[OpenWrt-Devel] 回复：[PATCH] ramips: reset m25p80 when shutdown

[Daniel Golle]

On Sat, Nov 21, 2015 at 09:41:25PM +0100, John Crispin wrote:
> Hi,
> 
> one more request
> 
> On 16/11/2015 18:03, 未命名 wrote:
> > Instead of use the set_4byte function in spi-nor.c, I use this patch
> > for simplest modification. In fact, set_4byte also send 0xe9 command to
> > the spi flash.

Using set_4byte also already contains the logic to check which vendor-
specific 4-byte mode to use (EN4B/EX4B or via explicite read4/write4
commands). Surely, having spi-nor provide a generic shutdown functions
using set_4byte and then using that in m25p80 is less simple than
implementing the work-around only in m25p80...


> > 
> > Signed-off-by: Shonn Lu <countrysideboy at qq.com>
> > ---
> >  .../0064-reset-m25p80-when-shutdown.patch          | 27
> > ++++++++++++++++++++++
> >  1 file changed, 27 insertions(+)
> >  create mode 100644
> > target/linux/ramips/patches-3.18/0064-reset-m25p80-when-shutdown.patch
> > 
> > diff --git
> > a/target/linux/ramips/patches-3.18/0064-reset-m25p80-when-shutdown.patch
> > b/target/linux/ramips/patches-3.18/0064-reset-m25p80-when-shutdown.patch
> > new file mode 100644
> > index 0000000..aca758d
> > --- /dev/null
> > +++ b/target/linux/ramips/patches-3.18/0064-reset-m25p80-when-shutdown.patch
> > @@ -0,0 +1,27 @@
> > +--- a/drivers/mtd/devices/m25p80.c
> > ++++ b/drivers/mtd/devices/m25p80.c
> > +@@ -322,6 +322,16 @@
> > + {
> > + struct m25p *flash = spi_get_drvdata(spi);
> > +
> > ++ if ((&flash->spi_nor)->addr_width > 3) {
> > ++ printk(KERN_INFO "m25p80: exit 4-byte address mode\n");
> > ++ flash->command[0] = SPINOR_OP_EX4B;  // exit 4-byte address mode: 0xe9
> > ++ spi_write(flash->spi, flash->command, 1);
> > ++ flash->command[0] = 0x66;  // enable reset
> > ++ spi_write(flash->spi, flash->command, 1); 
> > ++ flash->command[0] = 0x99;  // reset
> > ++ spi_write(flash->spi, flash->command, 1);

Are you sure the reset is actually needed?
When I tested on some Rt5350 boards, SPINOR_OP_EX4B (0xE9) did the job
and no subsequent reset was needed.

> 
> this needs to be indented with tabs
> 
> 	John
> 


Cheers


Daniel
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