On 01/13/2017 04:12 PM, Matthias Brugger wrote:
>
>
> On 13/01/17 15:17, Boris Brezillon wrote:
>> On Fri, 13 Jan 2017 15:13:29 +0800
>> Guochun Mao <guochun.mao@xxxxxxxxxxxx> wrote:
>>
>>> Add Mediatek nor flash node.
>>>
>>> Signed-off-by: Guochun Mao <guochun.mao@xxxxxxxxxxxx>
>>> ---
>>> arch/arm/boot/dts/mt2701-evb.dts | 25 +++++++++++++++++++++++++
>>> arch/arm/boot/dts/mt2701.dtsi | 12 ++++++++++++
>>> 2 files changed, 37 insertions(+)
>>>
>>> diff --git a/arch/arm/boot/dts/mt2701-evb.dts
>>> b/arch/arm/boot/dts/mt2701-evb.dts
>>> index 082ca88..85e5ae8 100644
>>> --- a/arch/arm/boot/dts/mt2701-evb.dts
>>> +++ b/arch/arm/boot/dts/mt2701-evb.dts
>>> @@ -24,6 +24,31 @@
>>> };
>>> };
>>>
>>> +&nor_flash {
>>> + pinctrl-names = "default";
>>> + pinctrl-0 = <&nor_pins_default>;
>>> + status = "okay";
>>> + flash@0 {
>>> + compatible = "jedec,spi-nor";
>>> + reg = <0>;
>>> + };
>>> +};
>>> +
>>> +&pio {
>>> + nor_pins_default: nor {
>>> + pins1 {
>>> + pinmux = <MT2701_PIN_240_EXT_XCS__FUNC_EXT_XCS>,
>>> + <MT2701_PIN_241_EXT_SCK__FUNC_EXT_SCK>,
>>> + <MT2701_PIN_239_EXT_SDIO0__FUNC_EXT_SDIO0>,
>>> + <MT2701_PIN_238_EXT_SDIO1__FUNC_EXT_SDIO1>,
>>> + <MT2701_PIN_237_EXT_SDIO2__FUNC_EXT_SDIO2>,
>>> + <MT2701_PIN_236_EXT_SDIO3__FUNC_EXT_SDIO3>;
>>> + drive-strength = <MTK_DRIVE_4mA>;
>>> + bias-pull-up;
>>> + };
>>> + };
>>> +};
>>> +
>>> &uart0 {
>>> status = "okay";
>>> };
>>> diff --git a/arch/arm/boot/dts/mt2701.dtsi
>>> b/arch/arm/boot/dts/mt2701.dtsi
>>> index bdf8954..1eefce4 100644
>>> --- a/arch/arm/boot/dts/mt2701.dtsi
>>> +++ b/arch/arm/boot/dts/mt2701.dtsi
>>> @@ -227,6 +227,18 @@
>>> status = "disabled";
>>> };
>>>
>>> + nor_flash: spi@11014000 {
>>> + compatible = "mediatek,mt2701-nor",
>>> + "mediatek,mt8173-nor";
>>
>> Why define both here? Is "mediatek,mt8173-nor" really providing a
>> subset of the features supported by "mediatek,mt2701-nor"?
>>
>
> I think even if the ip block is the same, we should provide both
> bindings, just in case in the future we find out that mt2701 has some
> hidden bug, feature or bug-feature. This way even if we update the
> driver, we stay compatible with older device tree blobs in the wild.
>
> We can drop the mt2701-nor in the bindings definition if you want.
This exactly. We should have a DT compat in the form:
compatible = "vendor,<soc>-block", "vendor,<oldest-compat-soc>-block";
Then if we find a problem in the future, we can match on the
"vendor,<soc>-block" and still support the old DTs.
The question is, does the "vendor,<soc>-block" go into the binding
document as well or do we only have "vendor,<oldest-compat-soc>-block"
there ?
--
Best regards,
Marek Vasut
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