From: Hongliang Wang <wanghongliang@loongson.cn>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Binbin Zhou <zhoubinbin@loongson.cn>,
Andi Shyti <andi.shyti@kernel.org>, Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
linux-i2c@vger.kernel.org, devicetree@vger.kernel.org,
loongarch@lists.linux.dev
Subject: Re: [PATCH v1 1/2] dt-bindings: i2c: ls2x-i2c: Add clock- related properties
Date: Fri, 10 Apr 2026 16:20:42 +0800 [thread overview]
Message-ID: <991204c6-6710-e62c-69ab-d7db91325013@loongson.cn> (raw)
In-Reply-To: <3c57275e-0574-46e5-9893-053ae5cc22cb@kernel.org>
On 2026/4/10 下午2:42, Krzysztof Kozlowski wrote:
> On 10/04/2026 05:04, Hongliang Wang wrote:
>> Hi, Krzysztof
>>
>> On 2026/4/9 下午8:11, Krzysztof Kozlowski wrote:
>>> On 09/04/2026 14:03, Hongliang Wang wrote:
>>>> I have a question, the input clock of i2c controller can be described by
>>>> "clocks",
>>>> but there is no existing attribute can describe the divisor of the input
>>>> clock,
>>>> Can I define a new attribute named "clock-div" to describe it in DT
>>>> bindings?
>>>> or do you have any standard solutions for the divisor problem? Thank you.
>>>>
>>> You should determine/calculate the divisor in the driver code, depending
>>> on clocks and bus frequencies. You don't need a property for that, usually.
>> Not only clocks and bus frequencies, but also a third property is required.
>>
>> The frequency divison calculation formula of i2c is
>> Prcescale = clock_a/(clock_div*clock_s)-1
>>
>> There is three parameters in this formula:
>> clock_a represents the input clock, which is described by "clocks",
>> clock_s represents the i2c bus frequency, which is described by
>> "clock-frequency",
>> but there is no existing property to describe clock_div, which has
>> different value
>> on different platform (for example, it is 5 on 7a1000/7a2000, 4 on
>> 2K1000/2K2000,
>> 5.5 on 2K3000.), So I need a property to describe clock_div in this formula.
> So it is fixed per compatible? Then you do not need.
>
OK, I will fix the clock_div based on per compatible. thank you.
> Best regards,
> Krzysztof
Best regards,
Hongliang Wang
next prev parent reply other threads:[~2026-04-10 8:20 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-25 1:18 [PATCH v2 0/2] i2c: ls2x: Add clock- related properties and parsing Hongliang Wang
2026-03-25 1:18 ` [PATCH v1 1/2] dt-bindings: i2c: ls2x-i2c: Add clock- related properties Hongliang Wang
2026-03-25 11:42 ` Krzysztof Kozlowski
2026-03-25 11:43 ` Krzysztof Kozlowski
2026-03-26 2:12 ` Hongliang Wang
2026-03-26 7:02 ` Krzysztof Kozlowski
2026-03-26 7:49 ` Krzysztof Kozlowski
2026-03-26 11:48 ` Hongliang Wang
2026-03-26 12:23 ` Krzysztof Kozlowski
2026-03-27 2:06 ` Hongliang Wang
2026-03-27 3:09 ` Hongliang Wang
2026-03-27 6:39 ` Krzysztof Kozlowski
2026-03-30 7:18 ` Hongliang Wang
2026-03-30 7:23 ` Krzysztof Kozlowski
2026-03-31 7:11 ` Hongliang Wang
2026-04-09 12:03 ` Hongliang Wang
2026-04-09 12:11 ` Krzysztof Kozlowski
2026-04-10 3:04 ` Hongliang Wang
2026-04-10 6:42 ` Krzysztof Kozlowski
2026-04-10 8:20 ` Hongliang Wang [this message]
2026-04-09 15:29 ` Yao Zi
2026-04-10 3:06 ` Hongliang Wang
2026-03-26 7:21 ` Andi Shyti
2026-03-27 2:08 ` Hongliang Wang
2026-03-25 1:18 ` [PATCH v1 2/2] i2c: ls2x: Add clock-input and clock-div properties parsing Hongliang Wang
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