Re: [RFC PATCH 0/6] spi: Add OSPI PHY calibration support for spi-cadence-quadspi
From: Michael Walle <hidden>
Date: 2021-03-12 13:33:22
Also in:
linux-devicetree, linux-spi, lkml
From: Michael Walle <hidden>
Date: 2021-03-12 13:33:22
Also in:
linux-devicetree, linux-spi, lkml
Am 2021-03-11 20:12, schrieb Pratyush Yadav:
The main problem here is telling the controller where to find the pattern and how to read it. This RFC uses nvmem cells which point to a fixed partition containing the data to do the reads. It depends on [0] and [1]. The obvious problem with this is it won't work when the partitions are defined via command line. I don't see any good way to add nvmem cells to command line partitions. I would like some help or ideas here. We don't necessarily have to use nvmem either. Any way that can cleanly and consistently let the controller find out where the pattern is stored is good.
The NXP LS1028A SoC has a similar calibration (although there its done in hardware it seems) and there the datasheet mentions there are flash devices which supports a preamble before a read function. The preamble is then some kind of learning pattern. Did you see a flash which actually supports that in the wild? I can't find any publicly available datasheets of 8bit I/O SPI NOR flashes. -michael _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel