linux-kernel - Re: [PATCH] clk: at91: clk-master: Add check for divide by 3

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Message-ID: <272ffdb9-9d7f-4a48-9968-7de1d32d721e@microchip.com>
Date: Mon, 15 Sep 2025 16:54:57 +0200
From: Nicolas Ferre <nicolas.ferre@...rochip.com>
To: <Ryan.Wanner@...rochip.com>, <mturquette@...libre.com>,
	<sboyd@...nel.org>, <alexandre.belloni@...tlin.com>,
	<claudiu.beznea@...on.dev>
CC: <linux-clk@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] clk: at91: clk-master: Add check for divide by 3

On 09/09/2025 at 09:57, Nicolas Ferre wrote:
> On 08/09/2025 at 22:07, Ryan.Wanner@...rochip.com wrote:
>> From: Ryan Wanner <Ryan.Wanner@...rochip.com>
>>
>> A potential divider for the master clock is div/3. The register
>> configuration for div/3 is MASTER_PRES_MAX. The current bit shifting
>> method does not work for this case. Checking for MASTER_PRES_MAX will
>> ensure the correct decimal value is stored in the system.
>>
>> Signed-off-by: Ryan Wanner <Ryan.Wanner@...rochip.com>
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@...rochip.com>

Added to clk-microchip, on its way upstream.
Thanks, regards,
   Nicolas

> Thanks Ryan, regards,
>     Nicolas
> 
>> ---
>>    drivers/clk/at91/clk-master.c | 3 +++
>>    1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/clk/at91/clk-master.c b/drivers/clk/at91/clk-master.c
>> index 7a544e429d34..d5ea2069ec83 100644
>> --- a/drivers/clk/at91/clk-master.c
>> +++ b/drivers/clk/at91/clk-master.c
>> @@ -580,6 +580,9 @@ clk_sama7g5_master_recalc_rate(struct clk_hw *hw,
>>    {
>>    	struct clk_master *master = to_clk_master(hw);
>>    
>> +	if (master->div == MASTER_PRES_MAX)
>> +		return DIV_ROUND_CLOSEST_ULL(parent_rate, 3);
>> +
>>    	return DIV_ROUND_CLOSEST_ULL(parent_rate, (1 << master->div));
>>    }
>>    
>