Re: [PATCH v9 2/3] mtd: nand: jz4780: driver for NAND devices on JZ4780 SoCs

Boris Brezillon
2015-12-08T16:13:10Z

On Tue, 8 Dec 2015 16:03:55 +0000
Harvey Hunt <harvey.hunt@imgtec.com> wrote:

> >
> > static void jz4780_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
> > unsigned int ctrl)
> > {
> > struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
> > struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);
> > struct jz4780_nand_cs *cs;
> >
> > if (WARN_ON(nfc->selected < 0))
> > return;
> >
> > cs = &nfc->cs[nfc->selected];
> >
> > if (ctrl & NAND_CTRL_CHANGE) {
> > if (cmd != NAND_CMD_NONE) {
> > if (ctrl & NAND_ALE)
> > writeb(cmd, cs->base + OFFSET_ADDR);
> > else if (ctrl & NAND_CLE)
> > writeb(cmd, cs->base + OFFSET_CMD);
> > }
> >
> > jz4780_nemc_assert(nfc->dev, cs->bank, ctrl & NAND_NCE);
> > }
> > }
> >
>
> Okay, I understand your point now. I would also have to implement the
> read/write functions to replace the defaults, correct? If so, it feels
> strange to add functions to reimplement the default ones.

I don't think you have to re-implement the {read,write}_{byte,buf,word}
functions, because you'll still assign the ->IO_ADDR_W and ->IO_ADDR_R
fields to cs->base + OFFSET_DATA in jz4780_nand_init_chip(), but maybe
I'm missing something.

--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering