[PATCH] powerpc/5200: update device tree binding documentation
Grant Likely
grant.likely at secretlab.ca
Fri Jan 30 10:59:21 EST 2009
From: Grant Likely <grant.likely at secretlab.ca>
This patch updates the mpc5200 binding documentation to match
actual usage conventions, to remove incorrect information, and
to remove topics which are more thoroughly described elsewhere.
Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
CC: devicetree-discuss at ozlabs.org
CC: Wolfram Sang <w.sang at pengutronix.de>
---
Documentation/powerpc/dts-bindings/fsl/mpc5200.txt | 180 +++++++++++++
.../powerpc/mpc52xx-device-tree-bindings.txt | 277 --------------------
2 files changed, 180 insertions(+), 277 deletions(-)
create mode 100644 Documentation/powerpc/dts-bindings/fsl/mpc5200.txt
delete mode 100644 Documentation/powerpc/mpc52xx-device-tree-bindings.txt
diff --git a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt
new file mode 100644
index 0000000..b8b09d3
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt
@@ -0,0 +1,180 @@
+MPC5200 Device Tree Bindings
+----------------------------
+
+(c) 2006-2009 Secret Lab Technologies Ltd
+Grant Likely <grant.likely at secretlab.ca>
+
+Naming conventions
+------------------
+For mpc5200 on-chip devices, the format for each compatible value is
+<chip>-<device>[-<mode>]. The OS should be able to match a device driver
+to the device based solely on the compatible value. If two drivers
+match on the compatible list; the 'most compatible' driver should be
+selected.
+
+The split between the MPC5200 and the MPC5200B leaves a bit of a
+conundrum. How should the compatible property be set up to provide
+maximum compatibility information; but still accurately describe the
+chip? For the MPC5200; the answer is easy. Most of the SoC devices
+originally appeared on the MPC5200. Since they didn't exist anywhere
+else; the 5200 compatible properties will contain only one item;
+"fsl,mpc5200-<device>".
+
+The 5200B is almost the same as the 5200, but not quite. It fixes
+silicon bugs and it adds a small number of enhancements. Most of the
+devices either provide exactly the same interface as on the 5200. A few
+devices have extra functions but still have a backwards compatible mode.
+To express this information as completely as possible, 5200B device trees
+should have two items in the compatible list:
+ compatible = "fsl,mpc5200b-<device>","fsl,mpc5200-<device>";
+
+It is *strongly* recommended that 5200B device trees follow this convention
+(instead of only listing the base mpc5200 item).
+
+ie. ethernet on mpc5200: compatible = "fsl,mpc5200-fec";
+ ethernet on mpc5200b: compatible = "fsl,mpc5200b-fec", "fsl,mpc5200-fec";
+
+Modal devices, like PSCs, also append the configured function to the
+end of the compatible field. ie. A PSC in i2s mode would specify
+"fsl,mpc5200-psc-i2s", not "fsl,mpc5200-i2s". This convention is chosen to
+avoid naming conflicts with non-psc devices providing the same
+function. For example, "fsl,mpc5200-spi" and "fsl,mpc5200-psc-spi" describe
+the mpc5200 simple spi device and a PSC spi mode respectively.
+
+At the time of writing, exact chip may be either 'fsl,mpc5200' or
+'fsl,mpc5200b'.
+
+The soc node
+------------
+This node describes the on chip SOC peripherals. Every mpc5200 based
+board will have this node, and as such there is a common naming
+convention for SOC devices.
+
+Required properties:
+name description
+---- -----------
+ranges Memory range of the internal memory mapped registers.
+ Should be <0 [baseaddr] 0xc000>
+reg Should be <[baseaddr] 0x100>
+compatible mpc5200: "fsl,mpc5200-immr"
+ mpc5200b: "fsl,mpc5200b-immr"
+system-frequency 'fsystem' frequency in Hz; XLB, IPB, USB and PCI
+ clocks are derived from the fsystem clock.
+bus-frequency IPB bus frequency in HZ. Clock rate
+ used by most of the soc devices.
+
+soc child nodes
+---------------
+Any on chip SOC devices available to Linux must appear as soc5200 child nodes.
+
+Note: The tables below show the value for the mpc5200. A mpc5200b device
+tree should use the "fsl,mpc5200b-<device>","fsl,mpc5200-<device>" form.
