About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / devicetree / bindings / gpio / gpio-mcp23s08.txt




Custom Search

Based on kernel version 4.8. Page generated on 2016-10-06 23:11 EST.

1	Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for
2	8-/16-bit I/O expander with serial interface (I2C/SPI)
3	
4	Required properties:
5	- compatible : Should be
6	    - "mcp,mcp23s08" (DEPRECATED) for  8 GPIO SPI version
7	    - "mcp,mcp23s17" (DEPRECATED) for 16 GPIO SPI version
8	    - "mcp,mcp23008" (DEPRECATED) for  8 GPIO I2C version or
9	    - "mcp,mcp23017" (DEPRECATED) for 16 GPIO I2C version of the chip
10	
11	    - "microchip,mcp23s08" for  8 GPIO SPI version
12	    - "microchip,mcp23s17" for 16 GPIO SPI version
13	    - "microchip,mcp23s18" for 16 GPIO SPI version
14	    - "microchip,mcp23008" for  8 GPIO I2C version or
15	    - "microchip,mcp23017" for 16 GPIO I2C version of the chip
16	    NOTE: Do not use the old mcp prefix any more. It is deprecated and will be
17	    removed.
18	- #gpio-cells : Should be two.
19	  - first cell is the pin number
20	  - second cell is used to specify flags. Flags are currently unused.
21	- gpio-controller : Marks the device node as a GPIO controller.
22	- reg : For an address on its bus. I2C uses this a the I2C address of the chip.
23	        SPI uses this to specify the chipselect line which the chip is
24	        connected to. The driver and the SPI variant of the chip support
25	        multiple chips on the same chipselect. Have a look at
26	        microchip,spi-present-mask below.
27	
28	Required device specific properties (only for SPI chips):
29	- mcp,spi-present-mask (DEPRECATED)
30	- microchip,spi-present-mask : This is a present flag, that makes only sense for SPI
31	        chips - as the name suggests. Multiple SPI chips can share the same
32	        SPI chipselect. Set a bit in bit0-7 in this mask to 1 if there is a
33	        chip connected with the corresponding spi address set. For example if
34	        you have a chip with address 3 connected, you have to set bit3 to 1,
35	        which is 0x08. mcp23s08 chip variant only supports bits 0-3. It is not
36	        possible to mix mcp23s08 and mcp23s17 on the same chipselect. Set at
37	        least one bit to 1 for SPI chips.
38	    NOTE: Do not use the old mcp prefix any more. It is deprecated and will be
39	    removed.
40	- spi-max-frequency = The maximum frequency this chip is able to handle
41	
42	Optional properties:
43	- #interrupt-cells : Should be two.
44	  - first cell is the pin number
45	  - second cell is used to specify flags.
46	- interrupt-controller: Marks the device node as a interrupt controller.
47	
48	Optional device specific properties:
49	- microchip,irq-mirror: Sets the mirror flag in the IOCON register. Devices
50	        with two interrupt outputs (these are the devices ending with 17 and
51	        those that have 16 IOs) have two IO banks: IO 0-7 form bank 1 and
52	        IO 8-15 are bank 2. These chips have two different interrupt outputs:
53	        One for bank 1 and another for bank 2. If irq-mirror is set, both
54	        interrupts are generated regardless of the bank that an input change
55	        occurred on. If it is not set, the interrupt are only generated for the
56	        bank they belong to.
57	        On devices with only one interrupt output this property is useless.
58	- microchip,irq-active-high: Sets the INTPOL flag in the IOCON register. This
59	        configures the IRQ output polarity as active high.
60	
61	Example I2C (with interrupt):
62	gpiom1: gpio@20 {
63	        compatible = "microchip,mcp23017";
64	        gpio-controller;
65	        #gpio-cells = <2>;
66	        reg = <0x20>;
67	
68	        interrupt-parent = <&gpio1>;
69	        interrupts = <17 IRQ_TYPE_LEVEL_LOW>;
70	        interrupt-controller;
71	        #interrupt-cells=<2>;
72	        microchip,irq-mirror;
73	};
74	
75	Example SPI:
76	gpiom1: gpio@0 {
77	        compatible = "microchip,mcp23s17";
78	        gpio-controller;
79	        #gpio-cells = <2>;
80	        spi-present-mask = <0x01>;
81	        reg = <0>;
82	        spi-max-frequency = <1000000>;
83	};
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.