From 9f4cd0200cae9821f9ae7994b86ec7a2023bbcd0 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Mon, 5 Jan 2015 20:05:23 -0700 Subject: dm: gpio: Bring in GPIO device tree binding Add the binding file that we are about to support. Signed-off-by: Simon Glass --- doc/device-tree-bindings/gpio/gpio.txt | 211 +++++++++++++++++++++++++++++++++ 1 file changed, 211 insertions(+) create mode 100644 doc/device-tree-bindings/gpio/gpio.txt (limited to 'doc/device-tree-bindings') diff --git a/doc/device-tree-bindings/gpio/gpio.txt b/doc/device-tree-bindings/gpio/gpio.txt new file mode 100644 index 0000000..b9bd1d6 --- /dev/null +++ b/doc/device-tree-bindings/gpio/gpio.txt @@ -0,0 +1,211 @@ +Specifying GPIO information for devices +============================================ + +1) gpios property +----------------- + +Nodes that makes use of GPIOs should specify them using one or more +properties, each containing a 'gpio-list': + + gpio-list ::= [gpio-list] + single-gpio ::= + gpio-phandle : phandle to gpio controller node + gpio-specifier : Array of #gpio-cells specifying specific gpio + (controller specific) + +GPIO properties should be named "[-]gpios", with being the purpose +of this GPIO for the device. While a non-existent is considered valid +for compatibility reasons (resolving to the "gpios" property), it is not allowed +for new bindings. + +GPIO properties can contain one or more GPIO phandles, but only in exceptional +cases should they contain more than one. If your device uses several GPIOs with +distinct functions, reference each of them under its own property, giving it a +meaningful name. The only case where an array of GPIOs is accepted is when +several GPIOs serve the same function (e.g. a parallel data line). + +The exact purpose of each gpios property must be documented in the device tree +binding of the device. + +The following example could be used to describe GPIO pins used as device enable +and bit-banged data signals: + + gpio1: gpio1 { + gpio-controller + #gpio-cells = <2>; + }; + gpio2: gpio2 { + gpio-controller + #gpio-cells = <1>; + }; + [...] + + enable-gpios = <&gpio2 2>; + data-gpios = <&gpio1 12 0>, + <&gpio1 13 0>, + <&gpio1 14 0>, + <&gpio1 15 0>; + +Note that gpio-specifier length is controller dependent. In the +above example, &gpio1 uses 2 cells to specify a gpio, while &gpio2 +only uses one. + +gpio-specifier may encode: bank, pin position inside the bank, +whether pin is open-drain and whether pin is logically inverted. +Exact meaning of each specifier cell is controller specific, and must +be documented in the device tree binding for the device. Use the macros +defined in include/dt-bindings/gpio/gpio.h whenever possible: + +Example of a node using GPIOs: + + node { + enable-gpios = <&qe_pio_e 18 GPIO_ACTIVE_HIGH>; + }; + +GPIO_ACTIVE_HIGH is 0, so in this example gpio-specifier is "18 0" and encodes +GPIO pin number, and GPIO flags as accepted by the "qe_pio_e" gpio-controller. + +1.1) GPIO specifier best practices +---------------------------------- + +A gpio-specifier should contain a flag indicating the GPIO polarity; active- +high or active-low. If it does, the follow best practices should be followed: + +The gpio-specifier's polarity flag should represent the physical level at the +GPIO controller that achieves (or represents, for inputs) a logically asserted +value at the device. The exact definition of logically asserted should be +defined by the binding for the device. If the board inverts the signal between +the GPIO controller and the device, then the gpio-specifier will represent the +opposite physical level than the signal at the device's pin. + +When the device's signal polarity is configurable, the binding for the +device must either: + +a) Define a single static polarity for the signal, with the expectation that +any software using that binding would statically program the device to use +that signal polarity. + +The static choice of polarity may be either: + +a1) (Preferred) Dictated by a binding-specific DT property. + +or: + +a2) Defined statically by the DT binding itself. + +In particular, the polarity cannot be derived from the gpio-specifier, since +that would prevent the DT from separately representing the two orthogonal +concepts of configurable signal polarity in the device, and possible board- +level signal inversion. + +or: + +b) Pick a single option for device signal polarity, and document this choice +in the binding. The gpio-specifier should represent the polarity of the signal +(at the GPIO controller) assuming that the device is configured for this +particular signal polarity choice. If software chooses to program the device +to generate or receive a signal of the opposite polarity, software will be +responsible for correctly interpreting (inverting) the GPIO signal at the GPIO +controller. + +2) gpio-controller nodes +------------------------ + +Every GPIO controller node must contain both an empty "gpio-controller" +property, and a #gpio-cells integer property, which indicates the number of +cells in a gpio-specifier. + +Example of two SOC GPIO banks defined as gpio-controller nodes: + + qe_pio_a: gpio-controller@1400 { + compatible = "fsl,qe-pario-bank-a", "fsl,qe-pario-bank"; + reg = <0x1400 0x18>; + gpio-controller; + #gpio-cells = <2>; + }; + + qe_pio_e: gpio-controller@1460 { + compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank"; + reg = <0x1460 0x18>; + gpio-controller; + #gpio-cells = <2>; + }; + +2.1) gpio- and pin-controller interaction +----------------------------------------- + +Some or all of the GPIOs provided by a GPIO controller may be routed to pins +on the package via a pin controller. This allows muxing those pins between +GPIO and other functions. + +It is useful to represent which GPIOs correspond to which pins on which pin +controllers. The gpio-ranges property described below represents this, and +contains information structures as follows: + + gpio-range-list ::= [gpio-range-list] + single-gpio-range ::= | + numeric-gpio-range ::= + + named-gpio-range ::= '<0 0>' + gpio-phandle : phandle to pin controller node. + gpio-base : Base GPIO ID in the GPIO controller + pinctrl-base : Base pinctrl pin ID in the pin controller + count : The number of GPIOs/pins in this range + +The "pin controller node" mentioned above must conform to the bindings +described in ../pinctrl/pinctrl-bindings.txt. + +In case named gpio ranges are used (ranges with both and + set to 0), the property gpio-ranges-group-names contains one string +for every single-gpio-range in gpio-ranges: + gpiorange-names-list ::= [gpiorange-names-list] + gpiorange-name : Name of the pingroup associated to the GPIO range in + the respective pin controller. + +Elements of gpiorange-names-list corresponding to numeric ranges contain +the empty string. Elements of gpiorange-names-list corresponding to named +ranges contain the name of a pin group defined in the respective pin +controller. The number of pins/GPIOs in the range is the number of pins in +that pin group. + +Previous versions of this binding required all pin controller nodes that +were referenced by any gpio-ranges property to contain a property named +#gpio-range-cells with value <3>. This requirement is now deprecated. +However, that property may still exist in older device trees for +compatibility reasons, and would still be required even in new device +trees that need to be compatible with older software. + +Example 1: + + qe_pio_e: gpio-controller@1460 { + #gpio-cells = <2>; + compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank"; + reg = <0x1460 0x18>; + gpio-controller; + gpio-ranges = <&pinctrl1 0 20 10>, <&pinctrl2 10 50 20>; + }; + +Here, a single GPIO controller has GPIOs 0..9 routed to pin controller +pinctrl1's pins 20..29, and GPIOs 10..19 routed to pin controller pinctrl2's +pins 50..59. + +Example 2: + + gpio_pio_i: gpio-controller@14B0 { + #gpio-cells = <2>; + compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank"; + reg = <0x1480 0x18>; + gpio-controller; + gpio-ranges = <&pinctrl1 0 20 10>, + <&pinctrl2 10 0 0>, + <&pinctrl1 15 0 10>, + <&pinctrl2 25 0 0>; + gpio-ranges-group-names = "", + "foo", + "", + "bar"; + }; + +Here, three GPIO ranges are defined wrt. two pin controllers. pinctrl1 GPIO +ranges are defined