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From: Juergen Borleis <juergen@kreuzholzen.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Stefan Wahren <stefan.wahren@i2se.com>,
	mark.rutland@arm.com, marex@denx.de, fabio.estevam@freescale.com,
	pawel.moll@arm.com, ijc+devicetree@hellion.org.uk,
	dbaryshkov@gmail.com, viresh.kumar@linaro.org,
	linux-pm@vger.kernel.org, rjw@rjwysocki.net, sre@kernel.org,
	robh+dt@kernel.org, lgirdwood@gmail.com,
	devicetree@vger.kernel.org, broonie@kernel.org,
	kernel@pengutronix.de, galak@codeaurora.org,
	sebastien.szymanski@armadeus.com, shawn.guo@linaro.org,
	dwmw2@infradead.org
Subject: Re: [PATCH 7/7] ARM: dts: add OPPs for i.MX23/i.MX28
Date: Tue, 24 Mar 2015 21:45:23 +0100	[thread overview]
Message-ID: <201503242145.26370.juergen@kreuzholzen.de> (raw)
In-Reply-To: <1426984203-9133-8-git-send-email-stefan.wahren@i2se.com>

Stefan Wahren wrote:
> [...]
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index 98c1be6..21c1921 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -38,12 +38,23 @@
>  	};
>
>  	cpus {
> -		#address-cells = <0>;
> +		#address-cells = <1>;
>  		#size-cells = <0>;
>
> -		cpu {
> +		cpu@0 {
>  			compatible = "arm,arm926ej-s";
>  			device_type = "cpu";
> +			reg = <0x0>;
> +			operating-points = <
> +				/* kHz	uV */
> +				261819  1350000
> +				360000  1350000
> +				392728  1450000
> +				454737  1550000
> +			>;
> +			clocks = <&clks 4>;
> +			clock-latency = <61036>; /* two CLK32 periods */
> +			cpu-supply = <&reg_vddd>;
>  		};
>  	};

Maybe you should take into account not to reduce VDD below 1.55 V if the SDRAM 
controller runs above 196 MHz. The i.MX28 datasheet[1] lists these 
restrictions. VDD powers the SDRAM controller as well. From the datasheet the 
table "Frequency versus Voltage for EMICLK" shows:
                     
             EMICLK Fmax (MHz)
VDDD (V)      DDR2       mDDR
--------------------------------
 1.550       205.71     205.71
 1.450       196.36     196.36
 1.350       196.36     196.36

jbe

[1]
  i.MX28 Applications
Processors for Consumer
     Products
  Silicon Version 1.2

Document Number: IMX28CEC
   Rev. 3, 07/2012

WARNING: multiple messages have this Message-ID (diff)
From: juergen@kreuzholzen.de (Juergen Borleis)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 7/7] ARM: dts: add OPPs for i.MX23/i.MX28
Date: Tue, 24 Mar 2015 21:45:23 +0100	[thread overview]
Message-ID: <201503242145.26370.juergen@kreuzholzen.de> (raw)
In-Reply-To: <1426984203-9133-8-git-send-email-stefan.wahren@i2se.com>

Stefan Wahren wrote:
> [...]
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index 98c1be6..21c1921 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -38,12 +38,23 @@
>  	};
>
>  	cpus {
> -		#address-cells = <0>;
> +		#address-cells = <1>;
>  		#size-cells = <0>;
>
> -		cpu {
> +		cpu at 0 {
>  			compatible = "arm,arm926ej-s";
>  			device_type = "cpu";
> +			reg = <0x0>;
> +			operating-points = <
> +				/* kHz	uV */
> +				261819  1350000
> +				360000  1350000
> +				392728  1450000
> +				454737  1550000
> +			>;
> +			clocks = <&clks 4>;
> +			clock-latency = <61036>; /* two CLK32 periods */
> +			cpu-supply = <&reg_vddd>;
>  		};
>  	};

