* [PATCH v3 1/3] dt-bindings: nvmem: mediatek: efuse: add mt6572
2026-09-09 10:48 [PATCH v3 0/3] nvmem: mtk-efuse: mt6572 support Roman Vivchar via B4 Relay
@ 2026-09-09 10:48 ` Roman Vivchar via B4 Relay
2026-09-09 10:48 ` [PATCH v3 2/3] nvmem: mtk-efuse: add support for 32-bit aligned reads Roman Vivchar via B4 Relay
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Roman Vivchar via B4 Relay @ 2026-09-09 10:48 UTC (permalink / raw)
To: Srinivas Kandagatla, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Matthias Brugger, AngeloGioacchino Del Regno,
Andrew-CT Chen, Lala Lin
Cc: devicetree, linux-kernel, linux-arm-kernel, linux-mediatek,
Roman Vivchar
From: Roman Vivchar <rva333@protonmail.com>
Add a compatible string for the mt6572 SoC efuse controller.
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
Documentation/devicetree/bindings/nvmem/mediatek,efuse.yaml | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/nvmem/mediatek,efuse.yaml b/Documentation/devicetree/bindings/nvmem/mediatek,efuse.yaml
index f9323b3ecfc8..e10947164941 100644
--- a/Documentation/devicetree/bindings/nvmem/mediatek,efuse.yaml
+++ b/Documentation/devicetree/bindings/nvmem/mediatek,efuse.yaml
@@ -24,13 +24,16 @@ properties:
compatible:
oneOf:
+ - enum:
+ - mediatek,mt6572-efuse
+ - mediatek,mt8186-efuse
+
- items:
- enum:
- mediatek,mt8188-efuse
- mediatek,mt8189-efuse
- mediatek,mt8196-efuse
- const: mediatek,mt8186-efuse
- - const: mediatek,mt8186-efuse
- items:
- enum:
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v3 2/3] nvmem: mtk-efuse: add support for 32-bit aligned reads
2026-09-09 10:48 [PATCH v3 0/3] nvmem: mtk-efuse: mt6572 support Roman Vivchar via B4 Relay
2026-09-09 10:48 ` [PATCH v3 1/3] dt-bindings: nvmem: mediatek: efuse: add mt6572 Roman Vivchar via B4 Relay
@ 2026-09-09 10:48 ` Roman Vivchar via B4 Relay
2026-09-09 10:48 ` [PATCH v3 3/3] nvmem: mtk-efuse: add mt6572 support Roman Vivchar via B4 Relay
2026-09-09 12:09 ` [PATCH v3 0/3] nvmem: mtk-efuse: " AngeloGioacchino Del Regno
3 siblings, 0 replies; 6+ messages in thread
From: Roman Vivchar via B4 Relay @ 2026-09-09 10:48 UTC (permalink / raw)
To: Srinivas Kandagatla, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Matthias Brugger, AngeloGioacchino Del Regno,
Andrew-CT Chen, Lala Lin
Cc: devicetree, linux-kernel, linux-arm-kernel, linux-mediatek,
Roman Vivchar
From: Roman Vivchar <rva333@protonmail.com>
Some MediaTek SoCs, such as mt6572, don't support 8-bit reads, leading
to zeroes or garbage data. 32-bit aligned reads must be used instead.
Introduce a 'mtk_reg_read_aligned' helper to enforce 32-bit aligned
register access. All reads will be performed by reading 4-byte words
and masking them.