+
+Required soc5200 child nodes:
+name compatible Description
+---- ---------- -----------
+cdm@<addr> fsl,mpc5200-cdm Clock Distribution
+interrupt-controller@<addr> fsl,mpc5200-pic need an interrupt
+ controller to boot
+bestcomm@<addr> fsl,mpc5200-bestcomm Bestcomm DMA controller
+
+Recommended soc5200 child nodes; populate as needed for your board
+name compatible Description
+---- ---------- -----------
+timer@<addr> fsl,mpc5200-gpt General purpose timers
+gpio@<addr> fsl,mpc5200-gpio MPC5200 simple gpio controller
+gpio@<addr> fsl,mpc5200-gpio-wkup MPC5200 wakeup gpio controller
+rtc@<addr> fsl,mpc5200-rtc Real time clock
+mscan@<addr> fsl,mpc5200-mscan CAN bus controller
+pci@<addr> fsl,mpc5200-pci PCI bridge
+serial@<addr> fsl,mpc5200-psc-uart PSC in serial mode
+i2s@<addr> fsl,mpc5200-psc-i2s PSC in i2s mode
+ac97@<addr> fsl,mpc5200-psc-ac97 PSC in ac97 mode
+spi@<addr> fsl,mpc5200-psc-spi PSC in spi mode
+irda@<addr> fsl,mpc5200-psc-irda PSC in IrDA mode
+spi@<addr> fsl,mpc5200-spi MPC5200 spi device
+ethernet@<addr> fsl,mpc5200-fec MPC5200 ethernet device
+ata@<addr> fsl,mpc5200-ata IDE ATA interface
+i2c@<addr> fsl,mpc5200-i2c I2C controller
+usb@<addr> fsl,mpc5200-ohci,ohci-be USB controller
+xlb@<addr> fsl,mpc5200-xlb XLB arbitrator
+
+fsl,mpc5200-gpt nodes
+---------------------
+On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board
+design supports the internal wdt, then the device node for GPT0 should
+include the empty property 'fsl,has-wdt'.
+
+An mpc5200-gpt can be used as a single line GPIO controller. To do so,
+add the following properties to the gpt node:
+ gpio-controller;
+ #gpio-cells = <2>;
+When referencing the GPIO line from another node, the first cell must always
+be zero and the second cell represents the gpio flags and described in the
+gpio device tree binding.
+
+An mpc5200-gpt can be used as a single line edge sensitive interrupt
+controller. To do so, add the following properties to the gpt node:
+ interrupt-controller;
+ #interrupt-cells = <1>;
+When referencing the IRQ line from another node, the cell represents the
+sense mode; 1 for edge rising, 2 for edge falling.
+
+fsl,mpc5200-psc nodes
+---------------------
+The PSCs should include a cell-index which is the index of the PSC in
+hardware. cell-index is used to determine which shared SoC registers to
+use when setting up PSC clocking. cell-index number starts at '0'. ie:
+ PSC1 has 'cell-index = <0>'
+ PSC4 has 'cell-index = <3>'
+
+PSC in i2s mode: The mpc5200 and mpc5200b PSCs are not compatible when in
+i2s mode. An 'mpc5200b-psc-i2s' node cannot include 'mpc5200-psc-i2s' in the
+compatible field.
+
+
+fsl,mpc5200-gpio and fsl,mpc5200-gpio-wkup nodes
+------------------------------------------------
+Each GPIO controller node should have the empty property gpio-controller and
+#gpio-cells set to 2. First cell is the GPIO number which is interpreted
+according to the bit numbers in the GPIO control registers. The second cell
+is for flags which is currently unused.
+
+fsl,mpc5200-fec nodes
+---------------------
+The FEC node can specify one of the following properties to configure
+the MII link:
+- fsl,7-wire-mode - An empty property that specifies the link uses 7-wire
+ mode instead of MII
+- current-speed - Specifies that the MII should be configured for a fixed
+ speed. This property should contain two cells. The
+ first cell specifies the speed in Mbps and the second
+ should be '0' for half duplex and '1' for full duplex
+- phy-handle - Contains a phandle to an Ethernet PHY.
+
+Interrupt controller (fsl,mpc5200-pic) node
+-------------------------------------------
+The mpc5200 pic binding splits hardware IRQ numbers into two levels. The
+split reflects the layout of the PIC hardware itself, which groups
+interrupts into one of three groups; CRIT, MAIN or PERP. Also, the
+Bestcomm dma engine has it's own set of interrupt sources which are
+cascaded off of peripheral interrupt 0, which the driver interprets as a
+fourth group, SDMA.
