Re: [PATCH v3) posix-timers: make it configurable

From: Nicolas Pitre
Date: Fri Sep 16 2016 - 22:58:17 EST


On Fri, 16 Sep 2016, Richard Cochran wrote:

> On Thu, Sep 15, 2016 at 02:56:49PM -0700, Josh Triplett wrote:
> > > I suspect there is more of a case for having net drivers _without_ ptp
> > > support. This could be implemented with a ptp_clock_register() stub
> > > returning NULL when ptp is not configured. I didn't look at most
> > > drivers but at least broadcom/tg3.c seems to be fine with such an
> > > approach.
>
> (I wouldn't be suprised if some drivers fail to deal with NULL
> gracefully, but those can always be fixed ;)

I've looked at all of them and I think they should be fine with the
minor changes I've included below. Tested with allyesconfig and
CONFIG_POSIX_TIMERS=n.

----- >8
Subject: [PATCH] ptp_clock: allow for it to be optional

In order to break the hard dependency between the PTP clock subsystem and
ethernet drivers capable of being clock providers, this patch provides
simple PTP stub functions to allow linkage of those drivers into the
kernel even when the PTP subsystem is configured out.

And to make it possible for PTP to be configured out, the select statement
in the Kconfig entry for those ethernet drivers is changed from selecting
PTP_1588_CLOCK to PTP_1588_CLOCK_DEFAULT whose purpose is to indicate the
default Kconfig value for the PTP subsystem.

This way the PTP subsystem may have Kconfig dependencies of its own, such
as POSIX_TIMERS, without making those ethernet drivers unavailable if
POSIX timers are cconfigured out. And when support for POSIX timers is
selected again then PTP clock support will also be selected accordingly.

Drivers must be ready to accept NULL from ptp_clock_register().
The pch_gbe driver is a bit special as it relies on extra code in
drivers/ptp/ptp_pch.c. Therefore we let the make process descend into
drivers/ptp/ even if PTP_1588_CLOCK is unselected.

Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxx>

diff --git a/drivers/Makefile b/drivers/Makefile
index 53abb4a5f7..8a538d0856 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -105,7 +105,7 @@ obj-$(CONFIG_INPUT) += input/
obj-$(CONFIG_RTC_LIB) += rtc/
obj-y += i2c/ media/
obj-$(CONFIG_PPS) += pps/
-obj-$(CONFIG_PTP_1588_CLOCK) += ptp/
+obj-y += ptp/
obj-$(CONFIG_W1) += w1/
obj-y += power/
obj-$(CONFIG_HWMON) += hwmon/
diff --git a/drivers/net/ethernet/adi/Kconfig b/drivers/net/ethernet/adi/Kconfig
index 6b94ba6103..eea414337c 100644
--- a/drivers/net/ethernet/adi/Kconfig
+++ b/drivers/net/ethernet/adi/Kconfig
@@ -55,10 +55,14 @@ config BFIN_RX_DESC_NUM
---help---
Set the number of buffer packets used in driver.

+config BFIN_MAC_HAS_HWSTAMP
+ def_tristate BFIN_MAC
+ depends on BF518
+ select PTP_1588_CLOCK_DEFAULT
+
config BFIN_MAC_USE_HWSTAMP
bool "Use IEEE 1588 hwstamp"
- depends on BFIN_MAC && BF518
- select PTP_1588_CLOCK
+ depends on BFIN_MAC_HAS_HWSTAMP && PTP_1588_CLOCK
default y
---help---
To support the IEEE 1588 Precision Time Protocol (PTP), select y here
diff --git a/drivers/net/ethernet/amd/Kconfig b/drivers/net/ethernet/amd/Kconfig
index 0038709fd3..c2aaa5f949 100644
--- a/drivers/net/ethernet/amd/Kconfig
+++ b/drivers/net/ethernet/amd/Kconfig
@@ -177,7 +177,7 @@ config AMD_XGBE
depends on ARM64 || COMPILE_TEST
select BITREVERSE
select CRC32
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports the AMD 10GbE Ethernet device found on an
AMD SoC.
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-main.c b/drivers/net/ethernet/amd/xgbe/xgbe-main.c
index 3eee3201b5..4aeeb018b6 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-main.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-main.c
@@ -773,7 +773,8 @@ static int xgbe_probe(struct platform_device *pdev)
goto err_wq;
}

