Add helpers in the generic PHY folder which can be used using 'select
GENERIC_PHY_COMMON_PROPS' from Kconfig, without otherwise needing to
enable GENERIC_PHY.
These helpers need to deal with the slight messiness of the fact that
the polarity properties are arrays per protocol, and with the fact that
there is no default value mandated by the standard properties, all
default values depend on driver and protocol (PHY_POL_NORMAL may be a
good default for SGMII, whereas PHY_POL_AUTO may be a good default for
PCIe).
Push the supported mask of polarities to these helpers, to simplify
drivers such that they don't need to validate what's in the device tree
(or other firmware description).
The proposed maintainership model is joint custody between netdev and
linux-phy, because of the fact that these properties can be applied to
Ethernet PCS blocks just as well as Generic PHY devices. I've added as
maintainers those from "ETHERNET PHY LIBRARY", "NETWORKING DRIVERS" and
"GENERIC PHY FRAMEWORK".
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
MAINTAINERS | 21 +++++
drivers/phy/Kconfig | 9 +++
drivers/phy/Makefile | 1 +
drivers/phy/phy-common-props.c | 117 +++++++++++++++++++++++++++
include/linux/phy/phy-common-props.h | 20 +++++
5 files changed, 168 insertions(+)
create mode 100644 drivers/phy/phy-common-props.c
create mode 100644 include/linux/phy/phy-common-props.h
diff --git a/MAINTAINERS b/MAINTAINERS
index e9a8d945632b..658feb06cc29 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10445,6 +10445,27 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git
F: include/asm-generic/
F: include/uapi/asm-generic/
+GENERIC PHY COMMON PROPERTIES
+M: Andrew Lunn <andrew@lunn.ch>
+M: "David S. Miller" <davem@davemloft.net>
+M: Eric Dumazet <edumazet@google.com>
+M: Heiner Kallweit <hkallweit1@gmail.com>
+M: Jakub Kicinski <kuba@kernel.org>
+M: Kishon Vijay Abraham I <kishon@kernel.org>
+M: Paolo Abeni <pabeni@redhat.com>
+R: Russell King <linux@armlinux.org.uk>
+M: Vinod Koul <vkoul@kernel.org>
+L: linux-phy@lists.infradead.org
+L: netdev@vger.kernel.org
+S: Maintained
+Q: https://patchwork.kernel.org/project/linux-phy/list/
+Q: https://patchwork.kernel.org/project/netdevbpf/list/
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy.git
+F: Documentation/devicetree/bindings/phy/phy-common-props.yaml
+F: drivers/phy/phy-common-props.c
+
GENERIC PHY FRAMEWORK
M: Vinod Koul <vkoul@kernel.org>
M: Kishon Vijay Abraham I <kishon@kernel.org>
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 678dd0452f0a..479986434086 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -16,6 +16,15 @@ config GENERIC_PHY
phy users can obtain reference to the PHY. All the users of this
framework should select this config.
+config GENERIC_PHY_COMMON_PROPS
+ bool
+ help
+ Generic PHY common property parsing.
+
+ Select this from consumer drivers to gain access to helpers for
+ parsing properties from the
+ Documentation/devicetree/bindings/phy/phy-common-props.yaml schema.
+
config GENERIC_PHY_MIPI_DPHY
bool
select GENERIC_PHY
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index bfb27fb5a494..d07accc15086 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -4,6 +4,7 @@
#
obj-$(CONFIG_GENERIC_PHY) += phy-core.o
+obj-$(CONFIG_GENERIC_PHY_COMMON_PROPS) += phy-common-props.o
obj-$(CONFIG_GENERIC_PHY_MIPI_DPHY) += phy-core-mipi-dphy.o
obj-$(CONFIG_PHY_CAN_TRANSCEIVER) += phy-can-transceiver.o
obj-$(CONFIG_PHY_LPC18XX_USB_OTG) += phy-lpc18xx-usb-otg.o
diff --git a/drivers/phy/phy-common-props.c b/drivers/phy/phy-common-props.c
new file mode 100644
index 000000000000..4c9dca98d23f
--- /dev/null
+++ b/drivers/phy/phy-common-props.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * phy-common-props.c -- Common PHY properties
+ *
+ * Copyright 2025 NXP
+ */
+#include <linux/export.h>
+#include <linux/fwnode.h>
+#include <linux/phy/phy-common-props.h>
+#include <linux/printk.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+static int phy_get_polarity_for_mode(struct fwnode_handle *fwnode,
+ const char *mode_name,
+ unsigned int supported,
+ unsigned int default_val,
+ const char *polarity_prop,
+ const char *names_prop)
+{
+ int err, n_pols, n_names, idx = -1;
+ u32 val, *pols;
+
+ if (!fwnode)
+ return default_val;
+
+ n_pols = fwnode_property_count_u32(fwnode, polarity_prop);
+ if (n_pols <= 0)
+ return default_val;
+
+ n_names = fwnode_property_string_array_count(fwnode, names_prop);
+ if (n_names >= 0 && n_pols != n_names) {
+ pr_err("%pfw mismatch between \"%s\" and \"%s\" property count (%d vs %d)\n",
+ fwnode, polarity_prop, names_prop, n_pols, n_names);
+ return -EINVAL;
+ }
+
+ if (mode_name)
+ idx = fwnode_property_match_string(fwnode, names_prop, mode_name);
+ if (idx < 0)
+ idx = fwnode_property_match_string(fwnode, names_prop, "default");
+ /*
+ * If the mode name is missing, it can only mean the specified polarity
+ * is the default one for all modes, so reject any other polarity count
+ * than 1.
