[v2,23/24] mtd: rawnand: jz4780: Drop the dependency on MACH_JZ4780

Message ID 20180709200945.30116-24-boris.brezillon@bootlin.com
State Accepted
Delegated to: Miquel Raynal
Headers show
Series
  • mtd: rawnand: Improve compile-test coverage
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Commit Message

Boris Brezillon July 9, 2018, 8:09 p.m.
This MACH_JZ4780 dependency is taken care of by JZ4780_NEMC, no need
to repeat it here.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
---
 drivers/mtd/nand/raw/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Boris Brezillon July 10, 2018, 5:10 p.m. | #1
Hi PrasannaKumar,

On Tue, 10 Jul 2018 22:16:50 +0530
PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> wrote:

> Hi Boris,
> 
> On 10 July 2018 at 01:39, Boris Brezillon <boris.brezillon@bootlin.com>
> wrote:
> 
> > This MACH_JZ4780 dependency is taken care of by JZ4780_NEMC, no need
> > to repeat it here.
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> > ---
> >  drivers/mtd/nand/raw/Kconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> > index 7b5e97719c25..d9cd9608bc2d 100644
> > --- a/drivers/mtd/nand/raw/Kconfig
> > +++ b/drivers/mtd/nand/raw/Kconfig
> > @@ -499,7 +499,7 @@ config MTD_NAND_JZ4740
> >
> >  config MTD_NAND_JZ4780
> >         tristate "Support for NAND on JZ4780 SoC"
> > -       depends on MACH_JZ4780 && JZ4780_NEMC
> > +       depends on JZ4780_NEMC
> >         help
> >           Enables support for NAND Flash connected to the NEMC on JZ4780
> > SoC
> >           based boards, using the BCH controller for hardware error
> > correction.
> > --
> > 2.14.1
> >
> >
> >  
> JZ4780 has MLC NAND.

Hm, the NAND controller supports both MLC and SLC NANDs. Maybe there
are only boards with MLC NANDs, but that doesn't mean we should remove
the driver for the controller. 

> As MLC NAND is not supported in mainline do you think
> this patch is required? Even wondering if the driver is required at all.

The fact that MLC NANDs are not supported by UBI is not necessarily
definitive. I have a branch with all the work we've done to add MLC
support to UBI [1]. If you have time to invest in it, feel free to take
over this work.

Anyway, the decision to remove this driver is not mine, and this patch
allows me to at least compile-test this driver.

Regards,

Boris

[1]https://github.com/bbrezillon/linux/commits/nand/mlc
PrasannaKumar Muralidharan July 11, 2018, 5:24 p.m. | #2
On 10 July 2018 at 22:40, Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> Hi PrasannaKumar,
>
> On Tue, 10 Jul 2018 22:16:50 +0530
> PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> wrote:
>
>> Hi Boris,
>>
>> On 10 July 2018 at 01:39, Boris Brezillon <boris.brezillon@bootlin.com>
>> wrote:
>>
>> > This MACH_JZ4780 dependency is taken care of by JZ4780_NEMC, no need
>> > to repeat it here.
>> >
>> > Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
>> > ---
>> >  drivers/mtd/nand/raw/Kconfig | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>> > index 7b5e97719c25..d9cd9608bc2d 100644
>> > --- a/drivers/mtd/nand/raw/Kconfig
>> > +++ b/drivers/mtd/nand/raw/Kconfig
>> > @@ -499,7 +499,7 @@ config MTD_NAND_JZ4740
>> >
>> >  config MTD_NAND_JZ4780
>> >         tristate "Support for NAND on JZ4780 SoC"
>> > -       depends on MACH_JZ4780 && JZ4780_NEMC
>> > +       depends on JZ4780_NEMC
>> >         help
>> >           Enables support for NAND Flash connected to the NEMC on JZ4780
>> > SoC
>> >           based boards, using the BCH controller for hardware error
>> > correction.
>> > --
>> > 2.14.1
>> >
>> >
>> >
>> JZ4780 has MLC NAND.
>
> Hm, the NAND controller supports both MLC and SLC NANDs. Maybe there
> are only boards with MLC NANDs, but that doesn't mean we should remove
> the driver for the controller.

Creator CI20 board which uses JZ4780 SoC is supported by upstream as
of now. It has MLC NAND.

But I agree that removing the driver is too extreme.

>> As MLC NAND is not supported in mainline do you think
>> this patch is required? Even wondering if the driver is required at all.
>
> The fact that MLC NANDs are not supported by UBI is not necessarily
> definitive. I have a branch with all the work we've done to add MLC
> support to UBI [1]. If you have time to invest in it, feel free to take
> over this work.

I am afraid I don't have time as well as knowledge to work on it yet.

> Anyway, the decision to remove this driver is not mine, and this patch
> allows me to at least compile-test this driver.
>
> Regards,
>
> Boris
>
> [1]https://github.com/bbrezillon/linux/commits/nand/mlc

Thanks,
PrasannaKumar

Patch

diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index 7b5e97719c25..d9cd9608bc2d 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -499,7 +499,7 @@  config MTD_NAND_JZ4740
 
 config MTD_NAND_JZ4780
 	tristate "Support for NAND on JZ4780 SoC"
-	depends on MACH_JZ4780 && JZ4780_NEMC
+	depends on JZ4780_NEMC
 	help
 	  Enables support for NAND Flash connected to the NEMC on JZ4780 SoC
 	  based boards, using the BCH controller for hardware error correction.