Re: [PATCH v2 2/3] nvmem: mtk-efuse: add support for 32-bit aligned reads

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [Medium] The mt6572 configuration and OF match entries are missing, rendering `mtk_reg_read_aligned` dead code.

Pre-existing issues:
- [High] Dereference of `pdata` without a NULL pointer check causes a kernel panic if `device_get_match_data()` returns NULL.
--

--- Patch [2]: [PATCH v2 2/3] nvmem: mtk-efuse: add support for 32-bit aligned reads ---
commit 9dba40bd7cf45894283042b51926cffdb798412f
Author: Roman Vivchar <rva333@protonmail.com>

nvmem: mtk-efuse: add support for 32-bit aligned reads

This commit introduces a helper mtk_reg_read_aligned to enforce 32-bit
aligned register access for MediaTek SoCs like mt6572 that do not support
8-bit reads. It conditionally uses this new read function based on the
needs_aligned_read flag in the device's platform data.

> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index af953e1d92302..178b9d85f813e 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
[ ... ]
> @@ -82,7 +108,12 @@ static int mtk_efuse_probe(struct platform_device *pdev)
>  	econfig.add_legacy_fixed_of_cells = true;
>  	econfig.stride = 1;
>  	econfig.word_size = 1;
> -	econfig.reg_read = mtk_reg_read;
> +
> +	if (pdata->needs_aligned_read)

[Severity: High]
This is a pre-existing issue, but it appears pdata can be NULL if the
device is instantiated without an OF/ACPI node (e.g., via sysfs manual
binding).

Since pdata is acquired via device_get_match_data(), won't unconditionally
dereferencing it here cause a kernel panic when matched by name instead of
device tree?

> +		econfig.reg_read = mtk_reg_read_aligned;
> +	else
> +		econfig.reg_read = mtk_reg_read;
> +
>  	econfig.size = resource_size(res);
>  	econfig.priv = priv;
>  	econfig.dev = dev;
> @@ -103,10 +134,12 @@ static int mtk_efuse_probe(struct platform_device *pdev)
>  
>  static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
>  	.uses_post_processing = true,
> +	.needs_aligned_read = false,
>  };
>  
>  static const struct mtk_efuse_pdata mtk_efuse_pdata = {
>  	.uses_post_processing = false,
> +	.needs_aligned_read = false,
>  };
>  
>  static const struct of_device_id mtk_efuse_of_match[] = {

[Severity: Medium]
The commit message mentions adding support for the mt6572 SoC, but are the
mtk_mt6572_efuse_pdata struct and the mediatek,mt6572-efuse compatible string
missing from mtk_efuse_of_match[]?

Without these entries, will mtk_reg_read_aligned() remain unreachable dead
code since needs_aligned_read is never true?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260724-6572-nvmem-v2-0-e58d16a29621@protonmail.com?part=2