abb7e84d29
This change will allow the at91-sama5d2_adc driver to use other triggers than it's own. In particular, tested with the sysfs trigger. To be able to achieve this functionality, some changes were required: 1) Do not enable/disable channels when enabling/disabling the trigger. This is because the trigger is enabled/disabled only for our trigger (obviously). We need channels enabled/disabled regardless of what trigger is being used. 2) Cope with DMA : DMA cannot be used when using another type of trigger. Other triggers work through pollfunc, so we get polled anyway on every trigger. Thus we have to obtain data at every trigger. 3) When to start conversion? The usual pollfunc (store time from subsystem) would be in hard irq and this would be a good way, but current iio subsystem recommends to have it in the threaded irq. Thus adding software start code in this handler. 4) Buffer config: we need to setup buffer regardless of our own device's trigger. We may get one attached later. 5) IRQ handling: we use our own device IRQ only if it's our own trigger and we do not use DMA . If we use DMA, we use the DMA controller's IRQ. Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.