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Message-ID: <1467653766.2224.76.camel@pengutronix.de>
Date: Mon, 04 Jul 2016 19:36:06 +0200
From: Philipp Zabel <p.zabel@...gutronix.de>
To: gabriel.fernandez@...com
Cc: Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Russell King <linux@...linux.org.uk>, patrice.chotard@...com,
alexandre.torgue@...com, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] dt-bindings: Document the STM32 reset bindings
Am Montag, den 04.07.2016, 15:47 +0200 schrieb gabriel.fernandez@...com:
> From: Maxime Coquelin <mcoquelin.stm32@...il.com>
>
> This adds documentation of device tree bindings for the
> STM32 reset controller.
>
> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@...il.com>
The way I understand Documentation/SubmittingPatches, this should also
have your Signed-off-by.
> ---
> .../devicetree/bindings/reset/st,stm32-rcc.txt | 50 ++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/reset/st,stm32-rcc.txt
>
> diff --git a/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt b/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt
> new file mode 100644
> index 0000000..333080c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt
> @@ -0,0 +1,50 @@
> +STMicroelectronics STM32 Peripheral Reset Controller
> +====================================================
> +
> +The RCC IP is both a reset and a clock controller. This documentation only
> +documents the reset part.
> +
> +Please also refer to reset.txt in this directory for common reset
> +controller binding usage.
> +
> +Required properties:
> +- compatible: Should be "st,stm32-rcc"
> +- reg: should be register base and length as documented in the
> + datasheet
> +- #reset-cells: 1, see below
> +
> +example:
> +
> +rcc: reset@...23800 {
> + #reset-cells = <1>;
> + compatible = "st,stm32-rcc";
> + reg = <0x40023800 0x400>;
> +};
> +
> +Specifying softreset control of devices
> +=======================================
> +
> +Device nodes should specify the reset channel required in their "resets"
> +property, containing a phandle to the reset device node and an index specifying
> +which channel to use.
> +The index is the bit number within the RCC registers bank, starting from RCC
> +base address.
> +It is calculated as: index = register_offset / 4 * 32 + bit_offset.
> +Where bit_offset is the bit offset within the register.
> +For example, for CRC reset:
> + crc = AHB1RSTR_offset / 4 * 32 + CRCRST_bit_offset = 0x10 / 4 * 32 + 12 = 140
I see you decided to keep the register offset encoded in the reset
index.
> +
> +To simplify the usagen and to share bit definition with the clock driver of
s/usagen/usage/
> +the RCC IP, macros are available to generate the index in human-readble
> +format.
> +
> +For STM32F4 series, the macro are available here:
> + - include/dt-bindings/mfd/stm32f4-rcc.h
If DT and ARM/STI and maintainers agree with the binding and header
macros, I'm inclined to take patches 1-3.
regards
Philipp
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