+ */
+ if (idx < 0 && n_pols != 1) {
+ pr_err("%pfw \"%s \" property has %d elements, but cannot find \"%s\" in \"%s\" and there is no default value\n",
+ fwnode, polarity_prop, n_pols, mode_name, names_prop);
+ return -EINVAL;
+ }
+
+ if (n_pols == 1) {
+ err = fwnode_property_read_u32(fwnode, polarity_prop, &val);
+ if (err)
+ return err;
+
+ return val;
+ }
+
+ /* We implicitly know idx >= 0 here */
+ pols = kcalloc(n_pols, sizeof(*pols), GFP_KERNEL);
+ if (!pols)
+ return -ENOMEM;
+
+ err = fwnode_property_read_u32_array(fwnode, polarity_prop, pols, n_pols);
+ if (err == 0) {
+ val = pols[idx];
+ if (!(supported & BIT(val))) {
+ pr_err("%pfw mismatch between '%s' and '%s' property count (%d vs %d)\n",
+ fwnode, polarity_prop, names_prop, n_pols, n_names);
+ err = -EOPNOTSUPP;
+ }
+ }
+
+ kfree(pols);
+
+ return (err < 0) ? err : val;
+}
+
+/**
+ * phy_get_rx_polarity - Get RX polarity for PHY differential lane
+ * @fwnode: Pointer to the PHY's firmware node.
+ * @mode_name: The name of the PHY mode to look up.
+ * @supported: Bit mask of PHY_POL_NORMAL, PHY_POL_INVERT and PHY_POL_AUTO
+ * @default_val: Default polarity value if property is missing
+ *
+ * Return: One of PHY_POL_NORMAL, PHY_POL_INVERT or PHY_POL_AUTO on success, or
+ * negative error on failure.
+ */
+int phy_get_rx_polarity(struct fwnode_handle *fwnode, const char *mode_name,
+ unsigned int supported, unsigned int default_val)
+{
+ return phy_get_polarity_for_mode(fwnode, mode_name, supported,
+ default_val, "rx-polarity",
+ "rx-polarity-names");
+}
+EXPORT_SYMBOL_GPL(phy_get_rx_polarity);
+
+/**
+ * phy_get_tx_polarity - Get TX polarity for PHY differential lane
+ * @fwnode: Pointer to the PHY's firmware node.
+ * @mode_name: The name of the PHY mode to look up.
+ * @supported: Bit mask of PHY_POL_NORMAL and PHY_POL_INVERT
+ * @default_val: Default polarity value if property is missing
+ *
+ * Return: One of PHY_POL_NORMAL or PHY_POL_INVERT on success, or negative
+ * error on failure.
