i.MX 93 ADC read using H/W trigger

[NZP]

Hello experts,

I want to read IMX9352 processors ADC CH0 using external hardware trigger (gpio pin interrupt on rising edge at 1 Khz frequency) but looking at linux kernel driver this functionality is currently not available. So can anybody please let me know that what necessary changes do I require at driver level to read ADC using external hardware trigger.

Thanks.

[NZP]

Hi joanxie,

Thanks for reply.

have you tested failed? Haven't tested yet because not able to understand the flow for this implementation (I know about these register's) but doesn`t know how to assign trigger source to this ADC channel.  

which driver do you mention in Linux kernel iio/adc/imx93_adc.c

Can you please give some more information like how to assign particular gpio as a external trigger source to this ADC channel. 

[joanxie]

you can select by TRGMUX. depends on injection start trigger or normal start trigger you need

different external trigger for SEL0 or SEL1, you can find the table as below

[NZP]

Hi joanxie,

Thank you very much for your support.

I am able to understand that we can select external trigger from SEL0 and SEL1 register. So, from the table attached by you, value Ah - is for GPIO1 which selects GPIO1 port as an ADC trigger source. 

So, my question is that,

1. How I can select/configure GPIO1.IO[0] (or any specific GPIO1 port's pin) as an ADC trigger source.

2. Here I am confused that GPIO1 is one port which has 0 to 15 number pins, so by configuring SEL register for GPIO1 which specific GPIO1's pin will be considered as an ADC trigger source.

Thanks.

[joanxie]

have you tested failed? which driver do you mention?refer to the RM,

By hardware trigger:
—
If external trigger is enabled (MCR[TRGEN] = 1), and an external trigger enable is detected, the conversion will start. The enable is checked only during the start of conversion. The hardware trigger needs to be active for a least 2 ADC bus clock cycles in order to recognized and start a conversion.
◦
Detection of an active edge is defined by MCR[EDGE] (rising = 1, falling = 0). When an external trigger is recognized, MSR[NSTART] is set and normal conversion starts.