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| author | Zeng Chi <zengchi@kylinos.cn> | 2026-09-21 18:24:42 +0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-09-22 08:36:16 -0700 |
| commit | 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d (patch) | |
| tree | 660d50d4139cb750fbde1ae3432452c20726c99d /Documentation/i2c/slave-eeprom-backend.rst | |
| download | linux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.tar.gz linux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.zip | |
KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted
Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.
Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'Documentation/i2c/slave-eeprom-backend.rst')
| -rw-r--r-- | Documentation/i2c/slave-eeprom-backend.rst | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/i2c/slave-eeprom-backend.rst b/Documentation/i2c/slave-eeprom-backend.rst new file mode 100644 index 000000000..38d951f10 --- /dev/null +++ b/Documentation/i2c/slave-eeprom-backend.rst @@ -0,0 +1,26 @@ +============================== +Linux I2C slave EEPROM backend +============================== + +by Wolfram Sang <wsa@sang-engineering.com> in 2014-20 + +This backend simulates an EEPROM on the connected I2C bus. Its memory contents +can be accessed from userspace via this file located in sysfs:: + + /sys/bus/i2c/devices/<device-directory>/slave-eeprom + +The following types are available: 24c02, 24c32, 24c64, and 24c512. Read-only +variants are also supported. The name needed for instantiating has the form +'slave-<type>[ro]'. Examples follow: + +24c02, read/write, address 0x64: + # echo slave-24c02 0x1064 > /sys/bus/i2c/devices/i2c-1/new_device + +24c512, read-only, address 0x42: + # echo slave-24c512ro 0x1042 > /sys/bus/i2c/devices/i2c-1/new_device + +You can also preload data during boot if a device-property named +'firmware-name' contains a valid filename (DT or ACPI only). + +As of 2015, Linux doesn't support poll on binary sysfs files, so there is no +notification when another master changed the content. |