Re: [PATCH 06/14] drivers: reset: Add STM32 reset driver

From: "Andreas Färber" <afaerber@suse.de>
To: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Russell King <linux@arm.linux.org.uk>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.cz>, Arnd Bergmann <arnd@arndb.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	"David S. Miller" <davem@davemloft.net>,
	Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
	Joe Perches <joe@perches.com>, Antti Palosaari <crope@iki.fi>,
	Tejun Heo <tj@kernel.org>, Will Deacon <will.deacon@arm.com>,
	Nikolay Borisov <Nikolay.Borisov@arm.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Kees Cook <keescook@chromium.org>, Michal Marek <mmarek@suse.cz>,
	linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-gpio@vger.kernel.org, linux-serial@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-api@vger.kernel.org
Subject: Re: [PATCH 06/14] drivers: reset: Add STM32 reset driver
Date: Mon, 16 Feb 2015 00:59:18 +0100	[thread overview]
Message-ID: <54E132D6.6010608@suse.de> (raw)
In-Reply-To: <1423763164-5606-7-git-send-email-mcoquelin.stm32@gmail.com>

Am 12.02.2015 um 18:45 schrieb Maxime Coquelin:
> The STM32 MCUs family IP can be reset by accessing some shared registers.
> 
> The specificity is that some reset lines are used by the timers.
> At timer initialization time, the timer has to be reset, that's why
> we cannot use a regular driver.
> 
> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> ---
>  .../devicetree/bindings/reset/st,stm32-reset.txt   |  19 ++++
>  drivers/reset/Makefile                             |   1 +
>  drivers/reset/reset-stm32.c                        | 124 +++++++++++++++++++++
>  3 files changed, 144 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/reset/st,stm32-reset.txt
>  create mode 100644 drivers/reset/reset-stm32.c
> 
> diff --git a/Documentation/devicetree/bindings/reset/st,stm32-reset.txt b/Documentation/devicetree/bindings/reset/st,stm32-reset.txt
> new file mode 100644
> index 0000000..add1298
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reset/st,stm32-reset.txt
> @@ -0,0 +1,19 @@
> +STMicroelectronics STM32 Peripheral Reset Controller
> +====================================================
> +
> +Please also refer to reset.txt in this directory for common reset
> +controller binding usage.
> +
> +Required properties:
> +- compatible: Should be "st,stm32-reset"
> +- reg: should be register base and length as documented in the
> +  datasheet
> +- #reset-cells: 1, see below
> +
> +example:
> +
> +reset_ahb1: reset@40023810 {
> +	#reset-cells = <1>;
> +	compatible = "st,stm32-reset";
> +	reg = <0x40023810 0x4>;
> +};
[snip]

RM0090 has two different chapters on the RCC IP:
* Reset and clock control for STM32F42xxx and STM32F43xxx (RCC)
* Reset and clock control for STM32F405xx/07xx and STM32F415xx/17xx(RCC)

I therefore feel it is wrong to use "stm32-" here; instead I used
"st,stm32f429-rcc" (also relates to 12/14 discussion). This may apply to
other identifiers, too.

Regards,
Andreas

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