diff options
Diffstat (limited to 'Documentation/devicetree')
23 files changed, 936 insertions, 23 deletions
diff --git a/Documentation/devicetree/bindings/arm/atmel-at91.txt b/Documentation/devicetree/bindings/arm/atmel-at91.txt index 1aeaf6f2a1ba..ecc81e368715 100644 --- a/Documentation/devicetree/bindings/arm/atmel-at91.txt +++ b/Documentation/devicetree/bindings/arm/atmel-at91.txt @@ -30,3 +30,63 @@ One interrupt per TC channel in a TC block: reg = <0xfffdc000 0x100>; interrupts = <26 4 27 4 28 4>; }; + +RSTC Reset Controller required properties: +- compatible: Should be "atmel,<chip>-rstc". + <chip> can be "at91sam9260" or "at91sam9g45" +- reg: Should contain registers location and length + +Example: + + rstc@fffffd00 { + compatible = "atmel,at91sam9260-rstc"; + reg = <0xfffffd00 0x10>; + }; + +RAMC SDRAM/DDR Controller required properties: +- compatible: Should be "atmel,at91sam9260-sdramc", + "atmel,at91sam9g45-ddramc", +- reg: Should contain registers location and length + For at91sam9263 and at91sam9g45 you must specify 2 entries. + +Examples: + + ramc0: ramc@ffffe800 { + compatible = "atmel,at91sam9g45-ddramc"; + reg = <0xffffe800 0x200>; + }; + + ramc0: ramc@ffffe400 { + compatible = "atmel,at91sam9g45-ddramc"; + reg = <0xffffe400 0x200 + 0xffffe600 0x200>; + }; + +SHDWC Shutdown Controller + +required properties: +- compatible: Should be "atmel,<chip>-shdwc". + <chip> can be "at91sam9260", "at91sam9rl" or "at91sam9x5". +- reg: Should contain registers location and length + +optional properties: +- atmel,wakeup-mode: String, operation mode of the wakeup mode. + Supported values are: "none", "high", "low", "any". +- atmel,wakeup-counter: Counter on Wake-up 0 (between 0x0 and 0xf). + +optional at91sam9260 properties: +- atmel,wakeup-rtt-timer: boolean to enable Real-time Timer Wake-up. + +optional at91sam9rl properties: +- atmel,wakeup-rtc-timer: boolean to enable Real-time Clock Wake-up. +- atmel,wakeup-rtt-timer: boolean to enable Real-time Timer Wake-up. + +optional at91sam9x5 properties: +- atmel,wakeup-rtc-timer: boolean to enable Real-time Clock Wake-up. + +Example: + + rstc@fffffd00 { + compatible = "atmel,at91sam9260-rstc"; + reg = <0xfffffd00 0x10>; + }; diff --git a/Documentation/devicetree/bindings/arm/atmel-pmc.txt b/Documentation/devicetree/bindings/arm/atmel-pmc.txt new file mode 100644 index 000000000000..389bed5056e8 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/atmel-pmc.txt @@ -0,0 +1,11 @@ +* Power Management Controller (PMC) + +Required properties: +- compatible: Should be "atmel,at91rm9200-pmc" +- reg: Should contain PMC registers location and length + +Examples: + pmc: pmc@fffffc00 { + compatible = "atmel,at91rm9200-pmc"; + reg = <0xfffffc00 0x100>; + }; diff --git a/Documentation/devicetree/bindings/arm/spear.txt b/Documentation/devicetree/bindings/arm/spear.txt new file mode 100644 index 000000000000..f8e54f092328 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/spear.txt @@ -0,0 +1,8 @@ +ST SPEAr Platforms Device Tree Bindings +--------------------------------------- + +Boards with the ST SPEAr600 SoC shall have the following properties: + +Required root node property: + +compatible = "st,spear600"; diff --git a/Documentation/devicetree/bindings/gpio/gpio-omap.txt b/Documentation/devicetree/bindings/gpio/gpio-omap.txt new file mode 100644 index 000000000000..bff51a2fee1e --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-omap.txt @@ -0,0 +1,36 @@ +OMAP GPIO controller bindings + +Required properties: +- compatible: + - "ti,omap2-gpio" for OMAP2 controllers + - "ti,omap3-gpio" for OMAP3 controllers + - "ti,omap4-gpio" for OMAP4 controllers +- #gpio-cells : Should be two. + - first cell is the pin number + - second cell is used to specify optional parameters (unused) +- gpio-controller : Marks the device node as a GPIO controller. +- #interrupt-cells : Should be 2. +- interrupt-controller: Mark the device node as an interrupt controller + The first cell is the GPIO number. + The second cell is used to specify flags: + bits[3:0] trigger type and level flags: + 1 = low-to-high edge triggered. + 2 = high-to-low edge triggered. + 4 = active high level-sensitive. + 8 = active low level-sensitive. + +OMAP specific properties: +- ti,hwmods: Name of the hwmod associated to the GPIO: + "gpio<X>", <X> being the 1-based instance number from the HW spec + + +Example: + +gpio4: gpio4 { + compatible = "ti,omap4-gpio"; + ti,hwmods = "gpio4"; + #gpio-cells = <2>; + gpio-controller; + #interrupt-cells = <2>; + interrupt-controller; +}; diff --git a/Documentation/devicetree/bindings/gpio/gpio-twl4030.txt b/Documentation/devicetree/bindings/gpio/gpio-twl4030.txt new file mode 100644 index 000000000000..16695d9cf1e8 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-twl4030.txt @@ -0,0 +1,23 @@ +twl4030 GPIO controller bindings + +Required properties: +- compatible: + - "ti,twl4030-gpio" for twl4030 GPIO controller +- #gpio-cells : Should be two. + - first cell is the pin number + - second cell is used to specify optional parameters (unused) +- gpio-controller : Marks the device node as a GPIO controller. +- #interrupt-cells : Should be 2. +- interrupt-controller: Mark the device node as an interrupt controller + The first cell is the GPIO number. + The second cell is not used. + +Example: + +twl_gpio: gpio { + compatible = "ti,twl4030-gpio"; + #gpio-cells = <2>; + gpio-controller; + #interrupt-cells = <2>; + interrupt-controller; +}; diff --git a/Documentation/devicetree/bindings/gpio/gpio_i2c.txt b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt new file mode 100644 index 000000000000..4f8ec947c6bd --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt @@ -0,0 +1,32 @@ +Device-Tree bindings for i2c gpio driver + +Required properties: + - compatible = "i2c-gpio"; + - gpios: sda and scl gpio + + +Optional properties: + - i2c-gpio,sda-open-drain: sda as open drain + - i2c-gpio,scl-open-drain: scl as open drain + - i2c-gpio,scl-output-only: scl as output only + - i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform) + - i2c-gpio,timeout-ms: timeout to get data + +Example nodes: + +i2c@0 { + compatible = "i2c-gpio"; + gpios = <&pioA 23 0 /* sda */ + &pioA 24 0 /* scl */ + >; + i2c-gpio,sda-open-drain; + i2c-gpio,scl-open-drain; + i2c-gpio,delay-us = <2>; /* ~100 kHz */ + #address-cells = <1>; + #size-cells = <0>; + + rv3029c2@56 { + compatible = "rv3029c2"; + reg = <0x56>; + }; +}; diff --git a/Documentation/devicetree/bindings/gpio/sodaville.txt b/Documentation/devicetree/bindings/gpio/sodaville.txt new file mode 100644 index 000000000000..563eff22b975 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/sodaville.txt @@ -0,0 +1,48 @@ +GPIO controller on CE4100 / Sodaville SoCs +========================================== + +The bindings for CE4100's GPIO controller match the generic description +which is covered by the gpio.txt file in this folder. + +The only additional property is the intel,muxctl property which holds the +value which is written into the MUXCNTL register. + +There is no compatible property for now because the driver is probed via +PCI id (vendor 0x8086 device 0x2e67). + +The interrupt specifier consists of two cells encoded as follows: + - <1st cell>: The interrupt-number that identifies the interrupt source. + - <2nd cell>: The level-sense information, encoded as follows: + 4 - active high level-sensitive + 8 - active low level-sensitive + +Example of the GPIO device and one user: + + pcigpio: gpio@b,1 { + /* two cells for GPIO and interrupt */ + #gpio-cells = <2>; + #interrupt-cells = <2>; + compatible = "pci8086,2e67.2", + "pci8086,2e67", + "pciclassff0000", + "pciclassff00"; + + reg = <0x15900 0x0 0x0 0x0 0x0>; + /* Interrupt line of the gpio device */ + interrupts = <15 1>; + /* It is an interrupt and GPIO controller itself */ + interrupt-controller; + gpio-controller; + intel,muxctl = <0>; + }; + + testuser@20 { + compatible = "example,testuser"; + /* User the 11th GPIO line as an active high triggered + * level interrupt + */ + interrupts = <11 8>; + interrupt-parent = <&pcigpio>; + /* Use this GPIO also with the gpio functions */ + gpios = <&pcigpio 11 0>; + }; diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt new file mode 100644 index 000000000000..dbd4368ab8cc --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt @@ -0,0 +1,33 @@ +* TI Highspeed MMC host controller for OMAP + +The Highspeed MMC Host Controller on TI OMAP family +provides an interface for MMC, SD, and SDIO types of memory cards. + +Required properties: +- compatible: + Should be "ti,omap2-hsmmc", for OMAP2 controllers + Should be "ti,omap3-hsmmc", for OMAP3 controllers + Should be "ti,omap4-hsmmc", for OMAP4 controllers +- ti,hwmods: Must be "mmc<n>", n is controller instance starting 1 +- reg : should contain hsmmc registers location and length + +Optional properties: +ti,dual-volt: boolean, supports dual voltage cards +<supply-name>-supply: phandle to the regulator device tree node +"supply-name" examples are "vmmc", "vmmc_aux" etc +ti,bus-width: Number of data lines, default assumed is 1 if the property is missing. +cd-gpios: GPIOs for card detection +wp-gpios: GPIOs for write protection +ti,non-removable: non-removable slot (like eMMC) +ti,needs-special-reset: Requires a special softreset sequence + +Example: + mmc1: mmc@0x4809c000 { + compatible = "ti,omap4-hsmmc"; + reg = <0x4809c000 0x400>; + ti,hwmods = "mmc1"; + ti,dual-volt; + ti,bus-width = <4>; + vmmc-supply = <&vmmc>; /* phandle to regulator node */ + ti,non-removable; + }; diff --git a/Documentation/devicetree/bindings/mtd/arm-versatile.txt b/Documentation/devicetree/bindings/mtd/arm-versatile.txt index 476845db94d0..beace4b89daa 100644 --- a/Documentation/devicetree/bindings/mtd/arm-versatile.txt +++ b/Documentation/devicetree/bindings/mtd/arm-versatile.txt @@ -4,5 +4,5 @@ Required properties: - compatible : must be "arm,versatile-flash"; - bank-width : width in bytes of flash interface. -Optional properties: -- Subnode partition map from mtd flash binding +The device tree may optionally contain sub-nodes describing partitions of the +address space. See partition.txt for more detail. diff --git a/Documentation/devicetree/bindings/mtd/atmel-dataflash.txt b/Documentation/devicetree/bindings/mtd/atmel-dataflash.txt index ef66ddd01da0..1889a4db5b7c 100644 --- a/Documentation/devicetree/bindings/mtd/atmel-dataflash.txt +++ b/Documentation/devicetree/bindings/mtd/atmel-dataflash.txt @@ -3,6 +3,9 @@ Required properties: - compatible : "atmel,<model>", "atmel,<series>", "atmel,dataflash". +The device tree may optionally contain sub-nodes describing partitions of the +address space. See partition.txt for more detail. + Example: flash@1 { diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt new file mode 100644 index 000000000000..a20069502f5a --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt @@ -0,0 +1,41 @@ +Atmel NAND flash + +Required properties: +- compatible : "atmel,at91rm9200-nand". +- reg : should specify localbus address and size used for the chip, + and if availlable the ECC. +- atmel,nand-addr-offset : offset for the address latch. +- atmel,nand-cmd-offset : offset for the command latch. +- #address-cells, #size-cells : Must be present if the device has sub-nodes + representing partitions. + +- gpios : specifies the gpio pins to control the NAND device. detect is an + optional gpio and may be set to 0 if not present. + +Optional properties: +- nand-ecc-mode : String, operation mode of the NAND ecc mode, soft by default. + Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first", + "soft_bch". +- nand-bus-width : 8 or 16 bus width if not present 8 +- nand-on-flash-bbt: boolean to enable on flash bbt option if not present false + +Examples: +nand0: nand@40000000,0 { + compatible = "atmel,at91rm9200-nand"; + #address-cells = <1>; + #size-cells = <1>; + reg = <0x40000000 0x10000000 + 0xffffe800 0x200 + >; + atmel,nand-addr-offset = <21>; /* ale */ + atmel,nand-cmd-offset = <22>; /* cle */ + nand-on-flash-bbt; + nand-ecc-mode = "soft"; + gpios = <&pioC 13 0 /* rdy */ + &pioC 14 0 /* nce */ + 0 /* cd */ + >; + partition@0 { + ... + }; +}; diff --git a/Documentation/devicetree/bindings/mtd/fsl-upm-nand.txt b/Documentation/devicetree/bindings/mtd/fsl-upm-nand.txt index 00f1f546b32e..fce4894f5a98 100644 --- a/Documentation/devicetree/bindings/mtd/fsl-upm-nand.txt +++ b/Documentation/devicetree/bindings/mtd/fsl-upm-nand.txt @@ -19,6 +19,10 @@ Optional properties: read registers (tR). Required if property "gpios" is not used (R/B# pins not connected). +Each flash chip described may optionally contain additional sub-nodes +describing partitions of the address space. See partition.txt for more +detail. + Examples: upm@1,0 { diff --git a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt new file mode 100644 index 000000000000..e2c663b354d2 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt @@ -0,0 +1,33 @@ +* FSMC NAND + +Required properties: +- compatible : "st,spear600-fsmc-nand" +- reg : Address range of the mtd chip +- reg-names: Should contain the reg names "fsmc_regs" and "nand_data" +- st,ale-off : Chip specific offset to ALE +- st,cle-off : Chip specific offset to CLE + +Optional properties: +- bank-width : Width (in bytes) of the device. If not present, the width + defaults to 1 byte +- nand-skip-bbtscan: Indicates the the BBT scanning should be skipped + +Example: + + fsmc: flash@d1800000 { + compatible = "st,spear600-fsmc-nand"; + #address-cells = <1>; + #size-cells = <1>; + reg = <0xd1800000 0x1000 /* FSMC Register */ + 0xd2000000 0x4000>; /* NAND Base */ + reg-names = "fsmc_regs", "nand_data"; + st,ale-off = <0x20000>; + st,cle-off = <0x10000>; + + bank-width = <1>; + nand-skip-bbtscan; + + partition@0 { + ... + }; + }; diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt index 719f4dc58df7..36ef07d3c90f 100644 --- a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt +++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt @@ -25,6 +25,9 @@ Optional properties: GPIO state and before and after command byte writes, this register will be read to ensure that the GPIO accesses have completed. +The device tree may optionally contain sub-nodes describing partitions of the +address space. See partition.txt for more detail. + Examples: gpio-nand@1,0 { diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt index 80152cb567d9..a63c2bd7de2b 100644 --- a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt +++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt @@ -23,27 +23,8 @@ are defined: - vendor-id : Contains the flash chip's vendor id (1 byte). - device-id : Contains the flash chip's device id (1 byte). -In addition to the information on the mtd bank itself, the -device tree may optionally contain additional information -describing partitions of the address space. This can be -used on platforms which have strong conventions about which -portions of a flash are used for what purposes, but which don't -use an on-flash partition table such as RedBoot. - -Each partition is represented as a sub-node of the mtd device. -Each node's name represents the name of the corresponding -partition of the mtd device. - -Flash partitions - - reg : The partition's offset and size within the mtd bank. - - label : (optional) The label / name for this partition. - If omitted, the label is taken from the node name (excluding - the unit address). - - read-only : (optional) This parameter, if present, is a hint to - Linux that this partition should only be mounted - read-only. This is usually used for flash partitions - containing early-boot firmware images or data which should not - be clobbered. +The device tree may optionally contain sub-nodes describing partitions of the +address space. See partition.txt for more detail. Example: diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt new file mode 100644 index 000000000000..03855c8c492a --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/nand.txt @@ -0,0 +1,7 @@ +* MTD generic binding + +- nand-ecc-mode : String, operation mode