| Message ID | 1373208662-7350-1-git-send-email-shc_work@mail.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Jul 07, 2013 at 06:51:02PM +0400, Alexander Shiyan wrote: > This patch adds core voltages for i.MX27 CPUs. Only 266 and 400 MHz modes > is documented in the datasheet, we add a 266 MHz frequency for conform this. > For 133 MHz CPU frequency minimal voltage is used (1.2V). > Ok, just checked i.MX27 data sheet, it seems that only 266 and 400 MHz set points are officially supported. So there is no documented voltage for 133 MHz. I'm wondering if we should have 133 MHz set point at all if it's not officially supported. Shawn > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > --- > arch/arm/boot/dts/imx27.dtsi | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/boot/dts/imx27.dtsi b/arch/arm/boot/dts/imx27.dtsi > index a587294..c9bacca 100644 > --- a/arch/arm/boot/dts/imx27.dtsi > +++ b/arch/arm/boot/dts/imx27.dtsi > @@ -57,13 +57,15 @@ > device_type = "cpu"; > compatible = "arm,arm926ej-s"; > operating-points = < > - /* kHz uV (No regulator support) */ > - 133000 0 > - 399000 0 > + /* kHz uV */ > + 133000 1200000 > + 266000 1300000 > + 399000 1450000 > >; > clock-latency = <61036>; /* two CLK32 periods */ > clocks = <&clks 18>; > clock-names = "cpu"; > + voltage-tolerance = <1>; > }; > }; > > -- > 1.8.1.5 >
On Mon, Jul 08, 2013 at 08:34:04AM +0400, Alexander Shiyan wrote: > > On Sun, Jul 07, 2013 at 06:51:02PM +0400, Alexander Shiyan wrote: > > > This patch adds core voltages for i.MX27 CPUs. Only 266 and 400 MHz modes > > > is documented in the datasheet, we add a 266 MHz frequency for conform this. > > > For 133 MHz CPU frequency minimal voltage is used (1.2V). > > > > > Ok, just checked i.MX27 data sheet, it seems that only 266 and 400 MHz > > set points are officially supported. So there is no documented voltage > > for 133 MHz. I'm wondering if we should have 133 MHz set point at all > > if it's not officially supported. > > Then how about removing the frequency of 133MHz, and increase tolerance > of up to 5% in order to be able to play voltages for devices demanding low > power consumption? Sounds good to me. Shawn
diff --git a/arch/arm/boot/dts/imx27.dtsi b/arch/arm/boot/dts/imx27.dtsi index a587294..c9bacca 100644 --- a/arch/arm/boot/dts/imx27.dtsi +++ b/arch/arm/boot/dts/imx27.dtsi @@ -57,13 +57,15 @@ device_type = "cpu"; compatible = "arm,arm926ej-s"; operating-points = < - /* kHz uV (No regulator support) */ - 133000 0 - 399000 0 + /* kHz uV */ + 133000 1200000 + 266000 1300000 + 399000 1450000 >; clock-latency = <61036>; /* two CLK32 periods */ clocks = <&clks 18>; clock-names = "cpu"; + voltage-tolerance = <1>; }; };
This patch adds core voltages for i.MX27 CPUs. Only 266 and 400 MHz modes is documented in the datasheet, we add a 266 MHz frequency for conform this. For 133 MHz CPU frequency minimal voltage is used (1.2V). Signed-off-by: Alexander Shiyan <shc_work@mail.ru> --- arch/arm/boot/dts/imx27.dtsi | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)