare@xxxxxxxx> >> --- >> drivers/hwmon/Kconfig | 10 + >> drivers/hwmon/Makefile | 1 + >> drivers/hwmon/stts751.c | 803 >> ++++++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 814 insertions(+) >> create mode 100644 drivers/hwmon/stts751.c >> >> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig >> index d1f82f2..8fdd241 100644 >> --- a/drivers/hwmon/Kconfig >> +++ b/drivers/hwmon/Kconfig >> @@ -1448,6 +1448,16 @@ config SENSORS_SCH5636 >> This driver can also be built as a module. If so, the module >> will be called sch5636. >> >> +config SENSORS_STTS751 >> + tristate "ST Microelectronics STTS751" >> + depends on I2C >> + help >> + If you say yes here you get support for STTS751 >> + temperature sensor chips. >> + >> + This driver can also be built as a module. If so, the module >> + will be called stts751. >> + >> config SENSORS_SMM665 >> tristate "Summit Microelectronics SMM665" >> depends on I2C >> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile >> index 7476b22..1114130 100644 >> --- a/drivers/hwmon/Makefile >> +++ b/drivers/hwmon/Makefile >> @@ -147,6 +147,7 @@ obj-$(CONFIG_SENSORS_SMM665) += smm665.o >> obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o >> obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o >> obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o >> +obj-$(CONFIG_SENSORS_STTS751) += stts751.o >> obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o >> obj-$(CONFIG_SENSORS_TC74) += tc74.o >> obj-$(CONFIG_SENSORS_THMC50) += thmc50.o >> diff --git a/drivers/hwmon/stts751.c b/drivers/hwmon/stts751.c >> new file mode 100644 >> index 0000000..de7298f >> --- /dev/null >> +++ b/drivers/hwmon/stts751.c >> @@ -0,0 +1,803 @@ >> +/* >> + * 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@xxxxxxxxx> >> + * >> + * 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 }, >> + { } >> +}; >> + >> +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; >> +}; >> + >> +/* >> + * 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->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); > > > Please align continuation lines with '('. OK > >> +} >> + >> +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); > > > This continuation line is unnecessary (there may be others, but I did not > check). OK > >> +} >> + >> +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->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->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->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->client->dev, >> + "Alert received, but can't communicate to the >> device. Something bad happening? Triggering all alarms!"); > > > I would suggest to drop the "Something bad happening?". That should be > obvious > from the message. OK > >> + } >> + >> + if (priv->max_alert) { >> + dev_notice(&client->dev, "got alert for HIGH >> temperature"); >> + >> + /* unblock alert poll */ >> + sysfs_notify(&priv->dev->kobj, NULL, "temp1_max_alarm"); >> + } >> + >> + if (priv->min_alert) { >> + dev_notice(&client->dev, "got alert for LOW temperature"); >> + >> + /* 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 = 0; >> + int cache_time = >> msecs_to_jiffies(stts751_intervals[priv->interval]); >> + >> + mutex_lock(&priv->access_lock); >> + if (time_after(jiffies, priv->last_update + cache_time) || >> + !priv->data_valid) { >> + ret = stts751_update_temp(priv); >> + if (ret) >> + goto exit; >> + >> + ret = stts751_update_alert(priv); >> + if (ret) >> + goto exit; >> + priv->data_valid = true; >> + priv->last_update = jiffies; >> + } >> +exit: >> + mutex_unlock(&priv->access_lock); >> + >> + return ret; >> +} >> + >> +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); >> + >> + ret = stts751_update(priv); >> + 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); >> + >> + ret = stts751_update(priv); >> + 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); >> + >> + ret = stts751_update(priv); >> + 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(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->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); >> + >> + ret = stts751_update(priv); >> + 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(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(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 = 0; >> + 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(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->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->dev, "modify convrate, then raise >> resolution"); >> + priv->interval = idx; >> + ret = stts751_adjust_resolution(priv); >> + if (ret) >> + goto exit; > > > All those gotos ignore the error. Is this really what you want ? You are right.. It was unintentional.. >> + } >> +exit: >> + mutex_unlock(&priv->access_lock); >> + >> + return count; > > > Should this be > > return ret ? ret : count; > > instead ? Or maybe > > ret = count; > exit: > mutex_unlock(&priv->access_lock); > return ret; going to use the latter one.. >> +} >> + >> >> +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 mfg_id, prod_id, rev_id; >> + >> + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) >> + return -ENODEV; >> + >> + mfg_id = i2c_smbus_read_byte_data(new_client, ST_MAN_ID); >> + if (mfg_id != ST_MAN_ID) >> + return -ENODEV; >> + >> + prod_id = i2c_smbus_read_byte_data(new_client, >> STTS751_REG_PROD_ID); >> + >> + switch (prod_id) { >> + 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); >> + >> + rev_id = i2c_smbus_read_byte_data(new_client, STTS751_REG_REV_ID); >> + if (rev_id < 0) >> + return -ENODEV; >> + if (rev_id != 0x1) { >> + dev_notice(&new_client->dev, >> + "Chip revision 0x%x is untested\nPlease report >> whether it works to andrea.merello@xxxxxxxxx", >> + rev_id); >> + } > > > You might consider moving the rev_id warning to the probe function. > In many if not most cases, the detect function won't run at all > (since the chip will be instantiated explicitly), and you won't get > the warning. > > On the other side, do you really think the warning adds any real value ? > I am a bit concerned that it will just create noise a few years down the > road. OK. I've moved this check to the probe function, and I've changed the dev_notice in dev_dbg: I would assume (hope) that different chip revisions are still register-compatible and should work, however if it happens that someone has trouble and he/she is debugging this driver, IMHO it's worth to eventually tell him/her that he/she is using an unknown chip revision. This way we will avoid noise during normal usage. > On the other side, it might be useful to add a couple of additional > registers > to the check to improve its reliability and reduce possible false positives. > The temperature low bytes (registers 0x02, 0x06, 0x08) would be good targets > with the lower 4 bits being 0. An excellent target would be the SMBus > timeout > register, which has 7 bits known to be 0. OK, good idea :) > >> + >> + 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 ret; > > > return 0; OK > >> +} >> + >> >> +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0); >> +static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_min, >> set_min, 0); >> +static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_max, >> set_max, 0); >> +static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_min_alarm, NULL, >> 0); >> +static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_max_alarm, NULL, >> 0); >> +static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_therm, >> + set_therm, 0); >> +static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_hyst, >> + set_hyst, 0); >> +static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_therm_trip, >> NULL, 0); >> +static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, >> + 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_to; >> + >> + priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); >> + if (!priv) >> + return -ENOMEM; >> + >> + priv->client = client; >> + i2c_set_clientdata(client, priv); >> + mutex_init(&priv->access_lock); >> + >> + if (device_property_present(&client->dev, >> + "smbus-timeout-disable")) { >> + smbus_to = !device_property_read_bool(&client->dev, >> + "smbus-timeout-disable"); >> + > > This "!" is really unnecessary. Just name the variable differently, > >> + ret = i2c_smbus_write_byte_data(priv->client, >> + STTS751_REG_SMBUS_TO, >> + smbus_to ? 0x80 : 0); > > > and reverse the logic here. OK > > >> + if (ret) >> + return ret; >> + } >> + >> + 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(priv->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, >> + }, >> + .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@xxxxxxxxx>"); >> +MODULE_DESCRIPTION("STTS751 sensor driver"); >> +MODULE_LICENSE("GPL"); >> > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html