How to use pca953x.c driver for 3 tca9535 devices.

Hello Pranav,

Could you provide a link to the driver you are referring to?

I am not familiar with Sitara programming, and will not be able to assist you too much in this other than providing some tidbits. I am also moving this to the Sitara forums for better support.

You do not provide much information for us to help you on, though. Could you provide the following:

The model of Sitara used, as well as the package

What pins are the INT outputs being connected to on the Sitara?

What I2C bus/pins are you using on the Sitara?

Hi Jonathan,

I am planning to use the driver in the below link.

"lxr.free-electrons.com/.../gpio-pca953x.c"  .

We are using am437x-gp processor..

1. First  TCA9535 is on  i2c0 and its INT pin is connected to GPIO3[22] / GPIO0[20].

2. Second TCA9535 is on  i2c2 and its INT pin is connected to GPIO4[19] 

3. Third TCA9535 is on i2c1 and its INT pin is connected to GPIO4[17].

Please guide me on how to handle these three interrupts in a single driver.

Hi,Jonathan,

Request your guidance.

Hello Pranav,

Unfortunately, this is more of a programming question about the Sitarra device with 3 interrupt inputs, and less about how to read from the TCA9535 device. I am not familiar with this level of programming. I will request someone with more programming knowledge assist you.

Hello Pranav,

Depending on your kernel, you need to create nodes for the three pce I/O expanders either in your device tree (dts) file or in your board file (for older kernel versions). IRQ parents (gpio3_22, gpio4_19 & gpio4_17) & interrupts are defined in i these nodes.
See example for device tree here: lxr.free-electrons.com/.../gpio-pca953x.txt

Hope this helps.

Best Regards,
Yordan

Hi Jonathan,

Thank you for the response.
I am already done with creating nodes using device tree.
Since all the three IO expanders will use the same driver, so I need to know how to handle the interrupts from 3 devices in one driver.
Request your help in this regards.

Hi Yordan,

Thank you for the hint. It handles the interrupt without modifying the driver.

Regards,
Pranav