[v4,06/10] ARM: defconfig: Use the new FSL QSPI driver under the SPI framework

Commit Message

Frieder Schrempf Nov. 7, 2018, 2:43 p.m. UTC

From: Frieder Schrempf <[e-mail]>

The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.

Signed-off-by: Frieder Schrempf <[e-mail]>
---
 arch/arm/configs/imx_v6_v7_defconfig | 2 +-
 arch/arm/configs/multi_v7_defconfig  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Comments

Olof Johansson Nov. 7, 2018, 4:20 p.m. UTC | #1

On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
<[e-mail]> wrote:
>
> From: Frieder Schrempf <[e-mail]>
>
> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
>
> Signed-off-by: Frieder Schrempf <[e-mail]>

Hi Frieder,

This patch is part of a series that I didn't see the rest of, but in
general we prefer to merge these through arm-soc even if the driver
goes in through another tree. The way we'd prefer to handle it is that
once the driver lands, we'll take the config option change to turn it
on. To avoid our branches to break until both sides have landed, it
might be a good idea to keep both drivers on for a short while (one
release).

So, I'm not going to ack this since we avoid taking defconfig changes
through driver trees (these two defconfigs tend to churn a lot and we
don't want to create merge conflicts where we don't have to), but
we'll be happy to pick it up when the time comes.


Thanks,

-Olof

Frieder Schrempf Nov. 7, 2018, 4:36 p.m. UTC | #2

Hi Olof,

On 07.11.18 17:20, Olof Johansson wrote:
> On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
> <[e-mail]> wrote:
>>
>> From: Frieder Schrempf <[e-mail]>
>>
>> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
>> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
>>
>> Signed-off-by: Frieder Schrempf <[e-mail]>
> 
> Hi Frieder,
> 
> This patch is part of a series that I didn't see the rest of, but in
> general we prefer to merge these through arm-soc even if the driver
> goes in through another tree. The way we'd prefer to handle it is that
> once the driver lands, we'll take the config option change to turn it
> on. To avoid our branches to break until both sides have landed, it
> might be a good idea to keep both drivers on for a short while (one
> release).
> 
> So, I'm not going to ack this since we avoid taking defconfig changes
> through driver trees (these two defconfigs tend to churn a lot and we
> don't want to create merge conflicts where we don't have to), but
> we'll be happy to pick it up when the time comes.

Ok, thank you for explaining the common practice. I will drop the config 
changes for the next version and send it separately when the time is ready.

Both the old driver and the new one use the same compatible strings for 
probing. Wouldn't that cause problems if both drivers are enabled for a 
while, or am I missing something?

Thanks,
Frieder

> 
> 
> Thanks,
> 
> -Olof
>

Olof Johansson Nov. 7, 2018, 11:08 p.m. UTC | #3

On Wed, Nov 7, 2018 at 8:36 AM Schrempf Frieder
<[e-mail]> wrote:
>
> Hi Olof,
>
> On 07.11.18 17:20, Olof Johansson wrote:
> > On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
> > <[e-mail]> wrote:
> >>
> >> From: Frieder Schrempf <[e-mail]>
> >>
> >> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
> >> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
> >>
> >> Signed-off-by: Frieder Schrempf <[e-mail]>
> >
> > Hi Frieder,
> >
> > This patch is part of a series that I didn't see the rest of, but in
> > general we prefer to merge these through arm-soc even if the driver
> > goes in through another tree. The way we'd prefer to handle it is that
> > once the driver lands, we'll take the config option change to turn it
> > on. To avoid our branches to break until both sides have landed, it
> > might be a good idea to keep both drivers on for a short while (one
> > release).
> >
> > So, I'm not going to ack this since we avoid taking defconfig changes
> > through driver trees (these two defconfigs tend to churn a lot and we
> > don't want to create merge conflicts where we don't have to), but
> > we'll be happy to pick it up when the time comes.
>
> Ok, thank you for explaining the common practice. I will drop the config
> changes for the next version and send it separately when the time is ready.
>
> Both the old driver and the new one use the same compatible strings for
> probing. Wouldn't that cause problems if both drivers are enabled for a
> while, or am I missing something?

Only one of them would be allowed to bind to a device, but it might
not be predictable which one does (especially in the case of modules).

So, it's far from ideal, but breaking the platform is possibly worse.
It might just be a good idea to merge the driver and not turn it on
until it's in for that case (i.e. we take the config change between
-rc1 and -rc2).


