Re: [PATCH v15 3/8] mfd: simple-mfd-i2c: Enable support for the silergy,sy7636a

From: Guenter Roeck <linux@roeck-us.net>
To: Andreas Kemnade <andreas@kemnade.info>
Cc: Alistair Francis <alistair23@gmail.com>,
	Alistair Francis <alistair@alistair23.me>,
	Lee Jones <lee.jones@linaro.org>, Mark Brown <broonie@kernel.org>,
	Sascha Hauer <kernel@pengutronix.de>,
	lgirdwood@gmail.com, Rob Herring <robh+dt@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	rui.zhang@intel.com, devicetree <devicetree@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	linux-hwmon@vger.kernel.org, amitk@kernel.org,
	linux-pm@vger.kernel.org, dl-linux-imx <linux-imx@nxp.com>,
	Shawn Guo <shawnguo@kernel.org>
Subject: Re: [PATCH v15 3/8] mfd: simple-mfd-i2c: Enable support for the silergy,sy7636a
Date: Wed, 24 Nov 2021 12:09:44 -0800	[thread overview]
Message-ID: <a2fd5089-14a5-e36e-63ce-d73be3cd99a2@roeck-us.net> (raw)
In-Reply-To: <20211124203532.30577a50@aktux>

On 11/24/21 11:35 AM, Andreas Kemnade wrote:
> Hi,
> 
> On Tue, 23 Nov 2021 07:39:05 -0800
> Guenter Roeck <linux@roeck-us.net> wrote:
> 
>> On 11/23/21 4:14 AM, Alistair Francis wrote:
>>> On Tue, Nov 16, 2021 at 9:10 AM Andreas Kemnade <andreas@kemnade.info> wrote:
>>>>
>>>> Hi,
>>>>
>>>> this all creates a lot of question marks...
>>>> One of my main question is whether sy7636a = sy7636 (at least the
>>>> driver in the kobo vendor kernels does not have the "A" at the end,
>>>> whic does not necessarily mean a difference).
>>>>
>>>> https://www.silergy.com/products/panel_pmic
>>>> lists only a SY7636ARMC, so chances are good that the letters were just
>>>> stripped away by the driver developers. Printing on chip package is
>>>> cryptic so it is not that helpful. It is just "BWNBDA"
>>>
>>> I don't have a definite answer for you. But I think it's sy7636a
>>>
>>> The page you linked to above lists SY7636ARMC as well as SY7627RMC,
>>> SY7570RMC. That makes me think that the RMC is a generic suffix and
>>> this actual IC is the SY7636A.
>>>    
>>
>> Almost all chips have an ordering suffix, indicating things like
>> temperature range or packaging. The datasheet says:
>>
> yes, they have. The only question is where it starts. So did you find a
> public datasheet which you can chere
> 

I registered an account on the Silergy web site, and I was subsequently
able to download the datasheet. The document has a "confidential"
watermark, so I can not share it. You should be able to register an
account and download it yourself, though.

>> Ordering Information
>> SY7636 □(□□)□
>>               | Temperature Code (C)
>>            | Package Code (RM)
>>          | Optional Spec Code (A)
>>
>> The datasheet otherwise refers to the chip as SY7636A.
>>
> so there is no indication of something like this where the A really
> makes a difference:
> 

I may be missing it, but I see nothing in the datasheet that would indicate
that or if the "A" has any relevance other than "Optional Spec Code",
and I do not see an explanation for that term either.

Guenter