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
drivers/nvmem/mtk-efuse.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
index af953e1d9230..178b9d85f813 100644
--- a/drivers/nvmem/mtk-efuse.c
+++ b/drivers/nvmem/mtk-efuse.c
@@ -4,6 +4,7 @@
* Author: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
*/
+#include <linux/align.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
@@ -14,12 +15,37 @@
struct mtk_efuse_pdata {
bool uses_post_processing;
+ bool needs_aligned_read;
};
struct mtk_efuse_priv {
void __iomem *base;
};
+static int mtk_reg_read_aligned(void *context,
+ unsigned int reg, void *_val, size_t bytes)
+{
+ struct mtk_efuse_priv *priv = context;
+ u8 *val = _val;
+ u32 i, pos, shift, val32;
+
+ for (i = 0; i < bytes; i++, val++) {
+ pos = reg + i;
+
+ /*
+ * Read on 32-bit word boundary or if it's the first
+ * iteration
+ */
+ if (i == 0 || IS_ALIGNED(pos, 4))
+ val32 = readl(priv->base + (pos & ~3));
+
+ shift = (pos & 3) * 8;
+ *val = (val32 >> shift) & 0xff;
+ }
+
+ return 0;
+}
+
static int mtk_reg_read(void *context,
unsigned int reg, void *_val, size_t bytes)
{
@@ -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)
+ 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[] = {
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v3 3/3] nvmem: mtk-efuse: add mt6572 support
2026-09-09 10:48 [PATCH v3 0/3] nvmem: mtk-efuse: mt6572 support Roman Vivchar via B4 Relay
2026-09-09 10:48 ` [PATCH v3 1/3] dt-bindings: nvmem: mediatek: efuse: add mt6572 Roman Vivchar via B4 Relay
2026-09-09 10:48 ` [PATCH v3 2/3] nvmem: mtk-efuse: add support for 32-bit aligned reads Roman Vivchar via B4 Relay
@ 2026-09-09 10:48 ` Roman Vivchar via B4 Relay
2026-09-09 11:28 ` sashiko-bot
2026-09-09 12:09 ` [PATCH v3 0/3] nvmem: mtk-efuse: " AngeloGioacchino Del Regno
3 siblings, 1 reply; 6+ messages in thread
From: Roman Vivchar via B4 Relay @ 2026-09-09 10:48 UTC (permalink / raw)
To: Srinivas Kandagatla, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Matthias Brugger, AngeloGioacchino Del Regno,
Andrew-CT Chen, Lala Lin
Cc: devicetree, linux-kernel, linux-arm-kernel, linux-mediatek,
Roman Vivchar
From: Roman Vivchar <rva333@protonmail.com>
Add a platform data struct for the efuse controller.
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
drivers/nvmem/mtk-efuse.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
index 178b9d85f813..99d061eef6e3 100644
--- a/drivers/nvmem/mtk-efuse.c
+++ b/drivers/nvmem/mtk-efuse.c
@@ -132,6 +132,11 @@ static int mtk_efuse_probe(struct platform_device *pdev)
return 0;
}
+static const struct mtk_efuse_pdata mtk_mt6572_efuse_pdata = {
+ .uses_post_processing = false,
+ .needs_aligned_read = true,
+};
+
static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
.uses_post_processing = true,
.needs_aligned_read = false,
@@ -143,6 +148,7 @@ static const struct mtk_efuse_pdata mtk_efuse_pdata = {
};
static const struct of_device_id mtk_efuse_of_match[] = {
+ { .compatible = "mediatek,mt6572-efuse", .data = &mtk_mt6572_efuse_pdata },
{ .compatible = "mediatek,mt8173-efuse", .data = &mtk_efuse_pdata },
{ .compatible = "mediatek,mt8186-efuse", .data = &mtk_mt8186_efuse_pdata },
{ .compatible = "mediatek,efuse", .data = &mtk_efuse_pdata },
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v3 3/3] nvmem: mtk-efuse: add mt6572 support
2026-09-09 10:48 ` [PATCH v3 3/3] nvmem: mtk-efuse: add mt6572 support Roman Vivchar via B4 Relay
@ 2026-09-09 11:28 ` sashiko-bot
0 siblings, 0 replies; 6+ messages in thread
From: sashiko-bot @ 2026-09-09 11:28 UTC (permalink / raw)
To: Roman Vivchar; +Cc: robh, conor+dt, devicetree
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
Pre-existing issues:
- [High] Flawed string comparison logic in `mtk_efuse_fixup_dt_cell_info` allows unintentional prefix matching.
--
commit a7b90ac028ac0c3f0279ff49927a48455c13bc74
Author: Roman Vivchar <rva333@protonmail.com>
nvmem: mtk-efuse: add mt6572 support
This commit adds a platform data struct for the efuse controller to support
the MediaTek MT6572 SoC, configuring read alignment and post-processing
behavior.
> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index 178b9d85f813e..99d061eef6e33 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -132,6 +132,11 @@ static int mtk_efuse_probe(struct platform_device *pdev)
> return 0;
> }
>
> +static const struct mtk_efuse_pdata mtk_mt6572_efuse_pdata = {
> + .uses_post_processing = false,
[Severity: High]
This is a pre-existing issue, but while reviewing the post-processing logic
controlled by this flag, I noticed a potential flaw in how cell names are
matched.
In mtk_efuse_fixup_dt_cell_info(), the string comparison allows shorter strings
to falsely match as a prefix:
drivers/nvmem/mtk-efuse.c:mtk_efuse_fixup_dt_cell_info() {
...
if (cell->nbits <= 3 &&
strncmp(cell->name, "gpu-speedbin", min(sz, strlen("gpu-speedbin"))) == 0)
cell->read_post_process = mtk_efuse_gpu_speedbin_pp;
...
