diff options
author | Ingo Molnar <mingo@kernel.org> | 2014-08-22 10:04:15 +0200 |
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committer | Ingo Molnar <mingo@kernel.org> | 2014-08-22 10:04:15 +0200 |
commit | 80b304fd00e8b667775ff791121b61ecd7cd0c03 (patch) | |
tree | b4f2ec59fe062c43343ee4c2f10a6bcd0e4dcd1b /Documentation/i2c/i2c-stub | |
parent | fb21b84e7f809ef04b1e5aed5d463cf0d4866638 (diff) | |
parent | 6a7519e81321343165f89abb8b616df186d3e57a (diff) |
Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent
Pull EFI fixes from Matt Fleming:
* WARN_ON(!spin_is_locked()) always triggers on non-SMP machines.
Swap it for the more canonical lockdep_assert_held() which always
does the right thing - Guenter Roeck
* Assign the correct value to efi.runtime_version on arm64 so that all
the runtime services can be invoked - Semen Protsenko
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/i2c/i2c-stub')
-rw-r--r-- | Documentation/i2c/i2c-stub | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub index fa4b669c166b..a16924fbd289 100644 --- a/Documentation/i2c/i2c-stub +++ b/Documentation/i2c/i2c-stub @@ -2,9 +2,9 @@ MODULE: i2c-stub DESCRIPTION: -This module is a very simple fake I2C/SMBus driver. It implements five +This module is a very simple fake I2C/SMBus driver. It implements six types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, (r/w) -word data, and (r/w) I2C block data. +word data, (r/w) I2C block data, and (r/w) SMBus block data. You need to provide chip addresses as a module parameter when loading this driver, which will then only react to SMBus commands to these addresses. @@ -19,6 +19,14 @@ A pointer register with auto-increment is implemented for all byte operations. This allows for continuous byte reads like those supported by EEPROMs, among others. +SMBus block command support is disabled by default, and must be enabled +explicitly by setting the respective bits (0x03000000) in the functionality +module parameter. + +SMBus block commands must be written to configure an SMBus command for +SMBus block operations. Writes can be partial. Block read commands always +return the number of bytes selected with the largest write so far. + The typical use-case is like this: 1. load this module 2. use i2cset (from the i2c-tools project) to pre-load some data @@ -39,15 +47,18 @@ unsigned long functionality: value 0x1f0000 would only enable the quick, byte and byte data commands. +u8 bank_reg[10] +u8 bank_mask[10] +u8 bank_start[10] +u8 bank_end[10]: + Optional bank settings. They tell which bits in which register + select the active bank, as well as the range of banked registers. + CAVEATS: If your target driver polls some byte or word waiting for it to change, the stub could lock it up. Use i2cset to unlock it. -If the hardware for your driver has banked registers (e.g. Winbond sensors -chips) this module will not work well - although it could be extended to -support that pretty easily. - If you spam it hard enough, printk can be lossy. This module really wants something like relayfs. |