using pin numbers whereas the GPIO ranges wrt. pinctrl2 +are named "foo" and "bar". -- cgit v1.1 From 35ea1bfde30a541188ffd24cdf9b3ba79b0e4684 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Mon, 5 Jan 2015 20:05:24 -0700 Subject: dm: exynos: Bring in GPIO device tree binding At present the exynos GPIO driver does not fully support the existing device tree binding, but add the binding file to cover the existing partial support. Signed-off-by: Simon Glass --- doc/device-tree-bindings/gpio/gpio-samsung.txt | 41 ++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 doc/device-tree-bindings/gpio/gpio-samsung.txt (limited to 'doc/device-tree-bindings') diff --git a/doc/device-tree-bindings/gpio/gpio-samsung.txt b/doc/device-tree-bindings/gpio/gpio-samsung.txt new file mode 100644 index 0000000..5375625 --- /dev/null +++ b/doc/device-tree-bindings/gpio/gpio-samsung.txt @@ -0,0 +1,41 @@ +Samsung Exynos4 GPIO Controller + +Required properties: +- compatible: Compatible property value should be "samsung,exynos4-gpio>". + +- reg: Physical base address of the controller and length of memory mapped + region. + +- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes + should be the following with values derived from the SoC user manual. + <[phandle of the gpio controller node] + [pin number within the gpio controller] + [mux function] + [flags and pull up/down] + [drive strength]> + + Values for gpio specifier: + - Pin number: is a value between 0 to 7. + - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled. + 1 - Pull Down Enabled. + 3 - Pull Up Enabled. + Bit 16 (0x00010000) - Input is active low. + - Drive Strength: 0 - 1x, + 1 - 3x, + 2 - 2x, + 3 - 4x + +- gpio-controller: Specifies that the node is a gpio controller. +- #address-cells: should be 1. +- #size-cells: should be 1. + +Example: + + gpa0: gpio-controller@11400000 { + #address-cells = <1>; + #size-cells = <1>; + compatible = "samsung,exynos4-gpio"; + reg = <0x11400000 0x20>; + #gpio-cells = <4>; + gpio-controller; + }; -- cgit v1.1 From 5cfc662c496a0e52301a9379f91755b1f8fbf368 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Mon, 5 Jan 2015 20:05:25 -0700 Subject: dm: tegra: Bring in GPIO device tree binding At present the tegra GPIO driver does not fully support the existing device tree binding, but add the binding file to cover the existing partial support. Signed-off-by: Simon Glass --- .../gpio/nvidia,tegra20-gpio.txt | 40 ++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 doc/device-tree-bindings/gpio/nvidia,tegra20-gpio.txt (limited to 'doc/device-tree-bindings') diff --git a/doc/device-tree-bindings/gpio/nvidia,tegra20-gpio.txt b/doc/device-tree-bindings/gpio/nvidia,tegra20-gpio.txt new file mode 100644 index 0000000..023c952 --- /dev/null +++ b/doc/device-tree-bindings/gpio/nvidia,tegra20-gpio.txt @@ -0,0 +1,40 @@ +NVIDIA Tegra GPIO controller + +Required properties: +- compatible : "nvidia,tegra-gpio" +- reg : Physical base address and length of the controller's registers. +- interrupts : The interrupt outputs from the controller. For Tegra20, + there should be 7 interrupts specified, and for Tegra30, there should + be 8 interrupts specified. +- #gpio-cells : Should be two. The first cell is the pin number and the + second cell is used to specify optional parameters: + - bit 0 specifies polarity (0 for normal, 1 for inverted) +- gpio-controller : Marks the device node as a GPIO controller. +- #interrupt-cells : Should be 2. + 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. + Valid combinations are 1, 2, 3, 4, 8. +- interrupt-controller : Marks the device node as an interrupt controller. + +Example: + +gpio: gpio@6000d000 { + compatible = "nvidia,tegra20-gpio"; + reg = < 0x6000d000 0x1000 >; + interrupts = < 0 32 0x04 + 0 33 0x04 + 0 34 0x04 + 0 35 0x04 + 0 55 0x04 + 0 87 0x04 + 0 89 0x04 >; + #gpio-cells = <2>; + gpio-controller; + #interrupt-cells = <2>; + interrupt-controller; +}; -- cgit v1.1 From 7132b9fd68a1c76bf557d56dd62756a6607cf761 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Mon, 26 Jan 2015 20:29:37 -0700 Subject: dm: i2c: dts: Support an offset-len device tree property Since