2015-06-01 07:47:11

by Daniel Thompson

[permalink] [raw]
Subject: Re: [PATCH v2 2/4] dt-bindings: Document the STM32F4 clock bindings

On 30/05/15 10:21, Maxime Coquelin wrote:
> HI Daniel,
>
> On 05/30/2015 09:54 AM, Daniel Thompson wrote:
>> This adds documentation of device tree bindings for the clock related
>> portions of the STM32 RCC block.
>>
>> Signed-off-by: Daniel Thompson <[email protected]>
>> ---
>> .../devicetree/bindings/clock/st,stm32-rcc.txt | 65
>> ++++++++++++++++++++++
>> 1 file changed, 65 insertions(+)
>> <snip>
>> +Example:
>> +
>> + /* Gated clock, AHB1 bit 0 (GPIOA) */
>> + ... {
>> + clocks = <&rcc 0 0>
>> + };
>> +
>> + /* Gated clock, AHB2 bit 4 (GPIOA) */
> s/GPIOA/CRYP/

Oops! Will fix.


>> + ... {
>> + clocks = <&rcc 0 36>
>> + };
>> +
>> +Specifying other clocks
>> +=======================
>> +
>> +The primary index must be set to 1.
>> +
>> +The secondary index is bound with the following magic numbers:
>> +
>> + 0 SYSTICK
>> + 1 FCLK
> How do you plan to handle the SAI & I2S clocks?
> By adding index 3?

Pretty much. Tentatively I'm thinking of:

2 I2S clocks
3 SAI1_A clock
4 SAI1_B clock
5 LCD-TFT clock

Note: Sort order is based on the vertical ordering in the clock tree
diagram in the data sheet.

Only reason not to include these in the bindings immediately is that I
wanted to check how/if these clocks are gated. The clock tree diagram
shows them having individual clock gates so before proposing them using
magic numbers I wanted to double check if these values can be identified
at gates clocks.


Daniel.