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authorLinus Torvalds <torvalds@linux-foundation.org>2020-07-05 10:35:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-07-05 10:35:01 -0700
commit7783485401e802b4802c93cb1b23deb7f0d168a4 (patch)
treeb841bb4488efc3b4e2e11a578f5d073b5d0eda44 /Documentation
parent45a5ac7a5cc3c71739d240c422c3818a5bc97fc4 (diff)
parent597911287fcd13c3a4b4aa3e0a52b33d431e0a8e (diff)
Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang: "The usual driver fixes and documentation updates" * 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: i2c: mlxcpld: check correct size of maximum RECV_LEN packet i2c: add Kconfig help text for slave mode i2c: slave-eeprom: update documentation i2c: eg20t: Load module automatically if ID matches i2c: designware: platdrv: Set class based on DMI i2c: algo-pca: Add 0x78 as SCL stuck low status for PCA9665
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/i2c/slave-eeprom-backend.rst22
1 files changed, 17 insertions, 5 deletions
diff --git a/Documentation/i2c/slave-eeprom-backend.rst b/Documentation/i2c/slave-eeprom-backend.rst
index 0b8cd83698e0..38d951f10302 100644
--- a/Documentation/i2c/slave-eeprom-backend.rst
+++ b/Documentation/i2c/slave-eeprom-backend.rst
@@ -1,14 +1,26 @@
==============================
-Linux I2C slave eeprom backend
+Linux I2C slave EEPROM backend
==============================
-by Wolfram Sang <wsa@sang-engineering.com> in 2014-15
+by Wolfram Sang <wsa@sang-engineering.com> in 2014-20
-This is a proof-of-concept backend which acts like an EEPROM on the connected
-I2C bus. The memory contents can be modified from userspace via this file
-located in sysfs::
+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.