-Olof

Boris Brezillon Nov. 8, 2018, 8:34 a.m. UTC | #4

On Wed, 7 Nov 2018 16:36:13 +0000
Schrempf Frieder <[e-mail]> wrote:

> Hi Olof,
> 
> On 07.11.18 17:20, Olof Johansson wrote:
> > On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
> > <[e-mail]> wrote:  
> >>
> >> From: Frieder Schrempf <[e-mail]>
> >>
> >> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
> >> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
> >>
> >> Signed-off-by: Frieder Schrempf <[e-mail]>  
> > 
> > Hi Frieder,
> > 
> > This patch is part of a series that I didn't see the rest of, but in
> > general we prefer to merge these through arm-soc even if the driver
> > goes in through another tree. The way we'd prefer to handle it is that
> > once the driver lands, we'll take the config option change to turn it
> > on. To avoid our branches to break until both sides have landed, it
> > might be a good idea to keep both drivers on for a short while (one
> > release).
> > 
> > So, I'm not going to ack this since we avoid taking defconfig changes
> > through driver trees (these two defconfigs tend to churn a lot and we
> > don't want to create merge conflicts where we don't have to), but
> > we'll be happy to pick it up when the time comes.  
> 
> Ok, thank you for explaining the common practice. I will drop the config 
> changes for the next version and send it separately when the time is ready.
> 
> Both the old driver and the new one use the same compatible strings for 
> probing. Wouldn't that cause problems if both drivers are enabled for a 
> while, or am I missing something?

Or maybe we should not introduce a new Kconfig option and just reuse
the old one. It probably requires re-ordering patches a bit (patch 1
should be moved after patch 5). Then you have 2 choices:

1/ merge patch 1 and 6 so that the new driver effectively replaces the
   old one but uses the same Kconfig option
2/ remove the ability to compile the old driver when the new one is
   introduced: remove the line from drivers/mtd/spi-nor Makefile and
   move the Kconfig entry from drivers/mtd/spi-nor/Kconfig to
   drivers/spi/Kconfig. And remove the old code in a separate patch

I'm fine either way, but option #2 will probably make the patch
introducing the new driver bigger and hurt readability.

Frieder Schrempf Nov. 12, 2018, 10:46 a.m. UTC | #5

On 08.11.18 09:34, Boris Brezillon wrote:
> On Wed, 7 Nov 2018 16:36:13 +0000
> Schrempf Frieder <[e-mail]> wrote:
> 
>> Hi Olof,
>>
>> On 07.11.18 17:20, Olof Johansson wrote:
>>> On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
>>> <[e-mail]> wrote:
>>>>
>>>> From: Frieder Schrempf <[e-mail]>
>>>>
>>>> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
>>>> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
>>>>
>>>> Signed-off-by: Frieder Schrempf <[e-mail]>
>>>
>>> Hi Frieder,
>>>
>>> This patch is part of a series that I didn't see the rest of, but in
>>> general we prefer to merge these through arm-soc even if the driver
>>> goes in through another tree. The way we'd prefer to handle it is that
>>> once the driver lands, we'll take the config option change to turn it
>>> on. To avoid our branches to break until both sides have landed, it
>>> might be a good idea to keep both drivers on for a short while (one
>>> release).
>>>
>>> So, I'm not going to ack this since we avoid taking defconfig changes
>>> through driver trees (these two defconfigs tend to churn a lot and we
>>> don't want to create merge conflicts where we don't have to), but
>>> we'll be happy to pick it up when the time comes.
>>
>> Ok, thank you for explaining the common practice. I will drop the config
>> changes for the next version and send it separately when the time is ready.
>>
>> Both the old driver and the new one use the same compatible strings for
>> probing. Wouldn't that cause problems if both drivers are enabled for a
>> while, or am I missing something?
> 
> Or maybe we should not introduce a new Kconfig option and just reuse
> the old one. It probably requires re-ordering patches a bit (patch 1
> should be moved after patch 5). Then you have 2 choices:
> 
> 1/ merge patch 1 and 6 so that the new driver effectively replaces the
>     old one but uses the same Kconfig option
> 2/ remove the ability to compile the old driver when the new one is
>     introduced: remove the line from drivers/mtd/spi-nor Makefile and
>     move the Kconfig entry from drivers/mtd/spi-nor/Kconfig to
>     drivers/spi/Kconfig. And remove the old code in a separate patch
> 
> I'm fine either way, but option #2 will probably make the patch
> introducing the new driver bigger and hurt readability.

I think having both drivers in the tree for a while wouldn't be so bad. 
So if any compatibility issues come up with the new driver, people can 
still use the old one.

Therefore I think I will drop the patches that change the defconfig and 
remove the old driver code and keep the different Kconfig options. And 
maybe add an exclusive dependency in Kconfig, so both drivers can not be 
enabled at the same time.

Does this make sense?

