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

[Harvey Hunt]

On 08/12/15 16:26, Boris Brezillon wrote:
> On Tue, 8 Dec 2015 16:03:55 +0000
> Harvey Hunt <harvey.hunt@xxxxxxxxxx> 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.
>
> Actually it should be something like this, because NAND_CTRL_CHANGE is
> cleared after the first address cycle.
>
> 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];
>
> 	jz4780_nemc_assert(nfc->dev, cs->bank, ctrl & NAND_NCE);
>
>   	if (cmd == NAND_CMD_NONE)
> 		return;
>
> 	if (ctrl & NAND_ALE)
> 		writeb(cmd, cs->base + OFFSET_ADDR);
>   	else if (ctrl & NAND_CLE)
>   		writeb(cmd, cs->base + OFFSET_CMD);
> }

Thanks for the example code, I'll try it out for the next version.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/