android_kernel_samsung_msm8976/Documentation/devicetree/bindings/i2c/i2c-qup.txt
Ankit Gupta 6ff9861dbc qup_i2c: support for configuarable noise rejection
allow to configure noise rejection value from device tree
which helps filter spikes in the i2c lines.

CRs-Fixed: 626250
Change-Id: If66132c8cc444294e4e6e275ece8b85108cf7abb
Signed-off-by: Ankit Gupta <ankgupta@codeaurora.org>
2014-04-03 14:33:09 -06:00

63 lines
2.8 KiB
Text

Qualcomm I2C controller
Required properties:
- reg : Offset and length of the register region(s) for the device
For GSBI based controller, GSBI and QUP regions are expected
For BLSP based controller, QUP region offset is expected
- reg-names : Register region name(s) referenced in reg above
BLSP based controller expects QUP region name ("qup_phys_addr")
GSBI controller expects QUP region name and GSBI region name
("gsbi_qup_i2c_addr")
- compatible : should be "qcom,i2c-qup"
- cell-index : I2C bus number used for this controller
- interrupts : QUP core interrupt(s). Core may have 1 error interrupt and flags
for input/output service, or 3 separate interrupts for the 3 services
- interrupt-names: QUP core interrupt name(s) referenced in interrupts above
Expected interrupt resource name(s) are: "qup_err_irq", "qup_in_irq",
and "qup_out_irq"
- qcom,i2c-bus-freq : desired I2C bus clock frequency is Hz
Optional property:
- qcom,noise-rjct-scl : Number of low samples on clock line to consider it low.
Range of values is 0-3. When missing default to 0.
- qcom,noise-rjct-sda : Number of low samples on data line to consider it low.
Range of values is 0-3. When missing default to 0.
- qcom,i2c-src-freq : Frequency of the source clocking this bus in Hz.
Divider value is set based on soruce-frequency and
desired I2C bus frequency. If this value is not
provided, the source clock is assumed to be running
at 19.2 MHz.
- qcom,scl-gpio : I2C clock GPIO number. Required for execution of bus
recovery procedure.
- qcom,sda-gpio : I2C data GPIO number. Required for execution of bus
recovery procedure.
- qcom,active-only : Vote for core clock when the application processor goes
to active state and remove that vote when it goes to idle
state. This flag may improve service time of first i2c
request at the expense of power consumption. When this
entry is not present, voting is done by the runtime-pm
callbacks.
- qcom,master-id : Master endpoint number used for voting on clocks using
bus-scaling driver.
- qcom,clk-ctl-xfer : When present, the clocks's state (prepare_enable/
unprepare_disable) is controlled by i2c-transaction's
begining and ending. When missing, the clock's state
is controlled by runtime-pm events.
Example:
i2c_3: i2c@f9966000 {
cell-index = <3>;
compatible = "qcom,i2c-qup";
reg = <0xf9966000 0x1000>;
reg-names = "qup_phys_addr";
interrupts = <0 104 0>;
qcom,noise-rjct-scl = <1>;
qcom,noise-rjct-sda = <1>;
interrupt-names = "qup_err_intr";
qcom,i2c-bus-freq = <100000>;
qcom,i2c-src-freq = <24000000>;
qcom,clk-ctl-xfer;
qcom,scl-gpio = <&msmgpio 7 0>;
qcom,sda-gpio = <&msmgpio 6 0>;
};