Device tree binding documentation for Broadcom Cygnus pinctrl driver
Signed-off-by: Ray Jui <rjui@xxxxxxxxxxxx>
Reviewed-by: Scott Branden <sbranden@xxxxxxxxxxxx>
---
.../bindings/pinctrl/brcm,cygnus-pinctrl.txt | 92 ++++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pinctrl/brcm,cygnus-pinctrl.txt
diff --git a/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-pinctrl.txt
new file mode 100644
index 0000000..86e4579
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-pinctrl.txt
@@ -0,0 +1,92 @@
+Broadcom Cygnus Pin Controller
+
+The Cygnus pin controller supports setting the alternate functions of groups
+of pins. Pinmux configuration on individual pins is not supported by the
+Cygnus A0 SoC.
+
+Required properties:
+
+- compatible:
+ Must be "brcm,cygnus-pinctrl"
+
+- reg:
+ Define the base and range of the I/O address space that contain the Cygnus
+pin control registers
+
+- brcm,groups:
+ This can be strings of one or more group names. This defines the group(s)
+that one wants to configure
+
+- brcm,function:
+ This is the alternate function that one wants to configure to. Valid
+alternate functions are "alt1", "alt2", "alt3", "alt4"
+
+Each child node represents a configuration. Client devices reference the the
+child node to enable the mux configuration.
+
+For example:
+
+ pinctrl: pinctrl@0x0301d0c8 {
+ compatible = "brcm,cygnus-pinctrl";
+ reg = <0x0301d0c8 0x2c>;
+
+ i2s_0: i2s_0 {
+ brcm,groups = "smart_card0", "smart_card0_fcb";
+ brcm,function = "alt2";
+ };
+
+ i2s_1: i2s_1 {
+ brcm,groups = "smart_card1", "smart_card1_fcb";
+ brcm,function = "alt2";
+ };
+
+ spi_0: spi_0 {
+ brcm,groups = "spi0";
+ brcm,function = "alt1";
+ };
+ }
+
+ spi0@18028000 {
+ compatible = "arm,pl022", "arm,primecell";
+ reg = <0x18028000 0x1000>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ interrupts = <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>;
+ pinctrl-0 = <&spi_0>;
+ clocks = <&axi81_clk>;
+ clock-names = "apb_pclk";
+ };
+
+Consider the following snapshot of Cygnus pinmux table:
+
+number pin group alt1 alt2 alt3 alt4
+------ --- ---- ---- ---- ---- ----
+42 sc0_clk smart_card0 SMART CARD0 I2S_0 N/A chip_gpio24
+43 sc0_cmdvcc_l smart_card0 SMART CARD0 I2S_0 N/A STRAP
+44 sc0_detect smart_card0 SMART CARD0 I2S_0 N/A chip_gpio25
+45 sc0_fcb smart_card0_fcb SMART CARD0_FCB I2S_0 N/A chip_gpio26
+46 sc0_io smart_card0 SMART CARD0 I2S_0 N/A chip_gpio27
+47 sc0_rst_l smart_card0 SMART CARD0 SPDIF N/A STRAP
+
+Note due to limitation of the Cygnus hardware, pinmux configuration can only
+be group based. To enable I2S_0 function, one needs the following child node
+configuration:
+
+ i2s_0: i2s_0 {
+ brcm,groups = "smart_card0", "smart_card0_fcb";
+ brcm,function = "alt2";
+ };
+
+This tells the Cygnus pin controller to configure groups "smart_card0" and
+"smart_card0_fcb" to I2S_0. With this configuration, pins 42, 43, 44, 45, 46
+become I2C_0, and pin 47 becomes SPDIF
+
+Consider another example, that one wants to configure the above pins as GPIO:
+
+ gpio_24_27: gpio_24_27 {
+ brcm,groups = "smart_card0", "smart_card0_fcb";
+ brcm,function = "alt4";
+ };
+
+With the above configuration, pins 42, 44, 45, 46 become GPIO, and 43 and 47
+become reserved for STRAP
--
1.7.9.5
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