of the NAND ecc mode. + Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first", + "soft_bch". +- nand-bus-width : 8 or 16 bus width if not present 8 +- nand-on-flash-bbt: boolean to enable on flash bbt option if not present false diff --git a/Documentation/devicetree/bindings/mtd/partition.txt b/Documentation/devicetree/bindings/mtd/partition.txt new file mode 100644 index 000000000000..f114ce1657c2 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/partition.txt @@ -0,0 +1,38 @@ +Representing flash partitions in devicetree + +Partitions can be represented by sub-nodes of an mtd device. This can be used +on platforms which have strong conventions about which portions of a flash are +used for what purposes, but which don't use an on-flash partition table such +as RedBoot. + +#address-cells & #size-cells must both be present in the mtd device and be +equal to 1. + +Required properties: +- reg : The partition's offset and size within the mtd bank. + +Optional properties: +- label : The label / name for this partition. If omitted, the label is taken + from the node name (excluding the unit address). +- read-only : This parameter, if present, is a hint to Linux that this + partition should only be mounted read-only. This is usually used for flash + partitions containing early-boot firmware images or data which should not be + clobbered. + +Examples: + + +flash@0 { + #address-cells = <1>; + #size-cells = <1>; + + partition@0 { + label = "u-boot"; + reg = <0x0000000 0x100000>; + read-only; + }; + + uimage@100000 { + reg = <0x0100000 0x200000>; + }; +]; diff --git a/Documentation/devicetree/bindings/mtd/spear_smi.txt b/Documentation/devicetree/bindings/mtd/spear_smi.txt new file mode 100644 index 000000000000..7248aadd89e4 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/spear_smi.txt @@ -0,0 +1,31 @@ +* SPEAr SMI + +Required properties: +- compatible : "st,spear600-smi" +- reg : Address range of the mtd chip +- #address-cells, #size-cells : Must be present if the device has sub-nodes + representing partitions. +- interrupt-parent: Should be the phandle for the interrupt controller + that services interrupts for this device +- interrupts: Should contain the STMMAC interrupts +- clock-rate : Functional clock rate of SMI in Hz + +Optional properties: +- st,smi-fast-mode : Flash supports read in fast mode + +Example: + + smi: flash@fc000000 { + compatible = "st,spear600-smi"; + #address-cells = <1>; + #size-cells = <1>; + reg = <0xfc000000 0x1000>; + interrupt-parent = <&vic1>; + interrupts = <12>; + clock-rate = <50000000>; /* 50MHz */ + + flash@f8000000 { + st,smi-fast-mode; + ... + }; + }; diff --git a/Documentation/devicetree/bindings/power_supply/max17042_battery.txt b/Documentation/devicetree/bindings/power_supply/max17042_battery.txt new file mode 100644 index 000000000000..5bc9b685cf8a --- /dev/null +++ b/Documentation/devicetree/bindings/power_supply/max17042_battery.txt @@ -0,0 +1,18 @@ +max17042_battery +~~~~~~~~~~~~~~~~ + +Required properties : + - compatible : "maxim,max17042" + +Optional properties : + - maxim,rsns-microohm : Resistance of rsns resistor in micro Ohms + (datasheet-recommended value is 10000). + Defining this property enables current-sense functionality. + +Example: + + battery-charger@36 { + compatible = "maxim,max17042"; + reg = <0x36>; + maxim,rsns-microohm = <10000>; + }; diff --git a/Documentation/devicetree/bindings/regulator/anatop-regulator.txt b/Documentation/devicetree/bindings/regulator/anatop-regulator.txt new file mode 100644 index 000000000000..357758cb6e92 --- /dev/null +++ b/Documentation/devicetree/bindings/regulator/anatop-regulator.txt @@ -0,0 +1,29 @@ +Anatop Voltage regulators + +Required properties: +- compatible: Must be "fsl,anatop-regulator" +- anatop-reg-offset: Anatop MFD register offset +- anatop-vol-bit-shift: Bit shift for the register +- anatop-vol-bit-width: Number of bits used in the register +- anatop-min-bit-val: Minimum value of this register +- anatop-min-voltage: Minimum voltage of this regulator +- anatop-max-voltage: Maximum voltage of this regulator + +Any property defined as part of the core regulator +binding, defined in regulator.txt, can also be used. + +Example: + + regulator-vddpu { + compatible = "fsl,anatop-regulator"; + regulator-name = "vddpu"; + regulator-min-microvolt = <725000>; + regulator-max-microvolt = <1300000>; + regulator-always-on; + anatop-reg-offset = <0x140>; + anatop-vol-bit-shift = <9>; + anatop-vol-bit-width = <5>; + anatop-min-bit-val = <1>; + anatop-min-voltage = <725000>; + anatop-max-voltage = <1300000>; + }; diff --git a/Documentation/devicetree/bindings/usb/atmel-usb.txt b/Documentation/devicetree/bindings/usb/atmel-usb.txt new file mode 100644 index 000000000000..60bd2150a3e6 --- /dev/null +++ b/Documentation/devicetree/bindings/usb/atmel-usb.txt @@ -0,0 +1,49 @@ +Atmel SOC USB controllers + +OHCI + +Required properties: + - compatible: Should be "atmel,at91rm9200-ohci" for USB controllers + used in host mode. + - num-ports: Number of ports. + - atmel,vbus-gpio: If present, specifies a gpio that needs to be + activated for the bus to be powered. + - atmel,oc-gpio: If present, specifies a gpio that needs to be + activated for the overcurrent detection. + +usb0: ohci@00500000 { + compatible = "atmel,at91rm9200-ohci", "usb-ohci"; + reg = <0x00500000 0x100000>; + interrupts = <20 4>; + num-ports = <2>; +}; + +EHCI + +Required properties: + - compatible: Should be "atmel,at91sam9g45-ehci" for USB controllers + used in host mode. + +usb1: ehci@00800000 { + compatible = "atmel,at91sam9g45-ehci", "usb-ehci"; + reg = <0x00800000 0x100000>; + interrupts = <22 4>; +}; + +AT91 USB device controller + +Required properties: + - compatible: Should be "atmel,at91rm9200-udc" + - reg: Address and length of the register set for the device + - interrupts: Should contain macb interrupt + +Optional properties: + - atmel,vbus-gpio: If present, specifies a gpio that needs to be + activated for the bus to be powered. + +usb1: gadget@fffa4000 { + compatible = "atmel,at91rm9200-udc"; + reg = <0xfffa4000 0x4000>; + interrupts = <10 4>; + atmel,vbus-gpio = <&pioC 5 0>; +}; diff --git a/Documentation/devicetree/bindings/usb/tegra-usb.txt b/Documentation/devicetree/bindings/usb/tegra-usb.txt index 035d63d5646d..007005ddbe12 100644 --- a/Documentation/devicetree/bindings/usb/tegra-usb.txt +++ b/Documentation/devicetree/bindings/usb/tegra-usb.txt @@ -11,3 +11,16 @@ Required properties : - phy_type : Should be one of "ulpi" or "utmi". - nvidia,vbus-gpio : If present, specifies a gpio that needs to be activated for the bus to be powered. + +Optional properties: + - dr_mode : dual role mode. Indicates the working mode for + nvidia,tegra20-ehci compatible controllers. Can be "host", "peripheral", + or "otg". Default to "host" if not defined for backward compatibility. + host means this is a host controller + peripheral means it is device controller + otg means it can operate as either ("on the go") + - nvidia,has-legacy-mode : boolean indicates whether this controller can + operate in legacy mode (as APX 2500 / 2600). In legacy mode some + registers are accessed through the APB_MISC base address instead of + the USB controller. Since this is a legacy issue it probably does not + warrant a compatible string of its own. diff --git a/Documentation/devicetree/usage-model.txt b/Documentation/devicetree/usage-model.txt new file mode 100644 index 000000000000..c5a80099b71c --- /dev/null +++ b/Documentation/devicetree/usage-model.txt @@ -0,0 +1,412 @@ +Linux and the Device Tree +------------------------- +The Linux usage model for device tree data + +Author: Grant Likely <grant.likely@secretlab.ca> + +This article describes how Linux uses the device tree. An overview of +the device tree data format can be found on the device tree usage page +at devicetree.org[1]. + +[1] http://devicetree.org/Device_Tree_Usage + +The "Open Firmware Device Tree", or simply Device Tree (DT), is a data +structure and language for describing hardware. More specifically, it +is a description of hardware that is readable by an operating system +so that the operating system doesn't need to hard code details of the +machine. + +Structurally, the DT is a tree, or acyclic graph with named nodes, and +nodes may have an arbitrary number of named properties encapsulating +arbitrary data. A mechanism also exists to create arbitrary +links from one node to another outside of the natural tree structure. + +Conceptually, a common set of usage conventions, called 'bindings', +is defined for how data should appear in the tree to describe typical +hardware characteristics including data busses, interrupt lines, GPIO +connections, and peripheral devices. + +As much as possible, hardware is described using existing bindings to +maximize use of existing support code, but since property and node +names are simply text strings, it is easy to extend existing bindings +or create new ones by defining new nodes and properties. Be wary, +however, of creating a new binding without first doing some homework +about what already exists. There are currently two different, +incompatible, bindings for i2c busses that came about because the new +binding was created without first investigating how i2c devices were +already being enumerated in existing systems. + +1. History +---------- +The DT was originally created by Open Firmware as part of the +communication method for passing data from Open Firmware to a client +program (like to an operating system). An operating system used the +Device Tree to discover the topology of the hardware at runtime, and +thereby support a majority of available hardware without hard coded +information (assuming drivers were available for all devices). + +Since Open Firmware is commonly used on PowerPC and SPARC platforms, +the Linux support for those architectures has for a long time used the +Device Tree. + +In 2005, when PowerPC Linux began a major cleanup and to merge 32-bit +and 64-bit support, the decision was made to require DT support on all +powerpc platforms, regardless of whether or not they used Open +Firmware. To do this, a DT representation called the Flattened Device +Tree (FDT) was created which could be passed to the kernel as a binary +blob without requiring a real Open Firmware implementation. U-Boot, +kexec, and other bootloaders were modified to support both passing a +Device Tree Binary (dtb) and to modify a dtb at boot time. DT was +also added to the PowerPC boot wrapper (arch/powerpc/boot/*) so that +a dtb could be wrapped up with the kernel image to support booting +existing non-DT aware firmware. + +Some time later, FDT infrastructure was generalized to be usable by +all architectures. At