Re: [PATCH 1/1] drivers: hwmon: pmbus: register with thermal for PSC_TEMPERATURE

[Guenter Roeck]

On Mon, Mar 21, 2022 at 06:46:50PM -0700, Eduardo Valentin wrote:
> Some pmbus device drivers have device tree support and
> may want to use of-thermal to register a thermal zone
> OF sensor for those device drivers.
> 
> This way we allow describing device tree thermal zones
> for pmbus device drivers with device tree support.
> 
> This patch achieves this by registering pmbus sensors
> with thermal subsystem if they are PSC_TEMPERATURE
> and are providing _input hwmon interface.
> 
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx> (maintainer:PMBUS HARDWARE MONITORING DRIVERS)
> Cc: Jean Delvare <jdelvare@xxxxxxxx> (maintainer:HARDWARE MONITORING)
> Cc: linux-hwmon@xxxxxxxxxxxxxxx (open list:PMBUS HARDWARE MONITORING DRIVERS)
> Cc: linux-kernel@xxxxxxxxxxxxxxx (open list)
> Signed-off-by: Eduardo Valentin <eduval@xxxxxxxxxx>
> Signed-off-by: Eduardo Valentin <evalenti@xxxxxxxxxx>
> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 88 +++++++++++++++++++++++++++++---
>  1 file changed, 80 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 776ee2237be2..a51cdfab1c3e 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -19,6 +19,8 @@
>  #include <linux/pmbus.h>
>  #include <linux/regulator/driver.h>
>  #include <linux/regulator/machine.h>
> +#include <linux/of.h>
> +#include <linux/thermal.h>
>  #include "pmbus.h"
>  
>  /*
> @@ -1078,7 +1080,71 @@ static int pmbus_add_boolean(struct pmbus_data *data,
>  	return pmbus_add_attribute(data, &a->dev_attr.attr);
>  }
>  
> -static struct pmbus_sensor *pmbus_add_sensor(struct pmbus_data *data,
> +/* of thermal for pmbus temperature sensors */
> +struct pmbus_thermal_data {
> +	struct i2c_client *client;
> +	struct pmbus_sensor *sensor;
> +};
> +
> +static int pmbus_thermal_get_temp(void *data, int *temp)
> +{
> +	struct pmbus_thermal_data *tdata = data;
> +	struct i2c_client *client = tdata->client;
> +	struct pmbus_sensor *sensor = tdata->sensor;
> +	struct pmbus_data *pmbus_data = i2c_get_clientdata(client);
> +	struct device *dev = pmbus_data->hwmon_dev;

The i2c client is also in to_i2c_client(pmbus_data->dev);
Since pmbus_data is needed anyway, I would suggest to store it
instead of struct i2c_client * in pmbus_thermal_data.
That avoids having to change the parameters of pmbus_add_sensor().

> +	int ret = 0;
> +
> +	if (!dev) {
> +		/* May not even get to hwmon yet */
> +		*temp = 0;
> +		return 0;
> +	}
> +
> +	mutex_lock(&pmbus_data->update_lock);
> +	pmbus_update_sensor_data(client, sensor);
> +	if (sensor->data < 0)
> +		ret = sensor->data;
> +	else
> +		*temp = (int)pmbus_reg2data(pmbus_data, sensor);
> +	mutex_unlock(&pmbus_data->update_lock);
> +
> +	return ret;
> +}
> +
> +static const struct thermal_zone_of_device_ops pmbus_thermal_ops = {
> +	.get_temp = pmbus_thermal_get_temp,
> +};
> +
> +static int pmbus_thermal_add_sensor(struct i2c_client *client,
> +				    struct pmbus_data *pmbus_data,
> +				    struct pmbus_sensor *sensor, int index)
> +{
> +	struct device *dev = pmbus_data->dev;
> +	struct pmbus_thermal_data *tdata;
> +	struct thermal_zone_device *tzd;
> +
> +	tdata = devm_kzalloc(dev, sizeof(*tdata), GFP_KERNEL);
> +	if (!tdata)
> +		return -ENOMEM;
> +
> +	tdata->sensor = sensor;
> +	tdata->client = client;
> +
> +	tzd = devm_thermal_zone_of_sensor_register(dev, index, tdata,
> +						   &pmbus_thermal_ops);
> +	/*
> +	 * If CONFIG_THERMAL_OF is disabled, this returns -ENODEV,
> +	 * so ignore that error but forward any other error.
> +	 */
> +	if (IS_ERR(tzd) && (PTR_ERR(tzd) != -ENODEV))
> +		return PTR_ERR(tzd);
> +
> +	return 0;
> +}
> +
> +static struct pmbus_sensor *pmbus_add_sensor(struct i2c_client *client,
> +					     struct pmbus_data *data,
>  					     const char *name, const char *type,
>  					     int seq, int page, int phase,
>  					     int reg,
> @@ -1121,6 +1187,10 @@ static struct pmbus_sensor *pmbus_add_sensor(struct pmbus_data *data,
>  	sensor->next = data->sensors;
>  	data->sensors = sensor;
>  
> +	/* temperature sensors with _input values are registered with thermal */
> +	if (class == PSC_TEMPERATURE && strcmp(type, "input") == 0)

