linux-kernel - Re: [PATCH v4 5/5] clk: meson: t7: add t7 clock peripherals controller driver

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Message-ID: <1jv7jlvke8.fsf@starbuckisacylon.baylibre.com>
Date: Fri, 07 Nov 2025 18:10:23 +0100
From: Jerome Brunet <jbrunet@...libre.com>
To: Jian Hu <jian.hu@...ogic.com>
Cc: Xianwei Zhao <xianwei.zhao@...ogic.com>,  Chuan Liu
 <chuan.liu@...ogic.com>,  Neil Armstrong <neil.armstrong@...aro.org>,
  Kevin Hilman <khilman@...libre.com>,  Stephen Boyd <sboyd@...nel.org>,
  Michael Turquette <mturquette@...libre.com>,  Dmitry Rokosov
 <ddrokosov@...rdevices.ru>,  robh+dt <robh+dt@...nel.org>,  Rob Herring
 <robh@...nel.org>,  devicetree <devicetree@...r.kernel.org>,  linux-clk
 <linux-clk@...r.kernel.org>,  linux-amlogic
 <linux-amlogic@...ts.infradead.org>,  linux-kernel
 <linux-kernel@...r.kernel.org>,  linux-arm-kernel
 <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v4 5/5] clk: meson: t7: add t7 clock peripherals
 controller driver

On Sat 08 Nov 2025 at 00:20, Jian Hu <jian.hu@...ogic.com> wrote:

> On 11/4/2025 6:14 PM, Jerome Brunet wrote:
>> [ EXTERNAL EMAIL ]
>>
>> On Tue 04 Nov 2025 at 17:17, Jian Hu <jian.hu@...ogic.com> wrote:
>>
>>>>> +
>>>>> +static struct clk_regmap t7_dspa = {
>>>>> +     .data = &(struct clk_regmap_mux_data){
>>>>> +             .offset = DSPA_CLK_CTRL0,
>>>>> +             .mask = 0x1,
>>>>> +             .shift = 15,
>>>>> +     },
>>>>> +     .hw.init = &(struct clk_init_data){
>>>>> +             .name = "dspa",
>>>>> +             .ops = &clk_regmap_mux_ops,
>>>>> +             .parent_hws = (const struct clk_hw *[]) {
>>>>> +                     &t7_dspa_a.hw,
>>>>> +                     &t7_dspa_b.hw,
>>>>> +             },
>>>>> +             .num_parents = 2,
>>>>> +             .flags = CLK_SET_RATE_PARENT,
>>>>> +     },
>>>>> +};
>>>>> +
>>>>> ......
>>>>> +
>>>>> +static struct clk_regmap t7_anakin_0 = {
>>>> Nitpick: for the DSP it was a/b, here it is 0/1
>>>> Could you pick one way or the other and stick to it ?
>>>
>>> ok , I will use 0/1 for DSP.
>> I think I prefer a/b if you don't mind. see below for why ...
>
>
> Mali is named as mali_0, mali_1 in this driver.   And G12A/S4/GXBB series
> do the same.

... A1 use dspa_a dspa_b (etc ...) 

>
> If they are named as anakin_a and anakin_b here, there will be two naming
> methods.
>

Already have that unfortunately

> Shall we keep consistent ?
>

Please try yes

>
> If use 0/1 to name them.
>
> dsp clocks are:
>
>     dspa_0_sel
>
>     dspa_0_div
>
>     dspa_0
>
>     dspa_1_sel
>
>     dspa_1_div
>
>     dspa_1
>
>     dspb_0_sel
>
>     dspb_0_div
>
>     dspb_0
>
>     dspb_1_sel
>
>     dspb_1_div
>
>     dspb_1
>
>
> anakin clocks are:
>
>     anakin_0_sel
>
>     anakin_0_div
>
>     anakin_0
>
>     anakin_1_sel
>
>     anakin_1_div
>
>     anakin_1
>
>     anakin_01_sel
>
>     anakin
>
>
> If use a/b to name them.
>
> dsp clocks are:
>
>     dspa_a_sel
>
>     dspa_a_div
>
>     dspa_a
>
>     dspa_b_sel
>
>     dspa_b_div
>
>     dspa_b
>
>     dspb_a_sel
>
>     dspb_a_div
>
>     dspb_a
>
>     dspb_b_sel
>
>     dspb_b_div
>
>     dspb_b
>
>
> anakin clocks are:
>
>     anakin_a_sel
>
>     anakin_a_div
>
>     anakin_a
>
>     anakin_b_sel
>
>     anakin_b_div
>
>     anakin_b
>
>     anakin_ab_sel
>
>     anakin
>
>
> Which one is better?

a/b or 0/1, we already have both

Pick which ever scheme you prefer, just stick to it from now on.

>
>>>>> +     .data = &(struct clk_regmap_gate_data){
>>>>> +             .offset = ANAKIN_CLK_CTRL,
>>>>> +             .bit_idx = 8,
>>>>> +     },
>>>>> +     .hw.init = &(struct clk_init_data) {
>>>>> +             .name = "anakin_0",
>>>>> +             .ops = &clk_regmap_gate_ops,
>>>>> +             .parent_hws = (const struct clk_hw *[]) { &t7_anakin_0_div.hw },
>>>>> +             .num_parents = 1,
>>>>> +             .flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT,
>>>>> +     },
>>>>> +};
>> [...]
>>
>>>>> +
>>>>> +static struct clk_regmap t7_anakin_clk = {
>>>>> +     .data = &(struct clk_regmap_gate_data){
>>>>> +             .offset = ANAKIN_CLK_CTRL,
>>>>> +             .bit_idx = 30,
>>>>> +     },
>>>>> +     .hw.init = &(struct clk_init_data) {
>>>>> +             .name = "anakin_clk",
>>>> Again, not a great name, especially considering the one above.
>>>> Is this really really how the doc refers to these 2 clocks ?
>>>
>>> bit30 gate clock is after bit31 mux clock,  and the gate clock is the final
>>> output clock, it is used to gate anakin clock.
>>>
>>> I will rename bit31 as anakin_pre, rename bit30 as anakin.
>> Ok for the last element
>>
>> ... but I don't  like "_pre" for a mux selecting one the 2 glitch free
>> path. It does not help understanding the tree.
>>
>> For such mux, when it is not the last element, I would suggest
>> "_ab_sel" ... at least it is clear what it does so, "anakin_ab_sel" ?
>>
>
> ok, anakin_ab_sel and anakin for these two clocks.
>
>
> Maybe anakin_01_sel and anakin for these two clocks, if you agree to 0/1
> naming convention.
>
>>>>> +             .ops = &clk_regmap_gate_ops,
>>>>> +             .parent_hws = (const struct clk_hw *[]) {
>>>>> +                     &t7_anakin.hw
>>>>> +             },
>>>>> +             .num_parents = 1,
>>>>> +             .flags = CLK_SET_RATE_PARENT
>>>>> +     },
>>>>> +};
>>>>> +

-- 
Jerome