+
+The interrupts property for device nodes using the mpc5200 pic consists
+of three cells; <L1 L2 level>
+
+ L1 := [CRIT=0, MAIN=1, PERP=2, SDMA=3]
+ L2 := interrupt number; directly mapped from the value in the
+ "ICTL PerStat, MainStat, CritStat Encoded Register"
+ level := [LEVEL_HIGH=0, EDGE_RISING=1, EDGE_FALLING=2, LEVEL_LOW=3]
+
+For external IRQs, use the following interrupt property values (how to
+specify external interrupts is a frequently asked question):
+External interrupts:
+ external irq0: interrupts = <0 0 n>;
+ external irq1: interrupts = <1 1 n>;
+ external irq2: interrupts = <1 2 n>;
+ external irq3: interrupts = <1 3 n>;
+'n' is sense (0: level high, 1: edge rising, 2: edge falling 3: level low)
+
diff --git a/Documentation/powerpc/mpc52xx-device-tree-bindings.txt b/Documentation/powerpc/mpc52xx-device-tree-bindings.txt
deleted file mode 100644
index 6f12f1c..0000000
--- a/Documentation/powerpc/mpc52xx-device-tree-bindings.txt
+++ /dev/null
@@ -1,277 +0,0 @@
-MPC5200 Device Tree Bindings
-----------------------------
-
-(c) 2006-2007 Secret Lab Technologies Ltd
-Grant Likely <grant.likely at secretlab.ca>
-
-********** DRAFT ***********
-* WARNING: Do not depend on the stability of these bindings just yet.
-* The MPC5200 device tree conventions are still in flux
-* Keep an eye on the linuxppc-dev mailing list for more details
-********** DRAFT ***********
-
-I - Introduction
-================
-Boards supported by the arch/powerpc architecture require device tree be
-passed by the boot loader to the kernel at boot time. The device tree
-describes what devices are present on the board and how they are
-connected. The device tree can either be passed as a binary blob (as
-described in Documentation/powerpc/booting-without-of.txt), or passed
-by Open Firmware (IEEE 1275) compatible firmware using an OF compatible
-client interface API.
-
-This document specifies the requirements on the device-tree for mpc5200
-based boards. These requirements are above and beyond the details
-specified in either the Open Firmware spec or booting-without-of.txt
-
-All new mpc5200-based boards are expected to match this document. In
-cases where this document is not sufficient to support a new board port,
-this document should be updated as part of adding the new board support.
-
-II - Philosophy
-===============
-The core of this document is naming convention. The whole point of
-defining this convention is to reduce or eliminate the number of
-special cases required to support a 5200 board. If all 5200 boards
-follow the same convention, then generic 5200 support code will work
-rather than coding special cases for each new board.
-
-This section tries to capture the thought process behind why the naming
-convention is what it is.
-
-1. names
----------
-There is strong convention/requirements already established for children
-of the root node. 'cpus' describes the processor cores, 'memory'
-describes memory, and 'chosen' provides boot configuration. Other nodes
-are added to describe devices attached to the processor local bus.
-
-Following convention already established with other system-on-chip
-processors, 5200 device trees should use the name 'soc5200' for the
-parent node of on chip devices, and the root node should be its parent.
-
-Child nodes are typically named after the configured function. ie.
-the FEC node is named 'ethernet', and a PSC in uart mode is named 'serial'.
-
-2. device_type property
------------------------
-similar to the node name convention above; the device_type reflects the
-configured function of a device. ie. 'serial' for a uart and 'spi' for
-an spi controller. However, while node names *should* reflect the
-configured function, device_type *must* match the configured function
-exactly.
-
-3. compatible property
-----------------------
-Since device_type isn't enough to match devices to drivers, there also
-needs to be a naming convention for the compatible property. Compatible
-is an list of device descriptions sorted from specific to generic. For
-the mpc5200, the required format for each compatible value is
-<chip>-<device>[-<mode>]. The OS should be able to match a device driver
-to the device based solely on the compatible value. If two drivers
-match on the compatible list; the 'most compatible' driver should be
-selected.
-
-The split between the MPC5200 and the MPC5200B leaves a bit of a
-conundrum. How should the compatible property be set up to provide
-maximum compatibility information; but still accurately describe the
-chip? For the MPC5200; the answer is easy. Most of the SoC devices
-originally appeared on the MPC5200. Since they didn't exist anywhere
-else; the 5200 compatible properties will contain only one item;
-"mpc5200-<device>".