the time of this writing, 6 mainlined +architectures (arm, microblaze, mips, powerpc, sparc, and x86) and 1 +out of mainline (nios) have some level of DT support. + +2. Data Model +------------- +If you haven't already read the Device Tree Usage[1] page, +then go read it now. It's okay, I'll wait.... + +2.1 High Level View +------------------- +The most important thing to understand is that the DT is simply a data +structure that describes the hardware. There is nothing magical about +it, and it doesn't magically make all hardware configuration problems +go away. What it does do is provide a language for decoupling the +hardware configuration from the board and device driver support in the +Linux kernel (or any other operating system for that matter). Using +it allows board and device support to become data driven; to make +setup decisions based on data passed into the kernel instead of on +per-machine hard coded selections. + +Ideally, data driven platform setup should result in less code +duplication and make it easier to support a wide range of hardware +with a single kernel image. + +Linux uses DT data for three major purposes: +1) platform identification, +2) runtime configuration, and +3) device population. + +2.2 Platform Identification +--------------------------- +First and foremost, the kernel will use data in the DT to identify the +specific machine. In a perfect world, the specific platform shouldn't +matter to the kernel because all platform details would be described +perfectly by the device tree in a consistent and reliable manner. +Hardware is not perfect though, and so the kernel must identify the +machine during early boot so that it has the opportunity to run +machine-specific fixups. + +In the majority of cases, the machine identity is irrelevant, and the +kernel will instead select setup code based on the machine's core +CPU or SoC. On ARM for example, setup_arch() in +arch/arm/kernel/setup.c will call setup_machine_fdt() in +arch/arm/kernel/devicetree.c which searches through the machine_desc +table and selects the machine_desc which best matches the device tree +data. It determines the best match by looking at the 'compatible' +property in the root device tree node, and comparing it with the +dt_compat list in struct machine_desc. + +The 'compatible' property contains a sorted list of strings starting +with the exact name of the machine, followed by an optional list of +boards it is compatible with sorted from most compatible to least. For +example, the root compatible properties for the TI BeagleBoard and its +successor, the BeagleBoard xM board might look like: + + compatible = "ti,omap3-beagleboard", "ti,omap3450", "ti,omap3"; + compatible = "ti,omap3-beagleboard-xm", "ti,omap3450", "ti,omap3"; + +Where "ti,omap3-beagleboard-xm" specifies the exact model, it also +claims that it compatible with the OMAP 3450 SoC, and the omap3 family +of SoCs in general. You'll notice that the list is sorted from most +specific (exact board) to least specific (SoC family). + +Astute readers might point out that the Beagle xM could also claim +compatibility with the original Beagle board. However, one should be +cautioned about doing so at the board level since there is typically a +high level of change from one board to another, even within the same +product line, and it is hard to nail down exactly what is meant when one +board claims to be compatible with another. For the top level, it is +better to err on the side of caution and not claim one board is +compatible with another. The notable exception would be when one +board is a carrier for another, such as a CPU module attached to a +carrier board. + +One more note on compatible values. Any string used in a compatible +property must be documented as to what it indicates. Add +documentation for compatible strings in Documentation/devicetree/bindings. + +Again on ARM, for each machine_desc, the kernel looks to see if +any of the dt_compat list entries appear in the compatible property. +If one does, then that machine_desc is a candidate for driving the +machine. After searching the entire table of machine_descs, +setup_machine_fdt() returns the 'most compatible' machine_desc based +on which entry in the compatible property each machine_desc matches +against. If no matching machine_desc is found, then it returns NULL. + +The reasoning behind this scheme is the observation that in the majority +of cases, a single machine_desc can support a large number of boards +if they all use the same SoC, or same family of SoCs. However, +invariably there will be some exceptions where a specific board will +require special setup code that is not useful in the generic case. +Special cases could be handled by explicitly checking for the +troublesome board(s) in generic setup code, but doing so very quickly +becomes ugly and/or unmaintainable if it is more than just a couple of +cases. + +Instead, the compatible list allows a generic machine_desc to provide +support for a wide common set of boards by specifying "less +compatible" value in the dt_compat list. In the example above, +generic board support can claim compatibility with "ti,omap3" or +"ti,omap3450". If a bug was discovered on the original beagleboard +that required special workaround code during early boot, then a new +machine_desc could be added which implements