}
Because it uses min(sz, strlen("gpu-speedbin")), wouldn't this incorrectly
apply GPU speedbin post-processing to any NVMEM cell whose name is merely a
prefix of "gpu-speedbin" (e.g., "gpu" or "gp") as long as it has nbits <= 3?
Could this lead to unintended data corruption by incorrectly modifying the
hardware read value for those unrelated NVMEM cells?
> + .needs_aligned_read = true,
> +};
> +
> static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
> .uses_post_processing = true,
> .needs_aligned_read = false,
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260909-6572-nvmem-v3-0-c0c441656431@protonmail.com?part=3
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3 0/3] nvmem: mtk-efuse: mt6572 support
2026-09-09 10:48 [PATCH v3 0/3] nvmem: mtk-efuse: mt6572 support Roman Vivchar via B4 Relay
` (2 preceding siblings ...)
2026-09-09 10:48 ` [PATCH v3 3/3] nvmem: mtk-efuse: add mt6572 support Roman Vivchar via B4 Relay
@ 2026-09-09 12:09 ` AngeloGioacchino Del Regno
3 siblings, 0 replies; 6+ messages in thread
From: AngeloGioacchino Del Regno @ 2026-09-09 12:09 UTC (permalink / raw)
To: rva333, Srinivas Kandagatla, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Matthias Brugger, Andrew-CT Chen, Lala Lin
Cc: devicetree, linux-kernel, linux-arm-kernel, linux-mediatek
On 9/9/26 12:48, Roman Vivchar via B4 Relay wrote:
> This patch series adds MediaTek mt6572 efuse support. Unlike newer SoCs,
> its efuse controller doesn't work properly with 8-bit reads, leading to
> invalid data with current mtk-efuse driver implementation.
>
Series is
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cheers,
Angelo
> This behavior can be observed with devmem (0x10009174 and 0x10009178 are
> thermal calibration cells):
> ~ # devmem 0x10009174 32
> 0x00CDD4CD
> ~ # devmem 0x10009178 32
> 0x0F76865D
> ~ # devmem 0x10009174 8
> 0xCD
> ~ # devmem 0x10009175 8
> 0x00
> ~ # devmem 0x10009176 8
> 0x00
> ~ # devmem 0x10009177 8
> 0x00
> ~ # devmem 0x10009178 8
> 0x5D
> ~ # devmem 0x10009179 8
> 0x00
> ~ # devmem 0x1000917a 8
> 0x00
> ~ # devmem 0x1000917b 8
> 0x00
>
> Patch 1 adds dt-bindings compatible for the mt6572,
> Patch 2 adds platform data option to use aligned 32-bit reads instead
> of plain readb().
> Patch 3 adds platform data for mt6572 SoC.
>
> Signed-off-by: Roman Vivchar <rva333@protonmail.com>
> ---
> Changes in v3:
> - Pick up Rob's r-b tag for dt-bindings
> - Patch 2 and 3 unchanged, for some reason cover letter and patch 1 were
> missing on the web mirror...
> - Link to v2: https://patch.msgid.link/20260724-6572-nvmem-v2-0-e58d16a29621@protonmail.com
>
> Changes in v2:
> - dt-bindings: make mediatek,mt6572-efuse standalone compatible
> - Driver: add 'mtk_reg_read_aligned' helper instead of modifying 'mtk_reg_read'
> - Link to v1: https://patch.msgid.link/20260715-6572-nvmem-v1-0-9c13be99d077@protonmail.com
>
> ---
> Roman Vivchar (3):
> dt-bindings: nvmem: mediatek: efuse: add mt6572
> nvmem: mtk-efuse: add support for 32-bit aligned reads
> nvmem: mtk-efuse: add mt6572 support
>
> .../devicetree/bindings/nvmem/mediatek,efuse.yaml | 5 ++-
> drivers/nvmem/mtk-efuse.c | 41 +++++++++++++++++++++-
> 2 files changed, 44 insertions(+), 2 deletions(-)
> ---
> base-commit: 8cd9520d35a6c38db6567e97dd93b1f11f185dc6
> change-id: 20260710-6572-nvmem-eb98c7a73351
>
> Best regards,
> --
> Roman Vivchar <rva333@protonmail.com>
^ permalink raw reply [flat|nested] 6+ messages in thread