diff options
Diffstat (limited to 'Documentation/devicetree')
20 files changed, 468 insertions, 23 deletions
diff --git a/Documentation/devicetree/bindings/dma/rcar-audmapp.txt b/Documentation/devicetree/bindings/dma/rcar-audmapp.txt index 9f1d750d76de..61bca509d7b9 100644 --- a/Documentation/devicetree/bindings/dma/rcar-audmapp.txt +++ b/Documentation/devicetree/bindings/dma/rcar-audmapp.txt @@ -16,9 +16,9 @@ Example: * DMA client Required properties: -- dmas: a list of <[DMA multiplexer phandle] [SRS/DRS value]> pairs, - where SRS/DRS values are fixed handles, specified in the SoC - manual as the value that would be written into the PDMACHCR. +- dmas: a list of <[DMA multiplexer phandle] [SRS << 8 | DRS]> pairs. + where SRS/DRS are specified in the SoC manual. + It will be written into PDMACHCR as high 16-bit parts. - dma-names: a list of DMA channel names, one per "dmas" entry Example: diff --git a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt index baef432e8369..1852906517ab 100644 --- a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt +++ b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt @@ -11,10 +11,17 @@ Required properties: Optional properties for main touchpad device: -- linux,gpio-keymap: An array of up to 4 entries indicating the Linux - keycode generated by each GPIO. Linux keycodes are defined in +- linux,gpio-keymap: When enabled, the SPT_GPIOPWN_T19 object sends messages + on GPIO bit changes. An array of up to 8 entries can be provided + indicating the Linux keycode mapped to each bit of the status byte, + starting at the LSB. Linux keycodes are defined in <dt-bindings/input/input.h>. + Note: the numbering of the GPIOs and the bit they start at varies between + maXTouch devices. You must either refer to the documentation, or + experiment to determine which bit corresponds to which input. Use + KEY_RESERVED for unused padding values. + Example: touch@4b { diff --git a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt index 1486497a24c1..ce6a1a072028 100644 --- a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt +++ b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt @@ -4,11 +4,13 @@ Specifying interrupt information for devices 1) Interrupt client nodes ------------------------- -Nodes that describe devices which generate interrupts must contain an either an -"interrupts" property or an "interrupts-extended" property. These properties -contain a list of interrupt specifiers, one per output interrupt. The format of -the interrupt specifier is determined by the interrupt controller to which the -interrupts are routed; see section 2 below for details. +Nodes that describe devices which generate interrupts must contain an +"interrupts" property, an "interrupts-extended" property, or both. If both are +present, the latter should take precedence; the former may be provided simply +for compatibility with software that does not recognize the latter. These +properties contain a list of interrupt specifiers, one per output interrupt. The +format of the interrupt specifier is determined by the interrupt controller to +which the interrupts are routed; see section 2 below for details. Example: interrupt-parent = <&intc1>; diff --git a/Documentation/devicetree/bindings/mfd/tc3589x.txt b/Documentation/devicetree/bindings/mfd/tc3589x.txt new file mode 100644 index 000000000000..6fcedba46ae9 --- /dev/null +++ b/Documentation/devicetree/bindings/mfd/tc3589x.txt @@ -0,0 +1,107 @@ +* Toshiba TC3589x multi-purpose expander + +The Toshiba TC3589x series are I2C-based MFD devices which may expose the +following built-in devices: gpio, keypad, rotator (vibrator), PWM (for +e.g. LEDs or vibrators) The included models are: + +- TC35890 +- TC35892 +- TC35893 +- TC35894 +- TC35895 +- TC35896 + +Required properties: + - compatible : must be "toshiba,tc35890", "toshiba,tc35892", "toshiba,tc35893", + "toshiba,tc35894", "toshiba,tc35895" or "toshiba,tc35896" + - reg : I2C address of the device + - interrupt-parent : specifies which IRQ controller we're connected to + - interrupts : the interrupt on the parent the controller is connected to + - interrupt-controller : marks the device node as an interrupt controller + - #interrupt-cells : should be <1>, the first cell is the IRQ offset on this + TC3589x interrupt controller. + +Optional nodes: + +- GPIO + This GPIO module inside the TC3589x has 24 (TC35890, TC35892) or 20 + (other models) GPIO lines. + - compatible : must be "toshiba,tc3589x-gpio" + - interrupts : interrupt on the parent, which must be the tc3589x MFD device + - interrupt-controller : marks the device node as an interrupt controller + - #interrupt-cells : should be <2>, the first cell is the IRQ offset on this + TC3589x GPIO interrupt controller, the second cell is the interrupt flags + in accordance with <dt-bindings/interrupt-controller/irq.h>. The following + flags are valid: + - IRQ_TYPE_LEVEL_LOW + - IRQ_TYPE_LEVEL_HIGH + - IRQ_TYPE_EDGE_RISING + - IRQ_TYPE_EDGE_FALLING + - IRQ_TYPE_EDGE_BOTH + - gpio-controller : marks the device node as a GPIO controller + - #gpio-cells : should be <2>, the first cell is the GPIO offset on this + GPIO controller, the second cell is the flags. + +- Keypad + This keypad is the same on all variants, supporting up to 96 different + keys. The linux-specific properties are modeled on those already existing + in other input drivers. + - compatible : must be "toshiba,tc3589x-keypad" + - debounce-delay-ms : debounce interval in milliseconds + - keypad,num-rows : number of rows in the matrix, see + bindings/input/matrix-keymap.txt + - keypad,num-columns : number of columns in the matrix, see + bindings/input/matrix-keymap.txt + - linux,keymap: the definition can be found in + bindings/input/matrix-keymap.txt + - linux,no-autorepeat: do no enable autorepeat feature. + - linux,wakeup: use any event on keypad as wakeup event. + +Example: + +tc35893@44 { + compatible = "toshiba,tc35893"; + reg = <0x44>; + interrupt-parent = <&gpio6>; + interrupts = <26 IRQ_TYPE_EDGE_RISING>; + + interrupt-controller; + #interrupt-cells = <1>; + + tc3589x_gpio { + compatible = "toshiba,tc3589x-gpio"; + interrupts = <0>; + + interrupt-controller; + #interrupt-cells = <2>; + gpio-controller; + #gpio-cells = <2>; + }; + tc3589x_keypad { + compatible = "toshiba,tc3589x-keypad"; + interrupts = <6>; + debounce-delay-ms = <4>; + keypad,num-columns = <8>; + keypad,num-rows = <8>; + linux,no-autorepeat; + linux,wakeup; + linux,keymap = <0x0301006b + 0x04010066 + 0x06040072 + 0x040200d7 + 0x0303006a + 0x0205000e + 0x0607008b + 0x0500001c + 0x0403000b + 0x03040034 + 0x05020067 + 0x0305006c + 0x040500e7 + 0x0005009e + 0x06020073 + 0x01030039 + 0x07060069 + 0x050500d9>; + }; +}; diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt index 65f4f7c43136..ee654e95d8ad 100644 --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt +++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt @@ -22,7 +22,7 @@ Optional properties: width of 8 is assumed. - ti,nand-ecc-opt: A string setting the ECC layout to use. One of: - "sw" <deprecated> use "ham1" instead + "sw" 1-bit Hamming ecc code via software "hw" <deprecated> use "ham1" instead "hw-romcode" <deprecated> use "ham1" instead "ham1" 1-bit Hamming ecc code diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt index 9b03c57563a4..e45ac3f926b1 100644 --- a/Documentation/devicetree/bindings/net/stmmac.txt +++ b/Documentation/devicetree/bindings/net/stmmac.txt @@ -39,6 +39,10 @@ Optional properties: further clocks may be specified in derived bindings. - clock-names: One name for each entry in the clocks property, the first one should be "stmmaceth". +- clk_ptp_ref: this is the PTP reference clock; in case of the PTP is + available this clock is used for programming the Timestamp Addend Register. + If not