Messages in this thread | | | Date | Tue, 22 Mar 2022 09:19:49 +0100 | From | Michael Walle <> | Subject | Re: [PATCH v2 4/8] mtd: spi-nor: core: Introduce method for RDID op |
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Am 2022-03-22 08:32, schrieb Pratyush Yadav: > On 21/03/22 11:56PM, Michael Walle wrote: >> Am 2022-02-28 12:17, schrieb Tudor Ambarus: >> > RDID is used in the core to auto detect the flash, but also by some >> > manufacturer drivers that contain flashes that support Octal DTR mode, >> > so that they can read the flash ID after the switch to Octal DTR was >> > made >> > to test if the switch was successful. Introduce a core method for RDID >> > op >> > to avoid code duplication. >> >> Some or all? Is that specific to the flash or can we just check that >> readid works in spi_nor_octal_dtr_enable()? That way we could also >> just get rid of the proto parameter for the read_id because it can >> be called after we set the reg_proto. > > It is specific to the flash. Not all flashes support RDID in 8D mode. > And the RDID command is also different in 8D mode for various flashes. > For example, Micron MT35XU512ABA flash expects 8 dummy cycles and 0 > address cycles. Cypress S28HS512T expects 4 address cycles and 3 dummy > cycles. > > The octal_dtr_enable hook would know what parameters to use but it is > harder for the core to know since this information is not discoverable > via SFDP.
Ah, I see, thanks for clarification.
-michael
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