From 6fdbc7b9aa20b1db47d13a5f2a4d31fb2f8f3822 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Th=C3=A9o=20Lebrun?= Date: Mon, 30 Dec 2024 14:30:27 +0000 Subject: [PATCH] nvmem: specify ->reg_read/reg_write() expected return values MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Both ->reg_read() and ->reg_write() return values are not easy to deduce. Explicit that they should return zero on success (and negative values otherwise). Such callbacks, in some alternative world, could return the number of bytes in the success case. That would be translated to errors in the nvmem core because of checks like: ret = nvmem->reg_write(nvmem->priv, offset, val, bytes); if (ret) { // error case } This mistake is not just theoretical, see commit 28b008751aa2 ("nvmem: rmem: Fix return value of rmem_read()"). Signed-off-by: Théo Lebrun Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20241230143035.265518-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman --- include/linux/nvmem-provider.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h index 3ebeaa0ded00..515676ebe598 100644 --- a/include/linux/nvmem-provider.h +++ b/include/linux/nvmem-provider.h @@ -92,8 +92,8 @@ struct nvmem_cell_info { * @read_only: Device is read-only. * @root_only: Device is accessibly to root only. * @of_node: If given, this will be used instead of the parent's of_node. - * @reg_read: Callback to read data. - * @reg_write: Callback to write data. + * @reg_read: Callback to read data; return zero if successful. + * @reg_write: Callback to write data; return zero if successful. * @size: Device size. * @word_size: Minimum read/write access granularity. * @stride: Minimum read/write access stride. -- 2.25.1