Before adding support to define bulk read/write callbacks in regmap_config by the commit d77e74561368 ("regmap: Add bulk read/write callbacks into regmap_config"), the regmap_noinc_read() function returned an errno early a map->bus->read callback wasn't set. But that commit dropped the check and now a call to _regmap_raw_read() is attempted even when bulk read operations are not supported. That function checks for map->read anyways but there's no point to continue if the read can't succeed. Also is a fragile assumption to make so is better to make it fail earlier.
Unified · Split
| @@ -2904,6 +2904,9 @@ int regmap_noinc_read(struct regmap *map, unsigned int reg, · 2903 unmodified lines | ||
| 2904 | 2904 | size_t read_len; |
| 2905 | 2905 | int ret; |
| 2906 | 2906 | |
| 2907 | + if (!map->read) | |
| 2908 | + return -ENOTSUPP; | |
| 2909 | + | |
| 2907 | 2910 | if (val_len % map->format.val_bytes) |
| 2908 | 2911 | return -EINVAL; |
| 2909 | 2912 | if (!IS_ALIGNED(reg, map->reg_stride)) |