Subject: [PATCH linux-next v6 1/8] mtd: spi-nor: read JEDEC ID with multiple I/O protocols

From: [email-masked] (Marek Vasut)
Date: Wed, 9 Sep 2015 15:59:40 +0200

On Wednesday, September 09, 2015 at 03:24:11 PM, Cyrille Pitchen wrote:
> When their quad or dual I/O mode is enabled, Micron and Macronix spi-nor
> memories don't reply to the regular Read ID (0x9f) command. Instead they
> reply to a new dedicated command Read ID Multiple I/O (0xaf).
> 
> If the Read ID (0x9f) command fails (the read ID is all 1's or all 0's),
> then the Read ID Multiple I/O (0xaf) is used, first with SPI 4-4-4 protocol
> (supported by both Micron and Macronix memories), lately with SPI-2-2-2
> protocol (supported only by Micron memories).
> 
> Signed-off-by: Cyrille Pitchen <[email-masked]>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 28 +++++++++++++++++++++++++++-
>  include/linux/mtd/spi-nor.h   | 23 +++++++++++++++++++++--
>  2 files changed, 48 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index f59aedfe1462..80a0db078aaa 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -703,8 +703,9 @@ static const struct flash_info spi_nor_ids[] = {
> 
>  static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
>  {
> -	int			tmp;
> +	int			i, tmp;
>  	u8			id[SPI_NOR_MAX_ID_LEN];
> +	enum spi_protocol	proto[2] = {SPI_PROTO_4_4_4, SPI_PROTO_2_2_2};
>  	const struct flash_info	*info;
> 
>  	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
> @@ -713,6 +714,25 @@ static const struct flash_info *spi_nor_read_id(struct
> spi_nor *nor) return ERR_PTR(tmp);
>  	}
> 
> +	/* Special case for Micron/Macronix qspi nor. */
> +	for (i = 0; i < ARRAY_SIZE(proto); ++i) {
> +		if (!((id[0] == 0xff && id[1] == 0xff && id[2] == 0xff) ||
> +		      (id[0] == 0x00 && id[1] == 0x00 && id[2] == 0x00)))
> +			break;
> +
> +		nor->erase_proto = proto[i];
> +		nor->read_proto = proto[i];
> +		nor->write_proto = proto[i];
> +		nor->reg_proto = proto[i];
> +		tmp = nor->read_reg(nor, SPINOR_OP_MIO_RDID,
> +				    id, SPI_NOR_MAX_ID_LEN);
> +		if (tmp < 0) {
> +			dev_dbg(nor->dev,
> +				" error %d reading JEDEC ID (MULTI IO)\n", tmp);

Don't you have one space too much in front of the " error" ?

> +			return ERR_PTR(tmp);
> +		}
> +	}
> +
>  	for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
>  		info = &spi_nor_ids[tmp];
>  		if (info->id_len) {

[...]