linux-kernel - Re: [PATCH v11 1/2] cpufreq: Add Kryo CPU scaling driver

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Date:   Wed, 23 May 2018 14:25:22 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Ilia Lin <ilialin@...eaurora.org>, vireshk@...nel.org, nm@...com,
        sboyd@...nel.org, robh@...nel.org, mark.rutland@....com,
        rjw@...ysocki.net, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Sudeep Holla <sudeep.holla@....com>
Subject: Re: [PATCH v11 1/2] cpufreq: Add Kryo CPU scaling driver



On 23/05/18 13:38, Ilia Lin wrote:
> In Certain QCOM SoCs like apq8096 and msm8996 that have KRYO processors,
> the CPU frequency subset and voltage value of each OPP varies
> based on the silicon variant in use. Qualcomm Process Voltage Scaling Tables
> defines the voltage and frequency value based on the msm-id in SMEM
> and speedbin blown in the efuse combination.
> The qcom-cpufreq-kryo driver reads the msm-id and efuse value from the SoC
> to provide the OPP framework with required information.
> This is used to determine the voltage and frequency value for each OPP of
> operating-points-v2 table when it is parsed by the OPP framework.
> 
> Signed-off-by: Ilia Lin <ilialin@...eaurora.org>
> ---
>  drivers/cpufreq/Kconfig.arm          |  10 ++
>  drivers/cpufreq/Makefile             |   1 +
>  drivers/cpufreq/cpufreq-dt-platdev.c |   3 +
>  drivers/cpufreq/qcom-cpufreq-kryo.c  | 181 +++++++++++++++++++++++++++++++++++
>  4 files changed, 195 insertions(+)
>  create mode 100644 drivers/cpufreq/qcom-cpufreq-kryo.c
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index de55c7d..0bfd40e 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -124,6 +124,16 @@ config ARM_OMAP2PLUS_CPUFREQ
>  	depends on ARCH_OMAP2PLUS
>  	default ARCH_OMAP2PLUS
>  
> +config ARM_QCOM_CPUFREQ_KRYO
> +	bool "Qualcomm Kryo based CPUFreq"
> +	depends on QCOM_QFPROM
> +	depends on QCOM_SMEM
> +	select PM_OPP
> +	help
> +	  This adds the CPUFreq driver for Qualcomm Kryo SoC based boards.
> +
> +	  If in doubt, say N.
> +

Sorry but just noticed now, any reason why this can't be module. I can't
imagine any.

[..]

> +static int qcom_cpufreq_kryo_probe(struct platform_device *pdev)
> +{
> +	struct opp_table *opp_tables[NR_CPUS] = {0};
> +	struct platform_device *cpufreq_dt_pdev;
> +	enum _msm8996_version msm8996_version;
> +	struct nvmem_cell *speedbin_nvmem;
> +	struct device_node *np;
> +	struct device *cpu_dev;

[..]

> +
> +	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
> +	if (!IS_ERR(cpufreq_dt_pdev))
> +		return 0;
> +
> +	ret = PTR_ERR(cpufreq_dt_pdev);
> +	dev_err(cpu_dev, "Failed to register platform device\n");
> +
> +free_opp:
> +	for_each_possible_cpu(cpu) {
> +		if (IS_ERR_OR_NULL(opp_tables[cpu]))
> +			break;
> +		dev_pm_opp_put_supported_hw(opp_tables[cpu]);
> +	}
> +
> +	return ret;
> +}
> +
> +static int __init qcom_cpufreq_kryo_init(void)
> +{
> +	/*
> +	 * Since the driver depends on smem and nvmem drivers, which may
> +	 * return EPROBE_DEFER, all the real activity is done in the probe,
> +	 * which may be defered as well. The init here is only registering
> +	 * a platform device.
> +	 */
> +	platform_device_register_simple("qcom-cpufreq-kryo", -1, NULL, 0);
> +	return 0;
> +}
> +module_init(qcom_cpufreq_kryo_init);

Do you need this at all ? See below on how to eliminate the need for this.

> +
> +static struct platform_driver qcom_cpufreq_kryo_driver = {
> +	.probe = qcom_cpufreq_kryo_probe,
> +	.driver = {
> +		.name = "qcom-cpufreq-kryo",
> +	},
> +};
> +builtin_platform_driver(qcom_cpufreq_kryo_driver);

Use builtin_platform_driver_probe and remove qcom_cpufreq_kryo_init
or use module_platform_driver_probe if it can be module.

-- 
Regards,
Sudeep