-
-The 5200B is almost the same as the 5200, but not quite. It fixes
-silicon bugs and it adds a small number of enhancements. Most of the
-devices either provide exactly the same interface as on the 5200. A few
-devices have extra functions but still have a backwards compatible mode.
-To express this information as completely as possible, 5200B device trees
-should have two items in the compatible list;
-"mpc5200b-<device>\0mpc5200-<device>". It is *strongly* recommended
-that 5200B device trees follow this convention (instead of only listing
-the base mpc5200 item).
-
-If another chip appear on the market with one of the mpc5200 SoC
-devices, then the compatible list should include mpc5200-<device>.
-
-ie. ethernet on mpc5200: compatible = "mpc5200-ethernet"
- ethernet on mpc5200b: compatible = "mpc5200b-ethernet\0mpc5200-ethernet"
-
-Modal devices, like PSCs, also append the configured function to the
-end of the compatible field. ie. A PSC in i2s mode would specify
-"mpc5200-psc-i2s", not "mpc5200-i2s". This convention is chosen to
-avoid naming conflicts with non-psc devices providing the same
-function. For example, "mpc5200-spi" and "mpc5200-psc-spi" describe
-the mpc5200 simple spi device and a PSC spi mode respectively.
-
-If the soc device is more generic and present on other SOCs, the
-compatible property can specify the more generic device type also.
-
-ie. mscan: compatible = "mpc5200-mscan\0fsl,mscan";
-
-At the time of writing, exact chip may be either 'mpc5200' or
-'mpc5200b'.
-
-Device drivers should always try to match as generically as possible.
-
-III - Structure
-===============
-The device tree for an mpc5200 board follows the structure defined in
-booting-without-of.txt with the following additional notes:
-
-0) the root node
-----------------
-Typical root description node; see booting-without-of
-
-1) The cpus node
-----------------
-The cpus node follows the basic layout described in booting-without-of.
-The bus-frequency property holds the XLB bus frequency
-The clock-frequency property holds the core frequency
-
-2) The memory node
-------------------
-Typical memory description node; see booting-without-of.
-
-3) The soc5200 node
--------------------
-This node describes the on chip SOC peripherals. Every mpc5200 based
-board will have this node, and as such there is a common naming
-convention for SOC devices.
-
-Required properties:
-name type description
----- ---- -----------
-device_type string must be "soc"
-ranges int should be <0 baseaddr baseaddr+10000>
-reg int must be <baseaddr 10000>
-compatible string mpc5200: "mpc5200-soc"
- mpc5200b: "mpc5200b-soc\0mpc5200-soc"
-system-frequency int Fsystem frequency; source of all
- other clocks.
-bus-frequency int IPB bus frequency in HZ. Clock rate
- used by most of the soc devices.
-#interrupt-cells int must be <3>.
-
-Recommended properties:
-name type description
----- ---- -----------
-model string Exact model of the chip;
- ie: model="fsl,mpc5200"
-revision string Silicon revision of chip
- ie: revision="M08A"
-
-The 'model' and 'revision' properties are *strongly* recommended. Having
-them presence acts as a bit of a safety net for working around as yet
-undiscovered bugs on one version of silicon. For example, device drivers
-can use the model and revision properties to decide if a bug fix should
-be turned on.
-
-4) soc5200 child nodes
-----------------------
-Any on chip SOC devices available to Linux must appear as soc5200 child nodes.
-
-Note: The tables below show the value for the mpc5200. A mpc5200b device
-tree should use the "mpc5200b-<device>\0mpc5200-<device> form.