type can be NULL. While that is not currently the case if the class
is PSC_TEMPERATURE, we should not rely on it.

> +		pmbus_thermal_add_sensor(client, data, sensor, seq);
> +
>  	return sensor;
>  }
>  
> @@ -1216,8 +1286,9 @@ static int pmbus_add_limit_attrs(struct i2c_client *client,
>  
>  	for (i = 0; i < nlimit; i++) {
>  		if (pmbus_check_word_register(client, page, l->reg)) {
> -			curr = pmbus_add_sensor(data, name, l->attr, index,
> -						page, 0xff, l->reg, attr->class,
> +			curr = pmbus_add_sensor(client, data, name, l->attr,
> +						index, page, 0xff, l->reg,
> +						attr->class,
>  						attr->update || l->update,
>  						false, true);
>  			if (!curr)
> @@ -1258,7 +1329,7 @@ static int pmbus_add_sensor_attrs_one(struct i2c_client *client,
>  		if (ret)
>  			return ret;
>  	}
> -	base = pmbus_add_sensor(data, name, "input", index, page, phase,
> +	base = pmbus_add_sensor(client, data, name, "input", index, page, phase,
>  				attr->reg, attr->class, true, true, true);
>  	if (!base)
>  		return -ENOMEM;
> @@ -1887,7 +1958,7 @@ static int pmbus_add_fan_ctrl(struct i2c_client *client,
>  {
>  	struct pmbus_sensor *sensor;
>  
> -	sensor = pmbus_add_sensor(data, "fan", "target", index, page,
> +	sensor = pmbus_add_sensor(client, data, "fan", "target", index, page,
>  				  0xff, PMBUS_VIRT_FAN_TARGET_1 + id, PSC_FAN,
>  				  false, false, true);
>  
> @@ -1898,14 +1969,14 @@ static int pmbus_add_fan_ctrl(struct i2c_client *client,
>  			(data->info->func[page] & PMBUS_HAVE_PWM34)))
>  		return 0;
>  
> -	sensor = pmbus_add_sensor(data, "pwm", NULL, index, page,
> +	sensor = pmbus_add_sensor(client, data, "pwm", NULL, index, page,
>  				  0xff, PMBUS_VIRT_PWM_1 + id, PSC_PWM,
>  				  false, false, true);
>  
>  	if (!sensor)
>  		return -ENOMEM;
>  
> -	sensor = pmbus_add_sensor(data, "pwm", "enable", index, page,
> +	sensor = pmbus_add_sensor(client, data, "pwm", "enable", index, page,
>  				  0xff, PMBUS_VIRT_PWM_ENABLE_1 + id, PSC_PWM,
>  				  true, false, false);
>  
> @@ -1947,7 +2018,8 @@ static int pmbus_add_fan_attributes(struct i2c_client *client,
>  			    (!(regval & (PB_FAN_1_INSTALLED >> ((f & 1) * 4)))))
>  				continue;
>  
> -			if (pmbus_add_sensor(data, "fan", "input", index,
> +			if (pmbus_add_sensor(client, data, "fan",
> +					     "input", index,
>  					     page, 0xff, pmbus_fan_registers[f],
>  					     PSC_FAN, true, true, true) == NULL)
>  				return -ENOMEM;