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Message-ID: <20180322153347.GX3417@piout.net>
Date: Thu, 22 Mar 2018 16:33:47 +0100
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Nicolas Ferre <nicolas.ferre@...rochip.com>,
Boris Brezillon <boris.brezillon@...tlin.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/6] clocksource: rework Atmel TCB timer driver
Hi Daniel,
I'd really like to get this in the kernel soon as we have platform that
still can't boot with a mainline kernel because they don't have a PIT.
On 23/02/2018 at 18:15:52 +0100, Alexandre Belloni wrote:
> Hi,
>
> This series gets back on the TCB drivers rework. It introduces a new driver to
> handle the clocksource and clockevent devices.
>
> As a reminder, this is necessary because:
> - the current tcb_clksrc driver is probed too late to be able to be used at
> boot and we now have SoCs that don't have a PIT. They currently are not able
> to boot a mainline kernel.
> - using the PIT doesn't work well with preempt-rt because its interrupt is
> shared (in particular with the UART and their interrupt flags are
> incompatible)
> - the current solution is wasting some TCB channels
>
> The plan is to get this driver upstream, then convert the TCB PWM driver to be
> able to get rid of the tcb_clksrc driver along with atmel_tclib.
>
> changes in v3:
> - use SPDX tag in include/soc/at91/atmel_tcb.h
> - rework option selection to make the clocksource option silent
>
> Main changes in v2:
> - use direct IO instead of regmap when accessing channel specific registers to
> avoid the regmap locking
> - implement suspend/resume
>
>
> Alexandre Belloni (6):
> ARM: at91: add TCB registers definitions
> clocksource/drivers: Add a new driver for the Atmel ARM TC blocks
> clocksource/drivers: atmel-pit: make option silent
> ARM: at91: Implement clocksource selection
> ARM: configs: at91: use new TCB timer driver
> ARM: configs: at91: unselect PIT
>
> arch/arm/configs/at91_dt_defconfig | 2 +-
> arch/arm/configs/sama5_defconfig | 2 +-
> arch/arm/mach-at91/Kconfig | 25 ++
> drivers/clocksource/Kconfig | 13 +-
> drivers/clocksource/Makefile | 3 +-
> drivers/clocksource/timer-atmel-tcb.c | 608 ++++++++++++++++++++++++++++++++++
> include/soc/at91/atmel_tcb.h | 216 ++++++++++++
> 7 files changed, 865 insertions(+), 4 deletions(-)
> create mode 100644 drivers/clocksource/timer-atmel-tcb.c
> create mode 100644 include/soc/at91/atmel_tcb.h
>
> --
> 2.16.1
>
--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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