- xgbe_ptp_register(pdata);
+ if (IS_REACHABLE(CONFIG_PTP_1588_CLOCK))
+ xgbe_ptp_register(pdata);

xgbe_debugfs_init(pdata);

@@ -812,7 +813,8 @@ static int xgbe_remove(struct platform_device *pdev)

xgbe_debugfs_exit(pdata);

- xgbe_ptp_unregister(pdata);
+ if (IS_REACHABLE(CONFIG_PTP_1588_CLOCK))
+ xgbe_ptp_unregister(pdata);

flush_workqueue(pdata->an_workqueue);
destroy_workqueue(pdata->an_workqueue);
diff --git a/drivers/net/ethernet/broadcom/Kconfig b/drivers/net/ethernet/broadcom/Kconfig
index bd8c80c0b7..9c53786a5c 100644
--- a/drivers/net/ethernet/broadcom/Kconfig
+++ b/drivers/net/ethernet/broadcom/Kconfig
@@ -110,7 +110,7 @@ config TIGON3
depends on PCI
select PHYLIB
select HWMON
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports Broadcom Tigon3 based gigabit Ethernet cards.

@@ -120,7 +120,7 @@ config TIGON3
config BNX2X
tristate "Broadcom NetXtremeII 10Gb support"
depends on PCI
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
select FW_LOADER
select ZLIB_INFLATE
select LIBCRC32C
diff --git a/drivers/net/ethernet/cavium/Kconfig b/drivers/net/ethernet/cavium/Kconfig
index e1b78b5003..ee08b27e4f 100644
--- a/drivers/net/ethernet/cavium/Kconfig
+++ b/drivers/net/ethernet/cavium/Kconfig
@@ -53,7 +53,7 @@ config THUNDER_NIC_RGX
config LIQUIDIO
tristate "Cavium LiquidIO support"
depends on 64BIT
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
select FW_LOADER
select LIBCRC32C
---help---
diff --git a/drivers/net/ethernet/freescale/Kconfig b/drivers/net/ethernet/freescale/Kconfig
index d1ca45fbb1..3b46e167e6 100644
--- a/drivers/net/ethernet/freescale/Kconfig
+++ b/drivers/net/ethernet/freescale/Kconfig
@@ -25,7 +25,7 @@ config FEC
ARCH_MXC || SOC_IMX28)
default ARCH_MXC || SOC_IMX28 if ARM
select PHYLIB
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
Say Y here if you want to use the built-in 10/100 Fast ethernet
controller on some Motorola ColdFire and Freescale i.MX processors.
diff --git a/drivers/net/ethernet/intel/Kconfig b/drivers/net/ethernet/intel/Kconfig
index c0e17433f6..d41b455e5f 100644
--- a/drivers/net/ethernet/intel/Kconfig
+++ b/drivers/net/ethernet/intel/Kconfig
@@ -58,7 +58,7 @@ config E1000E
tristate "Intel(R) PRO/1000 PCI-Express Gigabit Ethernet support"
depends on PCI && (!SPARC32 || BROKEN)
select CRC32
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports the PCI-Express Intel(R) PRO/1000 gigabit
ethernet family of adapters. For PCI or PCI-X e1000 adapters,
@@ -83,7 +83,7 @@ config E1000E_HWTS
config IGB
tristate "Intel(R) 82575/82576 PCI-Express Gigabit Ethernet support"
depends on PCI
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
select I2C
select I2C_ALGOBIT
---help---
@@ -156,7 +156,7 @@ config IXGBE
tristate "Intel(R) 10GbE PCI Express adapters support"
depends on PCI
select MDIO
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports Intel(R) 10GbE PCI Express family of
adapters. For more information on how to identify your adapter, go
@@ -213,7 +213,7 @@ config IXGBEVF

