Support temperature trips by HWMON core and LM90 driver
v3 cover Support temperature trips by HWMON core and LM90 driver
Hi,
It's typical for embedded devices to use LM90-compatible sensor for monitoring of CPU core and skin temperatures. The sensor is often used by thermal zone that performs passive cooling and emergency shutdown on overheat, hence it's more optimal to use interrupt for a faster notification about temperature changes. Thermal framework provides set_trips() callback for programming of temperature trips, let's support it by HWMON.
Changelog:
v3: - Improved patch that fixes integer overflows by fixing the hysteresis
underflow and improving the commit message, telling that min/max/crit fixes are only related to the LM99 sensor. Thanks to Guenter Roeck for the suggestion.
v2: - Reworked set_trips() by making it generic. Now callback invokes
the min/max temperature write method directly, instead of using additional new hwmon callback. This was suggested by Guenter Roeck.
- Added new patch that fixes integer overflows in the LM90 driver. The fixes are necessary for supporting set_trips().
Dmitry Osipenko (2):
hwmon: (lm90) Prevent integer underflows of temperature calculations
hwmon: Support set_trips() of thermal device ops
drivers/hwmon/hwmon.c | 32 ++++++++++++++++++++++++++++++++ drivers/hwmon/lm90.c | 9 +++++++++ 2 files changed, 41 insertions(+)
Signature · 1 line
2.30.2
PATCH v3 1/2 hwmon: (lm90) Prevent integer underflows of temperature calculations
The min/max/crit and all other temperature values that are passed to the driver are unlimited and value that is close to INT_MIN results in integer underflow of the temperature calculations made by the driver for LM99 sensor. Temperature hysteresis is among those values that need to be limited, but limiting of hysteresis is independent from the sensor version. Add the missing limits.
--- drivers/hwmon/lm90.c | 9 +++++++++ 1 file changed, 9 insertions(+)
drivers/hwmon/lm90.c +9 -0
@@ -1028,6 +1028,9 @@ static int lm90_set_temp11(struct lm90_data *data, int index, long val)struct reg *regp = ®[index];int err; +/* prevent integer underflow */ + val =max (val,-128000l ); +/* +16 degrees offset for temp2 for the LM99 */ if (data->kind == lm99 && index <=2 ) val -=16000 ;
@@ -1088,6 +1091,9 @@ static int lm90_set_temp8(struct lm90_data *data, int index, long val)struct i2c_client *client = data->client;int err; +/* prevent integer underflow */ + val =max (val,-128000l ); +/* +16 degrees offset for temp2 for the LM99 */ if (data->kind == lm99 && index ==3 ) val -=16000 ;
@@ -1130,6 +1136,9 @@ static int lm90_set_temphyst(struct lm90_data *data, long val)int temp;int err; +/* prevent integer underflow */ + val =max (val,-128000l ); +if (data->kind == adt7461 || data->kind == tmp451) temp =temp_from_u8_adt7461 (data, data->temp8[LOCAL_CRIT ]);else if (data->kind == max6646)
Signature · 1 line
2.30.2
PATCH v3 2/2 hwmon: Support set_trips() of thermal device ops
In reply to Dmitry OsipenkoSupport set_trips() callback of thermal device ops. This allows HWMON device to operatively notify thermal core about temperature changes, which is very handy to have in a case where HWMON sensor is used by CPU thermal zone that performs passive cooling and emergency shutdown on overheat. Thermal core will be able to react faster to temperature changes.
--- drivers/hwmon/hwmon.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
drivers/hwmon/hwmon.c +32 -0
@@ -153,8 +153,40 @@ static int hwmon_thermal_get_temp(void *data, int *temp)return 0 ; } +static int hwmon_thermal_set_trips (void *data,int low,int high) +{ +struct hwmon_thermal_data *tdata = data; +struct hwmon_device *hwdev =to_hwmon_device (tdata->dev); +const struct hwmon_chip_info *chip = hwdev->chip; +const struct hwmon_channel_info **info = chip->info; +unsigned int i; + +if (!chip->ops->write) +return 0 ; + +for (i =1 ; info[i] && info[i]->type != hwmon_temp; i++) +continue ; + +if (info[i] && info[i]->config[tdata->index] &HWMON_T_MIN ) { +int err = chip->ops->write (tdata->dev, hwmon_temp, + hwmon_temp_min, tdata->index, low); +if (err <0 && err != -EOPNOTSUPP ) +return err; + } + +if (info[i] && info[i]->config[tdata->index] &HWMON_T_MAX ) { +int err = chip->ops->write (tdata->dev, hwmon_temp, + hwmon_temp_max, tdata->index, high); +if (err <0 && err != -EOPNOTSUPP ) +return err; + } + +return 0 ; +} +static const struct thermal_zone_of_device_ops hwmon_thermal_ops = { .get_temp = hwmon_thermal_get_temp, + .set_trips = hwmon_thermal_set_trips, };static void hwmon_thermal_remove_sensor (void *data)
Signature · 1 line
2.30.2
Guenter Roeck
maintainerRe: [PATCH v3 2/2] hwmon: Support set_trips() of thermal device ops
Quoted 6 lines · Dmitry Osipenko
Support
set_trips()callback of thermal device ops. This allows HWMON device to operatively notify thermal core about temperature changes, which is very handy to have in a case where HWMON sensor is used by CPU thermal zone that performs passive cooling and emergency shutdown on overheat. Thermal core will be able to react faster to temperature changes.
I think that warrants an explanation why it doesn't matter if the code doesn't really set any trip points.
