Messages in this thread | | | Date | Thu, 10 Jul 2014 18:09:55 +0530 | Subject | Re: [RFC PATCH 1/2] spi: Add support for Zynq QSPI controller | From | Harini Katakam <> |
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Hi Mark,
On Thu, Jul 10, 2014 at 5:31 PM, Mark Brown <broonie@kernel.org> wrote: > On Thu, Jul 10, 2014 at 04:03:19PM +0530, Harini Katakam wrote: > >> OK. Correct me if I'm wrong but announcing this support in master->flags is >> just to say the controller supports it - Like Punnaiah mentioned in the other > > No, it's broken to set this if there is no ability to use it. > >> mail, nothing specific needs to be done from the controller driver to enable >> dual/quad support. This is at the SOC/IP level. > > How does the client driver select the width to use for a transfer?
This controller is meant to be used only with flash devices. The flash devices' supported width will be reflected in a table in MTD layer. When selecting, priority is given to quad over dual and single in the MTD and it will send commands using the supported tx/rx bus width accordingly. About the supported bus width on board, tx-bus-width and rx-bus-width properties in dts will have the info; which I believe spi core uses.
Regards, Harini
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