On Wed, Oct 10, 2018 at 02:23:40PM +0300, Talel Shenhar wrote: > On 10/10/2018 01:18 PM, Mark Brown wrote: > > On Wed, Oct 10, 2018 at 10:08:12AM +0300, Talel Shenhar wrote: > >> The dw spi controller has an auto-deselect of Chip-Select, in case there is > >> no data inside the Tx FIFO. While working on platforms with Alpine chips, > > Why would we ever want to use this behaviour? It will be broken for any > > non-trivial SPI message such as those made with multiple transfers > > anyway. Why not just unconditionally control it manually? > This behavior (auto-deselect of Chip-Select) is the default behavior of dw spi controller hw. > On Alpine chip there is additional behavior added to the dw spi controller hw that allows the sw to disable this behavior. > This patch allows the dw driver to enable this hw workaround and add the needed sw manual control for it. If this is a modified IP with additional features then it should be given a new compatible string rather than having a property - it's not just configuration of the existing IP, it's a new thing and we may find there are other quirks that have to be taken care of for it.
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