| Message ID | 20220222215244.1908067-1-broonie@kernel.org |
|---|---|
| State | Accepted |
| Commit | 42a55435b0ef6b80a3e81e8ca642cd866d260b08 |
| Headers | show |
| Series | media: i2c: max2175: Use rbtree rather than flat register cache | expand |
diff --git a/drivers/media/i2c/max2175.c b/drivers/media/i2c/max2175.c index bc46a0957b40..0eea200124d2 100644 --- a/drivers/media/i2c/max2175.c +++ b/drivers/media/i2c/max2175.c @@ -257,7 +257,7 @@ static const struct regmap_config max2175_regmap_config = { .reg_defaults = max2175_reg_defaults, .num_reg_defaults = ARRAY_SIZE(max2175_reg_defaults), .volatile_table = &max2175_volatile_regs, - .cache_type = REGCACHE_FLAT, + .cache_type = REGCACHE_RBTREE, }; struct max2175 {
The max2175 uses a flat register cache but supplies only a single default value and has many volatile registers. This is a poor fit for a flat cache since the cache will assume a default of zero for any register not yet written which can lead to bugs for example when regmap_update_bits() suppresses a noop write. A rbtree cache is a much better fit, this will only cache default values and values that have been written to the device with any reads of uncached values going to the hardware. Convert the driver to use a rbtree cache. Since the device is controlled via I2C the cost of manging the rbtree should be immaterial compared to the cost of accessing the device. Signed-off-by: Mark Brown <broonie@kernel.org> --- drivers/media/i2c/max2175.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)