+ */
+int phy_get_tx_polarity(struct fwnode_handle *fwnode, const char *mode_name,
+ unsigned int supported, unsigned int default_val)
+{
+ return phy_get_polarity_for_mode(fwnode, mode_name, supported,
+ default_val, "tx-polarity",
+ "tx-polarity-names");
+}
+EXPORT_SYMBOL_GPL(phy_get_tx_polarity);
diff --git a/include/linux/phy/phy-common-props.h b/include/linux/phy/phy-common-props.h
new file mode 100644
index 000000000000..0b8ba76e2a15
--- /dev/null
+++ b/include/linux/phy/phy-common-props.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phy-common-props.h -- Common properties for generic PHYs
+ *
+ * Copyright 2025 NXP
+ */
+
+#ifndef __PHY_COMMON_PROPS_H
+#define __PHY_COMMON_PROPS_H
+
+#include <dt-bindings/phy/phy.h>
+
+struct fwnode_handle;
+
+int phy_get_rx_polarity(struct fwnode_handle *fwnode, const char *mode_name,
+ unsigned int supported, unsigned int default_val);
+int phy_get_tx_polarity(struct fwnode_handle *fwnode, const char *mode_name,
+ unsigned int supported, unsigned int default_val);
+
+#endif /* __PHY_COMMON_PROPS_H */
--
2.34.1On Sat, 22 Nov 2025 21:33:37 +0200 Vladimir Oltean wrote: > Add helpers in the generic PHY folder which can be used using 'select > GENERIC_PHY_COMMON_PROPS' from Kconfig, without otherwise needing to > enable GENERIC_PHY. > > These helpers need to deal with the slight messiness of the fact that > the polarity properties are arrays per protocol, and with the fact that > there is no default value mandated by the standard properties, all > default values depend on driver and protocol (PHY_POL_NORMAL may be a > good default for SGMII, whereas PHY_POL_AUTO may be a good default for > PCIe). > > Push the supported mask of polarities to these helpers, to simplify > drivers such that they don't need to validate what's in the device tree > (or other firmware description). > > The proposed maintainership model is joint custody between netdev and > linux-phy, because of the fact that these properties can be applied to > Ethernet PCS blocks just as well as Generic PHY devices. I've added as > maintainers those from "ETHERNET PHY LIBRARY", "NETWORKING DRIVERS" and > "GENERIC PHY FRAMEWORK". I dunno.. ain't no such thing as "joint custody" maintainership. We have to pick one tree. Given the set of Ms here, I suspect the best course of action may be to bubble this up to its own tree. Ask Konstantin for a tree in k.org, then you can "co-post" the patches for review + PR link in the cover letter (e.g. how Tony from Intel submits their patches). This way not networking and PHY can pull the shared changes with stable commit IDs. We can do out-of-sequence netdev call tomorrow if folks want to talk this thru (8:30am Pacific) > +GENERIC PHY COMMON PROPERTIES > +M: Andrew Lunn <andrew@lunn.ch> > +M: "David S. Miller" <davem@davemloft.net> > +M: Eric Dumazet <edumazet@google.com> > +M: Heiner Kallweit <hkallweit1@gmail.com> > +M: Jakub Kicinski <kuba@kernel.org> > +M: Kishon Vijay Abraham I <kishon@kernel.org> > +M: Paolo Abeni <pabeni@redhat.com> > +R: Russell King <linux@armlinux.org.uk> > +M: Vinod Koul <vkoul@kernel.org> checkpatch nit: apparently it wants all Ms first, then all Rs. > +L: linux-phy@lists.infradead.org > +L: netdev@vger.kernel.org > +S: Maintained > +Q: https://patchwork.kernel.org/project/linux-phy/list/ > +Q: https://patchwork.kernel.org/project/netdevbpf/list/ > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy.git > +F: Documentation/devicetree/bindings/phy/phy-common-props.yaml > +F: drivers/phy/phy-common-props.c -- pw-bot: cr
On 24-11-25, 20:01, Jakub Kicinski wrote: > On Sat, 22 Nov 2025 21:33:37 +0200 Vladimir Oltean wrote: > > Add helpers in the generic PHY folder which can be used using 'select > > GENERIC_PHY_COMMON_PROPS' from Kconfig, without otherwise needing to > > enable GENERIC_PHY. > > > > These helpers need to deal with the slight messiness of the fact that > > the polarity properties are arrays per protocol, and with the fact that > > there is no default value mandated by the standard properties, all > > default values depend on driver and protocol (PHY_POL_NORMAL may be a > > good default for SGMII, whereas PHY_POL_AUTO may be a good default for > > PCIe). > > > > Push the supported mask of polarities to these helpers, to simplify > > drivers such that they don't need to validate what's in the device tree > > (or other firmware description). > > > > The proposed maintainership model is joint custody between netdev and > > linux-phy, because of the fact that these properties can be applied to > > Ethernet PCS blocks just as well as Generic PHY devices. I've added as > > maintainers those from "ETHERNET PHY LIBRARY", "NETWORKING DRIVERS" and > > "GENERIC PHY FRAMEWORK". > > I dunno.. ain't no such thing as "joint custody" maintainership. > We have to pick one tree. Given the set of Ms here, I suspect > the best course of action may be to bubble this up to its own tree. > Ask Konstantin for a tree in k.org, then you can "co-post" the patches > for review + PR link in the cover letter (e.g. how Tony from Intel > submits their patches). This way not networking and PHY can pull > the shared changes with stable commit IDs. How much is the volume of the changes that we are talking about, we can always ack and pull into each other trees..? BR -- ~Vinod
On Mon, 1 Dec 2025 14:07:58 +0530 Vinod Koul wrote: > > > Push the supported mask of polarities to these helpers, to simplify > > > drivers such that they don't need to validate what's in the device tree > > > (or other firmware description). > > > > > > The proposed maintainership model is joint custody between netdev and > > > linux-phy, because of the fact that these properties can be applied to > > > Ethernet PCS blocks just as well as Generic PHY devices. I've added as > > > maintainers those from "ETHERNET PHY LIBRARY", "NETWORKING DRIVERS" and > > > "GENERIC PHY FRAMEWORK". > > > > I dunno.. ain't no such thing as "joint custody" maintainership. > > We have to pick one tree. Given the set of Ms here, I suspect > > the best course of action may be to bubble this up to its own tree. > > Ask Konstantin for a tree in k.org, then you can "co-post" the patches > > for review + PR link in the cover letter (e.g. how Tony from Intel > > submits their patches). This way not networking and PHY can pull > > the shared changes with stable commit IDs. > > How much is the volume of the changes that we are talking about, we can > always ack and pull into each other trees..? We have such ad-hoc situations with multiple subsystems. Letting Vladimir and co create their own tree is basically shifting the work of managing the stable branches from netdev maintainers downstream. I'd strongly prefer that we lean on git in this way, rather than reenact the 3 spiderman meme multiple times in each release.
