Re: [RFC v2 5/5] cpufreq: add driver for Raspbery Pi

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: stefan.wahren@i2se.com, f.fainelli@gmail.com,
	linux-arm-kernel@lists.infradead.org, ptesarik@suse.com,
	sboyd@kernel.org, mturquette@baylibre.com,
	linux-pm@vger.kernel.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	linux-kernel@vger.kernel.org, eric@anholt.net,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
	mbrugger@suse.de, ssuloev@orpaltech.com
Subject: Re: [RFC v2 5/5] cpufreq: add driver for Raspbery Pi
Date: Mon, 20 May 2019 16:21:00 +0530	[thread overview]
Message-ID: <20190520105100.hol6cmvnsf3exzes@vireshk-i7> (raw)
In-Reply-To: <20190520104708.11980-6-nsaenzjulienne@suse.de>

On 20-05-19, 12:47, Nicolas Saenz Julienne wrote:
> Raspberry Pi's firmware offers and interface though which update it's
> performance requirements. It allows us to request for specific runtime
> frequencies, which the firmware might or might not respect, depending on
> the firmware configuration and thermals.
> 
> As the maximum and minimum frequencies are configurable in the firmware
> there is no way to know in advance their values. So the Raspberry Pi
> cpufreq driver queries them, builds an opp frequency table to then
> launch cpufreq-dt.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> ---
>  drivers/cpufreq/Kconfig.arm           |  8 +++
>  drivers/cpufreq/Makefile              |  1 +
>  drivers/cpufreq/raspberrypi-cpufreq.c | 83 +++++++++++++++++++++++++++
>  3 files changed, 92 insertions(+)
>  create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 179a1d302f48..f6eba7ae50d0 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -308,3 +308,11 @@ config ARM_PXA2xx_CPUFREQ
>  	  This add the CPUFreq driver support for Intel PXA2xx SOCs.
>  
>  	  If in doubt, say N.
> +
> +config ARM_RASPBERRYPI_CPUFREQ
> +	tristate "Raspberry Pi cpufreq support"
> +	depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST
> +	help
> +	  This adds the CPUFreq driver for Raspberry Pi
> +
> +	  If in doubt, say N.
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 689b26c6f949..02678e9b2ff5 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o
>  obj-$(CONFIG_ARM_TEGRA186_CPUFREQ)	+= tegra186-cpufreq.o
>  obj-$(CONFIG_ARM_TI_CPUFREQ)		+= ti-cpufreq.o
>  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)	+= vexpress-spc-cpufreq.o
> +obj-$(CONFIG_ARM_RASPBERRYPI_CPUFREQ) 	+= raspberrypi-cpufreq.o

My bad sorry, I noticed this earlier and forgot to comment. The above
two files are maintained in alphabetical order, please add the entries
at relevant places.

>  ##################################################################################
> diff --git a/drivers/cpufreq/raspberrypi-cpufreq.c b/drivers/cpufreq/raspberrypi-cpufreq.c
> new file mode 100644
> index 000000000000..a85988867d56
> --- /dev/null
> +++ b/drivers/cpufreq/raspberrypi-cpufreq.c
> @@ -0,0 +1,83 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Raspberry Pi cpufreq driver
> + *
> + * Copyright (C) 2019, Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> + */
> +
> +#include <linux/of.h>
> +#include <linux/clk.h>
> +#include <linux/cpu.h>
> +#include <linux/module.h>
> +#include <linux/pm_opp.h>
> +#include <linux/cpufreq.h>
> +#include <linux/platform_device.h>

Would be better to keep above in alphabetical order as well.

Please don't send another version now and wait for comments on the
other patches.

-- 
viresh

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