Re: [PATCH v3 1/2] cpufreq: imx6q/thermal: imx: register cooling device depending on OF

[Lucas Stach <l.stach@pengutronix.de>]

Am Freitag, den 08.06.2018, 11:06 +0200 schrieb Bastian Stender:
> The cooling device should be part of the i.MX cpufreq driver, but it
> cannot be removed for the sake of DT stability. So turn the cooling
> device registration into a separate function and perform the
> registration only if the CPU OF node does not have the #cooling-cells
> property.
> 
> Use of_cpufreq_power_cooling_register in imx_thermal code to link the
> cooling device to the device tree node provided.
> 
> This makes it possible to bind the cpufreq cooling device to a custom
> thermal zone via a cooling-maps entry like:
> 
> 	cooling-maps {
> > 		map0 {
> > 			trip = <&board_alert>;
> > 			cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> > 		};
> 	};
> 
> Assuming a cpu node exists with label "cpu0" and #cooling-cells
> property.
> 
> Signed-off-by: Bastian Stender <bst@pengutronix.de>

Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

> ---
> Changes since v2:
> - replace of_cpufreq_power_cooling_register with
>   of_cpufreq_cooling_register already handling capacitance/#cooling-cells
>   properties
> 
> Changes since implicit v1 ("cpufreq: imx6q/thermal: imx: move CPU cooling device from thermal to cpufreq",
> > id:20171115092332.9320-1-bst@pengutronix.de):
> 
> - create cooling device in imx_thermal in case no #cooling-cells
>   property is available instead of removing it (DT stability)
> - fix indentation
> ---
>  drivers/cpufreq/imx6q-cpufreq.c | 21 +++++++++++++++++++++
>  drivers/thermal/imx_thermal.c   | 28 ++++++++++++++++++++++++----
>  2 files changed, 45 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> index 83cf631fc9bc..a9259fb0302f 100644
> --- a/drivers/cpufreq/imx6q-cpufreq.c
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -9,6 +9,7 @@
>  #include <linux/clk.h>
>  #include <linux/cpu.h>
>  #include <linux/cpufreq.h>
> +#include <linux/cpu_cooling.h>
>  #include <linux/err.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> @@ -50,6 +51,7 @@ static struct clk_bulk_data clks[] = {
>  };
>  
>  static struct device *cpu_dev;
> +static struct thermal_cooling_device *cdev;
>  static bool free_opp;
>  static struct cpufreq_frequency_table *freq_table;
>  static unsigned int max_freq;
> @@ -191,6 +193,16 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
> >  	return 0;
>  }
>  
> +static void imx6q_cpufreq_ready(struct cpufreq_policy *policy)
> +{
> > +	cdev = of_cpufreq_cooling_register(policy);
> +
> > +	if (!cdev)
> > +		dev_err(cpu_dev,
> > +			"running cpufreq without cooling device: %ld\n",
> > +			PTR_ERR(cdev));
> +}
> +
>  static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
>  {
> >  	int ret;
> @@ -202,13 +214,22 @@ static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
> >  	return ret;
>  }
>  
> +static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
> +{
> > +	cpufreq_cooling_unregister(cdev);
> +
> > +	return 0;
> +}
> +
>  static struct cpufreq_driver imx6q_cpufreq_driver = {
> >  	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
> >  	.verify = cpufreq_generic_frequency_table_verify,
> >  	.target_index = imx6q_set_target,
> >  	.get = cpufreq_generic_get,
> >  	.init = imx6q_cpufreq_init,
> > +	.exit = imx6q_cpufreq_exit,
> >  	.name = "imx6q-cpufreq",
> > +	.ready = imx6q_cpufreq_ready,
> >  	.attr = cpufreq_generic_attr,
> >  	.suspend = cpufreq_generic_suspend,
>  };
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index 334d98be03b9..cbfcca828cd7 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -3,6 +3,7 @@
>  // Copyright 2013 Freescale Semiconductor, Inc.
>  
>  #include <linux/clk.h>
> +#include <linux/cpu.h>
>  #include <linux/cpufreq.h>
>  #include <linux/cpu_cooling.h>
>  #include <linux/delay.h>
> @@ -644,6 +645,27 @@ static const struct of_device_id of_imx_thermal_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, of_imx_thermal_match);
>  
> +/*
> + * 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);
> > +	int ret;
> +
> > +	if (!np || !of_find_property(np, "#cooling-cells", NULL)) {
> > +		data->cdev = cpufreq_cooling_register(data->policy);
> > +		if (IS_ERR(data->cdev)) {
> > +			ret = PTR_ERR(data->cdev);
> > +			cpufreq_cpu_put(data->policy);
> > +			return ret;
> > +		}
> > +	}
> +
> > +	return 0;
> +}
> +
>  static int imx_thermal_probe(struct platform_device *pdev)
>  {
> >  	struct imx_thermal_data *data;
> @@ -724,12 +746,10 @@ static int imx_thermal_probe(struct platform_device *pdev)
> >  		return -EPROBE_DEFER;
> >  	}
>  
> > -	data->cdev = cpufreq_cooling_register(data->policy);
> > -	if (IS_ERR(data->cdev)) {
> > -		ret = PTR_ERR(data->cdev);
> > +	ret = imx_thermal_register_legacy_cooling(data);
> > +	if (ret) {
> >  		dev_err(&pdev->dev,
> >  			"failed to register cpufreq cooling device: %d\n", ret);
> > -		cpufreq_cpu_put(data->policy);
> >  		return ret;
> >  	}
>