From: "Marek Behún" <kabel@kernel.org>
To: Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org
Cc: "Vladimir Oltean" <olteanv@gmail.com>,
"Holger Brunck" <holger.brunck@hitachienergy.com>,
"Andrew Lunn" <andrew@lunn.ch>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"Russell King" <rmk+kernel@armlinux.org.uk>,
linux-phy@lists.infradead.org, "Vinod Koul" <vkoul@kernel.org>,
"Kishon Vijay Abraham I" <kishon@ti.com>,
"Marek Behún" <kabel@kernel.org>
Subject: [PATCH devicetree 2/2] dt-bindings: phy: Add `tx-amplitude-microvolt` property binding
Date: Wed, 15 Dec 2021 00:34:32 +0100 [thread overview]
Message-ID: <20211214233432.22580-3-kabel@kernel.org> (raw)
In-Reply-To: <20211214233432.22580-1-kabel@kernel.org>
Common PHYs often have the possibility to specify peak-to-peak voltage
on the differential pair - the default voltage sometimes needs to be
changed for a particular board.
Add properties `tx-amplitude-microvolt` and
`tx-amplitude-microvolt-names` for this purpose. The second property is
needed to specify
Example usage with only one voltage (it will be used for all supported
PHY modes, the `tx-amplitude-microvolt-names` property is not needed in
this case):
tx-amplitude-microvolt = <915000>;
Example usage with voltages for multiple modes:
tx-amplitude-microvolt = <915000>, <1100000>, <1200000>;
tx-amplitude-microvolt-names = "2500base-x", "usb", "pcie";
Signed-off-by: Marek Behún <kabel@kernel.org>
---
I wanted to constrain the values allowed in the
`tx-amplitude-microvolt-names` property to:
- ethernet SerDes modes (sgmii, qsgmii, 10gbase-r, 2500base-x, ...)
- PCIe modes (pattern: ^pcie[1-6]?$)
- USB modes (pattern: ^usb((-host|-device|-otg)?-(ls|fs|hs|ss|ss\+|4))?$)
- DisplayPort modes (pattern: ^dp(-rbr|-hbr[23]?|-uhbr-(10|13.5|20))?$)
- Camera modes (mipi-dphy, mipi-dphy-univ, mipi-dphy-v2.5-univ)
- Storage modes (sata, ufs-hs, ufs-hs-a, ufs-hs-b)
But was unable to. The '-names' suffix implies string-array type, and
string-array type does not allow to specify a type for all items in a
simple way, i.e.:
items:
enum:
- sgmii
- sata
- usb
...
Such constraint does work when changing ethernet controller's
`phy-connection-type` to array, see
https://lore.kernel.org/netdev/20211123164027.15618-2-kabel@kernel.org/
But it seems that string-array type prohibits this.
---
.../devicetree/bindings/phy/phy.yaml | 22 +++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/Documentation/devicetree/bindings/phy/phy.yaml b/Documentation/devicetree/bindings/phy/phy.yaml
index a5b6b04cff5b..8915065cf6c2 100644
--- a/Documentation/devicetree/bindings/phy/phy.yaml
+++ b/Documentation/devicetree/bindings/phy/phy.yaml
@@ -31,9 +31,29 @@ properties:
Phandle to a regulator that provides power to the PHY. This regulator
will be managed during the PHY power on/off sequence.
+ tx-amplitude-microvolt:
+ description:
+ Transmit amplitude voltages in microvolts, peak-to-peak. If this property
+ contains multiple values for various PHY modes, the
+ 'tx-amplitude-microvolt-names' property must be provided and contain
+ corresponding mode names.
+
+ tx-amplitude-microvolt-names:
+ description: |
+ Names of the modes corresponding to voltages in the
+ 'tx-amplitude-microvolt' property. Required only if multiple voltages
+ are provided.
+
+ If a value of 'default' is provided, the system should use it for any PHY
+ mode that is otherwise not defined here. If 'default' is not provided, the
+ system should use manufacturer default value.
+
required:
- '#phy-cells'
+dependencies:
+ tx-amplitude-microvolt-names: [ tx-amplitude-microvolt ]
+
additionalProperties: true
examples:
@@ -46,6 +66,8 @@ examples:
phy: phy {
#phy-cells = <1>;
phy-supply = <&phy_regulator>;
+ tx-amplitude-microvolt = <915000>, <1100000>, <1200000>;
+ tx-amplitude-microvolt-names = "2500base-x", "usb-hs", "usb-ss";
};
ethernet-controller {
--
2.32.0
next prev parent reply other threads:[~2021-12-14 23:34 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-14 23:34 [PATCH devicetree 0/2] Common PHY to YAML + tx-amplitude property Marek Behún
2021-12-14 23:34 ` [PATCH devicetree 1/2] dt-bindings: phy: Convert generic PHY provider binding to YAML Marek Behún
2021-12-15 21:41 ` Rob Herring
2021-12-14 23:34 ` Marek Behún [this message]
2021-12-15 10:55 ` [PATCH devicetree 2/2] dt-bindings: phy: Add `tx-amplitude-microvolt` property binding Andrew Lunn
2021-12-15 17:22 ` Marek Behún
2021-12-15 17:29 ` Andrew Lunn
2021-12-15 22:01 ` Rob Herring
2021-12-15 21:58 ` Rob Herring
2022-01-12 17:29 ` Marek Behún
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