On Wednesday 11 March 2015 12:34:03 Javier Martinez Canillas wrote: > Hello Arnd, > > On Wed, Mar 11, 2015 at 10:53 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Wednesday 11 March 2015 02:00:59 Javier Martinez Canillas wrote: > >> > >> What do you mean by parsing here? IIUC there isn't a clock driver for > >> these clocks and are setup directly in the > >> drivers/net/wireless/ti/wl12xx/main.c driver. > >> > >> So you can't make the WLAN chip dev node a consumer of these clocks by > >> adding a phandle to a clock provider and clock specifiers since there > >> isn't a provider to be referenced in the DT. Or did I misunderstand? > > > > As I understand it, the clock signal is provided by an external oscillator, > > According to [0], it seems the chip can be connected to both external > oscillators or internal clocks provided by the chip itself. I see, that part wasn't clear to me. > > which we can easily model in DT, and then you call clk_get_rate on that. > > > > Right, my point wast that this can be done only if the external > oscillator have a proper clock driver / provider which I don't think > is the case here. Most of this stuff predates the common clock > framework. > > Or at least Luciano Coelho had a patch on his series to make the > wilink driver a clock provider itself by registering the refclock and > tcxoclock clocks [0]. I guess we should only do this if the clocks from the wilink device might be used by some other device. > Luciano also had patches for: > > * Adding the clock provider dev node in the DTS [1] > * Have a table to map the clock rate with the FW configuration values [2] > * Getting the clock from DT and the rate as you said to configure the > firmware accordingly [3] > > I think that patch [0] should not be needed since for external clocks, > the IP providing the clocks should have its own clock driver and for > internal clocks, a property should be used instead as you said. Right. > > If there is no external clock provider for this chip and the clocks > > are provided by the device itself, then all we need is a clock-frequency > > property in the device node. > > > > Agreed, IIUC Luciano wanted to expose the internal clocks by > registering in the common clock framework but if those clocks are not > really accessible from outside the wlan chip, then I also think that a > device node property should be used instead. If I understand this right, that measn we can easily distinguish between an external XTAL clock and the internal clock by they way they are described in the DT: for the internal clock, we just provide a clock-frequency property, while the external clock would be referenced through a clocks property. Arnd -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
