Hi, I finally got some time to work on that again.
On 18/11/2014 at 14:47:33 +0100, Olliver Schinagl wrote : > What I get from the datasheet is, that sun4i and sun5i are exactly the same, > with the exception that sun5i only has 1 PWM (~exposed~). I belive that is > easily solved with the bindings by having allwinner-sun4i and allwinner > sun5i bindings if I'm not mistaken. > > As for sun7i compared to the other ones, according to disp_lcd.c sun5i and > sun7i should behave exactly the same. This is contradicting to the > datasheet, where sun4i and sun5i are the same. > > So what are the major differences that I can see between the 3? sun4i > defines the PWM prescaler register value 0b1111 as being undefined, and > sun5i and sun7i as /1? Did you verify this (I haven't I admit, i bumped into > this while looking for your patch ;-) )? I wouldn't be supprised if it where > a typo on allwinners end in the datasheet ... disp_lcd.c stops at 72000 for > the last entry. We should just check sun4i, sun5i and sun7i hardware to see > if it behaves the same with a prescaler of 0b1111, which I would not be > totally surprised if it did. > > The other difference I notice is that sun7i and sun5i use 16bit period > register where sun4i uses a 8bit register. This is probably the only reason > why they put a #ifdef in disp_lcd.c, calculations turn out differently. I > don't recognize this behavior at all in your driver however. I do think they > that there is a difference here, since they did split up the original driver > here because of this difference. > That is something I overlooked and I can't test at all, I only have a cubietruck. Did you have some time to test on a sun4i? But, from the only datasheet I have access to [1], page 56: Each channel has a dedicated internal 16-bit up counter. If the counter reaches the value stored in the channel period register, it resets. At the beginning of a count period cycle, the PWMOUT is set to active state and count from 0x0000 So I would say that they all have a 16bits period. [1] http://dl.linux-sunxi.org/A10/A10%20Datasheet%20-%20v1.21%20%282012-04-06%29.pdf -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
