linux-kernel - Re: [PATCH v8 03/26] dt-bindings: Add doc for the Ingenic TCU drivers

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Date:   Mon, 17 Dec 2018 15:05:31 -0600
From:   Rob Herring <robh@...nel.org>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paul.burton@...s.com>,
        James Hogan <jhogan@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Mathieu Malaterre <malat@...ian.org>,
        Ezequiel Garcia <ezequiel@...labora.co.uk>,
        PrasannaKumar Muralidharan <prasannatsmkumar@...il.com>,
        linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-mips@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-clk@...r.kernel.org, od@...c.me
Subject: Re: [PATCH v8 03/26] dt-bindings: Add doc for the Ingenic TCU drivers

On Wed, Dec 12, 2018 at 11:08:58PM +0100, Paul Cercueil wrote:
> Add documentation about how to properly use the Ingenic TCU
> (Timer/Counter Unit) drivers from devicetree.
> 
> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> ---
> 
> Notes:
>      v4: New patch in this series. Corresponds to V2 patches 3-4-5 with
>          added content.
>     
>      v5: - Edited PWM/watchdog DT bindings documentation to point to the new
>            document.
>          - Moved main document to
>            Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>          - Updated documentation to reflect the new devicetree bindings.
>     
>      v6: - Removed PWM/watchdog documentation files as asked by upstream
>          - Removed doc about properties that should be implicit
>          - Removed doc about ingenic,timer-channel /
>            ingenic,clocksource-channel as they are gone
>          - Fix WDT clock name in the binding doc
>          - Fix lengths of register areas in watchdog/pwm nodes
>     
>      v7: No change
> 
>      v8: - Fix address of the PWM node
>          - Added doc about system timer and clocksource children nodes

I thought we'd sorted this out...

> 
>  .../devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt |  25 ---
>  .../devicetree/bindings/timer/ingenic,tcu.txt      | 176 +++++++++++++++++++++
>  .../bindings/watchdog/ingenic,jz4740-wdt.txt       |  17 --
>  3 files changed, 176 insertions(+), 42 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
>  create mode 100644 Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>  delete mode 100644 Documentation/devicetree/bindings/watchdog/ingenic,jz4740-wdt.txt
> 
> diff --git a/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt b/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
> deleted file mode 100644
> index 7d9d3f90641b..000000000000
> --- a/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
> +++ /dev/null
> @@ -1,25 +0,0 @@
> -Ingenic JZ47xx PWM Controller
> -=============================
> -
> -Required properties:
> -- compatible: One of:
> -  * "ingenic,jz4740-pwm"
> -  * "ingenic,jz4770-pwm"
> -  * "ingenic,jz4780-pwm"
> -- #pwm-cells: Should be 3. See pwm.txt in this directory for a description
> -  of the cells format.
> -- clocks : phandle to the external clock.
> -- clock-names : Should be "ext".
> -
> -
> -Example:
> -
> -	pwm: pwm@...02000 {
> -		compatible = "ingenic,jz4740-pwm";
> -		reg = <0x10002000 0x1000>;
> -
> -		#pwm-cells = <3>;
> -
> -		clocks = <&ext>;
> -		clock-names = "ext";
> -	};
> diff --git a/Documentation/devicetree/bindings/timer/ingenic,tcu.txt b/Documentation/devicetree/bindings/timer/ingenic,tcu.txt
> new file mode 100644
> index 000000000000..8a4ce7edf50f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/timer/ingenic,tcu.txt
> @@ -0,0 +1,176 @@
> +Ingenic JZ47xx SoCs Timer/Counter Unit devicetree bindings
> +==========================================================
> +
> +For a description of the TCU hardware and drivers, have a look at
> +Documentation/mips/ingenic-tcu.txt.
> +
> +Required properties:
> +
> +- compatible: Must be one of:
> +  * ingenic,jz4740-tcu
> +  * ingenic,jz4725b-tcu
> +  * ingenic,jz4770-tcu
> +- reg: Should be the offset/length value corresponding to the TCU registers
> +- clocks: List of phandle & clock specifiers for clocks external to the TCU.
> +  The "pclk", "rtc", "ext" and "tcu" clocks should be provided.
> +- clock-names: List of name strings for the external clocks.
> +- #clock-cells: Should be <1>;
> +  Clock consumers specify this argument to identify a clock. The valid values
> +  may be found in <dt-bindings/clock/ingenic,tcu.h>.
> +- interrupt-controller : Identifies the node as an interrupt controller
> +- #interrupt-cells : Specifies the number of cells needed to encode an
> +  interrupt source. The value should be 1.
> +- interrupt-parent : phandle of the interrupt controller.
> +- interrupts : Specifies the interrupt the controller is connected to.
> +
> +
> +Children nodes
> +==========================================================
> +
> +
> +PWM node:
> +---------
> +
> +Required properties:
> +
> +- compatible: Must be one of:
> +  * ingenic,jz4740-pwm
> +  * ingenic,jz4725b-pwm
> +- #pwm-cells: Should be 3. See ../pwm/pwm.txt for a description of the cell
> +  format.
> +- clocks: List of phandle & clock specifiers for the TCU clocks.
> +- clock-names: List of name strings for the TCU clocks.
> +
> +
> +Watchdog node:
> +--------------
> +
> +Required properties:
> +
> +- compatible: Must be one of:
> +  * ingenic,jz4740-watchdog
> +  * ingenic,jz4780-watchdog
> +- clocks: phandle to the WDT clock
> +- clock-names: should be "wdt"
> +
> +
> +OST node:
> +---------
> +
> +Required properties:
> +
> +- compatible: Must be one of:
> +  * ingenic,jz4725b-ost
> +  * ingenic,jz4770-ost
> +- clocks: phandle to the OST clock
> +- clock-names: should be "ost"
> +- interrupts : Specifies the interrupt the OST is connected to.
> +
> +
> +System timer node:
> +------------------
> +
> +Required properties:
> +
> +- compatible: Must be "ingenic,jz4740-tcu-timer"

Is this an actual sub-block? Or just a way to assign a timer to a 
clockevent?

> +- clocks: phandle to the clock of the TCU channel used
> +- clock-names: Should be "timer"
> +- interrupts : Specifies the interrupt line of the TCU channel used.
> +
> +
> +System clocksource node:
> +------------------------
> +
> +Required properties:
> +
> +- compatible: Must be "ingenic,jz4740-tcu-clocksource"

The h/w has a block called 'clocksource'?

If there's a difference in the timer channels, then that difference 
should be described in DT, not just 'use timer X for clocksource'.

> +- clocks: phandle to the clock of the TCU channel used
> +- clock-names: Should be "timer"