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

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Message-ID: <1j1pmew1cu.fsf@starbuckisacylon.baylibre.com>
Date: Tue, 04 Nov 2025 11:14:57 +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 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 ...

>
>>> +     .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" ?


>
>>> +             .ops = &clk_regmap_gate_ops,
>>> +             .parent_hws = (const struct clk_hw *[]) {
>>> +                     &t7_anakin.hw
>>> +             },
>>> +             .num_parents = 1,
>>> +             .flags = CLK_SET_RATE_PARENT
>>> +     },
>>> +};
>>> +