config I40E
tristate "Intel(R) Ethernet Controller XL710 Family support"
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
depends on PCI
---help---
This driver supports Intel(R) Ethernet Controller XL710 Family of
@@ -264,7 +264,7 @@ config FM10K
tristate "Intel(R) FM10000 Ethernet Switch Host Interface Support"
default n
depends on PCI_MSI
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports Intel(R) FM10000 Ethernet Switch Host
Interface. For more information on how to identify your adapter,
diff --git a/drivers/net/ethernet/intel/e1000e/ptp.c b/drivers/net/ethernet/intel/e1000e/ptp.c
index 2e1b17ad52..ad03763e00 100644
--- a/drivers/net/ethernet/intel/e1000e/ptp.c
+++ b/drivers/net/ethernet/intel/e1000e/ptp.c
@@ -334,7 +334,7 @@ void e1000e_ptp_init(struct e1000_adapter *adapter)
if (IS_ERR(adapter->ptp_clock)) {
adapter->ptp_clock = NULL;
e_err("ptp_clock_register failed\n");
- } else {
+ } else if (adapter->ptp_clock) {
e_info("registered PHC clock\n");
}
}
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ptp.c b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
index ed39cbad24..f1feceab75 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
@@ -669,7 +669,7 @@ void i40e_ptp_init(struct i40e_pf *pf)
pf->ptp_clock = NULL;
dev_err(&pf->pdev->dev, "%s: ptp_clock_register failed\n",
__func__);
- } else {
+ } else if (pf->ptp_clock) {
struct timespec64 ts;
u32 regval;

diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 66dfa2085c..1dd14e166d 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -1159,7 +1159,7 @@ void igb_ptp_init(struct igb_adapter *adapter)
if (IS_ERR(adapter->ptp_clock)) {
adapter->ptp_clock = NULL;
dev_err(&adapter->pdev->dev, "ptp_clock_register failed\n");
- } else {
+ } else if (adapter->ptp_clock) {
dev_info(&adapter->pdev->dev, "added PHC on %s\n",
adapter->netdev->name);
adapter->ptp_flags |= IGB_PTP_ENABLED;
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
index e5431bfe33..a92277683a 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
@@ -1254,7 +1254,7 @@ static long ixgbe_ptp_create_clock(struct ixgbe_adapter *adapter)
adapter->ptp_clock = NULL;
e_dev_err("ptp_clock_register failed\n");
return err;
- } else
+ } else if (adapter->ptp_clock)
e_dev_info("registered PHC device on %s\n", netdev->name);

/* set default timestamp mode to disabled here. We do this in
diff --git a/drivers/net/ethernet/mellanox/mlx4/Kconfig b/drivers/net/ethernet/mellanox/mlx4/Kconfig
index 5098e7f219..bc37746046 100644
--- a/drivers/net/ethernet/mellanox/mlx4/Kconfig
+++ b/drivers/net/ethernet/mellanox/mlx4/Kconfig
@@ -7,7 +7,7 @@ config MLX4_EN
depends on MAY_USE_DEVLINK
depends on PCI
select MLX4_CORE
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports Mellanox Technologies ConnectX Ethernet
devices.
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 1494997c4f..08fc5fc56d 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -298,7 +298,7 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
if (IS_ERR(mdev->ptp_clock)) {
mdev->ptp_clock = NULL;
mlx4_err(mdev, "ptp_clock_register failed\n");
- } else {
+ } else if (mdev->ptp_clock) {
mlx4_info(mdev, "registered PHC clock\n");
}

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/Kconfig b/drivers/net/ethernet/mellanox/mlx5/core/Kconfig
index aae46884bf..14e06b6cea 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/Kconfig
+++ b/drivers/net/ethernet/mellanox/mlx5/core/Kconfig
@@ -14,7 +14,7 @@ config MLX5_CORE
config MLX5_CORE_EN
bool "Mellanox Technologies ConnectX-4 Ethernet support"
depends on NETDEVICES && ETHERNET && PCI && MLX5_CORE
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
default n
---help---
Ethernet support in Mellanox Technologies ConnectX-4 NIC.
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
index 847a8f3ac2..13dc388667 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
@@ -273,7 +273,7 @@ void mlx5e_timestamp_init(struct mlx5e_priv *priv)

