linux-kernel - Re: [PATCH V4] thermal: imx: fix for dependency on cpu-freq

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Date:   Wed, 21 Nov 2018 10:50:53 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Anson Huang <anson.huang@....com>
Cc:     "rui.zhang@...el.com" <rui.zhang@...el.com>,
        "edubezval@...il.com" <edubezval@...il.com>,
        "daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        dl-linux-imx <linux-imx@....com>
Subject: Re: [PATCH V4] thermal: imx: fix for dependency on cpu-freq

On 21-11-18, 05:08, Anson Huang wrote:
> The thermal driver is a standalone driver for monitoring SoC temperature
> by enabling thermal sensor, so it can be enabled even when CONFIG_CPU_FREQ
> is NOT set. So remove the dependency with CPU_THERMAL.
> 
> Introduce dummy function of legacy cooling register/unregister to make
> thermal driver probe successfully when CONFIG_CPU_FREQ is NOT set.
> 
> Signed-off-by: Anson Huang <Anson.Huang@....com>
> ---
> changes since V3:
> 	rename the label of "cpufreq_put" with "legacy_cleanup".
>  drivers/thermal/Kconfig       |  2 +-
>  drivers/thermal/imx_thermal.c | 44 +++++++++++++++++++++++++++++++------------
>  2 files changed, 33 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 5422523..93bd3bb 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -212,7 +212,7 @@ config HISI_THERMAL
>  
>  config IMX_THERMAL
>  	tristate "Temperature sensor driver for Freescale i.MX SoCs"
> -	depends on (ARCH_MXC && CPU_THERMAL) || COMPILE_TEST
> +	depends on ARCH_MXC || COMPILE_TEST
>  	depends on NVMEM || !NVMEM
>  	depends on MFD_SYSCON
>  	depends on OF
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index 1566154..328ee05 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -648,15 +648,24 @@ static const struct of_device_id of_imx_thermal_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, of_imx_thermal_match);
>  
> +#ifdef CONFIG_CPU_FREQ
>  /*
>   * Create cooling device in case no #cooling-cells property is available in
>   * CPU node
>   */
>  static int imx_thermal_register_legacy_cooling(struct imx_thermal_data *data)
>  {
> -	struct device_node *np = of_get_cpu_node(data->policy->cpu, NULL);
> +	struct device_node *np;
>  	int ret;
>  
> +	data->policy = cpufreq_cpu_get(0);
> +	if (!data->policy) {
> +		pr_debug("%s: CPUFreq policy not found\n", __func__);
> +		return -EPROBE_DEFER;
> +	}
> +
> +	np = of_get_cpu_node(data->policy->cpu, NULL);
> +
>  	if (!np || !of_find_property(np, "#cooling-cells", NULL)) {
>  		data->cdev = cpufreq_cooling_register(data->policy);
>  		if (IS_ERR(data->cdev)) {
> @@ -669,6 +678,22 @@ static int imx_thermal_register_legacy_cooling(struct imx_thermal_data *data)
>  	return 0;
>  }
>  
> +static void imx_thermal_unregister_legacy_cooling(struct imx_thermal_data *data)
> +{
> +	cpufreq_cooling_unregister(data->cdev);
> +	cpufreq_cpu_put(data->policy);
> +}
> +#else
> +static inline int imx_thermal_register_legacy_cooling(struct imx_thermal_data *data)
> +{
> +	return 0;
> +}
> +
> +static inline void imx_thermal_unregister_legacy_cooling(struct imx_thermal_data *data)
> +{
> +}
> +#endif
> +
>  static int imx_thermal_probe(struct platform_device *pdev)
>  {
>  	struct imx_thermal_data *data;
> @@ -743,13 +768,9 @@ static int imx_thermal_probe(struct platform_device *pdev)
>  	regmap_write(map, data->socdata->sensor_ctrl + REG_SET,
>  		     data->socdata->power_down_mask);
>  
> -	data->policy = cpufreq_cpu_get(0);
> -	if (!data->policy) {
> -		pr_debug("%s: CPUFreq policy not found\n", __func__);
> -		return -EPROBE_DEFER;
> -	}
> -
>  	ret = imx_thermal_register_legacy_cooling(data);
> +	if (ret == -EPROBE_DEFER)
> +		return ret;
>  	if (ret) {

Sorry for not noticing earlier, but wouldn't it be better to move the
EPROBE_DEFER check inside of this if block ? Otherwise we will have
two conditional blocks in the success (normal) case.

Something like this:

if (ret) {
        if (ret == -EPROBE_DEFER)
                return ret;

        dev_err(..);
        ...
}

>  		dev_err(&pdev->dev,
>  			"failed to register cpufreq cooling device: %d\n", ret);
> @@ -762,7 +783,7 @@ static int imx_thermal_probe(struct platform_device *pdev)
>  		if (ret != -EPROBE_DEFER)
>  			dev_err(&pdev->dev,
>  				"failed to get thermal clk: %d\n", ret);
> -		goto cpufreq_put;
> +		goto legacy_cleanup;
>  	}
>  
>  	/*
> @@ -775,7 +796,7 @@ static int imx_thermal_probe(struct platform_device *pdev)
>  	ret = clk_prepare_enable(data->thermal_clk);
>  	if (ret) {
>  		dev_err(&pdev->dev, "failed to enable thermal clk: %d\n", ret);
> -		goto cpufreq_put;
> +		goto legacy_cleanup;
>  	}
>  
>  	data->tz = thermal_zone_device_register("imx_thermal_zone",
> @@ -829,9 +850,8 @@ static int imx_thermal_probe(struct platform_device *pdev)
>  	thermal_zone_device_unregister(data->tz);
>  clk_disable:
>  	clk_disable_unprepare(data->thermal_clk);
> -cpufreq_put:
> -	cpufreq_cooling_unregister(data->cdev);
> -	cpufreq_cpu_put(data->policy);
> +legacy_cleanup:
> +	imx_thermal_unregister_legacy_cooling(data);
>  
>  	return ret;
>  }
> -- 
> 2.7.4

-- 
viresh