diff options
Diffstat (limited to 'Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt | 95 |
1 files changed, 95 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 00000000..ab19e6bc --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt @@ -0,0 +1,95 @@ +* 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: two integers array, represents a group of pins mux and config + setting. The format is fsl,pins = <PIN_FUNC_ID CONFIG>, PIN_FUNC_ID is a + pin working on a specific function, CONFIG is the pad setting value like + pull-up on this pin. Please refer to fsl,<soc>-pinctrl.txt for the valid + pins and functions of each SoC. + +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@0219c000 { /* uSDHC4 */ + fsl,card-wired; + vmmc-supply = <®_3p3v>; + status = "okay"; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_usdhc4_1>; +}; + +iomuxc@020e0000 { + compatible = "fsl,imx6q-iomuxc"; + reg = <0x020e0000 0x4000>; + + /* shared pinctrl settings */ + usdhc4 { + pinctrl_usdhc4_1: usdhc4grp-1 { + fsl,pins = <1386 0x17059 /* MX6Q_PAD_SD4_CMD__USDHC4_CMD */ + 1392 0x10059 /* MX6Q_PAD_SD4_CLK__USDHC4_CLK */ + 1462 0x17059 /* MX6Q_PAD_SD4_DAT0__USDHC4_DAT0 */ + 1470 0x17059 /* MX6Q_PAD_SD4_DAT1__USDHC4_DAT1 */ + 1478 0x17059 /* MX6Q_PAD_SD4_DAT2__USDHC4_DAT2 */ + 1486 0x17059 /* MX6Q_PAD_SD4_DAT3__USDHC4_DAT3 */ + 1493 0x17059 /* MX6Q_PAD_SD4_DAT4__USDHC4_DAT4 */ + 1501 0x17059 /* MX6Q_PAD_SD4_DAT5__USDHC4_DAT5 */ + 1509 0x17059 /* MX6Q_PAD_SD4_DAT6__USDHC4_DAT6 */ + 1517 0x17059>; /* MX6Q_PAD_SD4_DAT7__USDHC4_DAT7 */ + }; + }; + .... +}; +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. + +TODO: when dtc macro support is available, we can change above raw data +to dt macro which can get better readability in dts file. |