tstamp->ptp = ptp_clock_register(&tstamp->ptp_info,
&priv->mdev->pdev->dev);
- if (IS_ERR_OR_NULL(tstamp->ptp)) {
+ if (IS_ERR(tstamp->ptp)) {
mlx5_core_warn(priv->mdev, "ptp_clock_register failed %ld\n",
PTR_ERR(tstamp->ptp));
tstamp->ptp = NULL;
diff --git a/drivers/net/ethernet/renesas/Kconfig b/drivers/net/ethernet/renesas/Kconfig
index 4f132cf177..ab2dec643f 100644
--- a/drivers/net/ethernet/renesas/Kconfig
+++ b/drivers/net/ethernet/renesas/Kconfig
@@ -37,7 +37,7 @@ config RAVB
select MII
select MDIO_BITBANG
select PHYLIB
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
help
Renesas Ethernet AVB device driver.
This driver supports the following SoCs:
diff --git a/drivers/net/ethernet/samsung/Kconfig b/drivers/net/ethernet/samsung/Kconfig
index 2360d81507..14fb8185d2 100644
--- a/drivers/net/ethernet/samsung/Kconfig
+++ b/drivers/net/ethernet/samsung/Kconfig
@@ -21,7 +21,7 @@ config SXGBE_ETH
depends on HAS_IOMEM && HAS_DMA
select PHYLIB
select CRC32
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This is the driver for the SXGBE 10G Ethernet IP block found on
Samsung platforms.
diff --git a/drivers/net/ethernet/sfc/Kconfig b/drivers/net/ethernet/sfc/Kconfig
index 4dd92b7b80..623731ce00 100644
--- a/drivers/net/ethernet/sfc/Kconfig
+++ b/drivers/net/ethernet/sfc/Kconfig
@@ -5,7 +5,7 @@ config SFC
select CRC32
select I2C
select I2C_ALGOBIT
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports 10/40-gigabit Ethernet cards based on
the Solarflare SFC4000, SFC9000-family and SFC9100-family
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index dd204d9704..77a5364f7a 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -1269,13 +1269,13 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
if (IS_ERR(ptp->phc_clock)) {
rc = PTR_ERR(ptp->phc_clock);
goto fail3;
- }
-
- INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
- ptp->pps_workwq = create_singlethread_workqueue("sfc_pps");
- if (!ptp->pps_workwq) {
- rc = -ENOMEM;
- goto fail4;
+ } else if (ptp->phc_clock) {
+ INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
+ ptp->pps_workwq = create_singlethread_workqueue("sfc_pps");
+ if (!ptp->pps_workwq) {
+ rc = -ENOMEM;
+ goto fail4;
+ }
}
}
ptp->nic_ts_enabled = false;
diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index 8f06a6621a..4bafe20d5f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -4,7 +4,7 @@ config STMMAC_ETH
select MII
select PHYLIB
select CRC32
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
select RESET_CONTROLLER
---help---
This is the driver for the Ethernet IPs are built around a
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 170a18b612..6e3b82972c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -187,7 +187,7 @@ int stmmac_ptp_register(struct stmmac_priv *priv)
if (IS_ERR(priv->ptp_clock)) {
priv->ptp_clock = NULL;
pr_err("ptp_clock_register() failed on %s\n", priv->dev->name);
- } else
+ } else if (priv->ptp_clock)
pr_debug("Added PTP HW clock successfully on %s\n",
priv->dev->name);

diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
index 9904d740d5..c7ae90858f 100644
--- a/drivers/net/ethernet/ti/Kconfig
+++ b/drivers/net/ethernet/ti/Kconfig
@@ -76,7 +76,7 @@ config TI_CPSW
config TI_CPTS
bool "TI Common Platform Time Sync (CPTS) Support"
depends on TI_CPSW
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
---help---
This driver supports the Common Platform Time Sync unit of
the CPSW Ethernet Switch. The unit can time stamp PTP UDP/IPv4
diff --git a/drivers/net/ethernet/tile/Kconfig b/drivers/net/ethernet/tile/Kconfig
index f59a6c2653..d21cd822c3 100644
--- a/drivers/net/ethernet/tile/Kconfig
+++ b/drivers/net/ethernet/tile/Kconfig
@@ -9,7 +9,7 @@ config TILE_NET
select CRC32
select TILE_GXIO_MPIPE if TILEGX
select HIGH_RES_TIMERS if TILEGX
- select PTP_1588_CLOCK if TILEGX
+ select PTP_1588_CLOCK_DEFAULT if TILEGX
---help---
This is a standard Linux network device driver for the
on-chip Tilera Gigabit Ethernet and XAUI interfaces.
diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index 00e6098e9a..c36c018f0f 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -4,8 +4,12 @@

menu "PTP clock support"

