Hi, On Fri, Nov 27, 2015 at 10:42:53PM +0100, Danny Milosavljevic wrote: > Hi, > > I'm trying to use A20 clk_out_a in Linux 4.4-rc1. > > I wrote a kernel module in order to enable the clock: > http://svn.nomike.com/playground/trunk/Navi/TSS463AA/Linux/tss463aa.c > > However, it does not work, in the following way: > > I connected an oscilloscope to the pin PI12. > > Then I used manual bitbanging to make sure it's the correct pin: > > http://svn.nomike.com/playground/trunk/Navi/WORKING_CLOCK > > When I do that, I see a nice square wave on the 'scope. > > However, when I then load the kernel module, the display on the 'scope > flatlines. > > On one hand that's a good sign since it means that it at least found > the clock definition in the device tree file and uses the right pin. > > On the other hand I can't figure out what the problem is. > > Does clk_out_a work for anyone? How to use it (I'd need a clock of > max 8 MHz for driving a TSS463AA, min 150 kHz)? > > The tss463aa definition in my device tree file is: > > &spi2 { > status = "okay"; > spidev0: spidev@1 { > compatible = "atmel,tss463aa"; > reg = <0>; > spi-max-frequency = <4000000>; > }; > };
Did you mux the clk_out pin somewhere? Did you enable the clock? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
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