Commit aeca0fe6 authored by Wolfram Sang's avatar Wolfram Sang
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Documentation: i2c: describe devicetree method for instantiating devices

Signed-off-by: default avatarWolfram Sang <>
parent 79970db2
......@@ -8,8 +8,8 @@ reason, the kernel code must instantiate I2C devices explicitly. There are
several ways to achieve this, depending on the context and requirements.
Method 1: Declare the I2C devices by bus number
Method 1a: Declare the I2C devices by bus number
This method is appropriate when the I2C bus is a system bus as is the case
for many embedded systems. On such systems, each I2C bus has a number
......@@ -51,6 +51,36 @@ The devices will be automatically unbound and destroyed when the I2C bus
they sit on goes away (if ever.)
Method 1b: Declare the I2C devices via devicetree
This method has the same implications as method 1a. The declaration of I2C
devices is here done via devicetree as subnodes of the master controller.
i2c1: i2c@400a0000 {
/* ... master properties skipped ... */
clock-frequency = <100000>;
flash@50 {
compatible = "atmel,24c256";
reg = <0x50>;
pca9532: gpio@60 {
compatible = "nxp,pca9532";
#gpio-cells = <2>;
reg = <0x60>;
Here, two devices are attached to the bus using a speed of 100kHz. For
additional properties which might be needed to set up the device, please refer
to its devicetree documentation in Documentation/devicetree/bindings/.
Method 2: Instantiate the devices explicitly
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