From: Frank Rowand <frowand.list@gmail.com>
To: Lee Jones <lee.jones@linaro.org>
Cc: andy.shevchenko@gmail.com, michael@walle.cc, robh+dt@kernel.org,
broonie@kernel.org, devicetree@vger.kernel.org,
linus.walleij@linaro.org, linux@roeck-us.net,
andriy.shevchenko@linux.intel.com, robin.murphy@arm.com,
gregkh@linuxfoundation.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/3] mfd: core: Make a best effort attempt to match devices with the correct of_nodes
Date: Thu, 18 Jun 2020 12:34:07 -0500 [thread overview]
Message-ID: <eef50a78-8571-5600-4fee-c824fd4a7f69@gmail.com> (raw)
In-Reply-To: <20200615092644.GA2608702@dell>
On 2020-06-15 04:26, Lee Jones wrote:
> On Sun, 14 Jun 2020, Frank Rowand wrote:
>
>> Hi Lee,
>>
>> I'm looking at 5.8-rc1.
>>
>> The only use of OF_MFD_CELL() where the same compatible is specified
>> for multiple elements of a struct mfd_cell array is for compatible
>> "stericsson,ab8500-pwm" in drivers/mfd/ab8500-core.c:
>>
>> OF_MFD_CELL("ab8500-pwm",
>> NULL, NULL, 0, 1, "stericsson,ab8500-pwm"),
>> OF_MFD_CELL("ab8500-pwm",
>> NULL, NULL, 0, 2, "stericsson,ab8500-pwm"),
>> OF_MFD_CELL("ab8500-pwm",
>> NULL, NULL, 0, 3, "stericsson,ab8500-pwm"),
OF_MFD_CELL("ab8500-pwm",
NULL, NULL, 0, 0, "stericsson,ab8500-pwm"),
OF_MFD_CELL_REG("ab8500-pwm-mc",
NULL, NULL, 0, 0, "stericsson,ab8500-pwm", 0),
OF_MFD_CELL_REG("ab8500-pwm-mc",
NULL, NULL, 0, 1, "stericsson,ab8500-pwm", 1),
OF_MFD_CELL_REG("ab8500-pwm-mc",
NULL, NULL, 0, 2, "stericsson,ab8500-pwm", 2),
>>
>> The only .dts or .dtsi files where I see compatible "stericsson,ab8500-pwm"
>> are:
>>
>> arch/arm/boot/dts/ste-ab8500.dtsi
>> arch/arm/boot/dts/ste-ab8505.dtsi
>>
>> These two .dtsi files only have a single node with this compatible.
>> Chasing back to .dts and .dtsi files that include these two .dtsi
>> files, I see no case where there are multiple nodes with this
>> compatible.
>>
>> So it looks to me like there is no .dts in mainline that is providing
>> the three "stericsson,ab8500-pwm" nodes that drivers/mfd/ab8500-core.c
>> is expecting. No case that there are multiple mfd child nodes where
>> mfd_add_device() would assign the first of n child nodes with the
>> same compatible to multiple devices.
>>
>> So it appears to me that drivers/mfd/ab8500-core.c is currently broken.
>> Am I missing something here?
>>
>> If I am correct, then either drivers/mfd/ab8500-core.c or
>> ste-ab8500.dtsi and ste-ab8505.dtsi need to be fixed.
>
> Your analysis is correct.
OK, if I'm not overlooking anything, that is good news.
Existing .dts source files only have one "ab8500-pwm" child. They already
work correcly.
Create a new compatible for the case of multiple children. In my example
I will add "-mc" (multiple children) to the existing compatible. There
is likely a better name, but this lets me provide an example.
Modify drivers/mfd/ab8500-core.c to use the new compatible, and new .dts
source files with multiple children use the new compatible:
OF_MFD_CELL("ab8500-pwm",
NULL, NULL, 0, 0, "stericsson,ab8500-pwm"),
OF_MFD_CELL_REG("ab8500-pwm-mc",
NULL, NULL, 0, 0, "stericsson,ab8500-pwm", 0),
OF_MFD_CELL_REG("ab8500-pwm-mc",
NULL, NULL, 0, 1, "stericsson,ab8500-pwm", 1),
OF_MFD_CELL_REG("ab8500-pwm-mc",
NULL, NULL, 0, 2, "stericsson,ab8500-pwm", 2),
The "OF_MFD_CELL" entry is the existing entry, which will handle current
.dts source files. The new "OF_MFD_CELL_REG" entries will handle new
.dts source files.
And of course the patch that creates OF_MFD_CELL_REG() needs to precede
this change.
I would remove the fallback code in the existing patch that tries to
handle an incorrect binding. Just error out if the binding is not
used properly.
-Frank
>
> Although it's not "broken", it just works when it really shouldn't.
>
> I will be fixing the 'ab8500-pwm' case in due course.
>
>> Moving forward, your proposed OF_MFD_CELL_REG() method seems a good
>> approach (I have not completely read the actual code in the patch yet
>> though).
>
> Thanks.
>
next prev parent reply other threads:[~2020-06-18 17:34 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 19:10 [PATCH v2 1/3] mfd: core: Make a best effort attempt to match devices with the correct of_nodes Lee Jones
2020-06-11 19:10 ` [PATCH v2 2/3] mfd: core: Fix formatting of MFD helpers Lee Jones
2020-06-12 12:27 ` Frank Rowand
2020-06-11 19:10 ` [PATCH v2 3/3] mfd: core: Add OF_MFD_CELL_REG() helper Lee Jones
2020-06-12 12:28 ` Frank Rowand
2020-06-12 12:26 ` [PATCH v2 1/3] mfd: core: Make a best effort attempt to match devices with the correct of_nodes Frank Rowand
2020-06-15 1:19 ` Frank Rowand
2020-06-15 9:26 ` Lee Jones
2020-06-18 17:34 ` Frank Rowand [this message]
2020-06-22 8:50 ` Lee Jones
2020-06-22 14:32 ` Frank Rowand
2020-06-22 14:35 ` Frank Rowand
2020-06-22 15:10 ` Lee Jones
2020-06-22 18:01 ` Frank Rowand
2020-06-22 18:04 ` Frank Rowand
2020-06-22 19:11 ` Lee Jones
2020-06-22 22:23 ` Frank Rowand
2020-06-23 1:17 ` Frank Rowand
2020-06-23 1:37 ` Frank Rowand
2020-06-23 6:47 ` Lee Jones
2020-06-23 17:55 ` Frank Rowand
2020-06-23 19:59 ` Lee Jones
2020-06-23 22:33 ` Frank Rowand
2020-06-24 7:46 ` Lee Jones
2020-06-24 15:51 ` Frank Rowand
2020-06-24 16:14 ` Lee Jones
2020-06-24 16:25 ` Frank Rowand
2020-06-22 8:09 ` Lee Jones
2020-06-22 16:09 ` Frank Rowand
2020-06-22 16:53 ` Lee Jones
2020-06-23 22:21 ` Frank Rowand
2020-06-24 6:45 ` Lee Jones
2020-06-23 23:03 ` Frank Rowand
2020-06-24 6:41 ` Lee Jones
2020-06-24 7:47 ` Michael Walle
2020-06-24 8:23 ` Lee Jones
2020-06-24 9:19 ` Michael Walle
2020-06-24 11:24 ` Lee Jones
2020-06-11 19:12 Lee Jones
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