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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-09 01:16:26 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-09 01:16:26 +0200 |
commit | acceba598eda9817bc187f3a683a2d2ee7e7fbc7 (patch) | |
tree | 761b3950789d5eee179b75ecdafafc988ee42a46 /Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt | |
parent | Merge tag 'rtc-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/abellon... (diff) | |
parent | i2c: mux: reg Change ioread endianness for readback (diff) | |
download | linux-acceba598eda9817bc187f3a683a2d2ee7e7fbc7.tar.xz linux-acceba598eda9817bc187f3a683a2d2ee7e7fbc7.zip |
Merge branch 'i2c/for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
"Features:
- new drivers: Renesas EMEV2, register based MUX, NXP LPC2xxx
- core: scans DT and assigns wakeup interrupts. no driver changes needed.
- core: some refcouting issues fixed and better API for that
- core: new helper function for best effort block read emulation
- slave framework: proper DT bindings and userspace instantiation
- some bigger work for xiic, pxa, omap drivers
.. and quite a number of smaller driver fixes, cleanups, improvements"
* 'i2c/for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (65 commits)
i2c: mux: reg Change ioread endianness for readback
i2c: mux: reg: fix compilation warnings
i2c: mux: reg: simplify register size checking
i2c: muxes: fix leaked i2c adapter device node references
i2c: allow specifying separate wakeup interrupt in device tree
of/irq: export of_get_irq_byname()
i2c: xgene-slimpro: dma_mapping_error() doesn't return an error code
i2c: Replace I2C_CROS_EC_TUNNEL dependency
eeprom: at24: use i2c_smbus_read_i2c_block_data_or_emulated
i2c: core: Add support for best effort block read emulation
i2c: lpc2k: add driver
i2c: mux: Add register-based mux i2c-mux-reg
i2c: dt: describe generic bindings
i2c: slave: print warning if slave flag not set
i2c: support 10 bit and slave addresses in sysfs 'new_device'
i2c: take address space into account when checking for used addresses
i2c: apply DT flags when probing
i2c: make address check indpendent from client struct
i2c: rename address check functions
i2c: apply address offset for slaves, too
...
Diffstat (limited to 'Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt')
-rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt new file mode 100644 index 000000000000..688783fbe696 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt @@ -0,0 +1,74 @@ +Register-based I2C Bus Mux + +This binding describes an I2C bus multiplexer that uses a single register +to route the I2C signals. + +Required properties: +- compatible: i2c-mux-reg +- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side + port is connected to. +* Standard I2C mux properties. See mux.txt in this directory. +* I2C child bus nodes. See mux.txt in this directory. + +Optional properties: +- reg: this pair of <offset size> specifies the register to control the mux. + The <offset size> depends on its parent node. It can be any memory-mapped + address. The size must be either 1, 2, or 4 bytes. If reg is omitted, the + resource of this device will be used. +- little-endian: The existence indicates the register is in little endian. +- big-endian: The existence indicates the register is in big endian. + If both little-endian and big-endian are omitted, the endianness of the + CPU will be used. +- write-only: The existence indicates the register is write-only. +- idle-state: value to set the muxer to when idle. When no value is + given, it defaults to the last value used. + +Whenever an access is made to a device on a child bus, the value set +in the revelant node's reg property will be output to the register. + +If an idle state is defined, using the idle-state (optional) property, +whenever an access is not being made to a device on a child bus, the +register will be set according to the idle value. + +If an idle state is not defined, the most recently used value will be +left programmed into the register. + +Example of a mux on PCIe card, the host is a powerpc SoC (big endian): + + i2c-mux { + /* the <offset size> depends on the address translation + * of the parent device. If omitted, device resource + * will be used instead. The size is to determine + * whether iowrite32, iowrite16, or iowrite8 will be used. + */ + reg = <0x6028 0x4>; + little-endian; /* little endian register on PCIe */ + compatible = "i2c-mux-reg"; + #address-cells = <1>; + #size-cells = <0>; + i2c-parent = <&i2c1>; + i2c@0 { + reg = <0>; + #address-cells = <1>; + #size-cells = <0>; + + si5338: clock-generator@70 { + compatible = "silabs,si5338"; + reg = <0x70>; + /* other stuff */ + }; + }; + + i2c@1 { + /* data is written using iowrite32 */ + reg = <1>; + #address-cells = <1>; + #size-cells = <0>; + + si5338: clock-generator@70 { + compatible = "silabs,si5338"; + reg = <0x70>; + /* other stuff */ + }; + }; + }; |