| Message ID | 20240326130017.226875-3-christophe.roullier@foss.st.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Add properties in dwmac-stm32 documentation | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
diff --git a/Documentation/devicetree/bindings/net/stm32-dwmac.yaml b/Documentation/devicetree/bindings/net/stm32-dwmac.yaml index 80937b28fa046..529665d4fc911 100644 --- a/Documentation/devicetree/bindings/net/stm32-dwmac.yaml +++ b/Documentation/devicetree/bindings/net/stm32-dwmac.yaml @@ -85,6 +85,13 @@ properties: phy-supply: description: PHY regulator + st,ext-phyclk: + description: + set this property in RMII mode when you have PHY without crystal 50MHz and want to + select RCC clock instead of ETH_REF_CLK. OR in RGMII mode when you want to select + RCC clock instead of ETH_CLK125. + type: boolean + st,eth-clk-sel: description: set this property in RGMII PHY when you want to select RCC clock instead of ETH_CLK125.
The Linux kernel dwmac-stm32 driver currently supports three DT properties used to configure whether PHY clock are generated by the MAC or supplied to the MAC from the PHY. Originally there were two properties, st,eth-clk-sel and st,eth-ref-clk-sel, each used to configure MAC clocking in different bus mode and for different MAC clock frequency. Since it is possible to determine the MAC 'eth-ck' clock frequency from the clock subsystem and PHY bus mode from the 'phy-mode' property, two disparate DT properties are no longer required to configure MAC clocking. Linux kernel commit 1bb694e20839 ("net: ethernet: stmmac: simplify phy modes management for stm32") introduced a third, unified, property st,ext-phyclk. This property covers both use cases of st,eth-clk-sel and st,eth-ref-clk-sel DT properties, as well as a new use case for 25 MHz clock generated by the MAC. The third property st,ext-phyclk is so far undocumented, document it. Below table summarizes the clock requirement and clock sources for supported PHY interface modes. __________________________________________________________________________ |PHY_MODE | Normal | PHY wo crystal| PHY wo crystal |No 125Mhz from PHY| | | | 25MHz | 50MHz | | --------------------------------------------------------------------------- | MII | - | eth-ck | n/a | n/a | | | | st,ext-phyclk | | | --------------------------------------------------------------------------- | GMII | - | eth-ck | n/a | n/a | | | | st,ext-phyclk | | | --------------------------------------------------------------------------- | RGMII | - | eth-ck | n/a | eth-ck | | | | st,ext-phyclk | | st,eth-clk-sel or| | | | | | st,ext-phyclk | --------------------------------------------------------------------------- | RMII | - | eth-ck | eth-ck | n/a | | | | st,ext-phyclk | st,eth-ref-clk-sel | | | | | | or st,ext-phyclk | | --------------------------------------------------------------------------- Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Christophe Roullier <christophe.roullier@foss.st.com> --- Documentation/devicetree/bindings/net/stm32-dwmac.yaml | 7 +++++++ 1 file changed, 7 insertions(+)