Re: [PATCH 7/8] mtd: spi-nor: factor out write_enable() for erase commands

[Brian Norris <computersforpeace@gmail.com>]

On Sat, Aug 09, 2014 at 06:52:34PM +0800, Huang Shijie wrote:
> On Wed, Aug 06, 2014 at 06:17:01PM -0700, Brian Norris wrote:
> > write_enable() was being duplicated to both m25p80.c and fsl-quadspi.c.
> > But this should be handled within the spi-nor abstraction layer.
> > 
> > At the same time, let's add write_disable() after erasing, so we don't
> > leave the flash in a write-enabled state afterward.
> > 
> > Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> > ---
> >  drivers/mtd/devices/m25p80.c      | 5 -----
> >  drivers/mtd/spi-nor/fsl-quadspi.c | 5 -----
> >  drivers/mtd/spi-nor/spi-nor.c     | 7 ++++---
> >  3 files changed, 4 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> > index 96226ea69f90..116d979ffdb9 100644
> > --- a/drivers/mtd/devices/m25p80.c
> > +++ b/drivers/mtd/devices/m25p80.c
> > @@ -158,11 +158,6 @@ static int m25p80_erase(struct spi_nor *nor, loff_t offset)
> >  	dev_dbg(nor->dev, "%dKiB at 0x%08x\n",
> >  		flash->mtd.erasesize / 1024, (u32)offset);
> >  
> > -	/* Send write enable, then erase commands. */
> > -	ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0);
> > -	if (ret)
> > -		return ret;
> > -
> >  	/* Set up command buffer. */
> >  	flash->command[0] = nor->erase_opcode;
> >  	m25p_addr2cmd(nor, offset, flash->command);
> > diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c
> > index 9c13622a0c7a..07fbfb0a7738 100644
> > --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> > +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> > @@ -738,11 +738,6 @@ static int fsl_qspi_erase(struct spi_nor *nor, loff_t offs)
> >  	dev_dbg(nor->dev, "%dKiB at 0x%08x:0x%08x\n",
> >  		nor->mtd->erasesize / 1024, q->chip_base_addr, (u32)offs);
> >  
> > -	/* Send write enable, then erase commands. */
> > -	ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0);
> > -	if (ret)
> > -		return ret;
> > -
> This write-enable is used for per-sector-erase, not for the whole chip
> erase.
> 
> So if you really want to remove this code, you should add an extra write-enable
> in the spi_nor_erase.

I don't understand your comment.

Before this patch, there is a write-enable command in:
 * m25p80.c, per-sector erase
 * fsl-quadspi, per-sector erase
 * spi-nor.c, whole-chip erase

With this patch, I am factoring all of these out into spi_nor_erase().

What is the problem?

Brian