passed then the system clock will be used and this is fine on some + platforms. Examples: diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt index d0d15ee42834..ed0d9b9fff2b 100644 --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt @@ -2,6 +2,10 @@ Required properties: - compatible: should contain "snps,dw-pcie" to identify the core. +- reg: Should contain the configuration address space. +- reg-names: Must be "config" for the PCIe configuration space. + (The old way of getting the configuration address space from "ranges" + is deprecated and should be avoided.) - #address-cells: set to <3> - #size-cells: set to <2> - device_type: set to "pci" diff --git a/Documentation/devicetree/bindings/pci/ti-pci.txt b/Documentation/devicetree/bindings/pci/ti-pci.txt new file mode 100644 index 000000000000..3d217911b313 --- /dev/null +++ b/Documentation/devicetree/bindings/pci/ti-pci.txt @@ -0,0 +1,59 @@ +TI PCI Controllers + +PCIe Designware Controller + - compatible: Should be "ti,dra7-pcie"" + - reg : Two register ranges as listed in the reg-names property + - reg-names : The first entry must be "ti-conf" for the TI specific registers + The second entry must be "rc-dbics" for the designware pcie + registers + The third entry must be "config" for the PCIe configuration space + - phys : list of PHY specifiers (used by generic PHY framework) + - phy-names : must be "pcie-phy0", "pcie-phy1", "pcie-phyN".. based on the + number of PHYs as specified in *phys* property. + - ti,hwmods : Name of the hwmod associated to the pcie, "pcie<X>", + where <X> is the instance number of the pcie from the HW spec. + - interrupts : Two interrupt entries must be specified. The first one is for + main interrupt line and the second for MSI interrupt line. + - #address-cells, + #size-cells, + #interrupt-cells, + device_type, + ranges, + num-lanes, + interrupt-map-mask, + interrupt-map : as specified in ../designware-pcie.txt + +Example: +axi { + compatible = "simple-bus"; + #size-cells = <1>; + #address-cells = <1>; + ranges = <0x51000000 0x51000000 0x3000 + 0x0 0x20000000 0x10000000>; + pcie@51000000 { + compatible = "ti,dra7-pcie"; + reg = <0x51000000 0x2000>, <0x51002000 0x14c>, <0x1000 0x2000>; + reg-names = "rc_dbics", "ti_conf", "config"; + interrupts = <0 232 0x4>, <0 233 0x4>; + #address-cells = <3>; + #size-cells = <2>; + device_type = "pci"; + ranges = <0x81000000 0 0 0x03000 0 0x00010000 + 0x82000000 0 0x20013000 0x13000 0 0xffed000>; + #interrupt-cells = <1>; + num-lanes = <1>; + ti,hwmods = "pcie1"; + phys = <&pcie1_phy>; + phy-names = "pcie-phy0"; + interrupt-map-mask = <0 0 0 7>; + interrupt-map = <0 0 0 1 &pcie_intc 1>, + <0 0 0 2 &pcie_intc 2>, + <0 0 0 3 &pcie_intc 3>, + <0 0 0 4 &pcie_intc 4>; + pcie_intc: interrupt-controller { + interrupt-controller; + #address-cells = <0>; + #interrupt-cells = <1>; + }; + }; +}; diff --git a/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt index 0211c6d8a522..92fae82f35f2 100644 --- a/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt +++ b/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt @@ -62,7 +62,7 @@ Example: #gpio-cells = <2>; interrupt-controller; #interrupt-cells = <2>; - interrupts = <0 32 0x4>; + interrupts = <0 16 0x4>; pinctrl-names = "default"; pinctrl-0 = <&gsbi5_uart_default>; diff --git a/Documentation/devicetree/bindings/regulator/tps65090.txt b/Documentation/devicetree/bindings/regulator/tps65090.txt index 340980239ea9..ca69f5e3040c 100644 --- a/Documentation/devicetree/bindings/regulator/tps65090.txt +++ b/Documentation/devicetree/bindings/regulator/tps65090.txt @@ -45,8 +45,8 @@ Example: infet5-supply = <&some_reg>; infet6-supply = <&some_reg>; infet7-supply = <&some_reg>; - vsys_l1-supply = <&some_reg>; - vsys_l2-supply = <&some_reg>; + vsys-l1-supply = <&some_reg>; + vsys-l2-supply = <&some_reg>; regulators { dcdc1 { diff --git a/Documentation/devicetree/bindings/sound/adi,axi-spdif-tx.txt