-
-Required soc5200 child nodes:
-name device_type compatible Description
----- ----------- ---------- -----------
-cdm@<addr> cdm mpc5200-cmd Clock Distribution
-pic@<addr> interrupt-controller mpc5200-pic need an interrupt
- controller to boot
-bestcomm@<addr> dma-controller mpc5200-bestcomm 5200 pic also requires
- the bestcomm device
-
-Recommended soc5200 child nodes; populate as needed for your board
-name device_type compatible Description
----- ----------- ---------- -----------
-gpt@<addr> gpt fsl,mpc5200-gpt General purpose timers
-gpt@<addr> gpt fsl,mpc5200-gpt-gpio General purpose
- timers in GPIO mode
-gpio@<addr> fsl,mpc5200-gpio MPC5200 simple gpio
- controller
-gpio@<addr> fsl,mpc5200-gpio-wkup MPC5200 wakeup gpio
- controller
-rtc@<addr> rtc mpc5200-rtc Real time clock
-mscan@<addr> mscan mpc5200-mscan CAN bus controller
-pci@<addr> pci mpc5200-pci PCI bridge
-serial@<addr> serial mpc5200-psc-uart PSC in serial mode
-i2s@<addr> sound mpc5200-psc-i2s PSC in i2s mode
-ac97@<addr> sound mpc5200-psc-ac97 PSC in ac97 mode
-spi@<addr> spi mpc5200-psc-spi PSC in spi mode
-irda@<addr> irda mpc5200-psc-irda PSC in IrDA mode
-spi@<addr> spi mpc5200-spi MPC5200 spi device
-ethernet@<addr> network mpc5200-fec MPC5200 ethernet device
-ata@<addr> ata mpc5200-ata IDE ATA interface
-i2c@<addr> i2c mpc5200-i2c I2C controller
-usb@<addr> usb-ohci-be mpc5200-ohci,ohci-be USB controller
-xlb@<addr> xlb mpc5200-xlb XLB arbitrator
-
-Important child node properties
-name type description
----- ---- -----------
-cell-index int When multiple devices are present, is the
- index of the device in the hardware (ie. There
- are 6 PSC on the 5200 numbered PSC1 to PSC6)
- PSC1 has 'cell-index = <0>'
- PSC4 has 'cell-index = <3>'
-
-5) General Purpose Timer nodes (child of soc5200 node)
-On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board
-design supports the internal wdt, then the device node for GPT0 should
-include the empty property 'fsl,has-wdt'.
-
-6) PSC nodes (child of soc5200 node)
-PSC nodes can define the optional 'port-number' property to force assignment
-order of serial ports. For example, PSC5 might be physically connected to
-the port labeled 'COM1' and PSC1 wired to 'COM1'. In this case, PSC5 would
-have a "port-number = <0>" property, and PSC1 would have "port-number = <1>".
-
-PSC in i2s mode: The mpc5200 and mpc5200b PSCs are not compatible when in
-i2s mode. An 'mpc5200b-psc-i2s' node cannot include 'mpc5200-psc-i2s' in the
-compatible field.
-
-7) GPIO controller nodes
-Each GPIO controller node should have the empty property gpio-controller and
-#gpio-cells set to 2. First cell is the GPIO number which is interpreted
-according to the bit numbers in the GPIO control registers. The second cell
-is for flags which is currently unsused.
-
-8) FEC nodes
-The FEC node can specify one of the following properties to configure
-the MII link:
-"fsl,7-wire-mode" - An empty property that specifies the link uses 7-wire
- mode instead of MII
-"current-speed" - Specifies that the MII should be configured for a fixed
- speed. This property should contain two cells. The
- first cell specifies the speed in Mbps and the second
- should be '0' for half duplex and '1' for full duplex
-"phy-handle" - Contains a phandle to an Ethernet PHY.
-
-IV - Extra Notes
-================
-
-1. Interrupt mapping
---------------------
-The mpc5200 pic driver splits hardware IRQ numbers into two levels. The
-split reflects the layout of the PIC hardware itself, which groups
-interrupts into one of three groups; CRIT, MAIN or PERP. Also, the
-Bestcomm dma engine has it's own set of interrupt sources which are
-cascaded off of peripheral interrupt 0, which the driver interprets as a
-fourth group, SDMA.
-
-The interrupts property for device nodes using the mpc5200 pic consists
-of three cells; <L1 L2 level>
-
- L1 := [CRIT=0, MAIN=1, PERP=2, SDMA=3]
- L2 := interrupt number; directly mapped from the value in the
- "ICTL PerStat, MainStat, CritStat Encoded Register"
- level := [LEVEL_HIGH=0, EDGE_RISING=1, EDGE_FALLING=2, LEVEL_LOW=3]
-
-2. Shared registers
--------------------
-Some SoC devices share registers between them. ie. the i2c devices use
-a single clock control register, and almost all device are affected by
-the port_config register. Devices which need to manipulate shared regs
-should look to the parent SoC node. The soc node is responsible
-for arbitrating all shared register access.
More information about the devicetree-discuss
mailing list