Re: Re: [PATCH v13 2/8] mtd: rawnand: rockchip: NFC drivers for RK3308, RK2928 and others

From: 赵仪峰 <yifeng.zhao@rock-chips.com>
To: "Miquel Raynal" <miquel.raynal@bootlin.com>
Cc: devicetree <devicetree@vger.kernel.org>,
	HeikoStübner <heiko@sntech.de>, richard <richard@nod.at>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-rockchip <linux-rockchip@lists.infradead.org>,
	robh+dt <robh+dt@kernel.org>,
	linux-mtd <linux-mtd@lists.infradead.org>,
	"Johan Jonker" <jbx6244@gmail.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	vigneshr <vigneshr@ti.com>
Subject: Re: Re: [PATCH v13 2/8] mtd: rawnand: rockchip: NFC drivers for RK3308, RK2928 and others
Date: Mon, 2 Nov 2020 16:14:01 +0800	[thread overview]
Message-ID: <20201102161300764203144@rock-chips.com> (raw)
In-Reply-To: 20201102083258.3a748c44@xps13

Hi Miquel,

The nand_base.c will call nand_deselect_target after NAND read/program... ops done, and set variable chip->cur_cs = -1,
but the nand controller do nothing and the cs of the NAND device is still selected, 
so the NAND device  will not enter auto power save mode.

--------------
Thanks,
Yifeng

>Hello,
>
>赵仪峰 <yifeng.zhao@rock-chips.com> wrote on Mon, 2 Nov 2020 11:46:04
>+0800:
>
>> Hi Johan,
>>
>> void nand_deselect_target(struct nand_chip *chip)
>> {
>> if (chip->legacy.select_chip)
>> chip->legacy.select_chip(chip, -1);
>>
>> chip->cur_cs = -1;
>> }
>>
>> I need add the code below and it work.
>>
>>    chip->legacy.select_chip = rk_nfc_select_chip;
>>
>> But I found almost all nandc drivers do not add this code. Is there any other way to implement it？
>
>Indeed, we don't accept new code we legacy bindings.
>
>I don't understand what extra consumption you are trying to avoid,
>because if it is the NAND device itself that is able to save power when
>it gets unselected, it's really none of you controller's business.
>
>Perhaps it's the time to focus on the controller support and tune the
>code base later in a bid to reduce consumption.
>
>Thanks,
>Miquèl
>
>
>
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