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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /Documentation/devicetree/bindings/mfd/cros-ec.txt
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+ChromeOS Embedded Controller
+
+Google's ChromeOS EC is a Cortex-M device which talks to the AP and
+implements various function such as keyboard and battery charging.
+
+The EC can be connect through various means (I2C, SPI, LPC) and the
+compatible string used depends on the interface. Each connection method has
+its own driver which connects to the top level interface-agnostic EC driver.
+Other Linux driver (such as cros-ec-keyb for the matrix keyboard) connect to
+the top-level driver.
+
+Required properties (I2C):
+- compatible: "google,cros-ec-i2c"
+- reg: I2C slave address
+
+Required properties (SPI):
+- compatible: "google,cros-ec-spi"
+- reg: SPI chip select
+
+Optional properties (SPI):
+- google,cros-ec-spi-msg-delay: Some implementations of the EC require some
+ additional processing time in order to accept new transactions. If the delay
+ between transactions is not long enough the EC may not be able to respond
+ properly to subsequent transactions and cause them to hang. This property
+ specifies the delay, in usecs, introduced between transactions to account
+ for the time required by the EC to get back into a state in which new data
+ can be accepted.
+
+Required properties (LPC):
+- compatible: "google,cros-ec-lpc"
+- reg: List of (IO address, size) pairs defining the interface uses
+
+
+Example for I2C:
+
+i2c@12CA0000 {
+ cros-ec@1e {
+ reg = <0x1e>;
+ compatible = "google,cros-ec-i2c";
+ interrupts = <14 0>;
+ interrupt-parent = <&wakeup_eint>;
+ wakeup-source;
+ };
+
+
+Example for SPI:
+
+spi@131b0000 {
+ ec@0 {
+ compatible = "google,cros-ec-spi";
+ reg = <0x0>;
+ interrupts = <14 0>;
+ interrupt-parent = <&wakeup_eint>;
+ wakeup-source;
+ spi-max-frequency = <5000000>;
+ controller-data {
+ cs-gpio = <&gpf0 3 4 3 0>;
+ samsung,spi-cs;
+ samsung,spi-feedback-delay = <2>;
+ };
+ };
+};
+
+
+Example for LPC is not supplied as it is not yet implemented.