the workarounds and only +matches on "ti,omap3-beagleboard". + +PowerPC uses a slightly different scheme where it calls the .probe() +hook from each machine_desc, and the first one returning TRUE is used. +However, this approach does not take into account the priority of the +compatible list, and probably should be avoided for new architecture +support. + +2.3 Runtime configuration +------------------------- +In most cases, a DT will be the sole method of communicating data from +firmware to the kernel, so also gets used to pass in runtime and +configuration data like the kernel parameters string and the location +of an initrd image. + +Most of this data is contained in the /chosen node, and when booting +Linux it will look something like this: + + chosen { + bootargs = "console=ttyS0,115200 loglevel=8"; + initrd-start = <0xc8000000>; + initrd-end = <0xc8200000>; + }; + +The bootargs property contains the kernel arguments, and the initrd-* +properties define the address and size of an initrd blob. The +chosen node may also optionally contain an arbitrary number of +additional properties for platform-specific configuration data. + +During early boot, the architecture setup code calls of_scan_flat_dt() +several times with different helper callbacks to parse device tree +data before paging is setup. The of_scan_flat_dt() code scans through +the device tree and uses the helpers to extract information required +during early boot. Typically the early_init_dt_scan_chosen() helper +is used to parse the chosen node including kernel parameters, +early_init_dt_scan_root() to initialize the DT address space model, +and early_init_dt_scan_memory() to determine the size and +location of usable RAM. + +On ARM, the function setup_machine_fdt() is responsible for early +scanning of the device tree after selecting the correct machine_desc +that supports the board. + +2.4 Device population +--------------------- +After the board has been identified, and after the early configuration data +has been parsed, then kernel initialization can proceed in the normal +way. At some point in this process, unflatten_device_tree() is called +to convert the data into a more efficient runtime representation. +This is also when machine-specific setup hooks will get called, like +the machine_desc .init_early(), .init_irq() and .init_machine() hooks +on ARM. The remainder of this section uses examples from the ARM +implementation, but all architectures will do pretty much the same +thing when using a DT. + +As can be guessed by the names, .init_early() is used for any machine- +specific setup that needs to be executed early in the boot process, +and .init_irq() is used to set up interrupt handling. Using a DT +doesn't materially change the behaviour of either of these functions. +If a DT is provided, then both .init_early() and .init_irq() are able +to call any of the DT query functions (of_* in include/linux/of*.h) to +get additional data about the platform. + +The most interesting hook in the DT context is .init_machine() which +is primarily responsible for populating the Linux device model with +data about the platform. Historically this has been implemented on +embedded platforms by defining a set of static clock structures, +platform_devices, and other data in the board support .c file, and +registering it en-masse in .init_machine(). When DT is used, then +instead of hard coding static devices for each platform, the list of +devices can be obtained by parsing the DT, and allocating device +structures dynamically. + +The simplest case is when .init_machine() is only responsible for +registering a block of platform_devices. A platform_device is a concept +used by Linux for memory or I/O mapped devices which cannot be detected +by hardware, and for 'composite' or 'virtual' devices (more on those +later). While there is no 'platform device' terminology for the DT, +platform devices roughly correspond to device nodes at the root of the +tree and children of simple memory mapped bus nodes. + +About now is a good time to lay out an example. Here is part of the +device tree for the NVIDIA Tegra board. + +/{ + compatible = "nvidia,harmony", "nvidia,tegra20"; + #address-cells = <1>; + #size-cells = <1>; + interrupt-parent = <&intc>; + + chosen { }; + aliases { }; + + memory { + device_type = "memory"; + reg = <0x00000000 0x40000000>; + }; + + soc { + compatible = "nvidia,tegra20-soc", "simple-bus"; + #address-cells = <1>; + #size-cells = <1>; + ranges; + + intc: interrupt-controller@50041000 { + compatible = "nvidia,tegra20-gic"; + interrupt-controller; + #interrupt-cells = <1>; + reg = <0x50041000 0x1000>, < 0x50040100 0x0100 >; + }; + + serial@70006300 { + compatible = "nvidia,tegra20-uart"; + reg = <0x70006300 0x100>; + interrupts = <122>; + }; + + i2s1: i2s@70002800 { + compatible = "nvidia,tegra20-i2s"; + reg = <0x70002800 0x100>; + interrupts = <77>; + codec = <&wm8903>; + }; + + i2c@7000c000 { + compatible = "nvidia,tegra20-i2c"; + #address-cells = <1>; + #size-cells = <0>; + reg = <0x7000c000 0x100>; + interrupts = <70>; + + wm8903: codec@1a { + compatible = "wlf,wm8903"; + reg = <0x1a>; + interrupts = <347>; + }; + }; + }; + + sound { + compatible = "nvidia,harmony-sound"; + i2s-controller = <&i2s1>; + i2s-codec = <&wm8903>; + }; +}; + +At .machine_init() time, Tegra board support code will need to look