On 01/12/2025 09:37, Vinod Koul wrote: > On 24-11-25, 20:01, Jakub Kicinski wrote: >> On Sat, 22 Nov 2025 21:33:37 +0200 Vladimir Oltean wrote: >>> Add helpers in the generic PHY folder which can be used using 'select >>> GENERIC_PHY_COMMON_PROPS' from Kconfig, without otherwise needing to >>> enable GENERIC_PHY. >>> >>> These helpers need to deal with the slight messiness of the fact that >>> the polarity properties are arrays per protocol, and with the fact that >>> there is no default value mandated by the standard properties, all >>> default values depend on driver and protocol (PHY_POL_NORMAL may be a >>> good default for SGMII, whereas PHY_POL_AUTO may be a good default for >>> PCIe). >>> >>> Push the supported mask of polarities to these helpers, to simplify >>> drivers such that they don't need to validate what's in the device tree >>> (or other firmware description). >>> >>> The proposed maintainership model is joint custody between netdev and >>> linux-phy, because of the fact that these properties can be applied to >>> Ethernet PCS blocks just as well as Generic PHY devices. I've added as >>> maintainers those from "ETHERNET PHY LIBRARY", "NETWORKING DRIVERS" and >>> "GENERIC PHY FRAMEWORK". >> >> I dunno.. ain't no such thing as "joint custody" maintainership. >> We have to pick one tree. Given the set of Ms here, I suspect >> the best course of action may be to bubble this up to its own tree. >> Ask Konstantin for a tree in k.org, then you can "co-post" the patches >> for review + PR link in the cover letter (e.g. how Tony from Intel >> submits their patches). This way not networking and PHY can pull >> the shared changes with stable commit IDs. > > How much is the volume of the changes that we are talking about, we can > always ack and pull into each other trees..? That's just one C file, isn't it? Having dedicated tree for one file feels like huge overhead. Best regards, Krzysztof
On Mon, Nov 24, 2025 at 08:01:21PM -0800, Jakub Kicinski wrote: > > The proposed maintainership model is joint custody between netdev and > > linux-phy, because of the fact that these properties can be applied to > > Ethernet PCS blocks just as well as Generic PHY devices. I've added as > > maintainers those from "ETHERNET PHY LIBRARY", "NETWORKING DRIVERS" and > > "GENERIC PHY FRAMEWORK". > > I dunno.. ain't no such thing as "joint custody" maintainership. > We have to pick one tree. Given the set of Ms here, I suspect > the best course of action may be to bubble this up to its own tree. > Ask Konstantin for a tree in k.org, then you can "co-post" the patches > for review + PR link in the cover letter (e.g. how Tony from Intel > submits their patches). This way not networking and PHY can pull > the shared changes with stable commit IDs. I can see how this makes some sense. If nobody has any objection, I'll follow up to this by emailing Konstantin about a git tree for shared infrastructure between generic PHY and networking. > We can do out-of-sequence netdev call tomorrow if folks want to talk > this thru (8:30am Pacific) Not sure it's that big of a discussion topic. > > +GENERIC PHY COMMON PROPERTIES > > +M: Andrew Lunn <andrew@lunn.ch> > > +M: "David S. Miller" <davem@davemloft.net> > > +M: Eric Dumazet <edumazet@google.com> > > +M: Heiner Kallweit <hkallweit1@gmail.com> > > +M: Jakub Kicinski <kuba@kernel.org> > > +M: Kishon Vijay Abraham I <kishon@kernel.org> > > +M: Paolo Abeni <pabeni@redhat.com> > > +R: Russell King <linux@armlinux.org.uk> > > +M: Vinod Koul <vkoul@kernel.org> > > checkpatch nit: apparently it wants all Ms first, then all Rs. Thanks for pointing this out. This will probably have to be changed quite a bit in v2 if the "separate git tree" idea is going to be implemented. I'll probably start with an empty list and request volunteers to step up.
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