linux-kernel - Re: [PATCH v7 05/24] clocksource: Add a new timer-ingenic driver

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Date:   Wed, 29 Aug 2018 10:43:41 -0700
From:   Paul Burton <paul.burton@...s.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Paul Cercueil <paul@...pouillou.net>,
        Rob Herring <robh+dt@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Jonathan Corbet <corbet@....net>, od@...c.me,
        Mathieu Malaterre <malat@...ian.org>,
        linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-mips@...ux-mips.org, linux-doc@...r.kernel.org,
        linux-clk@...r.kernel.org
Subject: Re: [PATCH v7 05/24] clocksource: Add a new timer-ingenic driver

Hi Daniel,

On Wed, Aug 29, 2018 at 11:10:42AM +0200, Daniel Lezcano wrote:
> On 28/08/2018 19:23, Paul Burton wrote:
> > On Tue, Aug 21, 2018 at 07:16:16PM +0200, Paul Cercueil wrote:
> >> This driver handles the TCU (Timer Counter Unit) present on the Ingenic
> >> JZ47xx SoCs, and provides the kernel with a system timer, and optionally
> >> with a clocksource and a sched_clock.
> >>
> >> It also provides clocks and interrupt handling to client drivers.
> >>
> >> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> >> ---
> >>
> >> Notes:
> >>      v2: Use SPDX identifier for the license
> >>     
> >>      v3: - Move documentation to its own patch
> >>          - Search the devicetree for PWM clients, and use all the TCU
> >>     	   channels that won't be used for PWM
> >>     
> >>      v4: - Add documentation about why we search for PWM clients
> >>          - Verify that the PWM clients are for the TCU PWM driver
> >>     
> >>      v5: Major overhaul. Too many changes to list. Consider it's a new
> >>          patch.
> >>     
> >>      v6: - Add two API functions ingenic_tcu_request_channel and
> >>            ingenic_tcu_release_channel. To be used by the PWM driver to
> >>            request the use of a TCU channel. The driver will now dynamically
> >>            move away the system timer or clocksource to a new TCU channel.
> >>          - The system timer now defaults to channel 0, the clocksource now
> >>            defaults to channel 1 and is no more optional. The
> >>            ingenic,timer-channel and ingenic,clocksource-channel devicetree
> >>            properties are now gone.
> >>          - Fix round_rate / set_rate not calculating the prescale divider
> >>            the same way. This caused problems when (parent_rate / div) would
> >>            give a non-integer result. The behaviour is correct now.
> >>          - The clocksource clock is turned off on suspend now.
> >>     
> >>      v7: Fix section mismatch by using builtin_platform_driver_probe()
> >>
> >>  drivers/clocksource/Kconfig         |   10 +
> >>  drivers/clocksource/Makefile        |    1 +
> >>  drivers/clocksource/ingenic-timer.c | 1124 +++++++++++++++++++++++++++++++++++
> >>  drivers/clocksource/ingenic-timer.h |   15 +
> >>  include/linux/mfd/ingenic-tcu.h     |    3 +
> >>  5 files changed, 1153 insertions(+)
> >>  create mode 100644 drivers/clocksource/ingenic-timer.c
> >>  create mode 100644 drivers/clocksource/ingenic-timer.h
> >> %
> > 
> > How is this & patch 6 of the series looking to you from a
> > drivers/clocksource perspective?
> 
> The presence of completion, mutexes, etc ... makes me think the driver
> is not going to the right direction.
> 
> I have to review the drivers again but it will take some time because
> I'm returning from vacations and there are a trillion emails to sort out :/

OK no problem, thanks for the heads up!

Paul