On Fri, Oct 06, 2017 at 05:51:30PM +0200, srinivas.kandagatla@linaro.org wrote:
From: Sagar Dharia sdharia@codeaurora.org
SLIMbus (Serial Low Power Interchip Media Bus) is a specification developed by MIPI (Mobile Industry Processor Interface) alliance. SLIMbus is a 2-wire implementation, which is used to communicate with peripheral components like audio-codec. SLIMbus uses Time-Division-Multiplexing to accommodate multiple data channels, and control channel. Control channel has messages to do device-enumeration, messages to send/receive control-data to/from slimbus devices, messages for port/channel management, and messages to do bandwidth allocation. The framework supports multiple instances of the bus (1 controller per bus), and multiple slave devices per controller.
This patch does device enumeration, logical address assignment, informing device when the device reports present/absent etc. Reporting present may need the driver to do the needful (e.g. turning on voltage regulators powering the device). Additionally device is probed when it reports present if that device doesn't need any such steps mentioned above.
Signed-off-by: Sagar Dharia sdharia@codeaurora.org Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org
Documentation/devicetree/bindings/slimbus/bus.txt | 57 ++
Split to separate patch.
Documentation/slimbus/summary | 109 ++++ drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/slimbus/Kconfig | 11 + drivers/slimbus/Makefile | 5 + drivers/slimbus/slim-core.c | 695 ++++++++++++++++++++++ include/linux/mod_devicetable.h | 13 + include/linux/slimbus.h | 299 ++++++++++ 9 files changed, 1192 insertions(+) create mode 100644 Documentation/devicetree/bindings/slimbus/bus.txt create mode 100644 Documentation/slimbus/summary create mode 100644 drivers/slimbus/Kconfig create mode 100644 drivers/slimbus/Makefile create mode 100644 drivers/slimbus/slim-core.c create mode 100644 include/linux/slimbus.h
diff --git a/Documentation/devicetree/bindings/slimbus/bus.txt b/Documentation/devicetree/bindings/slimbus/bus.txt new file mode 100644 index 0000000..cb658bb --- /dev/null +++ b/Documentation/devicetree/bindings/slimbus/bus.txt @@ -0,0 +1,57 @@ +SLIM(Serial Low Power Interchip Media Bus) bus
+SLIMbus is a 2-wire bus, and is used to communicate with peripheral +components like audio-codec.
+Controller is a normal device using binding for whatever bus it is +on (e.g. platform bus).
I can't have a PCI based slimbus controller? "platform bus" is a Linuxism.
+Required property for SLIMbus controller node: +- compatible - name of SLIMbus controller following generic names
recommended practice.
generic names aren't recommended. Allowed with some conditons, yes.
+- #address-cells - should be 2
You used 4 for your controller.
+- #size-cells - should be 0
+No other properties are required in the SLIMbus controller bus node.
That's not a useful statement. Almost every controller probably has other required properties.
+Child nodes: +Every SLIMbus controller node can contain zero or more child nodes +representing slave devices on the bus. Every SLIMbus slave device is +uniquely determined by the enumeration address containing 4 fields: +Manufacturer ID, Product code, Device index, and Instance value for +the device. +If child node is not present and it is instantiated after device +discovery (slave device reporting itself present).
+In some cases it may be necessary to describe non-probeable device +details such as non-standard ways of powering up a device. In +such cases, child nodes for those devices will be present as +slaves of the slimbus-controller, as detailed below.
+Required property for SLIMbus child node if it is present: +- reg - Is Duplex (Device index, Instance ID) from Enumeration
Address.Device Index Uniquely identifies multiple Devices withina single Component.Instance ID Is for the cases where multiple Devices of thesame type or Class are attached to the bus.+- compatible -"slimMID,PID". The textual representation of Manufacturer ID,
Product Code, shall be in lower case hexadecimal with leadingzeroes suppressed+SLIMbus example for Qualcomm's slimbus manager component:
- slim@28080000 {
compatible = "qcom,slim-msm";reg = <0x28080000 0x2000>,interrupts = <0 33 0>;clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;clock-names = "iface_clk", "core_clk";#address-cells = <2>;#size-cells = <0>;codec: wcd9310@1{
Is '1' by itself unique enough because you have 2 address cells. The unit-address is typically split up into fields with commas unless it's just a memory address. Anyway, you need to define the unit address format in this doc.
compatible = "slim217,60"";reg = <1 0>;};- };