kernel/linux.git/include/linux/nvmem-provider.h, branch v6.19.11

nvmem: update a comment related to struct nvmem_config

2025-09-14T00:32:45+00:00

Update a comment to match the function used in nvmem_register(). ida_simple_get() was replaced by ida_alloc() in commit 1eb51d6a4fce ("nvmem: switch to simpler IDA interface") Link: https://lkml.kernel.org/r/27a9dec93a9f79140b11a77df38b1b45bd342e09.1752480043.git.christophe.jaillet@wanadoo.fr Signed-off-by: Christophe JAILLET Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

nvmem: Remove unused nvmem cell table support

2025-05-21T12:28:27+00:00

Board files are deprecated by DT, and the last user of nvmem_add_cell_table() was removed by commit 2af4fcc0d3574482 ("ARM: davinci: remove unused board support") in v6.3. Hence remove all support for nvmem cell tables, and update the documentation. Device drivers can still register a single cell using nvmem_add_one_cell() (which was not documented before). Signed-off-by: Geert Uytterhoeven Acked-by: Arnd Bergmann Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20250509122452.11827-2-srini@kernel.org Signed-off-by: Greg Kroah-Hartman

nvmem: specify ->reg_read/reg_write() expected return values

2024-12-30T14:35:59+00:00

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

nvmem: layouts: store owner from modules with nvmem_layout_driver_register()

2024-05-03T05:26:38+00:00

Modules registering driver with nvmem_layout_driver_register() might forget to set .owner field. The field is used by some of other kernel parts for reference counting (try_module_get()), so it is expected that drivers will set it. Solve the problem by moving this task away from the drivers to the core code, just like we did for platform_driver in commit 9447057eaff8 ("platform_device: use a macro instead of platform_driver_register"). Signed-off-by: Krzysztof Kozlowski Reviewed-by: Michael Walle Reviewed-by: Miquel Raynal Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20240430084921.33387-2-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: drop nvmem_layout_get_match_data()

2024-01-04T16:01:13+00:00

Thanks for layouts refactoring we now have "struct device" associated with layout. Also its OF pointer points directly to the "nvmem-layout" DT node. All it takes to get match data is a generic of_device_get_match_data(). Signed-off-by: Rafał Miłecki Reviewed-by: Miquel Raynal Reviewed-by: Michael Walle Link: https://lore.kernel.org/r/20231219120104.3422-2-zajec5@gmail.com Signed-off-by: Greg Kroah-Hartman

nvmem: layouts: refactor .add_cells() callback arguments

2024-01-04T16:01:13+00:00

Simply pass whole "struct nvmem_layout" instead of single variables. There is nothing in "struct nvmem_layout" that we have to hide from layout drivers. They also access it during .probe() and .remove(). Thanks to this change: 1. API gets more consistent All layouts drivers callbacks get the same argument 2. Layouts get correct device Before this change NVMEM core code was passing NVMEM device instead of layout device. That resulted in: * Confusing prints * Calling devm_*() helpers on wrong device * Helpers like of_device_get_match_data() dereferencing NULLs 3. It gets possible to get match data First of all nvmem_layout_get_match_data() requires passing "struct nvmem_layout" which .add_cells() callback didn't have before this. It doesn't matter much as it's rather useless now anyway (and will be dropped). What's more important however is that of_device_get_match_data() can be used now thanks to owning a proper device pointer. Signed-off-by: Rafał Miłecki Reviewed-by: Miquel Raynal Reviewed-by: Michael Walle Link: https://lore.kernel.org/r/20231219120104.3422-1-zajec5@gmail.com Signed-off-by: Greg Kroah-Hartman

nvmem: core: Rework layouts to become regular devices

2023-12-15T12:30:07+00:00

Current layout support was initially written without modules support in mind. When the requirement for module support rose, the existing base was improved to adopt modularization support, but kind of a design flaw was introduced. With the existing implementation, when a storage device registers into NVMEM, the core tries to hook a layout (if any) and populates its cells immediately. This means, if the hardware description expects a layout to be hooked up, but no driver was provided for that, the storage medium will fail to probe and try later from scratch. Even if we consider that the hardware description shall be correct, we could still probe the storage device (especially if it contains the rootfs). One way to overcome this situation is to consider the layouts as devices, and leverage the native notifier mechanism. When a new NVMEM device is registered, we can populate its nvmem-layout child, if any, and wait for the matching to be done in order to get the cells (the waiting can be easily done with the NVMEM notifiers). If the layout driver is compiled as a module, it should automatically be loaded. This way, there is no strong order to enforce, any NVMEM device creation or NVMEM layout driver insertion will be observed as a new event which may lead to the creation of additional cells, without disturbing the probes with costly (and sometimes endless) deferrals. In order to achieve that goal we create a new bus for the nvmem-layouts with minimal logic to match nvmem-layout devices with nvmem-layout drivers. All this infrastructure code is created in the layouts.c file. Signed-off-by: Miquel Raynal Tested-by: Rafał Miłecki Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-7-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: Move and rename ->fixup_cell_info()

2023-12-15T12:30:07+00:00

This hook is meant to be used by any provider and instantiating a layout just for this is useless. Let's instead move this hook to the nvmem device and add it to the config structure to be easily shared by the providers. While at moving this hook, rename it ->fixup_dt_cell_info() to clarify its main intended purpose. Signed-off-by: Miquel Raynal Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-6-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: Simplify the ->add_cells() hook

2023-12-15T12:30:07+00:00

The layout entry is not used and will anyway be made useless by the new layout bus infrastructure coming next, so drop it. While at it, clarify the kdoc entry. Signed-off-by: Miquel Raynal Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-5-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: Move of_nvmem_layout_get_container() in another header

2023-12-15T12:30:07+00:00

nvmem-consumer.h is included by consumer devices, extracting data from NVMEM devices whereas nvmem-provider.h is included by devices providing NVMEM content. The only users of of_nvmem_layout_get_container() outside of the core are layout drivers, so better move its prototype to nvmem-provider.h. While we do so, we also move the kdoc associated with the function to the header rather than the .c file. Signed-off-by: Miquel Raynal Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-3-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman