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Date: Fri, 27 Jul 2018 00:40:32 +0200
From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Stefan Agner <stefan@agner.ch>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>, Richard Weinberger
 <richard@nod.at>, David Woodhouse <dwmw2@infradead.org>, Brian Norris
 <computersforpeace@gmail.com>, Marek Vasut <marek.vasut@gmail.com>,
 linux-mtd@lists.infradead.org
Subject: Re: [PATCH v3 2/2] mtd: rawnand: add hooks that may be called
 during nand_scan()
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On Fri, 27 Jul 2018 00:20:50 +0200
Stefan Agner <stefan@agner.ch> wrote:

> On 26.07.2018 20:12, Boris Brezillon wrote:
> > On Thu, 26 Jul 2018 18:22:10 +0200
> > Stefan Agner <stefan@agner.ch> wrote:  
> >> > +/**
> >> > + * struct nand_controller_ops - Controller operations
> >> > + *
> >> > + * @attach_chip: Callback that will be called between nand_detect() and
> >> > + *		 nand_scan_tail() during nand_scan() (optional).
> >> > + * @detach_chip: Callback that will be called from nand_cleanup() or if
> >> > + *		 nand_scan_tail() fails (optional).  
> >>
> >> This documentation reads not very helpful to me.
> >>
> >> It would be useful if it is written more from the driver developers
> >> perspective, e.g. what those callbacks ideally are supposed to do...
> >>  
> > 
> > Indeed. How about:
> > 
> > 	@attach_chip: this method is called between after the NAND  
> 
> I guess just after.

Yep.

> 
> > 		      detection phase to let controller driver
> > 		      tweak/customize the configuration based on the
> > 		      NAND properties (page size, OOB size, ECC
> > 		      requirements, ...).  
> 
> Maybe explicitly state that NAND flash parameters are available in this
> call, e.g.
> 
> 	@attach_chip: this method is called after the NAND detection 
> 		      phase after flash ID and MTD fields such as
> 		      erase size, page size and OOB size have been
> 		      set up. ECC requirements are available if
> 		      provided by the NAND chip or device tree.
> 		      Typically used to chose the appropriate ECC

					^ choose

> 		      config and allocate associated resources.
> 		      This hook is optional.
> 

Sounds good.

> 
> > 	@detach_chip: free all resources allocated/claimed in
> > 		      nand_controller_ops->detach_chip().  
> 
> That probably should read nand_controller_ops->attach_chip().

And yes, I meant attach_chip().

> 
> > 		      This hook is optional.  
> 
> --
> Stefan