A way to add it to the existing driver through the means of an “overlay”. I would also like to thank Adafruit for making their Fritzing library of parts which includes a Raspberry Pi freely available. In order to communicate with this chip, the Raspberry Pi has to send the following data sequences Both are detected at addresses 0x20 and 0x Add printk’s to the irq routine to detect the code path. All the code discussed in this blog entry can be downloaded from git here. But I plan to extend it to include support for all 4 ICs which are supported by the driver.

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Any help would be appreciated.

Should the probe be done manually to locate the devices? The instructions are as follows:.

Yes, please create a pull request with your overlay on https: In order to communicate with this chip, the Raspberry Pi has to send the following data sequences I found none, so I wrote my own Currently it only supports the MCP, as it is the only mcp230017 I have available here to test it. I followed the article you mentioned and the command to load the DT overlay.

CONFIG_GPIO_MCP23S08: Microchip MCP23xxx I/O expander

I replied to your questions in Update section in my answer. Driver ‘mcp23s08’ is already registered, aborting Instead of fixing it properly I decided to add a quick hack enabling all pull-ups and taking care of a proper patch later. The MCP has a 7-bit device address.


I haven’t tried it myself to do with the chip. The next two parameters represent the register address and the data to be written into that register address To set pin GPA0 LED to output and then toggle it, type the following in the command line: This file contains the names of kernel modules that should be loaded at boot time, one per line.

devicetree overlay for MCP GPIO expander – Raspberry Pi Forums

Writing as “out” defaults to initializing the value as low. Finally, test if our setup is correct. Default memory map of the MCP Please don’t send PMs mcp3017 for support – use the forum.

My feeling is you will lknux much better of with your original approach. Faschingbauer und Schaar JavaScript free Generated by nanoc. Mass writes and reads of all registers on the device are also possible.

MCP23017 IO Expansion

Sam Protsenko 8, 2 33 Today, I checked my hardware again, libux did an rpi-update to get the newest kernel, and surprise: So if you could get the pinctrl driver to pass the pcm interrupt number instead of its own, it might work.

You can load corresponding Device Tree Overlay to overcome this issue. This would make things like simulating PWM in software more feasible at higher frequencies. Sorry, I did not understand your question.


Configure the it as output, and switch it on, pi raspberrypi: All the code discussed in this blog entry can be downloaded from git here.

If that input pin is in a low state, that implies that the push button See fig 4. We installed the i2c-tools package just for that reason; if you want, you can uninstall it now. The Pinux have 26 or 40 pin expansion headers depending on the hardware revision.

Because I don’t mmcp23017 the other 3 ICs, I would like to invite owners of one or more of the following to get in contact with me, so we can test them Could you upload the final. Did you use lsmod to verify the driver was loaded? By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.