On Thu, Feb 12, 2015 at 11:06 PM, Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> wrote: > From: Mikko Perttunen <mperttunen@xxxxxxxxxx> > > Add binding documentation for the nvidia,tegra124-emc device tree node. > > Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx> > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> > > --- > > v5: * Add a short description for each of the register properties > > v4: * Remove mandatory naming of the timings subnode > * Remove constraint on the unit-address of the timings and timing subnodes > * Add some more information about nvidia,emc-configuration > * Make the example complete > > v2: * Specify the unit addresses for the timings and timing nodes > --- > .../bindings/memory-controllers/tegra-emc.txt | 379 +++++++++++++++++++++ > 1 file changed, 379 insertions(+) > create mode 100644 Documentation/devicetree/bindings/memory-controllers/tegra-emc.txt > > diff --git a/Documentation/devicetree/bindings/memory-controllers/tegra-emc.txt b/Documentation/devicetree/bindings/memory-controllers/tegra-emc.txt > new file mode 100644 > index 0000000..da923b1 > --- /dev/null > +++ b/Documentation/devicetree/bindings/memory-controllers/tegra-emc.txt > @@ -0,0 +1,379 @@ > +NVIDIA Tegra124 SoC EMC (external memory controller) > +==================================================== > + > +Required properties : > +- compatible : Should be "nvidia,tegra124-emc". > +- reg : physical base address and length of the controller's registers. > +- nvidia,memory-controller : phandle of the MC driver. > + > +The node should contain a "emc-timings" subnode for each supported RAM type (see field RAM_CODE in > +register PMC_STRAPPING_OPT_A), with its unit address being its RAM_CODE. > + > +Required properties for "emc-timings" nodes : > +- nvidia,ram-code : Should contain the value of RAM_CODE this timing set is used for. > + > +Each "emc-timings" node should contain a "timing" subnode for every supported EMC clock rate. The > +"timing" subnodes should have the clock rate in Hz as their unit address. > + > +Required properties for "timing" nodes : > +- clock-frequency : Should contain the memory clock rate in Hz. > +- The following properties contain EMC timing characterization values (specified in the board > +documentation) : > + - nvidia,emc-auto-cal-config : EMC_AUTO_CAL_CONFIG > + - nvidia,emc-auto-cal-config2 : EMC_AUTO_CAL_CONFIG2 > + - nvidia,emc-auto-cal-config3 : EMC_AUTO_CAL_CONFIG3 > + - nvidia,emc-auto-cal-interval : EMC_AUTO_CAL_INTERVAL > + - nvidia,emc-bgbias-ctl0 : EMC_BGBIAS_CTL0 > + - nvidia,emc-cfg : EMC_CFG > + - nvidia,emc-cfg-2 : EMC_CFG_2 > + - nvidia,emc-cfg-dig-dll : EMC_CFG_DIG_DLL > + - nvidia,emc-ctt-term-ctrl : EMC_CTT_TERM_CTRL > + - nvidia,emc-mode-1 : Mode Register 1 > + - nvidia,emc-mode-2 : Mode Register 2 > + - nvidia,emc-mode-4 : Mode Register 4 > + - nvidia,emc-mode-reset : Mode Register 0 > + - nvidia,emc-mrs-wait-cnt : EMC_MRS_WAIT_CNT > + - nvidia,emc-sel-dpd-ctrl : EMC_SEL_DPD_CTRL > + - nvidia,emc-xm2dqspadctrl2 : EMC_XM2DQSPADCTRL2 > + - nvidia,emc-zcal-cnt-long : EMC_ZCAL_WAIT_CNT > + - nvidia,emc-zcal-interval : EMC_ZCAL_INTERVAL > +- nvidia,emc-configuration : EMC timing characterization data. These are the registers (see section > +"15.6.2 EMC Registers" in the TRM) whose values need to be specified, according to the board > +documentation: I'm a little bit confused by this. On the one hand, some registers are defined by dedicated DT properties, and on the other some are simply specified in the nvidia,emc-configuration array. I guess the rationale for this is to isolate the registers whose value may control the driver vs. those that simply needs to be written as-is. But in this case, why are some registers (like EMC_CFG_DIG_DLL) present in both lists, sometimes with different values? In the case of EMC_CFG_DIG_DLL, I also see that the read value of "nvidia,emc-cfg-dig-dll" seems to never be used anywhere in tegra124-emc.c. Should this property exist at all? Note that I have only checked this one, there might be others in the same case. Or maybe I completely misunderstood the intent here, in which case, please enlighten me. :) -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
