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[0/3] reset: simple: enable for ASPEED SoCs

Message ID 20180219065438.19933-1-joel@jms.id.au
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Series reset: simple: enable for ASPEED SoCs | expand

Message

Joel Stanley Feb. 19, 2018, 6:54 a.m. UTC 
Hello Philip,

Here is a series that enables the simple reset driver for the ASPEED
SoCs. You may recall I posted a patch back in May 2017 with a
similar idea[1]. I was happy to see that you merged a driver that solves
the problem, and suits our purpose for the ASPEED. Thanks!

Cheers,

Joel

[1] https://lkml.org/lkml/2017/5/25/940


Joel Stanley (3):
  dt-bindings: aspeed-lpc: Add reset controller
  reset: simple: Enable for ASPEED systems
  reset: simple: Allow user selection of driver

 .../devicetree/bindings/mfd/aspeed-lpc.txt          | 21 +++++++++++++++++++++
 drivers/reset/Kconfig                               | 12 ++++++++----
 drivers/reset/reset-simple.c                        |  2 ++
 3 files changed, 31 insertions(+), 4 deletions(-)

Comments

Philipp Zabel Feb. 19, 2018, 11:46 a.m. UTC | #1 
Hi Joel,

On Mon, 2018-02-19 at 17:24 +1030, Joel Stanley wrote:
> Hello Philip,
> 
> Here is a series that enables the simple reset driver for the ASPEED
> SoCs. You may recall I posted a patch back in May 2017 with a
> similar idea[1]. I was happy to see that you merged a driver that solves
> the problem, and suits our purpose for the ASPEED. Thanks!

Yes, sometimes it takes a few drivers to see what the common patterns
are. When it came to unify them, starting from one of the preexisting
drivers seemed like the straightforward thing to do.

regards
Philipp
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Philipp Zabel Feb. 19, 2018, 11:46 a.m. UTC | #2 
On Mon, 2018-02-19 at 17:24 +1030, Joel Stanley wrote:
> Currently this driver is only user selectable if COMPILE_TEST is turned
> on. Users may wish to select (and deselect) it, so remove this
> restriction.

I would like to keep user visible options to a minimum unless there is a
good reason. What is the scenario in which a user would decide to
disable the default-enabled reset-simple driver, or the other way
around? This should be mentioned in the commit message.

Maybe this is an indication that there could be a better default than
just ARCH_ASPEED.

regards
Philipp

> Signed-off-by: Joel Stanley <joel@jms.id.au>
> ---
>  drivers/reset/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 18f152d251d7..7490a4370900 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -82,7 +82,7 @@ config RESET_PISTACHIO
>  	  This enables the reset driver for ImgTec Pistachio SoCs.
>  
>  config RESET_SIMPLE
> -	bool "Simple Reset Controller Driver" if COMPILE_TEST
> +	bool "Simple Reset Controller Driver"
>  	default ARCH_SOCFPGA || ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED
>  	help
>  	  This enables a simple reset controller driver for reset lines that
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Joel Stanley Feb. 19, 2018, 12:07 p.m. UTC | #3 
On Mon, Feb 19, 2018 at 10:16 PM, Philipp Zabel <p.zabel@pengutronix.de> wrote:
> On Mon, 2018-02-19 at 17:24 +1030, Joel Stanley wrote:
>> Currently this driver is only user selectable if COMPILE_TEST is turned
>> on. Users may wish to select (and deselect) it, so remove this
>> restriction.
>
> I would like to keep user visible options to a minimum unless there is a
> good reason. What is the scenario in which a user would decide to
> disable the default-enabled reset-simple driver, or the other way
> around? This should be mentioned in the commit message.

In this SoC's case the driver is not essential. A system that does not
use UART1..4 will not ever call on the driver. This situation is
common as the console uses UART5.

> Maybe this is an indication that there could be a better default than
> just ARCH_ASPEED.

This is an appropriate default, as it causes the least surprise to a
user. Without taking the UART out of reset, the kernel driver still
loads, but characters are never drained from the FIFO.

Advanced users may want to save the few kilobytes that an extra driver
adds, and the boot overhead of loading yet another driver. The saving
is small, so if you feel strongly about it we can drop this patch.

Cheers,

Joel

>
> regards
> Philipp
>
>> Signed-off-by: Joel Stanley <joel@jms.id.au>
>> ---
>>  drivers/reset/Kconfig | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
>> index 18f152d251d7..7490a4370900 100644
>> --- a/drivers/reset/Kconfig
>> +++ b/drivers/reset/Kconfig
>> @@ -82,7 +82,7 @@ config RESET_PISTACHIO
>>         This enables the reset driver for ImgTec Pistachio SoCs.
>>
>>  config RESET_SIMPLE
>> -     bool "Simple Reset Controller Driver" if COMPILE_TEST
>> +     bool "Simple Reset Controller Driver"
>>       default ARCH_SOCFPGA || ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED
>>       help
>>         This enables a simple reset controller driver for reset lines that
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