b/Documentation/devicetree/bindings/sound/adi,axi-spdif-tx.txt index 46f344965313..4eb7997674a0 100644 --- a/Documentation/devicetree/bindings/sound/adi,axi-spdif-tx.txt +++ b/Documentation/devicetree/bindings/sound/adi,axi-spdif-tx.txt @@ -1,7 +1,7 @@ ADI AXI-SPDIF controller Required properties: - - compatible : Must be "adi,axi-spdif-1.00.a" + - compatible : Must be "adi,axi-spdif-tx-1.00.a" - reg : Must contain SPDIF core's registers location and length - clocks : Pairs of phandle and specifier referencing the controller's clocks. The controller expects two clocks, the clock used for the AXI interface and diff --git a/Documentation/devicetree/bindings/sound/rockchip-i2s.txt b/Documentation/devicetree/bindings/sound/rockchip-i2s.txt index 6c55fcfe5e1d..9b82c20b306b 100644 --- a/Documentation/devicetree/bindings/sound/rockchip-i2s.txt +++ b/Documentation/devicetree/bindings/sound/rockchip-i2s.txt @@ -31,7 +31,7 @@ i2s@ff890000 { #address-cells = <1>; #size-cells = <0>; dmas = <&pdma1 0>, <&pdma1 1>; - dma-names = "rx", "tx"; + dma-names = "tx", "rx"; clock-names = "i2s_hclk", "i2s_clk"; clocks = <&cru HCLK_I2S0>, <&cru SCLK_I2S0>; }; diff --git a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt index 4256a6df9b79..aad527b357a0 100644 --- a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt +++ b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt @@ -7,6 +7,9 @@ Required properties: - interrupts : Should contain CSPI/eCSPI interrupt - fsl,spi-num-chipselects : Contains the number of the chipselect - cs-gpios : Specifies the gpio pins to be used for chipselects. +- dmas: DMA specifiers for tx and rx dma. See the DMA client binding, + Documentation/devicetree/bindings/dma/dma.txt +- dma-names: DMA request names should include "tx" and "rx" if present. Example: @@ -19,4 +22,6 @@ ecspi@70010000 { fsl,spi-num-chipselects = <2>; cs-gpios = <&gpio3 24 0>, /* GPIO3_24 */ <&gpio3 25 0>; /* GPIO3_25 */ + dmas = <&sdma 3 7 1>, <&sdma 4 7 2>; + dma-names = "rx", "tx"; }; diff --git a/Documentation/devicetree/bindings/spi/spi-davinci.txt b/Documentation/devicetree/bindings/spi/spi-davinci.txt index f80887bca0d6..12ecfe9e3599 100644 --- a/Documentation/devicetree/bindings/spi/spi-davinci.txt +++ b/Documentation/devicetree/bindings/spi/spi-davinci.txt @@ -1,5 +1,10 @@ Davinci SPI controller device bindings +Links on DM: +Keystone 2 - http://www.ti.com/lit/ug/sprugp2a/sprugp2a.pdf +dm644x - http://www.ti.com/lit/ug/sprue32a/sprue32a.pdf +OMAP-L138/da830 - http://www.ti.com/lit/ug/spruh77a/spruh77a.pdf + Required properties: - #address-cells: number of cells required to define a chip select address on the SPI bus. Should be set to 1. @@ -24,6 +29,30 @@ Optional: cs-gpios = <0>, <0>, <0>, <&gpio1 30 0>, <&gpio1 31 0>; where first three are internal CS and last two are GPIO CS. +Optional properties for slave devices: +SPI slave nodes can contain the following properties. +Not all SPI Peripherals from Texas Instruments support this. +Please check SPI peripheral documentation for a device before using these. + +- ti,spi-wdelay : delay between transmission of words + (SPIFMTn.WDELAY, SPIDAT1.WDEL) must be specified in number of SPI module + clock periods. + + delay = WDELAY * SPI_module_clock_period + 2 * SPI_module_clock_period + +Below is timing diagram which shows functional meaning of +"ti,spi-wdelay" parameter. + + +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +SPI_CLK | | | | | | | | | | | | | | | | + +----------+ +-+ +-+ +-+ +-+ +---------------------------+ +-+ +-+ +- + +SPI_SOMI/SIMO+-----------------+ +----------- + +----------+ word1 +---------------------------+word2 + +-----------------+ +----------- + WDELAY + <--------------------------> + Example of a NOR flash slave device (n25q032) connected to DaVinci SPI controller device over the SPI bus. @@ -43,6 +72,7 @@ spi0:spi@20BF0000 { compatible = "st,m25p32"; spi-max-frequency = <25000000>; reg = <0>; + ti,spi-wdelay = <8>; partition@0 { label = "u-boot-spl"; diff --git a/Documentation/devicetree/bindings/spi/spi-orion.txt b/Documentation/devicetree/bindings/spi/spi-orion.txt index a3ff50fc76fb..50c3a3de61c1 100644 --- a/Documentation/devicetree/bindings/spi/spi-orion.txt +++ b/Documentation/devicetree/bindings/spi/spi-orion.txt @@ -1,7 +1,7 @@ Marvell Orion SPI device Required properties: -- compatible : should be "marvell,orion-spi". +- compatible : should be "marvell,orion-spi" or "marvell,armada-370-spi". - reg : offset and length of the register set for the device - cell-index : Which of multiple SPI controllers is this. Optional properties: diff --git a/Documentation/devicetree/bindings/spi/spi-rockchip.txt b/Documentation/devicetree/bindings/spi/spi-rockchip.txt index 7bab35575817..467dec441c62 100644 --- a/Documentation/devicetree/bindings/spi/spi-rockchip.txt +++ b/Documentation/devicetree/bindings/spi/spi-rockchip.txt @@ -16,11 +16,15 @@ Required Properties: - clocks: Must contain an entry for each entry in clock-names. - clock-names: Shall be "spiclk" for the transfer-clock, and "apb_pclk" for the peripheral clock. +- #address-cells: should be 1. +- #size-cells: should be 0. + +Optional Properties: + - dmas: DMA specifiers for tx and rx dma. See the DMA client binding, Documentation/devicetree/bindings/dma/dma.txt - dma-names: DMA request names should include "tx" and "rx" if present. -- #address-cells: should be 1. -- #size-cells: should be 0. + Example: diff --git a/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt b/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt index 578a1fca366e..443bcb6134d5 100644 --- a/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt +++ b/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt @@ -56,6 +56,9 @@ Required properties: - fsl,data-width : should be <18> or <24> - port: A port node with endpoint definitions as defined in Documentation/devicetree/bindings/media/video-interfaces.txt. + On i.MX5, the internal two-input-multiplexer is used. + Due to hardware limitations, only one port (port@[0,1]) + can be used for each channel (lvds-channel@[0,1], respectively) On i.MX6, there should be four ports (port@[0-3]) that correspond to the four LVDS multiplexer inputs. @@ -78,6 +81,8 @@ ldb: ldb@53fa8008 { "di0", "di1"; lvds-channel@0 { + #address-cells = <1>; + #size-cells = <0>; reg = <0>; fsl,data-mapping = "spwg"; fsl,data-width = <24>; @@ -86,7 +91,9 @@ ldb: ldb@53fa8008 { /* ... */ }; - port { + port@0 { + reg = <0>; + lvds0_in: endpoint { remote-endpoint = <&ipu_di0_lvds0>; }; @@ -94,6 +101,8 @@ ldb: ldb@53fa8008 { }; lvds-channel@1 { + #address-cells = <1>; + #size-cells = <0>; reg = <1>; fsl,data-mapping = "spwg"; fsl,data-width = <24>; @@ -102,7 +111,9 @@ ldb: ldb@53fa8008 { /* ... */ }; - port { + port@1 { + reg = <1>; + lvds1_in: endpoint { remote-endpoint = <&ipu_di1_lvds1>; }; diff --git a/Documentation/devicetree/bindings/usb/mxs-phy.txt b/Documentation/devicetree/bindings/usb/mxs-phy.txt index cef181a9d8bd..96681c93b86d 100644 --- a/Documentation/devicetree/bindings/usb/mxs-phy.txt +++ b/Documentation/devicetree/bindings/usb/mxs-phy.txt @@ -5,6 +5,7 @@ Required properties: * "fsl,imx23-usbphy" for imx23 and imx28 * "fsl,imx6q-usbphy" for imx6dq and imx6dl * "fsl,imx6sl-usbphy" for imx6sl + * "fsl,imx6sx-usbphy" for imx6sx "fsl,imx23-usbphy" is still a fallback for other strings - reg: Should contain registers location and length - interrupts: Should contain phy interrupt diff --git a/Documentation/devicetree/bindings/video/analog-tv-connector.txt b/Documentation/devicetree/bindings/video/analog-tv-connector.txt index 0218fcdc1299..0c0970c210ab 100644 --- a/Documentation/devicetree/bindings/video/analog-tv-connector.txt +++ b/Documentation/devicetree/bindings/video/analog-tv-connector.txt @@ -2,7 +2,7 @@ Analog TV Connector =================== Required properties: -- compatible: "composite-connector" or "svideo-connector" +- compatible: "composite-video-connector" or "svideo-connector" Optional properties: - label: a symbolic name for the connector @@ -14,7 +14,7 @@ Example ------- tv: connector { - compatible = "composite-connector"; + compatible = "composite-video-connector"; label = "tv"; port { diff --git a/Documentation/devicetree/of_selftest.txt b/Documentation/devicetree/of_selftest.txt new file mode 100644 index 000000000000..3a2f54d07fc5 --- /dev/null +++ b/Documentation/devicetree/of_selftest.txt @@ -0,0 +1,211 @@ +Open Firmware Device Tree Selftest +---------------------------------- + +Author: Gaurav Minocha <gaurav.minocha.os@gmail.com> + +1. Introduction + +This document explains how the test data required for executing OF selftest +is attached to the live tree dynamically, independent of the machine's +architecture. + +It is recommended to read the following documents before moving ahead. + +[1] Documentation/devicetree/usage-model.txt +[2] http://www.devicetree.org/Device_Tree_Usage + +OF Selftest has been designed to test the interface (include/linux/of.h) +provided to device driver developers to fetch the device information..etc. +from the unflattened device tree data structure. This interface is used by +most of the device drivers in various use cases. + + +2. Test-data + +The Device Tree Source file (drivers/of/testcase-data/testcases.dts) contains +the test data required for executing the unit tests automated in +drivers/of/selftests.c. Currently, following Device Tree Source Include files +(.dtsi) are included in testcase.dts: + +drivers/of/testcase-data/tests-interrupts.dtsi +drivers/of/testcase-data/tests-platform.dtsi +drivers/of/testcase-data/tests-phandle.dtsi +drivers/of/testcase-data/tests-match.dtsi + +When the kernel is build with OF_SELFTEST enabled, then the following make rule + +$(obj)/%.dtb: $(src)/%.dts FORCE + $(call if_changed_dep, dtc) + +is used to compile the DT source file (testcase.dts) into a binary blob +(testcase.dtb), also referred as flattened DT. + +After that, using the following rule the binary blob above is wrapped as an +assembly file (testcase.dtb.S). + +$(obj)/%.dtb.S: $(obj)/%.dtb + $(call cmd, dt_S_dtb) + +The assembly file is compiled into an object file (testcase.dtb.o), and is +linked into the kernel image. + + +2.1. Adding the test data + +Un-flattened device tree structure: + +Un-flattened device tree consists of connected device_node(s) in form of a tree +structure described below. + +// following struct members are used to construct the tree +struct device_node { + ... + struct device_node *parent; + struct device_node *child; + struct device_node *sibling; + struct device_node *allnext; /* next in list of all nodes */ + ... + }; + +Figure 1, describes a generic structure of machine’s un-flattened device tree +considering only child and sibling pointers. There exists another pointer, +*parent, that is used to traverse the tree in the reverse direction. So, at +a particular level the child node and all the sibling nodes will have a parent +pointer pointing to a common node (e.g. child1, sibling2, sibling3, sibling4’s +parent points to root node) + +root (‘/’) + | +child1 -> sibling2 -> sibling3 -> sibling4 -> null + | | | | + | | | null + | | | + | | child31 -> sibling32 -> null + | | | | + | | null null + | | + | child21 -> sibling22 -> sibling23 -> null + | | | | + | null null null + | +child11 -> sibling12 -> sibling13 -> sibling14 -> null + | | | | + | | | null + | | | + null null child131 -> null + | + null + +Figure 1: Generic structure of un-flattened device tree + + +*allnext: it is used to link all the nodes of DT into a list. So, for the + above tree the list would be as follows: + +root->child1->child11->sibling12->sibling13->child131->sibling14->sibling2-> +child21->sibling22->sibling23->sibling3->child31->sibling32->sibling4->null + +Before executing OF selftest, it is required to attach the test data to +machine's device tree (if present). So, when selftest_data_add() is called, +at first it reads the flattened device tree data linked into the kernel image +via the following kernel symbols: + +__dtb_testcases_begin - address marking the start of test data blob +__dtb_testcases_end - address marking the end of test data blob + +Secondly, it calls of_fdt_unflatten_device_tree() to unflatten the flattened +blob. And finally, if the machine’s device tree (i.e live tree) is present, +then it attaches the unflattened test data tree to the live tree, else it +attaches itself as a live device tree. + +attach_node_and_children() uses of_attach_node() to attach the nodes into the +live tree as explained below. To explain the same, the test data tree described + in Figure 2 is attached to the live tree described in Figure 1. + +root (‘/’) + | + testcase-data + | + test-child0 -> test-sibling1 -> test-sibling2 -> test-sibling3 -> null + | | | | + test-child01 null null null + + +allnext list: + +root->testcase-data->test-child0->test-child01->test-sibling1->test-sibling2 +->test-sibling3->null + +Figure 2: Example test data tree to be attached to live tree. + +According to the scenario above, the live tree is already present so it isn’t +required to attach the root(‘/’) node. All other nodes are attached by calling +of_attach_node() on each node. + +In the function of_attach_node(), the new node is attached as the child of the +given parent in live tree. But, if parent already has a child then the new node +replaces the current child and turns it into its sibling. So, when the testcase +data node is attached to the live tree above (Figure 1), the final structure is + as shown in Figure 3. + +root (‘/’) + | +testcase-data -> child1 -> sibling2 -> sibling3 -> sibling4 -> null + | | | | | + (...) | | | null + | | child31 -> sibling32 -> null + | | | | + | | null null + | | + | child21 -> sibling22 -> sibling23 -> null + | | | | + | null null null + | + child11 -> sibling12 -> sibling13 -> sibling14 -> null + | | | | + null null | null + | + child131 -> null + | + null +----------------------------------------------------------------------- + +root (‘/’) + | +testcase-data -> child1 -> sibling2 -> sibling3 -> sibling4 -> null + | | | | | + | (...) (...) (...) null + | +test-sibling3 -> test-sibling2 -> test-sibling1 -> test-child0 -> null + | | | | + null null null test-child01 + + +Figure 3: Live device tree structure after attaching the testcase-data. + + +Astute readers would have noticed that test-child0 node becomes the last +sibling compared to the earlier structure (Figure 2). After attaching first +test-child0 the test-sibling1 is attached that pushes the child node +(i.e. test-child0) to become a sibling and makes itself a child node, + as mentioned above. + +If a duplicate node is found (i.e. if a node with same full_name property is +already present in the live tree), then the node isn’t attached rather its +properties are updated to the live tree’s node by calling the function +update_node_properties(). + + +2.2. Removing the test data + +Once the test case execution is complete, selftest_data_remove is called in +order to remove the device nodes attached initially (first the leaf nodes are +detached and then moving up the parent nodes are removed, and eventually the +whole tree). selftest_data_remove() calls detach_node_and_children() that uses +of_detach_node() to detach the nodes from the live device tree. + +To detach a node, of_detach_node() first updates all_next linked list, by +attaching the previous node’s allnext to current node’s allnext pointer. And +then, it either updates the child pointer of given node’s parent to its +sibling or attaches the previous sibling to the given node’s sibling, as +appropriate. That is it :) |