diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/devicetree/bindings/i2c/i2c-ocores.txt | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/devicetree/bindings/i2c/i2c-ocores.txt')
-rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-ocores.txt | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt new file mode 100644 index 000000000..6b25a80ae --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt @@ -0,0 +1,74 @@ +Device tree configuration for i2c-ocores + +Required properties: +- compatible : "opencores,i2c-ocores" + "aeroflexgaisler,i2cmst" + "sifive,fu540-c000-i2c", "sifive,i2c0" + For Opencore based I2C IP block reimplemented in + FU540-C000 SoC. Please refer to sifive-blocks-ip-versioning.txt + for additional details. +- reg : bus address start and address range size of device +- clocks : handle to the controller clock; see the note below. + Mutually exclusive with opencores,ip-clock-frequency +- opencores,ip-clock-frequency: frequency of the controller clock in Hz; + see the note below. Mutually exclusive with clocks +- #address-cells : should be <1> +- #size-cells : should be <0> + +Optional properties: +- interrupts : interrupt number. +- clock-frequency : frequency of bus clock in Hz; see the note below. + Defaults to 100 KHz when the property is not specified +- reg-shift : device register offsets are shifted by this value +- reg-io-width : io register width in bytes (1, 2 or 4) +- regstep : deprecated, use reg-shift above + +Note +clock-frequency property is meant to control the bus frequency for i2c bus +drivers, but it was incorrectly used to specify i2c controller input clock +frequency. So the following rules are set to fix this situation: +- if clock-frequency is present and neither opencores,ip-clock-frequency nor + clocks are, then clock-frequency specifies i2c controller clock frequency. + This is to keep backwards compatibility with setups using old DTB. i2c bus + frequency is fixed at 100 KHz. +- if clocks is present it specifies i2c controller clock. clock-frequency + property specifies i2c bus frequency. +- if opencores,ip-clock-frequency is present it specifies i2c controller + clock frequency. clock-frequency property specifies i2c bus frequency. + +Examples: + + i2c0: ocores@a0000000 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "opencores,i2c-ocores"; + reg = <0xa0000000 0x8>; + interrupts = <10>; + opencores,ip-clock-frequency = <20000000>; + + reg-shift = <0>; /* 8 bit registers */ + reg-io-width = <1>; /* 8 bit read/write */ + + dummy@60 { + compatible = "dummy"; + reg = <0x60>; + }; + }; +or + i2c0: ocores@a0000000 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "opencores,i2c-ocores"; + reg = <0xa0000000 0x8>; + interrupts = <10>; + clocks = <&osc>; + clock-frequency = <400000>; /* i2c bus frequency 400 KHz */ + + reg-shift = <0>; /* 8 bit registers */ + reg-io-width = <1>; /* 8 bit read/write */ + + dummy@60 { + compatible = "dummy"; + reg = <0x60>; + }; + }; |