linux-kernel - Re: [PATCH v3 06/19] clk: at91: Allow enabling main_rc

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Message-ID: <6d68a46b-f43b-4248-8031-58192da26c2b@tuxon.dev>
Date: Sat, 31 Jan 2026 17:45:37 +0200
From: Claudiu Beznea <claudiu.beznea@...on.dev>
To: Alexander Dahl <ada@...rsis.com>
Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>,
 Alexandre Belloni <alexandre.belloni@...tlin.com>,
 Ryan Wanner <ryan.wanner@...rochip.com>,
 linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Cristian Birsan <cristian.birsan@...rochip.com>,
 Varshini Rajendran <varshini.rajendran@...rochip.com>,
 Balamanikandan Gunasundar <balamanikandan.gunasundar@...rochip.com>
Subject: Re: [PATCH v3 06/19] clk: at91: Allow enabling main_rc_osc through DT



On 1/20/26 16:37, Alexander Dahl wrote:
> SAM9X60 Datasheet (DS60001579G) Section "23.4 Product Dependencies"
> says:

s/says/states

> 
>      "The OTPC is clocked through the Power Management Controller (PMC).
>      The user must power on the main RC oscillator and enable the
>      peripheral clock of the OTPC prior to reading or writing the OTP
>      memory."
> 
> The code for enabling/disabling that clock is already present

s/that clock/the main RC oscillator clock

 > it was
> just not possible to hook into DT anymore, after at91 clk devicetree
> binding rework back in 2018 for kernel v4.19.

I would re-write this as:

however, after the at91 clock device tree binding rework in 2018
(kernel v4.19), it was no longer possible to hook it up via DT.

> 
> Do it for all controllers with an OTPC controller, where the main rc
> oscillator is required for proper operation.

I would re-write it as:

Export the main RC oscillator for all SoCs featuring an OTPC controller where 
the main RC oscillator is required for proper operation.


> 
> Signed-off-by: Alexander Dahl <ada@...rsis.com>

The code LGTM.

> ---
> 
> Notes:
>      v3:
>      - no changes
>      
>      v2:
>      - split out dt-bindings changes into separate patch
>      - extend to drivers for other SoCs providing the OTPC
> 
>   drivers/clk/at91/sam9x60.c  | 1 +
>   drivers/clk/at91/sam9x7.c   | 1 +
>   drivers/clk/at91/sama7d65.c | 1 +
>   drivers/clk/at91/sama7g5.c  | 1 +
>   4 files changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/at91/sam9x60.c b/drivers/clk/at91/sam9x60.c
> index dbcdb1d2161a9..a9f293a8e3b26 100644
> --- a/drivers/clk/at91/sam9x60.c
> +++ b/drivers/clk/at91/sam9x60.c
> @@ -227,6 +227,7 @@ static void __init sam9x60_pmc_setup(struct device_node *np)
>   					   50000000);
>   	if (IS_ERR(hw))
>   		goto err_free;
> +	sam9x60_pmc->chws[SAM9X60_PMC_MAIN_RC] = hw;
>   
>   	hw = at91_clk_register_main_osc(regmap, "main_osc", mainxtal_name, NULL, 0);
>   	if (IS_ERR(hw))
> diff --git a/drivers/clk/at91/sam9x7.c b/drivers/clk/at91/sam9x7.c
> index 07eadb712a1e4..9a5afd258cb86 100644
> --- a/drivers/clk/at91/sam9x7.c
> +++ b/drivers/clk/at91/sam9x7.c
> @@ -764,6 +764,7 @@ static void __init sam9x7_pmc_setup(struct device_node *np)
>   					   50000000);
>   	if (IS_ERR(hw))
>   		goto err_free;
> +	sam9x7_pmc->chws[SAM9X7_PMC_MAIN_RC] = hw;
>   
>   	hw = at91_clk_register_main_osc(regmap, "main_osc", mainxtal_name, NULL, 0);
>   	if (IS_ERR(hw))
> diff --git a/drivers/clk/at91/sama7d65.c b/drivers/clk/at91/sama7d65.c
> index 4ccffa8db43a5..5d8973aa50a53 100644
> --- a/drivers/clk/at91/sama7d65.c
> +++ b/drivers/clk/at91/sama7d65.c
> @@ -1135,6 +1135,7 @@ static void __init sama7d65_pmc_setup(struct device_node *np)
>   						   50000000);
>   	if (IS_ERR(main_rc_hw))
>   		goto err_free;
> +	sama7d65_pmc->chws[SAMA7D65_PMC_MAIN_RC] = hw;
>   
>   	bypass = of_property_read_bool(np, "atmel,osc-bypass");
>   
> diff --git a/drivers/clk/at91/sama7g5.c b/drivers/clk/at91/sama7g5.c
> index 99b4c1d9bdcca..9a6f0f30b2b7e 100644
> --- a/drivers/clk/at91/sama7g5.c
> +++ b/drivers/clk/at91/sama7g5.c
> @@ -1014,6 +1014,7 @@ static void __init sama7g5_pmc_setup(struct device_node *np)
>   						   50000000);
>   	if (IS_ERR(main_rc_hw))
>   		goto err_free;
> +	sama7g5_pmc->chws[SAMA7G5_PMC_MAIN_RC] = hw;
>   
>   	bypass = of_property_read_bool(np, "atmel,osc-bypass");
>