[U-Boot] [PATCH] sunxi: fix DCDC2 output in CHIP_defconfig

[U-Boot] [PATCH] sunxi: fix DCDC2 output in CHIP_defconfig

[Maxime Ripard]

From: Boris Brezillon <boris.brezillon@free-electrons.com>

Unlike the datasheet recommendation, the R8 SoC requires a 1.4V supply
for its CPU when operating at 1Ghz.

Rely on the default value specified in the Kconfig entry.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 configs/CHIP_defconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/configs/CHIP_defconfig b/configs/CHIP_defconfig
index 78b2c511bfa2..3135d1c88e79 100644
--- a/configs/CHIP_defconfig
+++ b/configs/CHIP_defconfig
@@ -9,7 +9,6 @@ CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=2"
 # CONFIG_CMD_IMLS is not set
 CONFIG_CMD_GPIO=y
-CONFIG_AXP_DCDC2_VOLT=1300
 CONFIG_AXP_ALDO3_VOLT=3300
 CONFIG_AXP_ALDO4_VOLT=3300
 CONFIG_USB_MUSB_GADGET=y
-- 
2.7.1

[U-Boot] [PATCH] sunxi: fix DCDC2 output in CHIP_defconfig

[Siarhei Siamashka]

On Mon,  7 Mar 2016 13:44:11 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> From: Boris Brezillon <boris.brezillon@free-electrons.com>
> 
> Unlike the datasheet recommendation, the R8 SoC requires a 1.4V supply
> for its CPU when operating at 1Ghz.

That's interesting. Is this R8 SoC datasheet with the Allwinner
recommended cpufreq operating points available in public access
somewhere?

Are they really recommending 1008MHz @1.3V there?

> Rely on the default value specified in the Kconfig entry.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  configs/CHIP_defconfig | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/configs/CHIP_defconfig b/configs/CHIP_defconfig
> index 78b2c511bfa2..3135d1c88e79 100644
> --- a/configs/CHIP_defconfig
> +++ b/configs/CHIP_defconfig
> @@ -9,7 +9,6 @@ CONFIG_SPL=y
>  CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=2"
>  # CONFIG_CMD_IMLS is not set
>  CONFIG_CMD_GPIO=y
> -CONFIG_AXP_DCDC2_VOLT=1300
>  CONFIG_AXP_ALDO3_VOLT=3300
>  CONFIG_AXP_ALDO4_VOLT=3300
>  CONFIG_USB_MUSB_GADGET=y

-- 
Best regards,
Siarhei Siamashka

[U-Boot] [PATCH] sunxi: fix DCDC2 output in CHIP_defconfig

[Maxime Ripard]

On Mon, Mar 07, 2016 at 03:50:11PM +0200, Siarhei Siamashka wrote:
> On Mon,  7 Mar 2016 13:44:11 +0100
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
> > From: Boris Brezillon <boris.brezillon@free-electrons.com>
> > 
> > Unlike the datasheet recommendation, the R8 SoC requires a 1.4V supply
> > for its CPU when operating at 1Ghz.
> 
> That's interesting. Is this R8 SoC datasheet with the Allwinner
> recommended cpufreq operating points available in public access
> somewhere?

Yeah:
https://github.com/NextThingCo/CHIP-Hardware/tree/master/CHIP%5Bv1_0%5D/CHIPv1_0-BOM-Datasheets

But note that it's the usual datasheet from Allwinner, you don't have
a list of operating points.

> Are they really recommending 1008MHz @1.3V there?

It was a misunderstanding on our side. We thought that the nominal
tension was the recommended one, and our prototypes were running just
fine with it. Later samples (probably from a different batch) turned
out to have memory corruptions because of the lower voltage.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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[U-Boot] [PATCH] sunxi: fix DCDC2 output in CHIP_defconfig

[Hans de Goede]

Hi,

On 07-03-16 13:44, Maxime Ripard wrote:
> From: Boris Brezillon <boris.brezillon@free-electrons.com>
>
> Unlike the datasheet recommendation, the R8 SoC requires a 1.4V supply
> for its CPU when operating at 1Ghz.
>
> Rely on the default value specified in the Kconfig entry.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Thanks, merged.

Regards,

Hans


> ---
>   configs/CHIP_defconfig | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/configs/CHIP_defconfig b/configs/CHIP_defconfig
> index 78b2c511bfa2..3135d1c88e79 100644
> --- a/configs/CHIP_defconfig
> +++ b/configs/CHIP_defconfig
> @@ -9,7 +9,6 @@ CONFIG_SPL=y
>   CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=2"
>   # CONFIG_CMD_IMLS is not set
>   CONFIG_CMD_GPIO=y
> -CONFIG_AXP_DCDC2_VOLT=1300
>   CONFIG_AXP_ALDO3_VOLT=3300
>   CONFIG_AXP_ALDO4_VOLT=3300
>   CONFIG_USB_MUSB_GADGET=y
>