From: Stefan Wahren <stefan.wahren@i2se.com>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Florian Fainelli <f.fainelli@gmail.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
bcm-kernel-feedback-list@broadcom.com,
Eric Anholt <eric@anholt.net>
Cc: linux-pm@vger.kernel.org, sboyd@kernel.org,
viresh.kumar@linaro.org, mturquette@baylibre.com,
ptesarik@suse.com, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, mbrugger@suse.de,
linux-rpi-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, ssuloev@orpaltech.com
Subject: Re: [RFC v2 3/5] clk: bcm2835: use firmware interface to update pllb
Date: Tue, 21 May 2019 14:40:58 +0200 [thread overview]
Message-ID: <6383b357-3f7e-f031-f59f-61c598e44763@i2se.com> (raw)
In-Reply-To: <ebc78880-418f-f507-021c-41295113e041@i2se.com>
Hi Nicolas,
On 20.05.19 14:11, Stefan Wahren wrote:
> Hi Nicolas,
>
> the following comments applies only in case Eric is fine with the whole
> approach.
>
> On 20.05.19 12:47, Nicolas Saenz Julienne wrote:
>> Raspberry Pi's firmware, which runs in a dedicated processor, keeps
> maybe we should clarify that the firmware is running in the VPU
>> track of the board's temperature and voltage. It's resposible for
>> scaling the CPU frequency whenever it deems the device reached an unsafe
>> state. On top of that the firmware provides an interface which allows
>> Linux to to query the clock's state or change it's frequency.
> I think this requires a separate update of the devicetree binding.
>> Being the sole user of the bcm2835 clock driver, this integrates the
>> firmware interface into the clock driver and adds a first user: the CPU
>> pll, also known as 'pllb'.
> Please verify that the kernel still works (and this clock driver probe)
> under the following conditions:
>
> - CONFIG_RASPBERRYPI_FIRMWARE=n
> - CONFIG_RASPBERRYPI_FIRMWARE=m
> - older DTBs without patch #1
i thought about this and the case this driver would return
-EPROBE_DEFER. The clock driver is too essential for doing such a thing.
So i think the best solution would be to move these changes into a
separate driver which should be register by the clock driver (similiar
to vchiq). This also avoid the need of a new device tree binding.
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next prev parent reply other threads:[~2019-05-21 12:41 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-20 10:47 [RFC v2 0/5] cpufreq support for the Raspberry Pi Nicolas Saenz Julienne
2019-05-20 10:47 ` [RFC v2 1/5] clk: bcm2835: set CLK_GET_RATE_NOCACHE on CPU clocks Nicolas Saenz Julienne
2019-05-20 11:42 ` Stefan Wahren
2019-05-20 10:47 ` [RFC v2 2/5] clk: bcm2835: set pllb_arm divisor as readonly Nicolas Saenz Julienne
2019-05-20 11:43 ` Stefan Wahren
2019-05-20 10:47 ` [RFC v2 3/5] clk: bcm2835: use firmware interface to update pllb Nicolas Saenz Julienne
2019-05-20 12:11 ` Stefan Wahren
2019-05-20 12:14 ` Stefan Wahren
2019-05-21 12:40 ` Stefan Wahren [this message]
2019-05-21 15:47 ` Nicolas Saenz Julienne
2019-05-21 21:43 ` Stefan Wahren
2019-05-23 8:51 ` Nicolas Saenz Julienne
2019-05-20 12:43 ` Oliver Neukum
2019-05-21 11:39 ` Nicolas Saenz Julienne
2019-05-21 12:14 ` Petr Tesarik
2019-05-21 12:18 ` Nicolas Saenz Julienne
2019-05-20 10:47 ` [RFC v2 4/5] dts: bcm2837: add per-cpu clock devices Nicolas Saenz Julienne
2019-05-20 12:19 ` Stefan Wahren
2019-05-21 11:40 ` Nicolas Saenz Julienne
2019-05-20 10:47 ` [RFC v2 5/5] cpufreq: add driver for Raspbery Pi Nicolas Saenz Julienne
2019-05-20 10:51 ` Viresh Kumar
2019-05-20 12:30 ` Stefan Wahren
2019-05-20 10:51 ` [RFC v2 0/5] cpufreq support for the Raspberry Pi Viresh Kumar
2019-05-21 12:02 ` Nicolas Saenz Julienne
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