Hi all, in order to be able to use Micron Quad SPI memories with the new Atmel QSPI controller I added a new set_protocol() callback into struct spi_nor. Indeed, once the quad I/O mode has been enabled on a Micron QSPI flash by clearing bit 7 in its Enhanced Volatile Configuration Register, this memory expects all the following commands to use the QSPI 4-4-4 protocol. So the QSPI controller needs to be notified about this protocol change before reading the Status register, 0x05 command sent by the spi_nor_wail_till_ready() function, in micron_quad_enable(). Reading spi-nor.h, I saw an interesting struct spi_nor_xfer_cfg and its associated callbacks write_xfer() and read_xfer(). However these callbacks don't seem to be used at all for now. They look to have been designed to add QSPI support to the generic spi-nor framework. So before extending the framework with my own callback, I'd like to know whether I should have tried to used the read_xfer()/write_xfer() callbacks to join an already existing effort to add QSPI support. If so, I think either the read/write_reg() prototypes should be updated or new callbacks should be added for register reads/writes. As explained above, even for reading the Status register the QSPI 4-4-4 protocol must be used with Micron memories in quad I/O mode. So the framework has to find a way to tell the QSPI controller which protocol it should use. So I'm interested in your comments! :) Best Regards, Cyrille ChangeLog v1: This series of patches add support for the new Atmel QSPI controller embedded inside sama5d2x SoCs. These patches were first developped for linux-3.18-at91 and tested on a sama5d27 Xplained ultra board, which embeds a Micron n25q128a13 QSPI NOR flash memory. Then the series was adapted for mainline. Cyrille Pitchen (7): Documentation: mtd: add a DT property to set the number of dummy cycles mtd: spi-nor: notify (Q)SPI controller about protocol change mtd: spi-nor: allow to tune the number of dummy cycles Documentation: mtd: add a DT property to set the latency code of Spansion memory mtd: spi-nor: allow the set the latency code on Spansion memories Documentation: atmel-quadspi: add binding file for Atmel QSPI driver mtd: atmel-quadspi: add driver for Atmel QSPI controller .../devicetree/bindings/mtd/atmel-quadspi.txt | 29 + .../devicetree/bindings/mtd/jedec,spi-nor.txt | 6 + .../devicetree/bindings/mtd/spansion-nor.txt | 22 + drivers/mtd/spi-nor/Kconfig | 7 + drivers/mtd/spi-nor/Makefile | 1 + drivers/mtd/spi-nor/atmel-quadspi.c | 901 +++++++++++++++++++++ drivers/mtd/spi-nor/spi-nor.c | 160 +++- include/linux/mtd/spi-nor.h | 15 + 8 files changed, 1122 insertions(+), 19 deletions(-) create mode 100644 Documentation/devicetree/bindings/mtd/atmel-quadspi.txt create mode 100644 Documentation/devicetree/bindings/mtd/spansion-nor.txt create mode 100644 drivers/mtd/spi-nor/atmel-quadspi.c -- 1.8.2.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html