On 08/12/15 16:26, Boris Brezillon wrote:
On Tue, 8 Dec 2015 16:03:55 +0000
Harvey Hunt <harvey.h...@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.


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.
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