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SubjectRe: [PATCH linux-next v6 1/8] mtd: spi-nor: read JEDEC ID with multiple I/O protocols
Date
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 <cyrille.pitchen@atmel.com>
> ---
> 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) {

[...]


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