linux-kernel - Re: [PATCH v4 11/31] clk: at91: clk-usb: add support for clk_parent

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Message-ID: <9b97b3b8-9e46-4482-8420-ebabe00254fe@microchip.com>
Date: Mon, 5 Jan 2026 17:58:26 +0000
From: <Ryan.Wanner@...rochip.com>
To: <claudiu.beznea@...on.dev>, <mturquette@...libre.com>, <sboyd@...nel.org>,
	<alexandre.belloni@...tlin.com>, <Nicolas.Ferre@...rochip.com>
CC: <linux-clk@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <Varshini.Rajendran@...rochip.com>
Subject: Re: [PATCH v4 11/31] clk: at91: clk-usb: add support for
 clk_parent_data

On 12/23/25 07:00, claudiu beznea wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know
> the content is safe
> 
> On 12/18/25 18:23, Ryan.Wanner@...rochip.com wrote:
>> On 10/20/25 12:17, Claudiu Beznea wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you
>>> know the content is safe
>>>
>>> Hi, Ryan,
>>>
>>> On 9/19/25 00:15, Ryan.Wanner@...rochip.com wrote:
>>>> From: Claudiu Beznea <claudiu.beznea@...on.dev>
>>>>
>>>> Add support for clk_parent_data in usb clock driver.
>>>>
>>>> All the SoC based drivers that rely on clk-usb were adapted
>>>> to the new API change. The switch itself for SoCs will be done
>>>> in subsequent patches.
>>>>
>>>> Remove the use of __clk_get_hw() for the slow clocks.
>>>>
>>>> Signed-off-by: Claudiu Beznea <claudiu.beznea@...on.dev>
>>>> [ryan.wanner@...rochip: Add SAMA7D65 and SAM9X75 SoCs to the changes.
>>>> Change how the main_xtal and slcks are initialized so they match the
>>>> parent_data API]
>>>> Signed-off-by: Ryan Wanner <Ryan.Wanner@...rochip.com>
>>>> ---
>>>>   drivers/clk/at91/at91rm9200.c  |  2 +-
>>>>   drivers/clk/at91/at91sam9260.c |  2 +-
>>>>   drivers/clk/at91/at91sam9g45.c |  2 +-
>>>>   drivers/clk/at91/at91sam9n12.c |  2 +-
>>>>   drivers/clk/at91/at91sam9x5.c  |  2 +-
>>>>   drivers/clk/at91/clk-usb.c     | 41 +++++++++++++++++++++
>>>> +------------
>>>>   drivers/clk/at91/dt-compat.c   |  6 ++---
>>>>   drivers/clk/at91/pmc.h         | 11 +++++----
>>>>   drivers/clk/at91/sam9x60.c     |  2 +-
>>>>   drivers/clk/at91/sam9x7.c      | 21 +++++++++--------
>>>>   drivers/clk/at91/sama5d2.c     |  2 +-
>>>>   drivers/clk/at91/sama5d3.c     |  2 +-
>>>>   drivers/clk/at91/sama5d4.c     |  2 +-
>>>>   drivers/clk/at91/sama7d65.c    | 24 +++++++++++---------
>>>>   14 files changed, 72 insertions(+), 49 deletions(-)
>>>>
>>>
>>> [ ... ]
>>>
>>>> @@ -882,10 +885,10 @@ static void __init sam9x7_pmc_setup(struct
>>>> device_node *np)
>>>>
>>>>        sam9x7_pmc->chws[PMC_MCK] = hw;
>>>>
>>>> -     parent_names[0] = "plla_divpmcck";
>>>> -     parent_names[1] = "upll_divpmcck";
>>>> -     parent_names[2] = "main_osc";
>>>> -     usbck_hw = sam9x60_clk_register_usb(regmap, "usbck",
>>>> parent_names, 3);
>>>> +     parent_data[0] = AT91_CLK_PD_HW(sam9x7_plls[PLL_ID_PLLA]
>>>> [PLL_COMPID_DIV0].hw);
>>>> +     parent_data[1] = AT91_CLK_PD_HW(sam9x7_plls[PLL_ID_UPLL]
>>>> [PLL_COMPID_DIV0].hw);
>>>> +     parent_data[2] = AT91_CLK_PD_HW(main_osc_hw);
>>>> +     usbck_hw = sam9x60_clk_register_usb(regmap, "usbck", NULL,
>>>> parent_data, 3);
>>>
>>> sam9x60_clk_register_usb() could be converted to use parent_hws
>>> member of
>>> struct clk_init_data instead of parent_data.
>>
>> So this would mean that I would pass in an array of the plls as
>> parent_hws, and use that to load the clk_init_data struct instead of
>> filling the array of parent_data as it is changed to in this patch set?
>>
>> And this would be functionally the same since parent_data points to
>> clk_hw?>
>>
> 
> It should be something like:

I see, I guess my question is why the usbclk system only? Is it just due
to how little parents there are for the usbclk? Or is it because this is
the only clock that only uses clk_hw for all of its parents?

> 
>        usb = kzalloc(sizeof(*usb), GFP_KERNEL);
> @@ -235,7 +235,10 @@ _at91sam9x5_clk_register_usb(struct regmap *regmap,
> const
> char *name, const clk_hw **parent_hws)
> 
>        init.name = name;
>        init.ops = &at91sam9x5_usb_ops;
> -       init.parent_names = parent_names;
> +       if (parent_hws)
> +               init.parent_hws = parent_hws;
> +       else
> +               init.parent_names = parent_names;
> 
> Thank you,
> Claudiu
Thank you,
Ryan