diff options
Diffstat (limited to 'Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt new file mode 100644 index 000000000..a1050b598 --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt @@ -0,0 +1,93 @@ +* Freescale IOMUX Controller (IOMUXC) for i.MX + +The IOMUX Controller (IOMUXC), together with the IOMUX, enables the IC +to share one PAD to several functional blocks. The sharing is done by +multiplexing the PAD input/output signals. For each PAD there are up to +8 muxing options (called ALT modes). Since different modules require +different PAD settings (like pull up, keeper, etc) the IOMUXC controls +also the PAD settings parameters. + +Please refer to pinctrl-bindings.txt in this directory for details of the +common pinctrl bindings used by client devices, including the meaning of the +phrase "pin configuration node". + +Freescale IMX pin configuration node is a node of a group of pins which can be +used for a specific device or function. This node represents both mux and config +of the pins in that group. The 'mux' selects the function mode(also named mux +mode) this pin can work on and the 'config' configures various pad settings +such as pull-up, open drain, drive strength, etc. + +Required properties for iomux controller: +- compatible: "fsl,<soc>-iomuxc" + Please refer to each fsl,<soc>-pinctrl.txt binding doc for supported SoCs. + +Required properties for pin configuration node: +- fsl,pins: each entry consists of 6 integers and represents the mux and config + setting for one pin. The first 5 integers <mux_reg conf_reg input_reg mux_val + input_val> are specified using a PIN_FUNC_ID macro, which can be found in + imx*-pinfunc.h under device tree source folder. The last integer CONFIG is + the pad setting value like pull-up on this pin. And that's why fsl,pins entry + looks like <PIN_FUNC_ID CONFIG> in the example below. + +Bits used for CONFIG: +NO_PAD_CTL(1 << 31): indicate this pin does not need config. + +SION(1 << 30): Software Input On Field. +Force the selected mux mode input path no matter of MUX_MODE functionality. +By default the input path is determined by functionality of the selected +mux mode (regular). + +Other bits are used for PAD setting. +Please refer to each fsl,<soc>-pinctrl,txt binding doc for SoC specific part +of bits definitions. + +NOTE: +Some requirements for using fsl,imx-pinctrl binding: +1. We have pin function node defined under iomux controller node to represent + what pinmux functions this SoC supports. +2. The pin configuration node intends to work on a specific function should + to be defined under that specific function node. + The function node's name should represent well about what function + this group of pins in this pin configuration node are working on. +3. The driver can use the function node's name and pin configuration node's + name describe the pin function and group hierarchy. + For example, Linux IMX pinctrl driver takes the function node's name + as the function name and pin configuration node's name as group name to + create the map table. +4. Each pin configuration node should have a phandle, devices can set pins + configurations by referring to the phandle of that pin configuration node. + +Examples: +usdhc@219c000 { /* uSDHC4 */ + non-removable; + vmmc-supply = <®_3p3v>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_usdhc4_1>; +}; + +iomuxc@20e0000 { + compatible = "fsl,imx6q-iomuxc"; + reg = <0x020e0000 0x4000>; + + /* shared pinctrl settings */ + usdhc4 { + pinctrl_usdhc4_1: usdhc4grp-1 { + fsl,pins = < + MX6QDL_PAD_SD4_CMD__SD4_CMD 0x17059 + MX6QDL_PAD_SD4_CLK__SD4_CLK 0x10059 + MX6QDL_PAD_SD4_DAT0__SD4_DATA0 0x17059 + MX6QDL_PAD_SD4_DAT1__SD4_DATA1 0x17059 + MX6QDL_PAD_SD4_DAT2__SD4_DATA2 0x17059 + MX6QDL_PAD_SD4_DAT3__SD4_DATA3 0x17059 + MX6QDL_PAD_SD4_DAT4__SD4_DATA4 0x17059 + MX6QDL_PAD_SD4_DAT5__SD4_DATA5 0x17059 + MX6QDL_PAD_SD4_DAT6__SD4_DATA6 0x17059 + MX6QDL_PAD_SD4_DAT7__SD4_DATA7 0x17059 + >; + }; + .... +}; +Refer to the IOMUXC controller chapter in imx6q datasheet, +0x17059 means enable hysteresis, 47KOhm Pull Up, 50Mhz speed, +80Ohm driver strength and Fast Slew Rate. +User should refer to each SoC spec to set the correct value. |