Messages in this thread | | | Date | Fri, 11 Jul 2014 15:27:44 +0300 | From | Baruch Siach <> | Subject | Re: [PATCH v2 1/2] gpio: Add driver for Zynq GPIO controller |
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Hi Linus,
On Fri, Jul 11, 2014 at 02:06:29PM +0200, Linus Walleij wrote: > On Fri, Jul 11, 2014 at 8:28 AM, Baruch Siach <baruch@tkos.co.il> wrote: > > On Tue, Jul 08, 2014 at 11:27:57AM +0200, Linus Walleij wrote: > > >> What is the usecase here? > > > > During boot I need to know, for example, when an FPGA is ready to be > > programmed, and when said FPGA has finished its initialization. I also read > > the sate of on-board DIP switches to determine the desired boot method. I find > > the current sysfs interface quite convenient for these and similar tasks. > > So given that an FPGA is a piece of hardware, it should have its firmware > loaded from the kernel and a kernel driver communicating with it I guess? > > I feel the smell of a huge bundle of userspace drivers for something that > should be handled by the kernel.
The FPGA can be loaded using simple SPI bit-banging, for which I used the userspace SPI interface. Nothing fancy, just a few hundred LoC. Kernel driver along with a userspace interface to be maintained forever for this task seems an overkill to me.
baruch
-- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
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