1eb0f3d2f0
Usually it is sufficient to use iicbus_transfer_excl(), or one of the higher-level convenience functions that use it, to reserve the bus for the duration of each register access. Occasionally it is important that a series of accesses or read-modify-write operations must be done without any other intervening access to the device, to prevent corrupting state. Without support for nested request/release, slave device drivers would have to stop using high-level convenience functions and resort to working with arrays of iic_msg structs just for a few operations (often involving one-time device setup or infrequent configuration changes). The changes here appear large from a glance at the diff, but in fact they're nearly trivial, and the large diff is because of changes in indentation and the re-wrapping of comments caused by that. One notable change is that iicbus_release_bus() now ignores the IICBUS_CALLBACK(IIC_RELEASE_BUS) return value. The old error handling left the bus in a kind of limbo state where it was still owned at the iicbus layer, but drivers rarely check the return of the release call, and it's unclear what they would do to recover from an error return anyway. No existing low-level drivers return any kind of error from IIC_RELEASE_BUS except one EINVAL for "you don't own the bus", to which the right response is probably to carry on with the process of releasing the reference to the bus anyway. |
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| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
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the Makefile in this directory for more information on the
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