On 09/01/2016 01:50 AM, Lars Persson wrote:
On 08/31/2016 11:48 PM, Stephen Warren wrote:
On 08/31/2016 03:15 AM, Lars Persson wrote:
On 08/30/2016 10:50 PM, Stephen Warren wrote:
On 08/30/2016 01:01 PM, Rob Herring wrote:
On Wed, Aug 24, 2016 at 03:20:46PM -0600, Stephen Warren wrote:
The Synopsys DWC EQoS is a configurable IP block which supports
multiple
options for bus type, clocking and reset structure, and feature list.
Extend the DT binding to define a "compatible value" for the
configuration
contained in NVIDIA's Tegra186 SoC, and define some new properties
and
list property entries required by that configuration.
diff --git
a/Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt
b/Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt
+- clock-names: May contain any/all of the following depending on
the IP
+ configuration, in any order:
+ The EQOS transmit path clock. The HW signal name is clk_tx_i.
+ In some configurations (e.g. GMII/RGMII), this clock also drives
the PHY TX
+ path. In other configurations, other clocks (such as tx_125,
rmii) may
+ drive the PHY TX path.
+ - "rx"
+ The EQOS receive path clock. The HW signal name is clk_rx_i.
+ In some configurations (e.g. GMII/RGMII), this clock also drives
the PHY RX
+ path. In other configurations, other clocks (such as rx_125,
pmarx_0,
+ pmarx_1, rmii) may drive the PHY RX path.
It is not correct that clk_rx_i drives the PHY rx path for GMII/RGMII.
The PHY is the source of the rx clock for these modes.
I think both of our statements are true.
There's a clock input to the EQOS module (clk_rx_i) that does drive the
RX path in the EQOS module.
That clock also drives the PHY's RX path.
Those statements make no comment regarding the /source/ of that clock;
either of the following might be true:
1) The PHY could generate the clock internally somehow, feed its own
internal logic with that clock, and send the clock out to feed the EQOS
RX path too.
or,
2) SoC integration could drive the same clock into both the EQOS and
PHY modules, so that both sets of logic are fed from the same external
clock.
Perhaps the phrase "PHY RX path" is confusing; I was talking about the
EQOS modules' RX path from the PHY more than the PHY itself, although
given what I said above I believe either interpretation is valid and
correct.
Will the driver need to make any clock ops on the "rx" clock ?
Yes. The EQOS driver needs to ensure that the clock is running before
attempting to receive data from the PHY, otherwise the EQOS's own RX
logic won't be clocked.
Whether the phandle for this clock points at a SoC-level provider (it
will in Tegra) or a clock provider in the PHY (it might in other SoCs),
shouldn't matter as far as the DT binding goes, although it might affect
device probe ordering in some implementations.
I understand your point. The lines between PHY, MAC and SoC gets blurred
with high integration.
The thing is that when we talk about standard PHY interfaces the clock
is a well defined part of the interface and it should not be mixed up
with SoC-specific implementations that deviate from this. Please update
the description of the rx clock to only cover cases when the clock is
not implicitly sourced from the PHY.
When the PHY is the source of the clock then it is managed by the phy
library and the phy driver so it does not need to be also handled by the
common clock framework.
Ah, I've found the source of confusion. We don't have an SoC-level clock
that feeds both the MAC and the PHY RX logic, but simply a clock gate
that sits between the RX clock output of the PHY and the RX clock input
of the MAC (clk_rx_i). This gate is what's currently represented by the
"rx" clock name the binding mentions.
tl;dr is that yes I agree to update the description of this rx clock
along the lines you ask for.
--
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
