Messages in this thread | | | From | <> | Subject | Re: [PATCH v2 2/2] mtd: spi-nor: macronix: Add support for mx66lm1g45g | Date | Mon, 20 Dec 2021 11:05:47 +0000 |
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On 12/20/21 12:16 PM, Pratyush Yadav wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Hi Tudor, > > On 17/12/21 12:38PM, Tudor.Ambarus@microchip.com wrote: >> On 12/17/21 1:38 PM, Pratyush Yadav wrote: >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>> >>> On 09/12/21 09:04PM, Tudor Ambarus wrote: >>>> mx66lm1g45g supports just 1-1-1, 8-8-8 and 8d-8d-8d modes. There are >>>> versions of mx66lm1g45g which do not support SFDP, thus use >>>> SPI_NOR_SKIP_SFDP. The RDID command issued through the octal peripheral >>>> interface outputs data always in STR mode for whatever reason. Since >>> >>> Huh! I hope this is a mistake from the chip designers, because if it >>> isn't they need a stern talking-to ;-) >>> >>>> 8d-8d-8s is not common, avoid reading the ID when enabling the octal dtr >>>> mode. Instead, read back the CR2 to check if the switch was successful. >>>> Tested in 1-1-1 and 8d-8d-8d modes using sama7g5 QSPI IP. >>> >>> Datasheet? >> >> MX66LM1G45G datasheet: >> https://www.macronix.com/Lists/Datasheet/Attachments/7929/MX66LM1G45G,%203V,%201Gb,%20v1.1.pdf > > Thanks. > > I see that the RDID waveform holds each byte of the ID for a whole clock > cycle. So you would read ab ab cd cd ef ef. I've seen this before > somewhere, and sure enough, digging through my inbox I've found this > patch [0]. In this read ID is performed but only alternate bytes are > compared since they are repeated. I think you should do the same. I feel > like reading/comparing 3 bytes is more "robust".
I didn't want to do the 8D-8D-8S readID because I'm not sure if macronix generalizes 8D-8D-8S for all its octal flashes. Since 8D-8D-8S is odd, I felt that reading CR2 is safer. But maybe we'll follow the read CR2 approach when the need arises, so I'll follow Zhengxun's proposal. > > BTW, this patch series also adds support for mx66lm1g45g. You might want > to use this as reference. > > [0] https://lore.kernel.org/all/20210812150135.4005-2-zhengxunli.mxic@gmail.com/ >
Right. I will rework it's 01/15 patch and keep Zhengxunli as author, I assume Zhengxunli sent the proposal before me.
ta
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