U-Boot can support different offset lengths (0-4 bytes), add a device tree property to specify this. This avoids hard-coding it in the driver. Signed-off-by: Simon Glass --- doc/device-tree-bindings/i2c/i2c.txt | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 doc/device-tree-bindings/i2c/i2c.txt (limited to 'doc/device-tree-bindings') diff --git a/doc/device-tree-bindings/i2c/i2c.txt b/doc/device-tree-bindings/i2c/i2c.txt new file mode 100644 index 0000000..ea918dd --- /dev/null +++ b/doc/device-tree-bindings/i2c/i2c.txt @@ -0,0 +1,28 @@ +U-Boot I2C +---------- + +U-Boot's I2C model has the concept of an offset within a chip (I2C target +device). The offset can be up to 4 bytes long, but is normally 1 byte, +meaning that offsets from 0 to 255 are supported by the chip. This often +corresponds to register numbers. + +Apart from the controller-specific I2C bindings, U-Boot supports a special +property which allows the chip offset length to be selected. + +Optional properties: +- u-boot,i2c-offset-len - length of chip offset in bytes. If omitted the + default value of 1 is used. + + +Example +------- + +i2c4: i2c@12ca0000 { + cros-ec@1e { + reg = <0x1e>; + compatible = "google,cros-ec"; + i2c-max-frequency = <100000>; + u-boot,i2c-offset-len = <0>; + ec-interrupt = <&gpx1 6 GPIO_ACTIVE_LOW>; + }; +}; -- cgit v1.1 From aa8e00fab5e65a07c2cae52274946a908805ea60 Mon Sep 17 00:00:00 2001 From: Joonyoung Shim Date: Thu, 15 Jan 2015 11:45:56 +0900 Subject: samsung: board: support eMMC reset using DT Some exynos boards require special handling of nRESET_OUT line for eMMC memory to perform complete reboot e.g. Odroid X2/U3/XU3 boards. This will support eMMC reset using DT from reset_misc of samsung common board file. Signed-off-by: Joonyoung Shim Signed-off-by: Minkyu Kang --- doc/device-tree-bindings/exynos/emmc-reset.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 doc/device-tree-bindings/exynos/emmc-reset.txt (limited to 'doc/device-tree-bindings') diff --git a/doc/device-tree-bindings/exynos/emmc-reset.txt b/doc/device-tree-bindings/exynos/emmc-reset.txt new file mode 100644 index 0000000..5e7ba26 --- /dev/null +++ b/doc/device-tree-bindings/exynos/emmc-reset.txt @@ -0,0 +1,15 @@ +* Samsung eMMC reset + +Some exynos boards require special handling of nRESET_OUT line for eMMC memory +to perform complete reboot. + +Required properties: +- compatible: should be "samsung,emmc-reset" +- reset-gpio: gpio chip for eMMC reset. + +Example: + +emmc-reset { + compatible = "samsung,emmc-reset"; + reset-gpio = <&gpk1 2 0>; +}; -- cgit v1.1 From ba25779384671c533a778e53d59fe3f317bfefa8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 12 Feb 2015 18:49:33 +0900 Subject: Documentation: gpio: fix bindings document [ imported from Linux Kernel, commit 74981fb81d83 ] Signed-off-by: Masahiro Yamada Acked-by: Laurent Pinchart Signed-off-by: Linus Walleij Acked-by: Simon Glass --- doc/device-tree-bindings/gpio/gpio.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'doc/device-tree-bindings') diff --git a/doc/device-tree-bindings/gpio/gpio.txt b/doc/device-tree-bindings/gpio/gpio.txt index b9bd1d6..f7a158d 100644 --- a/doc/device-tree-bindings/gpio/gpio.txt +++ b/doc/device-tree-bindings/gpio/gpio.txt @@ -69,7 +69,8 @@ GPIO pin number, and GPIO flags as accepted by the "qe_pio_e" gpio-controller. ---------------------------------- A gpio-specifier should contain a flag indicating the GPIO polarity; active- -high or active-low. If it does, the follow best practices should be followed: +high or active-low. If it does, the following best practices should be +followed: The gpio-specifier's polarity flag should represent the physical level at the GPIO controller that achieves (or represents, for inputs) a logically asserted @@ -147,7 +148,7 @@ contains information structures as follows: numeric-gpio-range ::= named-gpio-range ::= '<0 0>' - gpio-phandle : phandle to pin controller node. + pinctrl-phandle : phandle to pin controller node gpio-base : Base GPIO ID in the GPIO controller pinctrl-base : Base pinctrl pin ID in the pin controller count : The number of GPIOs/pins in this range -- cgit v1.1