[PATCH v2 0/2] ASoC: tegra210: simplify byte map handling in ADX and AMX

[Piyush Patle]

The Tegra210 ADX and AMX drivers both keep their "Byte Map N" ALSA
control state as a byte-packed u32 map[] array along with a separate
byte_mask[] bitmap. This is because the control range exposed to
userspace is [0, 256], where 256 is the "disabled" sentinel and
does not fit in a byte, so the two arrays have to be cross-checked
on every get()/put().

This series stores each slot as a u16 holding the user-visible
value directly, turning get_byte_map() into a direct return and
put_byte_map() into a compare-and-store. The hardware-facing packed
RAM word and the IN_BYTE_EN / OUT_BYTE_EN enable masks are computed
on the fly inside each write_map_ram() callback, which is the only
place that needs to know the hardware layout. The byte_mask[] field
is dropped from both driver state structs.

There is no userspace-visible ABI change. Control declarations,
ranges, initial values and handling of out-of-range writes is
preserved by treating values outside [0, 255] as disabled (256),
matching previous behavior. As a side effect each patch also fixes
a latent bug in put_byte_map() where an enabled-to-enabled value
change was not persisted.

The packed RAM word construction is also updated to ensure the shift
operates on a u32 value, avoiding potential undefined behavior due
to signed integer promotion.

Addresses TODO comments left in tegra210_{adx,amx}_get_byte_map().

Changes since v1:
 - Allocate byte_mask[] dynamically using kcalloc() based on
   soc_data->byte_mask_size instead of fixed-size arrays
 - Propagate -ENOMEM from write_map_ram() to callers
 - Replace magic numbers with TEGRA_{ADX,AMX}_SLOTS_PER_WORD
 - Use BITS_PER_BYTE and BITS_PER_TYPE() instead of literal shifts
 - Add <linux/bits.h> and <linux/slab.h> includes

Patch 1/2: ASoC: tegra210_adx: simplify byte map get/put logic
Patch 2/2: ASoC: tegra210_amx: simplify byte map get/put logic

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2.34.1