at +this DT and decide which nodes to create platform_devices for. +However, looking at the tree, it is not immediately obvious what kind +of device each node represents, or even if a node represents a device +at all. The /chosen, /aliases, and /memory nodes are informational +nodes that don't describe devices (although arguably memory could be +considered a device). The children of the /soc node are memory mapped +devices, but the codec@1a is an i2c device, and the sound node +represents not a device, but rather how other devices are connected +together to create the audio subsystem. I know what each device is +because I'm familiar with the board design, but how does the kernel +know what to do with each node? + +The trick is that the kernel starts at the root of the tree and looks +for nodes that have a 'compatible' property. First, it is generally +assumed that any node with a 'compatible' property represents a device +of some kind, and second, it can be assumed that any node at the root +of the tree is either directly attached to the processor bus, or is a +miscellaneous system device that cannot be described any other way. +For each of these nodes, Linux allocates and registers a +platform_device, which in turn may get bound to a platform_driver. + +Why is using a platform_device for these nodes a safe assumption? +Well, for the way that Linux models devices, just about all bus_types +assume that its devices are children of a bus controller. For +example, each i2c_client is a child of an i2c_master. Each spi_device +is a child of an SPI bus. Similarly for USB, PCI, MDIO, etc. The +same hierarchy is also found in the DT, where I2C device nodes only +ever appear as children of an I2C bus node. Ditto for SPI, MDIO, USB, +etc. The only devices which do not require a specific type of parent +device are platform_devices (and amba_devices, but more on that +later), which will happily live at the base of the Linux /sys/devices +tree. Therefore, if a DT node is at the root of the tree, then it +really probably is best registered as a platform_device. + +Linux board support code calls of_platform_populate(NULL, NULL, NULL) +to kick off discovery of devices at the root of the tree. The +parameters are all NULL because when starting from the root of the +tree, there is no need to provide a starting node (the first NULL), a +parent struct device (the last NULL), and we're not using a match +table (yet). For a board that only needs to register devices, +.init_machine() can be completely empty except for the +of_platform_populate() call. + +In the Tegra example, this accounts for the /soc and /sound nodes, but +what about the children of the SoC node? Shouldn't they be registered +as platform devices too? For Linux DT support, the generic behaviour +is for child devices to be registered by the parent's device driver at +driver .probe() time. So, an i2c bus device driver will register a +i2c_client for each child node, an SPI bus driver will register +its spi_device children, and similarly for other bus_types. +According to that model, a driver could be written that binds to the +SoC node and simply registers platform_devices for each of its +children. The board support code would allocate and register an SoC +device, a (theoretical) SoC device driver could bind to the SoC device, +and register platform_devices for /soc/interrupt-controller, /soc/serial, +/soc/i2s, and /soc/i2c in its .probe() hook. Easy, right? + +Actually, it turns out that registering children of some +platform_devices as more platform_devices is a common pattern, and the +device tree support code reflects that and makes the above example +simpler. The second argument to of_platform_populate() is an +of_device_id table, and any node that matches an entry in that table +will also get its child nodes registered. In the tegra case, the code +can look something like this: + +static void __init harmony_init_machine(void) +{ + /* ... */ + of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); +} + +"simple-bus" is defined in the ePAPR 1.0 specification as a property +meaning a simple memory mapped bus, so the of_platform_populate() code +could be written to just assume simple-bus compatible nodes will +always be traversed. However, we pass it in as an argument so that +board support code can always override the default behaviour. + +[Need to add discussion of adding i2c/spi/etc child devices] + +Appendix A: AMBA devices +------------------------ + +ARM Primecells are a certain kind of device attached to the ARM AMBA +bus which include some support for hardware detection and power +management. In Linux, struct amba_device and the amba_bus_type is +used to represent Primecell devices. However, the fiddly bit is that +not all devices on an AMBA bus are Primecells, and for Linux it is +typical for both amba_device and platform_device instances to be +siblings of the same bus segment. + +When using the DT, this creates problems for of_platform_populate() +because it must decide whether to register each node as either a +platform_device or an amba_device. This unfortunately complicates the +device creation model a little bit, but the solution turns out not to +be too invasive. If a node is compatible with "arm,amba-primecell", then +of_platform_populate() will register it as an amba_device instead of a +platform_device. |