[PATCH v3 1/8] MTD: xway: add some more documentation

[Boris Brezillon]

On Sun, 19 Jun 2016 18:08:10 +0200
Hauke Mehrtens <hauke at hauke-m.de> wrote:

> This adds some register documentation which should make it easier to
> understand how this controller works.

This commits also adds some new definitions and replace (1 << x) by
BIT(x).
Can you update the commit description accordingly?

> 
> Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
> ---
>  drivers/mtd/nand/xway_nand.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
> index 0cf0ac0..2d74637 100644
> --- a/drivers/mtd/nand/xway_nand.c
> +++ b/drivers/mtd/nand/xway_nand.c
> @@ -16,20 +16,29 @@
>  #define EBU_ADDSEL1		0x24
>  #define EBU_NAND_CON		0xB0
>  #define EBU_NAND_WAIT		0xB4
> +#define  NAND_WAIT_RD		BIT(0) /* NAND flash status output */
> +#define  NAND_WAIT_WR_C		BIT(3) /* NAND Write/Read complete */
>  #define EBU_NAND_ECC0		0xB8
>  #define EBU_NAND_ECC_AC		0xBC
>  
> -/* nand commands */
> -#define NAND_CMD_ALE		(1 << 2)
> -#define NAND_CMD_CLE		(1 << 3)
> -#define NAND_CMD_CS		(1 << 4)
> +/*
> + * nand commands
> + * The pins of the NAND chip are selected based on the address bits of the
> + * "register" read and write. There are no special registers, but an
> + * address range and the lower address bits are used to activate the
> + * correct line. For example when the bit (1 << 2) is set in the address
> + * the ALE pin will be activated.
> + */
> +#define NAND_CMD_ALE		BIT(2) /* address latch enable */
> +#define NAND_CMD_CLE		BIT(3) /* command latch enable */
> +#define NAND_CMD_CS		BIT(4) /* chip select */
> +#define NAND_CMD_SE		BIT(5) /* spare area access latch */
> +#define NAND_CMD_WP		BIT(6) /* write protect */
>  #define NAND_WRITE_CMD_RESET	0xff
>  #define NAND_WRITE_CMD		(NAND_CMD_CS | NAND_CMD_CLE)
>  #define NAND_WRITE_ADDR		(NAND_CMD_CS | NAND_CMD_ALE)
>  #define NAND_WRITE_DATA		(NAND_CMD_CS)
>  #define NAND_READ_DATA		(NAND_CMD_CS)
> -#define NAND_WAIT_WR_C		(1 << 3)
> -#define NAND_WAIT_RD		(0x1)
>  
>  /* we need to tel the ebu which addr we mapped the nand to */
>  #define ADDSEL1_MASK(x)		(x << 4)