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thermal/drivers/imx_sc: Rely on the platform data to get the resource id

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Currently the imx_sc driver is reimplementing part of the thermal zone
parsing from the thermal OF tree code to get the sensor id associated
with a thermal zone sensor.

The driver platform specific code should know what sensor is present
and not rely on the thermal zone description to do a discovery. Well
that is arguable but all the other drivers have a per platform data
telling what sensor id to use.

The imx_sc thermal driver is the only one using a different
approach. Not invalid but forcing to keep a specific function
'thermal_zone_of_get_sensor_id()' to get the sensor id for a specific
thermal zone as the self-explanatory function tells and having device
tree code inside the driver.

The thermal OF code had a rework and remains now self-encapsulated
with a register/unregister functions and their 'devm' variants, except
for the function mentioned above.

After investigating, it appears the imx_sc sensor is defined in
arch/arm64/boot/dts/freescale/imx8qxp.dtsi:

which defines the cpu-thermal zone with the id: IMX_SC_R_SYSTEM

This dtsi is included by:
 - imx8qxp-ai_ml.dts
 - imx8qxp-colibri.dtsi
 - imx8qxp-mek.dts

The two first ones do not define more thermal zones
The third one adds the pmic-thermal0 zone with id: IMX_SC_R_PMIC_0

The thermal OF code returns -ENODEV if the thermal zone registration
with a specific id fails because the description is not available in
the DT for such a sensor id. In this case we continue with the other
ids without bailing out with an error.

So we can build for the 'fsl,imx-sc-thermal' a compatible data, an
array of sensor ids containing IMX_SC_R_SYSTEM and IMX_SC_R_PMIC_0.

The latter won't be found but that will not result in an error but a
normal case where we continue the initialization with other ids.

Just to clarify, it is what the thermal framework does and what the
other drivers are expecting: when a registration fails with -ENODEV
this is not an error but a case where the description is not found in
the device tree, that be can the entire thermal zones description or a
specific thermal zone with an unknown id.

There is one small functional change but without impact. When there is
no 'thermal-zones' description the probe function was returning
'-ENODEV', now it returns zero. When a thermal zone fails to register
with an error different from '-ENODEV', the error is detected and
returned.

Change the code accordingly and remove the OF code from the driver.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220818082316.2717095-1-daniel.lezcano@linaro.org
This commit is contained in:
Daniel Lezcano 2022-08-18 10:23:15 +02:00
parent 2e70ea7fb9
commit 31fd4b9db1
1 changed files with 33 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
drivers/thermal/imx_sc_thermal.c
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@ -76,59 +76,55 @@ static const struct thermal_zone_device_ops imx_sc_thermal_ops = {
static int imx_sc_thermal_probe(struct platform_device *pdev)
{
struct device_node *np, *child, *sensor_np;
struct imx_sc_sensor *sensor;
int ret;
const int *resource_id;
int i, ret;
ret = imx_scu_get_handle(&thermal_ipc_handle);
if (ret)
return ret;
np = of_find_node_by_name(NULL, "thermal-zones");
if (!np)
return -ENODEV;
resource_id = of_device_get_match_data(&pdev->dev);
if (!resource_id)
return -EINVAL;
sensor_np = of_node_get(pdev->dev.of_node);
for (i = 0; resource_id[i] > 0; i++) {
for_each_available_child_of_node(np, child) {
sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
if (!sensor) {
of_node_put(child);
ret = -ENOMEM;
goto put_node;
}
if (!sensor)
return -ENOMEM;
ret = thermal_zone_of_get_sensor_id(child,
sensor_np,
&sensor->resource_id);
if (ret < 0) {
dev_err(&pdev->dev,
"failed to get valid sensor resource id: %d\n",
ret);
of_node_put(child);
break;
}
sensor->resource_id = resource_id[i];
sensor->tzd = devm_thermal_of_zone_register(&pdev->dev,
sensor->resource_id,
sensor,
&imx_sc_thermal_ops);
sensor->tzd = devm_thermal_of_zone_register(&pdev->dev, sensor->resource_id,
sensor, &imx_sc_thermal_ops);
if (IS_ERR(sensor->tzd)) {
dev_err(&pdev->dev, "failed to register thermal zone\n");
/*
* Save the error value before freeing the
* sensor pointer, otherwise we endup with a
* use-after-free error
*/
ret = PTR_ERR(sensor->tzd);
of_node_put(child);
break;
devm_kfree(&pdev->dev, sensor);
/*
* The thermal framework notifies us there is
* no thermal zone description for such a
* sensor id
*/
if (ret == -ENODEV)
continue;
dev_err(&pdev->dev, "failed to register thermal zone\n");
return ret;
}
if (devm_thermal_add_hwmon_sysfs(sensor->tzd))
dev_warn(&pdev->dev, "failed to add hwmon sysfs attributes\n");
}
put_node:
of_node_put(sensor_np);
of_node_put(np);
return ret;
return 0;
}
static int imx_sc_thermal_remove(struct platform_device *pdev)
@ -136,8 +132,10 @@ static int imx_sc_thermal_remove(struct platform_device *pdev)
return 0;
}
static int imx_sc_sensors[] = { IMX_SC_R_SYSTEM, IMX_SC_R_PMIC_0, -1 };
static const struct of_device_id imx_sc_thermal_table[] = {
{ .compatible = "fsl,imx-sc-thermal", },
{ .compatible = "fsl,imx-sc-thermal", .data = imx_sc_sensors },
{}
};
MODULE_DEVICE_TABLE(of, imx_sc_thermal_table);