4.14/4.18: Please add "eeprom: at24: Add support for address-width property"

4.14/4.18: Please add "eeprom: at24: Add support for address-width property"

[Adrian Bunk]

Please cherry-pick the following commit to 4.14 and 4.18:

    commit a2b3bf4846e5eed62ea6abb096af2c950961033c
    Author: Alan Chiang <alanx.chiang@intel.com>
    Date:   Wed Jul 25 11:20:22 2018 +0800

    eeprom: at24: Add support for address-width property
    
    Provide a flexible way to determine the addressing bits of eeprom.
    Pass the addressing bits to driver through address-width property.

    Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
    Signed-off-by: Andy Yeh <andy.yeh@intel.com>
    Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>


Confirmed to work on 4.14 with the Identification Page
of an ST M24M02-DR (256 bytes but 16 bit addressing).

Cannot be cherry-picked trivially on 4.9.

The corresponding documentation commit 21d04054501fb27b56e995b54ac74e39aee79a46
can be cherry-picked to 4.18, the backport for 4.14 is below.

Thanks
Adrian


>From 2562e333f39b8077ffb06bdf79430f10b74c11f5 Mon Sep 17 00:00:00 2001
From: Alan Chiang <alanx.chiang@intel.com>
Date: Wed, 25 Jul 2018 11:20:21 +0800
Subject: [PATCH] dt-bindings: at24: Add address-width property

Currently the only way to use a variant of a supported model with
a different address width is to define a new compatible string and
the corresponding chip data structure.

Provide a flexible way to specify the size of the address pointer
by defining a new property: address-width.

Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
Signed-off-by: Andy Yeh <andy.yeh@intel.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
[Bartosz: fixed the commit message]
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
[Adrian Bunk: backported to 4.14]
Signed-off-by: Adrian Bunk <bunk@kernel.org>
---
 Documentation/devicetree/bindings/eeprom/eeprom.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt b/Documentation/devicetree/bindings/eeprom/eeprom.txt
index afc04589eadf..44bfffc43bed 100644
--- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
+++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
@@ -36,6 +36,8 @@ Optional properties:
 
   - read-only: this parameterless property disables writes to the eeprom
 
+  - address-width: number of address bits (one of 8, 16).
+
 Example:
 
 eeprom@52 {
-- 
2.11.0

Re: 4.14/4.18: Please add "eeprom: at24: Add support for address-width property"

[Sasha Levin]

On Mon, Oct 22, 2018 at 11:38:35AM +0300, Adrian Bunk wrote:
>Please cherry-pick the following commit to 4.14 and 4.18:
>
>    commit a2b3bf4846e5eed62ea6abb096af2c950961033c
>    Author: Alan Chiang <alanx.chiang@intel.com>
>    Date:   Wed Jul 25 11:20:22 2018 +0800
>
>    eeprom: at24: Add support for address-width property
>
>    Provide a flexible way to determine the addressing bits of eeprom.
>    Pass the addressing bits to driver through address-width property.
>
>    Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
>    Signed-off-by: Andy Yeh <andy.yeh@intel.com>
>    Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>
>
>Confirmed to work on 4.14 with the Identification Page
>of an ST M24M02-DR (256 bytes but 16 bit addressing).

This patch doesn't look like stable material. The hardware never worked
before, so this is not a regression and falls under new hardware
enablement, but the patch is more complex than what we usually allow for
hardware enablement (adding various IDs/quirks/etc).

Am I missing something?

Re: 4.14/4.18: Please add "eeprom: at24: Add support for address-width property"

[Adrian Bunk]

On Wed, Oct 31, 2018 at 10:27:45AM -0400, Sasha Levin wrote:
> On Mon, Oct 22, 2018 at 11:38:35AM +0300, Adrian Bunk wrote:
> > Please cherry-pick the following commit to 4.14 and 4.18:
> > 
> >    commit a2b3bf4846e5eed62ea6abb096af2c950961033c
> >    Author: Alan Chiang <alanx.chiang@intel.com>
> >    Date:   Wed Jul 25 11:20:22 2018 +0800
> > 
> >    eeprom: at24: Add support for address-width property
> > 
> >    Provide a flexible way to determine the addressing bits of eeprom.
> >    Pass the addressing bits to driver through address-width property.
> > 
> >    Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
> >    Signed-off-by: Andy Yeh <andy.yeh@intel.com>
> >    Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> > 
> > 
> > Confirmed to work on 4.14 with the Identification Page
> > of an ST M24M02-DR (256 bytes but 16 bit addressing).
> 
> This patch doesn't look like stable material. The hardware never worked
> before, so this is not a regression and falls under new hardware
> enablement, but the patch is more complex than what we usually allow for
> hardware enablement (adding various IDs/quirks/etc).
> 
> Am I missing something?

IMHO it is a pretty straightforward quirk for hardware enablement.

Note that the quirk will only be used if explicitely enabled in the
device tree, for everyone else this code is a nop.

