Re: [PATCH v3 07/11] dt-bindings: clock: Add StarFive JH7110 system clock and reset generator

[Conor Dooley]

On 23 February 2023 03:03:04 GMT, Hal Feng <hal.feng at starfivetech.com> wrote:
>On Wed, 22 Feb 2023 16:26:46 +0000, Conor Dooley wrote:
>> On Wed, Feb 22, 2023 at 09:27:37PM +0800, Hal Feng wrote:
>>> On Tue, 21 Feb 2023 23:39:32 +0000, Conor Dooley wrote:
>>> > On Tue, Feb 21, 2023 at 02:17:17PM -0800, Stephen Boyd wrote:
>>> >> Quoting Conor Dooley (2023-02-16 10:20:34)
>>> >> > On Thu, Feb 16, 2023 at 10:42:20PM +0800, Hal Feng wrote:
>>> >> > > On Tue, 27 Dec 2022 20:15:20 +0000, Conor Dooley wrote:
>>> >> > > > On Mon, Dec 26, 2022 at 12:26:32AM +0800, Hal Feng wrote:
>>> >> > > Please see the picture of these external clocks in clock tree.
>>> >> > > 
>>> >> > > # mount -t debugfs none /mnt
>>> >> > > # cat /mnt/clk/clk_summary
>>> >> > >                                  enable  prepare  protect                                duty  hardware
>>> >> > >    clock                          count    count    count        rate   accuracy phase  cycle    enable
>>> >> > > -------------------------------------------------------------------------------------------------------
>>> >> > >  *mclk_ext*                             0        0        0    12288000          0     0  50000         Y
>>> >> > >  *tdm_ext*                              0        0        0    49152000          0     0  50000         Y
>>> >> > >  *i2srx_lrck_ext*                       0        0        0      192000          0     0  50000         Y
>>> >> > >  *i2srx_bclk_ext*                       0        0        0    12288000          0     0  50000         Y
>>> >> > >  *i2stx_lrck_ext*                       0        0        0      192000          0     0  50000         Y
>>> >> > >  *i2stx_bclk_ext*                       0        0        0    12288000          0     0  50000         Y
>>> >> > >  *gmac1_rgmii_rxin*                     0        0        0   125000000          0     0  50000         Y
>>> >> > >     gmac1_rx                          0        0        0   125000000          0     0  50000         Y
>>> >> > >        gmac1_rx_inv                   0        0        0   125000000          0   180  50000         Y
>>> >> > >  *gmac1_rmii_refin*                     0        0        0    50000000          0     0  50000         Y
>>> >> > >     gmac1_rmii_rtx                    0        0        0    50000000          0     0  50000         Y
>>> >> > >        gmac1_tx                       0        0        0    50000000          0     0  50000         N
>>> >> > >           gmac1_tx_inv                0        0        0    50000000          0   180  50000         Y
>>> >> > >  *osc*                                  4        4        0    24000000          0     0  50000         Y
>>> >> > >     apb_func                          0        0        0    24000000          0     0  50000         Y
>>> >> > >  ...
>>> >> > > 
>>> >> > > The clock "gmac1_rgmii_rxin" and the clock "gmac1_rmii_refin" are
>>> >> > > actually used as the parent of other clocks.
>>> >> > 
>>> >> > > The "dummy" clocks
>>> >> > > you said are all internal clocks.
>>> >> > 
>>> >> > No, what I meant by "dummy" clocks is that if you make clocks "required"
>>> >> > in the binding that are not needed by the hardware for operation a
>>> >> > customer of yours might have to add "dummy" clocks to their devicetree
>>> >> > to pass dtbs_check.
>>> >> 
>>> >> They can set the phandle specifier to '<0>' to fill in the required
>>> >> property when there isn't anything there. If this is inside an SoC, it
>>> >> is always connected because silicon can't change after it is made
>>> >> (unless this is an FPGA). Therefore, any and all input clocks should be
>>> >> listed as required.
>>> > 
>>> >> If the clk controller has inputs that are
>>> >> pads/balls/pins on the SoC then they can be optional if a valid design
>>> >> can leave those pins not connected.
>>> > 
>>> > From the discussion on the dts patches, where the clocks have been put
>>> > (intentionally) into board.dts, I've been under the impression that we
>>> > are in this situation.
>>> 
>>> For the system (sys) clock controller, we are in this situation.
>>> For the always-on (aon) clock controller, we are not, because some input
>>> clocks are inside the SoC.
>>> 
>>> > Up to Hal to tell us if the hardware is capable of having those inputs
>>> > left unfilled!
>>> 
>>> The situation is different for v1.2A and v1.3B boards.
>>> 
>>> For the v1.2A board,
>>> gmac1 only requires "gmac1_rmii_refin", which support 100MHz
>>> gmac0 only requires "gmac0_rgmii_rxin", which support 1000MHz
>>> 
>>> For the v1.3B board,
>>> gmac1 only requires "gmac1_rgmii_rxin", which support 1000MHz
>>> gmac0 only requires "gmac0_rgmii_rxin", which support 1000MHz
>>> 
>>> So we should set the "required" property depending on different
>>> boards.
>> 
>> These were Krzk's suggestions:
>> oneOf:
>>  - clock-names:
>>      minItems: 3
>>      items:
>>        - a
>>        - b
>>        - c
>>        - d
>>  - clock-names:
>>      items:
>>        - a
>>        - b
>>        - d
>> 
>> or maybe:
>>  - clock-names:
>>      minItems: 3
>>      items:
>>        - a
>>        - b
>>        - enum: [c, d]
>>        - d
>> 
>> Might be making a mess here, but I think that becomes:
>>   clock-names:
>>     oneOf:
>>       - items:
>>           - const: osc
>>           - enum:
>>               - gmac1_rmii_refin
>>               - gmac1_rgmii_rxin
>>           - const: i2stx_bclk_ext
>>           - const: i2stx_lrck_ext
>>           - const: i2srx_bclk_ext
>>           - const: i2srx_lrck_ext
>>           - const: tdm_ext
>>           - const: mclk_ext
>> 
>>       - items:
>>           - const: osc
>>           - const: gmac1_rmii_refin
>>           - const: gmac1_rgmii_rxin
>>           - const: i2stx_bclk_ext
>>           - const: i2stx_lrck_ext
>>           - const: i2srx_bclk_ext
>>           - const: i2srx_lrck_ext
>>           - const: tdm_ext
>>           - const: mclk_ext
>
>Will modify it and improve the description of clock items for
>pointing out which clock is required on different boards.

I don't think you need to mention the boards in it.

>Thank you all for your helpful suggestions.
>
>Best regards,
>Hal