linux-kernel - Re: [PATCH v3 3/3] thermal: tegra: parse sensor id before sensor register

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Date:   Wed, 28 Nov 2018 11:25:20 +0100
From:   Thierry Reding <thierry.reding@...il.com>
To:     Wei Ni <wni@...dia.com>
Cc:     daniel.lezcano@...aro.org, linux-tegra@...r.kernel.org,
        rui.zhang@...el.com, edubezval@...il.com, srikars@...dia.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/3] thermal: tegra: parse sensor id before sensor
 register

On Wed, Nov 28, 2018 at 01:44:37PM +0800, Wei Ni wrote:
> Since different platforms may not support all 4
> sensors, so the sensor registration may be failed.
> Add codes to parse dt to find sensor id which
> need to be registered. So that the registration
> can be successful on all platform.
> 
> Signed-off-by: Wei Ni <wni@...dia.com>
> ---
>  drivers/thermal/tegra/soctherm.c | 46 ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 44 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
> index 375cadbc24cd..79e4628224d7 100644
> --- a/drivers/thermal/tegra/soctherm.c
> +++ b/drivers/thermal/tegra/soctherm.c
> @@ -1224,6 +1224,44 @@ static void soctherm_init(struct platform_device *pdev)
>  	tegra_soctherm_throttle(&pdev->dev);
>  }
>  
> +static bool tegra_soctherm_find_sensor_id(int sensor_id)
> +{
> +	int id;

You might want to make this and the sensor_id parameter unsigned int to
match the signedness of the ID in the specifier arguments and the sensor
groups.

Thierry

> +	bool ret = false;
> +	struct of_phandle_args sensor_specs;
> +	struct device_node *np, *sensor_np;
> +
> +	np = of_find_node_by_name(NULL, "thermal-zones");
> +	if (!np)
> +		return ret;
> +
> +	sensor_np = of_get_next_child(np, NULL);
> +	for_each_available_child_of_node(np, sensor_np) {

Aren't we leaking np here? I think we need of_node_put() after
of_get_next_child() to make sure the reference to the "thermal-zones"
node is properly released.

> +		if (of_parse_phandle_with_args(sensor_np, "thermal-sensors",
> +						 "#thermal-sensor-cells",
> +						 0, &sensor_specs))
> +			continue;
> +
> +		if (sensor_specs.args_count != 1) {
> +			WARN(sensor_specs.args_count > 1,
> +			     "%s: wrong cells in sensor specifier %d\n",
> +			     sensor_specs.np->name, sensor_specs.args_count);
> +			continue;

This is odd. You check for args_count != 1 but then WARN on args_count >
1. Shouldn't both of these conditions be the same?

> +		} else {

Also, since the above has "continue;", we don't really need the else
block.

> +			id = sensor_specs.args[0];
> +			if (sensor_id == id) {

It might not be worth to store the ID in a separate variable, we could
just do:

	if (sensor_specs.args[0] == sensor_id)

Thierry
> +				ret = true;
> +				break;
> +			}
> +		}
> +	}
> +
> +	of_node_put(np);
> +	of_node_put(sensor_np);
> +
> +	return ret;
> +}
> +
>  static const struct of_device_id tegra_soctherm_of_match[] = {
>  #ifdef CONFIG_ARCH_TEGRA_124_SOC
>  	{
> @@ -1365,13 +1403,15 @@ static int tegra_soctherm_probe(struct platform_device *pdev)
>  		zone->sg = soc->ttgs[i];
>  		zone->ts = tegra;
>  
> +		if (!tegra_soctherm_find_sensor_id(soc->ttgs[i]->id))
> +			continue;
>  		z = devm_thermal_zone_of_sensor_register(&pdev->dev,

I'd would prefer a blank line after the if block for readability.

>  							 soc->ttgs[i]->id, zone,
>  							 &tegra_of_thermal_ops);
>  		if (IS_ERR(z)) {
>  			err = PTR_ERR(z);
> -			dev_err(&pdev->dev, "failed to register sensor: %d\n",
> -				err);
> +			dev_err(&pdev->dev, "failed to register sensor %s: %d\n",
> +				soc->ttgs[i]->name, err);
>  			goto disable_clocks;
>  		}
>  
> @@ -1434,6 +1474,8 @@ static int __maybe_unused soctherm_resume(struct device *dev)
>  		struct thermal_zone_device *tz;
>  
>  		tz = tegra->thermctl_tzs[soc->ttgs[i]->id];
> +		if (!tz)
> +			continue;
>  		err = tegra_soctherm_set_hwtrips(dev, soc->ttgs[i], tz);

Same here:

		if (!tz)
			continue;

		err = ...

Thierry

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