kernel/drivers/base/regmap/internal.h, branch linux-6.9.y

regmap: rework ->max_register handling

2024-02-05T14:32:35Z

When regmap consists of single register, 'regmap' subsystem is unable to understand whether ->max_register is set or not, because in both cases it is equal to zero. It leads to that the logic based on value of ->max_register doesn't work. For example using of REGCACHE_FLAT fails. This patch introduces an extra parameter to regmap config, indicating that zero value in ->max_register is authentic. Signed-off-by: Jan Dakinevich Link: https://lore.kernel.org/r/20240126200836.1829995-1-jan.dakinevich@salutedevices.com Signed-off-by: Mark Brown

regmap: ram: support noinc semantics

2023-11-13T01:26:17Z

Support noinc semantics in RAM backed regmaps, for testing purposes. Add a new callback that selects registers which should have noinc behavior. Bulk writes to a noinc register will cause the last value in the buffer to be assigned to the register, while bulk reads will copy the same value repeatedly into the buffer. This patch only adds support to regmap-raw-ram, since regmap-ram does not support bulk operations. Signed-off-by: Ben Wolsieffer Link: https://lore.kernel.org/r/20231102203039.3069305-1-ben.wolsieffer@hefring.com Signed-off-by: Mark Brown

regmap: Add debugfs file for forcing field writes

2023-06-13T12:15:04Z

`_regmap_update_bits()` checks if the current register value differs from the new value, and only writes to the register if they differ. When testing hardware drivers, it might be desirable to always force a register write, for example when writing to a `regmap_field`. This enables and simplifies testing and verification of the hardware interaction. For example, when using a hardware mock/simulation model, one can then more easily verify that the driver makes the correct expected register writes during certain events. Add a bool variable `force_write_field` and a corresponding debugfs entry to enable this. Since this feature could interfere with driver operation, guard it with a macro. Signed-off-by: Waqar Hameed Link: https://lore.kernel.org/r/pnd1qifa7sj.fsf@axis.com Signed-off-by: Mark Brown

regmap: Provide basic test coverage for raw I/O

2023-06-12T17:14:53Z

Merge series from Mark Brown : Our existing coverage only deals with buses that provide single register read and write operations, extend it to cover raw buses using a similar approach with a RAM backed register map that the tests can inspect to check operations. This coverage could be more complete but provides a good start.

regmap: Don't check for changes in regcache_set_val()

2023-06-12T13:51:07Z

The only user of regcache_set_val() ignores the return value so we may as well not bother checking if the value we are trying to set is the same as the value already stored. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230609-regcache-set-val-no-ret-v1-1-9a6932760cf8@kernel.org Signed-off-by: Mark Brown

regmap: maple: Implement block sync for the maple tree cache

2023-06-12T13:51:06Z

For register maps where we can write multiple values in a single bus operation it is generally much faster to do so. Improve the performance of maple tree cache syncs on such devices by identifying blocks of adjacent registers that need to be written out and combining them into a single operation. Combining writes does mean that we need to allocate a scratch buffer and format the data into it but it is expected that for most cases where caches are in use the cost of I/O will be much greater than the cost of doing the allocation and format. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230609-regcache-maple-sync-raw-v1-1-8ddeb4e2b9ab@kernel.org Signed-off-by: Mark Brown

regmap: Provide a ram backed regmap with raw support

2023-06-12T13:47:54Z

Provide a simple, 16 bit only, RAM backed regmap which supports raw I/O for use in testing. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230610-regcache-raw-kunit-v1-1-583112cd28ac@kernel.org Signed-off-by: Mark Brown

regmap: allow upshifting register addresses before performing operations

2023-04-07T16:28:19Z

Similar to the existing reg_downshift mechanism, that is used to translate register addresses on busses that have a smaller address stride, it's also possible to want to upshift register addresses. Such a case was encountered when network PHYs and PCS that usually sit on a MDIO bus (16-bits register with a stride of 1) are integrated directly as memory-mapped devices. Here, the same register layout defined in 802.3 is used, but the register now have a larger stride. Introduce a mechanism to also allow upshifting register addresses. Re-purpose reg_downshift into a more generic, signed reg_shift, whose sign indicates the direction of the shift. To avoid confusion, also introduce macros to explicitly indicate if we want to downshift or upshift. For bisectability, change any use of reg_downshift to use reg_shift. Signed-off-by: Maxime Chevallier Tested-by: Colin Foster Link: https://lore.kernel.org/r/20230407152604.105467-1-maxime.chevallier@bootlin.com Signed-off-by: Mark Brown

regmap: Add maple tree based register cache

2023-04-03T11:53:44Z

The current state of the art for sparse register maps is the rbtree cache. This works well for most applications but isn't always ideal for sparser register maps since the rbtree can get deep, requiring a lot of walking. Fortunately the kernel has a data structure intended to address this very problem, the maple tree. Provide an initial implementation of a register cache based on the maple tree to start taking advantage of it. The entries stored in the maple tree are arrays of register values, with the maple tree keys holding the register addresses. We store data in host native format rather than device native format as we do for rbtree, this will be a benefit for devices where we don't marshal data within regmap and simplifies the code but will result in additional CPU overhead when syncing the cache on devices where we do marshal data in regmap. This should work well for a lot of devices, though there's some additional areas that could be looked at such as caching the last accessed entry like we do for rbtree and trying to minimise the maple tree level locking. We should also use bulk writes rather than single register writes when resyncing the cache where possible, even if we don't store in device native format. Very small register maps may continue to to better with rbtree longer term. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230325-regcache-maple-v3-2-23e271f93dc7@kernel.org Signed-off-by: Mark Brown

regmap: Factor out single value register syncing

2023-04-03T11:53:43Z

In order to support sparse caches that don't store data in raw format factor out the parts of the raw block sync implementation that deal with writing a single register via _regmap_write(). Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230325-regcache-maple-v3-1-23e271f93dc7@kernel.org Signed-off-by: Mark Brown