Boris Brezillon Nov. 12, 2018, 10:56 a.m. UTC | #6

On Mon, 12 Nov 2018 10:46:45 +0000
Schrempf Frieder <[e-mail]> wrote:

> On 08.11.18 09:34, Boris Brezillon wrote:
> > On Wed, 7 Nov 2018 16:36:13 +0000
> > Schrempf Frieder <[e-mail]> wrote:
> >   
> >> Hi Olof,
> >>
> >> On 07.11.18 17:20, Olof Johansson wrote:  
> >>> On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
> >>> <[e-mail]> wrote:  
> >>>>
> >>>> From: Frieder Schrempf <[e-mail]>
> >>>>
> >>>> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
> >>>> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
> >>>>
> >>>> Signed-off-by: Frieder Schrempf <[e-mail]>  
> >>>
> >>> Hi Frieder,
> >>>
> >>> This patch is part of a series that I didn't see the rest of, but in
> >>> general we prefer to merge these through arm-soc even if the driver
> >>> goes in through another tree. The way we'd prefer to handle it is that
> >>> once the driver lands, we'll take the config option change to turn it
> >>> on. To avoid our branches to break until both sides have landed, it
> >>> might be a good idea to keep both drivers on for a short while (one
> >>> release).
> >>>
> >>> So, I'm not going to ack this since we avoid taking defconfig changes
> >>> through driver trees (these two defconfigs tend to churn a lot and we
> >>> don't want to create merge conflicts where we don't have to), but
> >>> we'll be happy to pick it up when the time comes.  
> >>
> >> Ok, thank you for explaining the common practice. I will drop the config
> >> changes for the next version and send it separately when the time is ready.
> >>
> >> Both the old driver and the new one use the same compatible strings for
> >> probing. Wouldn't that cause problems if both drivers are enabled for a
> >> while, or am I missing something?  
> > 
> > Or maybe we should not introduce a new Kconfig option and just reuse
> > the old one. It probably requires re-ordering patches a bit (patch 1
> > should be moved after patch 5). Then you have 2 choices:
> > 
> > 1/ merge patch 1 and 6 so that the new driver effectively replaces the
> >     old one but uses the same Kconfig option
> > 2/ remove the ability to compile the old driver when the new one is
> >     introduced: remove the line from drivers/mtd/spi-nor Makefile and
> >     move the Kconfig entry from drivers/mtd/spi-nor/Kconfig to
> >     drivers/spi/Kconfig. And remove the old code in a separate patch
> > 
> > I'm fine either way, but option #2 will probably make the patch
> > introducing the new driver bigger and hurt readability.  
> 
> I think having both drivers in the tree for a while wouldn't be so bad. 
> So if any compatibility issues come up with the new driver, people can 
> still use the old one.

Except that's not what happens in practice. Believe me, I tried this
approach several times, and people keep using the old driver until
they're forced to switch to the new one. So you actually don't address
the problem, you just delay it a bit, and you'll have to fix
regressions anyway.

> 
> Therefore I think I will drop the patches that change the defconfig and 
> remove the old driver code and keep the different Kconfig options. And 
> maybe add an exclusive dependency in Kconfig, so both drivers can not be 
> enabled at the same time.
> 
> Does this make sense?

I'd really prefer to have the removal of the old driver in the same
release the new driver is introduced but if that's not possible, let's
have a clear plan, like "introduce new driver in release X, remove the
old one in release X+1".

Frieder Schrempf Nov. 12, 2018, 11:24 a.m. UTC | #7

On 12.11.18 11:56, Boris Brezillon wrote:
> On Mon, 12 Nov 2018 10:46:45 +0000
> Schrempf Frieder <[e-mail]> wrote:
> 
>> On 08.11.18 09:34, Boris Brezillon wrote:
>>> On Wed, 7 Nov 2018 16:36:13 +0000
>>> Schrempf Frieder <[e-mail]> wrote:
>>>    
>>>> Hi Olof,
>>>>
>>>> On 07.11.18 17:20, Olof Johansson wrote:
>>>>> On Wed, Nov 7, 2018 at 6:44 AM Frieder Schrempf
>>>>> <[e-mail]> wrote:
>>>>>>
>>>>>> From: Frieder Schrempf <[e-mail]>
>>>>>>
>>>>>> The new driver at spi/spi-fsl-qspi.c replaces the old SPI NOR driver
>>>>>> at mtd/fsl-quadspi.c. Switch to the new driver in the defconfigs.
>>>>>>
>>>>>> Signed-off-by: Frieder Schrempf <[e-mail]>
>>>>>
>>>>> Hi Frieder,
>>>>>
>>>>> This patch is part of a series that I didn't see the rest of, but in
>>>>> general we prefer to merge these through arm-soc even if the driver
>>>>> goes in through another tree. The way we'd prefer to handle it is that
>>>>> once the driver lands, we'll take the config option change to turn it
>>>>> on. To avoid our branches to break until both sides have landed, it
>>>>> might be a good idea to keep both drivers on for a short while (one
>>>>> release).
>>>>>
>>>>> So, I'm not going to ack this since we avoid taking defconfig changes
>>>>> through driver trees (these two defconfigs tend to churn a lot and we
>>>>> don't want to create merge conflicts where we don't have to), but
>>>>> we'll be happy to pick it up when the time comes.
>>>>
>>>> Ok, thank you for explaining the common practice. I will drop the config
>>>> changes for the next version and send it separately when the time is ready.
>>>>
>>>> Both the old driver and the new one use the same compatible strings for
>>>> probing. Wouldn't that cause problems if both drivers are enabled for a
>>>> while, or am I missing something?
>>>
>>> Or maybe we should not introduce a new Kconfig option and just reuse
>>> the old one. It probably requires re-ordering patches a bit (patch 1
>>> should be moved after patch 5). Then you have 2 choices:
>>>
>>> 1/ merge patch 1 and 6 so that the new driver effectively replaces the
>>>      old one but uses the same Kconfig option
>>> 2/ remove the ability to compile the old driver when the new one is
>>>      introduced: remove the line from drivers/mtd/spi-nor Makefile and
>>>      move the Kconfig entry from drivers/mtd/spi-nor/Kconfig to
>>>      drivers/spi/Kconfig. And remove the old code in a separate patch
>>>
>>> I'm fine either way, but option #2 will probably make the patch
>>> introducing the new driver bigger and hurt readability.
>>
>> I think having both drivers in the tree for a while wouldn't be so bad.
>> So if any compatibility issues come up with the new driver, people can
>> still use the old one.
> 
> Except that's not what happens in practice. Believe me, I tried this
> approach several times, and people keep using the old driver until
> they're forced to switch to the new one. So you actually don't address
> the problem, you just delay it a bit, and you'll have to fix
> regressions anyway.

Ok, I see.

>> Therefore I think I will drop the patches that change the defconfig and
>> remove the old driver code and keep the different Kconfig options. And
>> maybe add an exclusive dependency in Kconfig, so both drivers can not be
>> enabled at the same time.
>>
>> Does this make sense?
> 
> I'd really prefer to have the removal of the old driver in the same
> release the new driver is introduced but if that's not possible, let's
> have a clear plan, like "introduce new driver in release X, remove the
> old one in release X+1".

We can do it as you suggested. I will think about whether to use option 
#1 or #2.
With #1 we will have the removal of the old driver and adding the new 
driver in one single patch.
With #2 we will have the disabling of the old driver via Makefile in the 
same patch thats adding the new driver.

Patch

diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig
index 1ad5736..1741d87 100644
--- a/arch/arm/configs/imx_v6_v7_defconfig
+++ b/arch/arm/configs/imx_v6_v7_defconfig
@@ -113,7 +113,6 @@  CONFIG_MTD_NAND_GPMI_NAND=y
 CONFIG_MTD_NAND_VF610_NFC=y
 CONFIG_MTD_NAND_MXC=y
 CONFIG_MTD_SPI_NOR=y
-CONFIG_SPI_FSL_QUADSPI=y
 CONFIG_MTD_UBI=y
 CONFIG_MTD_UBI_FASTMAP=y
 CONFIG_MTD_UBI_BLOCK=y
@@ -204,6 +203,7 @@  CONFIG_I2C_ALGOPCA=m
 CONFIG_I2C_GPIO=y
 CONFIG_I2C_IMX=y
 CONFIG_SPI=y
+CONFIG_SPI_FSL_QSPI=y
 CONFIG_SPI_GPIO=y
 CONFIG_SPI_IMX=y
 CONFIG_SPI_FSL_DSPI=y
diff --git a/arch/arm/configs/multi_v7_defconfig b/arch/arm/configs/multi_v7_defconfig
index 1c76168..faddf29 100644
--- a/arch/arm/configs/multi_v7_defconfig
+++ b/arch/arm/configs/multi_v7_defconfig
@@ -193,7 +193,6 @@  CONFIG_MTD_NAND_BRCMNAND=y
 CONFIG_MTD_NAND_VF610_NFC=y
 CONFIG_MTD_NAND_DAVINCI=y
 CONFIG_MTD_SPI_NOR=y
-CONFIG_SPI_FSL_QUADSPI=m
 CONFIG_MTD_UBI=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
@@ -383,6 +382,7 @@  CONFIG_SPI_BCM2835=y
 CONFIG_SPI_BCM2835AUX=y
 CONFIG_SPI_CADENCE=y
 CONFIG_SPI_DAVINCI=y
+CONFIG_SPI_FSL_QSPI=m
 CONFIG_SPI_GPIO=m
 CONFIG_SPI_FSL_DSPI=m
 CONFIG_SPI_OMAP24XX=y