Lines Matching full:i2c

2 How to instantiate I2C devices
5 Unlike PCI or USB devices, I2C devices are not enumerated at the hardware
7 I2C bus segment, and what address these devices are using. For this
8 reason, the kernel code must instantiate I2C devices explicitly. There are
12 Method 1a: Declare the I2C devices by bus number
15 This method is appropriate when the I2C bus is a system bus as is the case
16 for many embedded systems. On such systems, each I2C bus has a number
17 which is known in advance. It is thus possible to pre-declare the I2C
46 The above code declares 3 devices on I2C bus 1, including their respective
47 addresses and custom data needed by their drivers. When the I2C bus in
48 question is registered, the I2C devices will be instantiated automatically
49 by i2c-core.
51 The devices will be automatically unbound and destroyed when the I2C bus
55 Method 1b: Declare the I2C devices via devicetree
58 This method has the same implications as method 1a. The declaration of I2C
63 	i2c1: i2c@400a0000 {
85 Method 1c: Declare the I2C devices via ACPI
88 ACPI can also describe I2C devices. There is special documentation for this
95 This method is appropriate when a larger device uses an I2C bus for
98 main chip by the means of an I2C bus. You won't know the number of the I2C
100 you can instantiate your I2C devices explicitly. This is done by filling
118 The above code instantiates 1 I2C device on the I2C bus which is on the
121 A variant of this is when you don't know for sure if an I2C device is
148 The above code instantiates up to 1 I2C device on the I2C bus which is on
153 The driver which instantiated the I2C device is responsible for destroying
159 Method 3: Probe an I2C bus for certain devices
162 Sometimes you do not have enough information about an I2C device, not even
171 In that case, I2C devices are neither declared nor instantiated
172 explicitly. Instead, i2c-core will probe for such devices as soon as their
173 drivers are loaded, and if any is found, an I2C device will be
177 * The I2C device driver must implement the detect() method, which
186 I2C devices instantiated as a result of such a successful probe will be
188 or when the underlying I2C bus is itself destroyed, whichever happens
191 Those of you familiar with the i2c subsystem of 2.4 kernels and early 2.6
195 * Probing is only one way to instantiate I2C devices now, while it was the
199 * I2C buses must now explicitly say which I2C driver classes can probe
200   them (by the means of the class bitfield), while all I2C buses were
213 In general, the kernel should know which I2C devices are connected and
216 interface is made of 2 attribute files which are created in every I2C bus
219 respectively delete, an I2C device.
221 File new_device takes 2 parameters: the name of the I2C device (a string)
222 and the address of the I2C device (a number, typically expressed in
225 File delete_device takes a single parameter: the address of the I2C
226 device. As no two devices can live at the same address on a given I2C
232   # echo eeprom 0x50 > /sys/bus/i2c/devices/i2c-3/new_device
237 * The I2C driver usually detects devices (method 3 above) but the bus
240 * The I2C driver usually detects devices, but your device lives at an
242 * The I2C driver usually detects devices, but your device is not detected,
245 * You are developing a driver on a test board, where you soldered the I2C
248 This interface is a replacement for the force_* module parameters some I2C
249 drivers implement. Being implemented in i2c-core rather than in each