Re: [PATCH net-next] bindings: net: stmmac: correctify note about LPI interrupt

From: Alexandre Torgue
Date: Fri Nov 10 2017 - 05:47:54 EST




On 11/09/2017 06:09 PM, Niklas Cassel wrote:
There are two different combined signal for various interrupt events:
In EQOS-CORE and EQOS-MTL configurations, mci_intr_o is the interrupt
signal.
In EQOS-DMA, EQOS-AHB and EQOS-AXI configurations, these interrupt events
are combined with the events in the DMA on the sbd_intr_o signal.

Depending on configuration, the device tree irq "macirq" will refer to
either mci_intr_o or sbd_intr_o.

The databook states:
"The MAC generates the LPI interrupt when the Tx or Rx side enters or exits
the LPI state. The interrupt mci_intr_o (sbd_intr_o in certain
configurations) is asserted when the LPI interrupt status is set.

When the MAC exits the Rx LPI state, then in addition to the mci_intr_o
(sbd_intr_o in certain configurations), the sideband signal lpi_intr_o is
asserted.

If you do not want to gate-off the application clock during the Rx LPI
state, you can leave the lpi_intr_o signal unconnected and use the
mci_intr_o (sbd_intr_o in certain configurations) signal to detect Rx LPI
exit."

Since the "macirq" is always raised when Tx or Rx enters/exits the LPI
state, "eth_lpi" must therefore refer to lpi_intr_o, which is only raised
when Rx exits the LPI state. Update the DT binding description to reflect
reality.

Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxx>
---
Documentation/devicetree/bindings/net/stmmac.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
index c3a7be6615c5..3a28a5d8857d 100644
--- a/Documentation/devicetree/bindings/net/stmmac.txt
+++ b/Documentation/devicetree/bindings/net/stmmac.txt
@@ -12,7 +12,7 @@ Required properties:
Valid interrupt names are:
- "macirq" (combined signal for various interrupt events)
- "eth_wake_irq" (the interrupt to manage the remote wake-up packet detection)
- - "eth_lpi" (the interrupt that occurs when Tx or Rx enters/exits LPI state)
+ - "eth_lpi" (the interrupt that occurs when Rx exits the LPI state)
- phy-mode: See ethernet.txt file in the same directory.
- snps,reset-gpio gpio number for phy reset.
- snps,reset-active-low boolean flag to indicate if phy reset is active low.

Acked-by: Alexandre TORGUE <alexandre.torgue@xxxxxx>