From 06b360155d1281931fc6a3363dc6323a7858c1f0 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 29 Jul 2026 10:46:35 +0100 Subject: [PATCH] nvmem: return -EOPNOTSUPP to in-kernel users on missing callbacks __nvmem_reg_read/write() currently return -EINVAL if the relevant callback is not present. User-space helpers again check the presence of the callbacks to see if they should return -EPERM. Ahead of adding SRCU synchronization: change the error code returned to in-kernel users to -EOPNOTSUPP which is more indicative of the actual reason for the failure. Remove the checks from the sysfs attribute callbacks as these are not visible without the required callbacks. Signed-off-by: Bartosz Golaszewski Tested-by: Loic Poulain Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260729094647.111468-3-srini@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/core.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 6bcb90760bee..40a00f650261 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -55,10 +55,10 @@ static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, void *val, size_t bytes) { - if (nvmem->reg_read) - return nvmem->reg_read(nvmem->priv, offset, val, bytes); + if (!nvmem->reg_read) + return -EOPNOTSUPP; - return -EINVAL; + return nvmem->reg_read(nvmem->priv, offset, val, bytes); } static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, @@ -66,14 +66,14 @@ static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, { int ret; - if (nvmem->reg_write) { - gpiod_set_value_cansleep(nvmem->wp_gpio, 0); - ret = nvmem->reg_write(nvmem->priv, offset, val, bytes); - gpiod_set_value_cansleep(nvmem->wp_gpio, 1); - return ret; - } + if (!nvmem->reg_write) + return -EOPNOTSUPP; - return -EINVAL; + gpiod_set_value_cansleep(nvmem->wp_gpio, 0); + ret = nvmem->reg_write(nvmem->priv, offset, val, bytes); + gpiod_set_value_cansleep(nvmem->wp_gpio, 1); + + return ret; } static int nvmem_access_with_keepouts(struct nvmem_device *nvmem, @@ -231,13 +231,12 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj, count = round_down(count, nvmem->word_size); - if (!nvmem->reg_read) - return -EPERM; - rc = nvmem_reg_read(nvmem, pos, buf, count); - - if (rc) + if (rc) { + if (rc == -EOPNOTSUPP) + return -EPERM; return rc; + } return count; } @@ -264,13 +263,15 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, count = round_down(count, nvmem->word_size); - if (!nvmem->reg_write || nvmem->read_only) + if (nvmem->read_only) return -EPERM; rc = nvmem_reg_write(nvmem, pos, buf, count); - - if (rc) + if (rc) { + if (rc == -EOPNOTSUPP) + return -EPERM; return rc; + } return count; }