+config PTP_1588_CLOCK_DEFAULT
+ tristate
+
config PTP_1588_CLOCK
tristate "PTP clock support"
+ default PTP_1588_CLOCK_DEFAULT
depends on NET && POSIX_TIMERS
select PPS
select NET_PTP_CLASSIFY
@@ -28,7 +32,7 @@ config PTP_1588_CLOCK
config PTP_1588_CLOCK_GIANFAR
tristate "Freescale eTSEC as PTP clock"
depends on GIANFAR
- select PTP_1588_CLOCK
+ depends on PTP_1588_CLOCK
default y
help
This driver adds support for using the eTSEC as a PTP
@@ -42,7 +46,7 @@ config PTP_1588_CLOCK_GIANFAR
config PTP_1588_CLOCK_IXP46X
tristate "Intel IXP46x as PTP clock"
depends on IXP4XX_ETH
- select PTP_1588_CLOCK
+ depends on PTP_1588_CLOCK
default y
help
This driver adds support for using the IXP46X as a PTP
@@ -60,7 +64,7 @@ config DP83640_PHY
tristate "Driver for the National Semiconductor DP83640 PHYTER"
depends on NETWORK_PHY_TIMESTAMPING
depends on PHYLIB
- select PTP_1588_CLOCK
+ depends on PTP_1588_CLOCK
---help---
Supports the DP83640 PHYTER with IEEE 1588 features.

@@ -76,7 +80,7 @@ config PTP_1588_CLOCK_PCH
tristate "Intel PCH EG20T as PTP clock"
depends on X86_32 || COMPILE_TEST
depends on HAS_IOMEM && NET
- select PTP_1588_CLOCK
+ select PTP_1588_CLOCK_DEFAULT
help
This driver adds support for using the PCH EG20T as a PTP
clock. The hardware supports time stamping of PTP packets
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 6b15e16814..4ce8bf74be 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -122,24 +122,6 @@ struct ptp_clock_info {

struct ptp_clock;

-/**
- * ptp_clock_register() - register a PTP hardware clock driver
- *
- * @info: Structure describing the new clock.
- * @parent: Pointer to the parent device of the new clock.
- */
-
-extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
- struct device *parent);
-
-/**
- * ptp_clock_unregister() - unregister a PTP hardware clock driver
- *
- * @ptp: The clock to remove from service.
- */
-
-extern int ptp_clock_unregister(struct ptp_clock *ptp);
-

enum ptp_clock_events {
PTP_CLOCK_ALARM,
@@ -166,6 +148,26 @@ struct ptp_clock_event {
};
};

+#if IS_REACHABLE(CONFIG_PTP_1588_CLOCK)
+
+/**
+ * ptp_clock_register() - register a PTP hardware clock driver
+ *
+ * @info: Structure describing the new clock.
+ * @parent: Pointer to the parent device of the new clock.
+ */
+
+extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
+ struct device *parent);
+
+/**
+ * ptp_clock_unregister() - unregister a PTP hardware clock driver
+ *
+ * @ptp: The clock to remove from service.
+ */
+
+extern int ptp_clock_unregister(struct ptp_clock *ptp);
+
/**
* ptp_clock_event() - notify the PTP layer about an event
*
@@ -197,4 +199,20 @@ extern int ptp_clock_index(struct ptp_clock *ptp);
int ptp_find_pin(struct ptp_clock *ptp,
enum ptp_pin_function func, unsigned int chan);

+#else
+static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
+ struct device *parent)
+{ return NULL; }
+static inline int ptp_clock_unregister(struct ptp_clock *ptp)
+{ return 0; }
+static inline void ptp_clock_event(struct ptp_clock *ptp,
+ struct ptp_clock_event *event)
+{ (void)event; }
+static inline int ptp_clock_index(struct ptp_clock *ptp)
+{ return -1; }
+static inline int ptp_find_pin(struct ptp_clock *ptp,
+ enum ptp_pin_function func, unsigned int chan)
+{ return -1; }
+#endif
+
#endif