On Thu, Aug 06, 2015 at 04:23:51PM +0800, James Liao wrote:

Hi Sascha,

On Wed, 2015-08-05 at 08:46 +0200, Sascha Hauer wrote:

quoted

On Tue, Aug 04, 2015 at 04:16:56PM +0800, James Liao wrote:

quoted

 static const struct mtk_fixed_clk fixed_clks[] __initconst = {
 	FIXED_CLK(CLK_TOP_CLKPH_MCK_O, "clkph_mck_o", "clk26m", 400 * MHZ),
 	FIXED_CLK(CLK_TOP_USB_SYSPLL_125M, "usb_syspll_125m", "clk26m", 125 * MHZ),
+	FIXED_CLK(CLK_TOP_DSI0_DIG, "dsi0_dig", "clk26m", 130 * MHZ),
+	FIXED_CLK(CLK_TOP_DSI1_DIG, "dsi1_dig", "clk26m", 130 * MHZ),
+	FIXED_CLK(CLK_TOP_LVDS_PXL, "lvds_pxl", "lvdspll", 148.5 * MHZ),
+	FIXED_CLK(CLK_TOP_LVDS_CTS, "lvds_cts", "lvdspll", 51.975 * MHZ),

I would expect 51975 * KHZ here to avoid fractional numbers. Probably
gcc calculates that during compile time so this will work as expected,
still I'm not sure this is good style to use fractional numbers here.

As I know all constants will be calculated in compile time, so there
should be no difference between 51.975 * MHZ and 51975 * KHz. 

quoted

Anyway, on my system lvdspll is running at 150MHz. Are you sure there is
a clock derived from this running at 148.5MHz? Is it really correct to
use a fixed clock here or should it rather be lvdspll directly?

Here is the clock hierarchy between lvdspll and lvds_pxl:

            --------       AD_VPLL_DPIX_CK  --------   lvds_pxl  -----
           |        |--------------------->|        |---------->|
           |        |                      | cksys  |           |
LVDSPLL -->| LVDSTX |                      | buffer |           | MMSYS
           |        | AD_LVDSTX_CLKDIG_CTS | test   |  lvds_cts |
           |        |--------------------->|        |---------->|
            --------                        --------             -----

Some clocks and blocks are not modeled into CCF. But we prefer to enable
lvdspll before enabling lvds_pxl. So I modeled lvds_pxl (and lvds_cts)
as a fixed-rate clock with a source from lvdspll.

The frequency of these fixed-rate clocks (such as 148.5 MHz) are typical
rate. In fact, we don't care about the actual rate of these clocks. We
just care about the enable / disable sequence of them.

Please either use the real rate or 0 (along with a explaining why). Using
a frequency with four to five significant digits makes me think that the
actual rate is very important.

Sascha

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