UPSTREAM: regmap: make LZO cache optional

Commit 2cbbb57 ("regmap: Add the LZO cache support") added support
for LZO compression in regcache, but there were never any users added
afterwards. Since LZO support itself has its own size, it currently is
rather a deoptimization.

So make it optional by introducing a symbol that can be selected by
drivers wanting to make use of it.

Saves e.g. ~46 kB on MIPS (size of LZO support + regcache LZO code).

Change-Id: I38a5164c2169f889a10f6c47968c1dbd187c6725
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Tao Huang <huangtao@rock-chips.com>
(cherry picked from commit 34a730aa74c7c743f4ca9635e0d0b2479d6ed53c)

Author: KanjiMonster

drivers/base/regmap/Kconfig

@@ -4,9 +4,12 @@
 
 config REGMAP
 	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ)
+	select IRQ_DOMAIN if REGMAP_IRQ
+	bool
+
+config REGCACHE_COMPRESSED
 	select LZO_COMPRESS
 	select LZO_DECOMPRESS
-	select IRQ_DOMAIN if REGMAP_IRQ
 	bool
 
 config REGMAP_AC97

drivers/base/regmap/Makefile

@@ -2,7 +2,8 @@
 CFLAGS_regmap.o := -I$(src)
 
 obj-$(CONFIG_REGMAP) += regmap.o regcache.o
-obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o regcache-flat.o
+obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-flat.o
+obj-$(CONFIG_REGCACHE_COMPRESSED) += regcache-lzo.o
 obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
 obj-$(CONFIG_REGMAP_AC97) += regmap-ac97.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o

drivers/base/regmap/regcache.c

@@ -21,7 +21,9 @@
 
 static const struct regcache_ops *cache_types[] = {
 	&regcache_rbtree_ops,
+#if IS_ENABLED(CONFIG_REGCHACHE_COMPRESSED)
 	&regcache_lzo_ops,
+#endif
 	&regcache_flat_ops,
 };