[PATCH 1/2] dm: core: Add functions to read 8/16-bit integers

[Stefan Herbrechtsmeier]

Hi Simon,

Am 13.07.2022 um 17:28 schrieb Simon Glass:
> Hi Stefan,
> 
> On Tue, 12 Jul 2022 at 12:31, Stefan Herbrechtsmeier
> <stefan.herbrechtsmeier-oss at weidmueller.com> wrote:
>>
>> Hi Simon,
>>
>> Am 12.07.2022 um 12:58 schrieb Simon Glass:
>>> Hi Stefan,
>>>
>>> On Tue, 14 Jun 2022 at 07:22, Stefan Herbrechtsmeier
>>> <stefan.herbrechtsmeier-oss at weidmueller.com> wrote:
>>>>
>>>> From: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
>>>>
>>>> Add functions to read 8/16-bit integers like the existing functions for
>>>> 32/64-bit to simplify read of 8/16-bit integers from device tree
>>>> properties.
>>>>
>>>> Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
>>>> ---
>>>>
>>>>    arch/sandbox/dts/test.dts |  2 ++
>>>>    drivers/core/of_access.c  | 38 +++++++++++++++++++++++
>>>>    drivers/core/ofnode.c     | 62 +++++++++++++++++++++++++++++++++++++
>>>>    drivers/core/read.c       | 21 +++++++++++++
>>>>    include/dm/of_access.h    | 32 +++++++++++++++++++
>>>>    include/dm/ofnode.h       | 40 ++++++++++++++++++++++++
>>>>    include/dm/read.h         | 65 +++++++++++++++++++++++++++++++++++++++
>>>>    test/dm/test-fdt.c        | 19 ++++++++++++
>>>>    8 files changed, 279 insertions(+)
>>>
>>> This looks good but is very expensive in terms of code size. Can you
>>> update your u8 and u16 functions to reuse the existing u32 function
>>> and just convert the value?
>>
>> The u32 function requires a 32 bit value inside the device tree because
>> it checks the size and maybe swap the bytes.
>>
>> The u8 and u16 function requires only a 8 and 16 bit value inside the
>> device tree.
> 
> Yes that's true. What is the use case for these functions?

The usb251xb driver requires this functions [1]. The usb251xb device 
tree binding [2] defines the ids as 16 bit values and the Linux driver 
use 8 bit for an unspecified property. Without this changes the driver 
doesn't satisfy the specification and is incompatible to the Linux driver.

[1] https://lists.denx.de/pipermail/u-boot/2022-June/486424.html
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/usb/usb251xb.txt

Regards
   Stefan