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From: Sven Peter via B4 Relay <devnull+sven.svenpeter.dev@kernel.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	 Janne Grunau <j@jannau.net>,
	Alyssa Rosenzweig <alyssa@rosenzweig.io>,
	 Neal Gompa <neal@gompa.dev>, Rob Herring <robh@kernel.org>,
	 Krzysztof Kozlowski <krzk+dt@kernel.org>,
	 Conor Dooley <conor+dt@kernel.org>
Cc: linux-kernel@vger.kernel.org, asahi@lists.linux.dev,
	 linux-arm-kernel@lists.infradead.org,
	devicetree@vger.kernel.org,  Sven Peter <sven@svenpeter.dev>
Subject: [PATCH 2/7] nvmem: core: round up to word_size
Date: Sat, 10 May 2025 07:44:42 +0000	[thread overview]
Message-ID: <20250510-nvmem-dt-v1-2-eccfa6e33f6a@svenpeter.dev> (raw)
In-Reply-To: <20250510-nvmem-dt-v1-0-eccfa6e33f6a@svenpeter.dev>

From: Sven Peter <sven@svenpeter.dev>

Some nvmem controllers like Apple's eFuses or Nintendo's OTP have a cell
word size that's larger than one byte and cannot read anything smaller.
Round up cell->bytes correctly when accessing a subset of bits.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/nvmem/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 1bd39b12c21a86b9b135be95251a52a10543c2ea..02081c93fa467e5448bd78a4920072d437365fb9 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -595,8 +595,8 @@ static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
 	cell->np = info->np;
 
 	if (cell->nbits)
-		cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
-					   BITS_PER_BYTE);
+		cell->bytes = round_up(DIV_ROUND_UP(cell->nbits + cell->bit_offset,
+					   BITS_PER_BYTE), nvmem->word_size);
 
 	if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
 		dev_err(&nvmem->dev,

-- 
2.34.1



  parent reply	other threads:[~2025-05-10  7:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-10  7:44 [PATCH 0/7] Support exposing bits of any byte as NVMEM cells Sven Peter via B4 Relay
2025-05-10  7:44 ` [PATCH 1/7] nvmem: core: allow bit offset > 8 Sven Peter via B4 Relay
2025-05-10  7:44 ` Sven Peter via B4 Relay [this message]
2025-05-10  7:44 ` [PATCH 3/7] Revert "nvmem: core: Print error on wrong bits DT property" Sven Peter via B4 Relay
2025-05-10  7:44 ` [PATCH 4/7] dt-bindings: nvmem: apple: Add T8112 compatible Sven Peter via B4 Relay
2025-05-14 20:34   ` Rob Herring
2025-05-10  7:44 ` [PATCH 5/7] arm64: dts: apple: t8103: Add eFuses node Sven Peter via B4 Relay
2025-05-10  7:44 ` [PATCH 6/7] arm64: dts: apple: t600x: " Sven Peter via B4 Relay
2025-05-10  7:44 ` [PATCH 7/7] arm64: dts: apple: t8112: " Sven Peter via B4 Relay
2025-05-12 12:49 ` [PATCH 0/7] Support exposing bits of any byte as NVMEM cells Rob Herring (Arm)
2025-05-14 20:32 ` Rob Herring
2025-05-14 20:38   ` Sven Peter

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