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

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@axis.com>
---
 Documentation/devicetree/bindings/net/stmmac.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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@axis.com>
> ---
>   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@st.com>
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From: Niklas Cassel <niklas.cassel@axis.com>
Date: Thu,  9 Nov 2017 18:09:26 +0100

> 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@axis.com>

Applied.
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