On Thu, Apr 24, 2014 at 03:43:51PM +0200, Marek Vasut wrote: > On Thursday, April 24, 2014 at 06:53:34 AM, Huang Shijie wrote: > > On Wed, Apr 23, 2014 at 09:45:57PM +0200, Marek Vasut wrote: > > > On Wednesday, April 23, 2014 at 12:16:50 PM, Huang Shijie wrote: > > > > This patch adds the DDR quad read support by the following: > > > > [1] add SPI_NOR_DDR_QUAD read mode. > > > > > > > > [2] add DDR Quad read opcodes: > > > > SPINOR_OP_READ_1_4_4_D / SPINOR_OP_READ4_1_4_4_D > > > > > > > > [3] add set_ddr_quad_mode() to initialize for the DDR quad read. > > > > > > > > Currently it only works for Spansion NOR. > > > > > > > > [3] set the dummy with 8 for DDR quad read. > > > > > > > > The m25p80.c can not support the DDR quad read, the SPI NOR > > > > > > > > controller can set the dummy value in its driver, such as > > > > fsl-quadspi.c. > > > > > > > > Test this patch for Spansion s25fl128s NOR flash. > > > > > > > > Signed-off-by: Huang Shijie <[email protected]> > > > > --- > > > > > > > > drivers/mtd/spi-nor/spi-nor.c | 50 > > > > > > > > +++++++++++++++++++++++++++++++++++++++- include/linux/mtd/spi-nor.h > > > > | > > > > > > > > 8 +++++- > > > > 2 files changed, 54 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c > > > > b/drivers/mtd/spi-nor/spi-nor.c index 1a12f81..e2f69db 100644 > > > > --- a/drivers/mtd/spi-nor/spi-nor.c > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c > > > > @@ -74,6 +74,15 @@ static int read_cr(struct spi_nor *nor) > > > > > > > > static inline int spi_nor_read_dummy_cycles(struct spi_nor *nor) > > > > { > > > > > > > > switch (nor->flash_read) { > > > > > > > > + case SPI_NOR_DDR_QUAD: > > > > + /* > > > > + * The m25p80.c can not support the DDR quad read. > > > > + * We set the dummy cycles to 8 by default. If the SPI > > > > NOR > > > > + * controller driver has already set it before call the > > > > + * spi_nor_scan(), we just keep it as it is. > > > > + */ > > > > + if (nor->read_dummy) > > > > + return nor->read_dummy; > > > > > > Can the controller set this variable to zero ? > > > > The default value of this variable is zero. It it meaningless to set zero. > > The DDR Quad read definitely will use a non-zero dummy. > > Can you back this by some documentation please ?
I can not find a document for this. :( But i have decided to parse out the DT node in here, not in the driver. thanks Huang Shijie -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
