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SubjectRe: [PATCH 01/14] dt-bindings: Document STM32MP1 Reset Clock Controller (RCC) bindings
On Mon, Feb 5, 2018 at 1:01 AM, Gabriel FERNANDEZ
<gabriel.fernandez@st.com> wrote:
> Hi Rob,
>
> Thanks for reviewing.
>
>
> On 02/05/2018 07:09 AM, Rob Herring wrote:
>> On Fri, Feb 02, 2018 at 03:03:29PM +0100, gabriel.fernandez@st.com wrote:
>>> From: Gabriel Fernandez <gabriel.fernandez@st.com>
>>>
>>> The RCC block is responsible of the management of the clock and reset
>>> generation for the complete circuit.
>>>
>>> Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
>>> ---
>>> .../devicetree/bindings/mfd/st,stm32-rcc.txt | 85 ++++++++++++++++++++++
>>> 1 file changed, 85 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/mfd/st,stm32-rcc.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/mfd/st,stm32-rcc.txt b/Documentation/devicetree/bindings/mfd/st,stm32-rcc.txt
>>> new file mode 100644
>>> index 0000000..28017a1
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/mfd/st,stm32-rcc.txt
>>> @@ -0,0 +1,85 @@
>>> +STMicroelectronics STM32 Peripheral Reset Clock Controller
>>> +==========================================================
>>> +
>>> +The RCC IP is both a reset and a clock controller.
>>> +
>>> +Please also refer to reset.txt for common reset controller binding usage.
>>> +
>>> +Please also refer to clock-bindings.txt for common clock controller
>>> +binding usage.
>>> +
>>> +
>>> +Required properties:
>>> +- compatible: "simple-mfd", "syscon"
>>
>>> +- reg: should be register base and length as documented in the datasheet
>>> +
>>> +- Sub-nodes:
>>> + - compatible: "st,stm32mp1-rcc-clk"
>>> + - #clock-cells: 1, device nodes should specify the clock in their
>>> + "clocks" property, containing a phandle to the clock device node,
>>> + an index specifying the clock to use.
>>> +
>>> + - compatible: "st,stm32mp1-rcc-rst"
>>> + - #reset-cells: Shall be 1
>>> +
>>> +Example:
>>> + rcc: rcc@50000000 {
>>> + compatible = "syscon", "simple-mfd";
>>> + reg = <0x50000000 0x1000>;
>>> +
>>> + rcc_clk: rcc-clk@50000000 {
>>> + #clock-cells = <1>;
>>> + compatible = "st,stm32mp1-rcc-clk";
>>> + };
>>> +
>>> + rcc_rst: rcc-reset@50000000 {
>> You should not have the same unit-address twice.
>>
>> IMO, this should just be:
>>
>> rcc: rcc@50000000 {
>> compatible = "st-stm32mp1-rcc";
>> reg = <0x50000000 0x1000>;
>> #clock-cells = <1>;
>> #reset-cells = <1>;
>> };
>>
>> There's no reason a node can't provide more than 1 function.
> RCC is an dedicated IP for clocks and resets, but also for power
> management (patches will be sent later)

If there's additional functions, they should be part of the binding
now, not later. bindings should not unnecessarily evolve.

> Then i need to probe 3 drivers with same IP.

Drivers and DT nodes don't have to be 1-1. A parent driver can create
additional child devices.

Also, looking at your existing bindings for RCC IP, it is done as I suggested.

> It's also a way to avoid use of 'CLK_OF_DECLARE_DRIVER' and i need it to
> probe the 3th driver.

Sounds like a Linux problem, not a DT issue.

Rob

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