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

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Date:	Wed, 9 Sep 2015 17:55:22 +0200
From:	Cyrille Pitchen <cyrille.pitchen@...el.com>
To:	Marek Vasut <marex@...x.de>
CC:	<nicolas.ferre@...el.com>, <broonie@...nel.org>,
	<linux-spi@...r.kernel.org>, <dwmw2@...radead.org>,
	<computersforpeace@...il.com>, <zajec5@...il.com>,
	<beanhuo@...ron.com>, <juhosg@...nwrt.org>, <ben@...adent.org.uk>,
	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<devicetree@...r.kernel.org>, <robh+dt@...nel.org>,
	<pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>,
	<linux-mtd@...ts.infradead.org>
Subject: Re: [PATCH linux-next v6 1/8] mtd: spi-nor: read JEDEC ID with
 multiple I/O protocols

Hi Marek,

Le 09/09/2015 15:59, Marek Vasut a écrit :
> 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@...el.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" ?
> 

Probably, I've just copied and pasted the dev_dbg() message few lines above when
the regular SPINOR_OP_RDID fails, then appended the "(MULTI IO)" string to make
think consistent but I don't mind removing the leading space.

	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
	if (tmp < 0) {
		dev_dbg(nor->dev, " error %d reading JEDEC ID\n", tmp);
		return ERR_PTR(tmp);
	}

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

Best Regards,

Cyrille
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