Quoted 16 lines
Signed-off-by Dmitry Osipenko <[email protected]>--- drivers/hwmon/hwmon.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)drivers/hwmon/hwmon.c +3
-0@@ -153,8 +153,40 @@ static int hwmon_thermal_get_temp(void *data, int *temp)return 0 ; } +static int hwmon_thermal_set_trips (void *data,int low,int high) +{ +struct hwmon_thermal_data *tdata = data;
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 168
Quoted 10 lines
drivers/hwmon/hwmon.c +10
-0+struct hwmon_device *hwdev =to_hwmon_device (tdata->dev); +const struct hwmon_chip_info *chip = hwdev->chip; +const struct hwmon_channel_info **info = chip->info; +unsigned int i; + +if (!chip->ops->write) +return 0 ; + +for (i =1 ; info[i] && info[i]->type != hwmon_temp; i++) +continue ;
Why start with index 1 ? While index 0 is commonly used for chip data, that is not mandatory.
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 172
Quoted 4 lines
drivers/hwmon/hwmon.c +4
-0+ +if (info[i] && info[i]->config[tdata->index] &HWMON_T_MIN ) { +int err = chip->ops->write (tdata->dev, hwmon_temp, + hwmon_temp_min, tdata->index, low);
checkpatch will complain here because it expects an empty line after a declaration. Since err is used in multiple conditionals, I would suggest to declare it once in the function header.
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 173
Quoted 1 line
drivers/hwmon/hwmon.c +1
-0+if (err <0 && err != -EOPNOTSUPP )
"< 0" is unnecessary.
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 180
Quoted 7 lines
drivers/hwmon/hwmon.c +7
-0+return err; + } + +if (info[i] && info[i]->config[tdata->index] &HWMON_T_MAX ) { +int err = chip->ops->write (tdata->dev, hwmon_temp, + hwmon_temp_max, tdata->index, high); +if (err <0 && err != -EOPNOTSUPP )
"< 0" is unnecessary.
Quoted 12 lines
drivers/hwmon/hwmon.c +7
-0+return err; + } + +return 0 ; +} +static const struct thermal_zone_of_device_ops hwmon_thermal_ops = { .get_temp = hwmon_thermal_get_temp, + .set_trips = hwmon_thermal_set_trips, };static void hwmon_thermal_remove_sensor (void *data)
Re: [PATCH v3 2/2] hwmon: Support set_trips() of thermal device ops
21.06.2021 23:30, Guenter Roeck пишет:
Quoted 10 lines · Dmitry Osipenko
Quoted 6 lines
Support
set_trips()callback of thermal device ops. This allows HWMON device to operatively notify thermal core about temperature changes, which is very handy to have in a case where HWMON sensor is used by CPU thermal zone that performs passive cooling and emergency shutdown on overheat. Thermal core will be able to react faster to temperature changes.I think that warrants an explanation why it doesn't matter if the code doesn't really set any trip points.
I'll extend the commit message.
Quoted 13 lines
Quoted 13 lines
Signed-off-by Dmitry Osipenko <[email protected]>--- drivers/hwmon/hwmon.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)drivers/hwmon/hwmon.c +0
-0@@ -153,8 +153,40 @@ static int hwmon_thermal_get_temp(void *data, int *temp)return 0 ; }
Quoted 16 lines
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 168
Quoted 13 lines
drivers/hwmon/hwmon.c +13
-0+static int hwmon_thermal_set_trips (void *data,int low,int high) +{ +struct hwmon_thermal_data *tdata = data; +struct hwmon_device *hwdev =to_hwmon_device (tdata->dev); +const struct hwmon_chip_info *chip = hwdev->chip; +const struct hwmon_channel_info **info = chip->info; +unsigned int i; + +if (!chip->ops->write) +return 0 ; + +for (i =1 ; info[i] && info[i]->type != hwmon_temp; i++) +continue ;Why start with index 1 ? While index 0 is commonly used for chip data, that is not mandatory.
This is borrowed from hwmon_thermal_register_sensors().
Quoted 8 lines
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 172
Quoted 4 lines
drivers/hwmon/hwmon.c +4
-0+ +if (info[i] && info[i]->config[tdata->index] &HWMON_T_MIN ) { +int err = chip->ops->write (tdata->dev, hwmon_temp, + hwmon_temp_min, tdata->index, low);checkpatch will complain here because it expects an empty line after a declaration. Since err is used in multiple conditionals, I would suggest to declare it once in the function header.
Okay, although checkpatch is happy.
./scripts/checkpatch.pl --strict v3*
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v3-0001-hwmon-lm90-Prevent-integer-underflows-of-temperat.patch
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total: 0 errors, 0 warnings, 0 checks, 27 lines checked
v3-0001-hwmon-lm90-Prevent-integer-underflows-of-temperat.patch has no obvious style problems and is ready for submission.
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v3-0002-hwmon-Support-set_trips-of-thermal-device-ops.patch
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total: 0 errors, 0 warnings, 0 checks, 40 lines checked
Quoted 4 lines
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 173
Quoted 1 line
drivers/hwmon/hwmon.c +1
-0+if (err <0 && err != -EOPNOTSUPP )"< 0" is unnecessary.
Quoted 9 lines
drivers/hwmon/hwmon.c static int hwmon_thermal_get_temp(void *data, int *temp) · line 180
Quoted 7 lines
drivers/hwmon/hwmon.c +7
-0+return err; + } + +if (info[i] && info[i]->config[tdata->index] &HWMON_T_MAX ) { +int err = chip->ops->write (tdata->dev, hwmon_temp, + hwmon_temp_max, tdata->index, high); +if (err <0 && err != -EOPNOTSUPP )"< 0" is unnecessary.
I'll remove it in v4.