> Thanks,
> Sasha

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: 4.14/4.18: Please add "eeprom: at24: Add support for address-width property"

[Sasha Levin]

On Wed, Oct 31, 2018 at 10:49:59PM +0200, Adrian Bunk wrote:
>On Wed, Oct 31, 2018 at 10:27:45AM -0400, Sasha Levin wrote:
>> On Mon, Oct 22, 2018 at 11:38:35AM +0300, Adrian Bunk wrote:
>> > Please cherry-pick the following commit to 4.14 and 4.18:
>> >
>> >    commit a2b3bf4846e5eed62ea6abb096af2c950961033c
>> >    Author: Alan Chiang <alanx.chiang@intel.com>
>> >    Date:   Wed Jul 25 11:20:22 2018 +0800
>> >
>> >    eeprom: at24: Add support for address-width property
>> >
>> >    Provide a flexible way to determine the addressing bits of eeprom.
>> >    Pass the addressing bits to driver through address-width property.
>> >
>> >    Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
>> >    Signed-off-by: Andy Yeh <andy.yeh@intel.com>
>> >    Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>> >
>> >
>> > Confirmed to work on 4.14 with the Identification Page
>> > of an ST M24M02-DR (256 bytes but 16 bit addressing).
>>
>> This patch doesn't look like stable material. The hardware never worked
>> before, so this is not a regression and falls under new hardware
>> enablement, but the patch is more complex than what we usually allow for
>> hardware enablement (adding various IDs/quirks/etc).
>>
>> Am I missing something?
>
>IMHO it is a pretty straightforward quirk for hardware enablement.
>
>Note that the quirk will only be used if explicitely enabled in the
>device tree, for everyone else this code is a nop.

Fair enough. I've queued it for 4.18 and 4.14.

RE: 4.14/4.18: Please add "eeprom: at24: Add support for address-width property"

[Yeh, Andy]

All,

The original author Alanx chiang has left the company. I assigned Ken to help handle the cherrypick task (4.14 and 4.18).

Regards, Andy

>-----Original Message-----
>From: Adrian Bunk [mailto:bunk@kernel.org]
>Sent: Monday, October 22, 2018 4:39 PM
>To: stable@vger.kernel.org
>Cc: Alan Chiang <alanx.chiang@intel.com>; Yeh, Andy <andy.yeh@intel.com>;
>Bartosz Golaszewski <brgl@bgdev.pl>; linux-i2c@vger.kernel.org
>Subject: 4.14/4.18: Please add "eeprom: at24: Add support for address-width
>property"
>
>Please cherry-pick the following commit to 4.14 and 4.18:
>
>    commit a2b3bf4846e5eed62ea6abb096af2c950961033c
>    Author: Alan Chiang <alanx.chiang@intel.com>
>    Date:   Wed Jul 25 11:20:22 2018 +0800
>
>    eeprom: at24: Add support for address-width property
>
>    Provide a flexible way to determine the addressing bits of eeprom.
>    Pass the addressing bits to driver through address-width property.
>
>    Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
>    Signed-off-by: Andy Yeh <andy.yeh@intel.com>
>    Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>
>
>Confirmed to work on 4.14 with the Identification Page of an ST M24M02-DR
>(256 bytes but 16 bit addressing).
>
>Cannot be cherry-picked trivially on 4.9.
>
>The corresponding documentation commit
>21d04054501fb27b56e995b54ac74e39aee79a46
>can be cherry-picked to 4.18, the backport for 4.14 is below.
>
>Thanks
>Adrian
>
>
>From 2562e333f39b8077ffb06bdf79430f10b74c11f5 Mon Sep 17 00:00:00
>2001
>From: Alan Chiang <alanx.chiang@intel.com>
>Date: Wed, 25 Jul 2018 11:20:21 +0800
>Subject: [PATCH] dt-bindings: at24: Add address-width property
>
>Currently the only way to use a variant of a supported model with a different
>address width is to define a new compatible string and the corresponding chip
>data structure.
>
>Provide a flexible way to specify the size of the address pointer by defining a
>new property: address-width.
>
>Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
>Signed-off-by: Andy Yeh <andy.yeh@intel.com>
>Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>Reviewed-by: Rob Herring <robh@kernel.org>
>[Bartosz: fixed the commit message]
>Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl> [Adrian Bunk: backported
>to 4.14]
>Signed-off-by: Adrian Bunk <bunk@kernel.org>
>---
> Documentation/devicetree/bindings/eeprom/eeprom.txt | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt
>b/Documentation/devicetree/bindings/eeprom/eeprom.txt
>index afc04589eadf..44bfffc43bed 100644
>--- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
>+++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
>@@ -36,6 +36,8 @@ Optional properties:
>
>   - read-only: this parameterless property disables writes to the eeprom
>
>+  - address-width: number of address bits (one of 8, 16).
>+
> Example:
>
> eeprom@52 {
>--
>2.11.0