From mboxrd@z Thu Jan  1 00:00:00 1970
From: mark.rutland@arm.com (Mark Rutland)
Date: Wed, 1 Apr 2015 14:24:00 +0100
Subject: [RESEND PATCH 4/8] layerscape/ftm: Add compatible string for
 FTM0 be used as alarm timer.
In-Reply-To: <1427888858-29636-5-git-send-email-bhupesh.sharma@freescale.com>
References: <1427888858-29636-1-git-send-email-bhupesh.sharma@freescale.com>
 <1427888858-29636-5-git-send-email-bhupesh.sharma@freescale.com>
Message-ID: <20150401132400.GF11403@leverpostej>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Apr 01, 2015 at 12:47:34PM +0100, Bhupesh Sharma wrote:
> From: Wang Dongsheng <dongsheng.wang@freescale.com>
> 
> Only FTM0 can be used as an alarm timer, so add a "fsl,ftm-alarm"
> compatible string to describe FTM0 alarm mode.
> 
> Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
> Reviewed-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
> ---
>  .../devicetree/bindings/timer/fsl,ftm-timer.txt    |   46 ++++++++++++++------
>  1 file changed, 32 insertions(+), 14 deletions(-)

Shouldn't there be a corresponding driver update?

There wasn't one in this series.

> 
> diff --git a/Documentation/devicetree/bindings/timer/fsl,ftm-timer.txt b/Documentation/devicetree/bindings/timer/fsl,ftm-timer.txt
> index aa8c402..a372ed7 100644
> --- a/Documentation/devicetree/bindings/timer/fsl,ftm-timer.txt
> +++ b/Documentation/devicetree/bindings/timer/fsl,ftm-timer.txt
> @@ -2,12 +2,18 @@ Freescale FlexTimer Module (FTM) Timer
>  
>  Required properties:
>  
> -- compatible : should be "fsl,ftm-timer"
> +- compatible : should be "fsl,ftm-timer" & "fsl,ftm-alarm".
> +  (a) "fsl,ftm-timer", for FlexTimer compatible as normal timer.
> +  (b) "fsl,ftm-alarm", for FlexTimer compatible when FTM0 as an ALARM timer.


Lets not be redundant here. This would be better as:

- compatible: should contain one of:
  * "fsl,ftm-timer" for a FlexTimer usable as a normal timer.
  * "fsl,ftm-alarm" for a FlexTimer usable as an ALARM timer.

I don't think FTM0 is useful to mention here; it sounds like that's just
the name of an instance on a particular design.

What exactly is the difference between a "normal" timer and an "alarm"
timer?

> +
>  - reg : Specifies base physical address and size of the register sets for the
>    clock event device and clock source device.
> +
>  - interrupts : Should be the clock event device interrupt.
> +
>  - clocks : The clocks provided by the SoC to drive the timer, must contain an
>    entry for each entry in clock-names.
> +
>  - clock-names : Must include the following entries:
>    o "ftm-evt"
>    o "ftm-src"
> @@ -16,16 +22,28 @@ Required properties:
>  - big-endian: One boolean property, the big endian mode will be in use if it is
>    present, or the little endian mode will be in use for all the device registers.
>  
> -Example:
> -ftm: ftm at 400b8000 {
> -	compatible = "fsl,ftm-timer";
> -	reg = <0x400b8000 0x1000 0x400b9000 0x1000>;
> -	interrupts = <0 44 IRQ_TYPE_LEVEL_HIGH>;
> -	clock-names = "ftm-evt", "ftm-src",
> -		"ftm-evt-counter-en", "ftm-src-counter-en";
> -	clocks = <&clks VF610_CLK_FTM2>,
> -		<&clks VF610_CLK_FTM3>,
> -		<&clks VF610_CLK_FTM2_EXT_FIX_EN>,
> -		<&clks VF610_CLK_FTM3_EXT_FIX_EN>;
> -	big-endian;
> -};
> +Example 1: In this example, The FlexTimer module (FTM) is a two-to-eight,
> +	   channel timer that supports input capture, output compare, and
> +	   the generation of PWM signals to control electric motor and power
> +	   management applications.
> +
> +	ftm: ftm at 400b8000 {
> +		compatible = "fsl,ftm-timer";
> +		reg = <0x400b8000 0x1000 0x400b9000 0x1000>;
> +		interrupts = <0 44 IRQ_TYPE_LEVEL_HIGH>;
> +		clock-names = "ftm-evt", "ftm-src",
> +			"ftm-evt-counter-en", "ftm-src-counter-en";
> +		clocks = <&clks VF610_CLK_FTM2>,
> +			<&clks VF610_CLK_FTM3>,
> +			<&clks VF610_CLK_FTM2_EXT_FIX_EN>,
> +			<&clks VF610_CLK_FTM3_EXT_FIX_EN>;
> +		big-endian;
> +	};
> +
> +Example 2: In this example, FTM0 only be used as an alarm timer.

Do you mean that FTM0 is the only instance usable as an alarm timer, or
that the FTM0 instance can only be used as an alarm timer?

> +
> +	ftm0: ftm0 at 2800000 {
> +		compatible = "fsl,ftm-alarm";
> +		reg = <0x0 0x2800000 0x0 0x10000>;
> +		interrupts = <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>;
> +	};

Missing properties?

Mark.