Maybe you should take into account not to reduce VDD below 1.55 V if the SDRAM 
controller runs above 196 MHz. The i.MX28 datasheet[1] lists these 
restrictions. VDD powers the SDRAM controller as well. From the datasheet the 
table "Frequency versus Voltage for EMICLK" shows:
                     
             EMICLK Fmax (MHz)
VDDD (V)      DDR2       mDDR
--------------------------------
 1.550       205.71     205.71
 1.450       196.36     196.36
 1.350       196.36     196.36

jbe

[1]
  i.MX28 Applications
Processors for Consumer
     Products
  Silicon Version 1.2

Document Number: IMX28CEC
   Rev. 3, 07/2012

  reply	other threads:[~2015-03-24 20:45 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-22  0:29 [PATCH 0/7] power: enable cpufreq-dt support for i.MX23/i.MX28 Stefan Wahren
2015-03-22  0:29 ` Stefan Wahren
2015-03-22  0:29 ` [PATCH 1/7] DT: add binding for mxs power subsystem Stefan Wahren
2015-03-22  0:29   ` Stefan Wahren
2015-03-22  0:29 ` [PATCH 2/7] power: mxs_power: add driver " Stefan Wahren
2015-03-22  0:29   ` Stefan Wahren
2015-03-22 10:40   ` Sebastian Reichel
2015-03-22 10:40     ` Sebastian Reichel
     [not found] ` <1426984203-9133-1-git-send-email-stefan.wahren-eS4NqCHxEME@public.gmane.org>
2015-03-22  0:29   ` [PATCH 3/7] DT: add binding for MXS regulator Stefan Wahren
2015-03-22  0:29     ` Stefan Wahren
2015-03-22  0:30 ` [PATCH 4/7] regulator: add mxs regulator driver Stefan Wahren
2015-03-22  0:30   ` Stefan Wahren
2015-03-22 16:14   ` Mark Brown
2015-03-22 16:14     ` Mark Brown
2015-03-23 17:45     ` Stefan Wahren
2015-03-23 17:45       ` Stefan Wahren
2015-03-23 18:39       ` Mark Brown
2015-03-23 18:39         ` Mark Brown
2015-03-22  0:30 ` [PATCH 5/7] ARM: dts: enable regulator support for i.MX23/i.MX28 Stefan Wahren
2015-03-22  0:30   ` Stefan Wahren
2015-03-23  6:07   ` Sascha Hauer
2015-03-23  6:07     ` Sascha Hauer
2015-03-23 17:54     ` Stefan Wahren
2015-03-23 17:54       ` Stefan Wahren
2015-03-23 18:37       ` Mark Brown
2015-03-23 18:37         ` Mark Brown
     [not found]         ` <20150323183740.GI14954-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-03-24  6:45           ` Stefan Wahren
2015-03-24  6:45             ` Stefan Wahren
2015-03-24 17:01             ` Mark Brown
2015-03-24 17:01               ` Mark Brown
2015-03-24  6:12       ` Sascha Hauer
2015-03-24  6:12         ` Sascha Hauer
2015-03-22  0:30 ` [PATCH 6/7] ARM: mxs: register cpufreq-dt in pm init Stefan Wahren
2015-03-22  0:30   ` Stefan Wahren
2015-03-22  0:30 ` [PATCH 7/7] ARM: dts: add OPPs for i.MX23/i.MX28 Stefan Wahren
2015-03-22  0:30   ` Stefan Wahren
2015-03-24 20:45   ` Juergen Borleis [this message]
2015-03-24 20:45     ` Juergen Borleis
     [not found]     ` <201503242145.26370.juergen-vozXLyro3r7AVMDmWPUVSw@public.gmane.org>
2015-03-25 20:20       ` Stefan Wahren
2015-03-25 20:20         ` Stefan Wahren
2015-03-28 17:53 Stefan Wahren
2015-03-29 14:40 ` Juergen Borleis
2015-03-29 14:40   ` Juergen Borleis
2015-03-29 19:09   ` Stefan Wahren
2015-03-29 19:09     ` Stefan Wahren

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