Implement routines (adjfine, adjtime, gettime and settime) for
manipulating the chip's PTP clock.

Signed-off-by: Christian Eggers <cegg...@arri.de>
Reviewed-by: Vladimir Oltean <olte...@gmail.com>
---
 drivers/net/dsa/microchip/Kconfig        |   8 +
 drivers/net/dsa/microchip/Makefile       |   1 +
 drivers/net/dsa/microchip/ksz9477_i2c.c  |   2 +-
 drivers/net/dsa/microchip/ksz9477_main.c |  17 ++
 drivers/net/dsa/microchip/ksz9477_ptp.c  | 308 +++++++++++++++++++++++
 drivers/net/dsa/microchip/ksz9477_ptp.h  |  27 ++
 drivers/net/dsa/microchip/ksz9477_spi.c  |   2 +-
 drivers/net/dsa/microchip/ksz_common.h   |   8 +
 8 files changed, 371 insertions(+), 2 deletions(-)
 create mode 100644 drivers/net/dsa/microchip/ksz9477_ptp.c
 create mode 100644 drivers/net/dsa/microchip/ksz9477_ptp.h

diff --git a/drivers/net/dsa/microchip/Kconfig 
b/drivers/net/dsa/microchip/Kconfig
index 4ec6a47b7f72..7a4e06bab238 100644
--- a/drivers/net/dsa/microchip/Kconfig
+++ b/drivers/net/dsa/microchip/Kconfig
@@ -24,6 +24,14 @@ config NET_DSA_MICROCHIP_KSZ9477_SPI
        help
          Select to enable support for registering switches configured through 
SPI.
 
+config NET_DSA_MICROCHIP_KSZ9477_PTP
+       bool "PTP support for Microchip KSZ9477 series"
+       depends on NET_DSA_MICROCHIP_KSZ9477
+       depends on PTP_1588_CLOCK
+       help
+         Say Y to enable PTP hardware timestamping on Microchip KSZ switch
+         chips that support it.
+
 menuconfig NET_DSA_MICROCHIP_KSZ8795
        tristate "Microchip KSZ8795 series switch support"
        depends on NET_DSA
diff --git a/drivers/net/dsa/microchip/Makefile 
b/drivers/net/dsa/microchip/Makefile
index c5cc1d5dea06..35c4356bad65 100644
--- a/drivers/net/dsa/microchip/Makefile
+++ b/drivers/net/dsa/microchip/Makefile
@@ -2,6 +2,7 @@
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ_COMMON)     += ksz_common.o
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477)                += ksz9477.o
 ksz9477-objs := ksz9477_main.o
+ksz9477-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_PTP)        += ksz9477_ptp.o
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_I2C)    += ksz9477_i2c.o
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_SPI)    += ksz9477_spi.o
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ8795)                += ksz8795.o
diff --git a/drivers/net/dsa/microchip/ksz9477_i2c.c 
b/drivers/net/dsa/microchip/ksz9477_i2c.c
index 4ed1f503044a..315eb24c444d 100644
--- a/drivers/net/dsa/microchip/ksz9477_i2c.c
+++ b/drivers/net/dsa/microchip/ksz9477_i2c.c
@@ -58,7 +58,7 @@ static int ksz9477_i2c_remove(struct i2c_client *i2c)
 {
        struct ksz_device *dev = i2c_get_clientdata(i2c);
 
-       ksz_switch_remove(dev);
+       ksz9477_switch_remove(dev);
 
        return 0;
 }
diff --git a/drivers/net/dsa/microchip/ksz9477_main.c 
b/drivers/net/dsa/microchip/ksz9477_main.c
index f869041e3be0..2cb33e9beb4c 100644
--- a/drivers/net/dsa/microchip/ksz9477_main.c
+++ b/drivers/net/dsa/microchip/ksz9477_main.c
@@ -19,6 +19,7 @@
 
 #include "ksz9477_reg.h"
 #include "ksz_common.h"
+#include "ksz9477_ptp.h"
 
 /* Used with variable features to indicate capabilities. */
 #define GBIT_SUPPORT                   BIT(0)
@@ -1695,10 +1696,26 @@ int ksz9477_switch_register(struct ksz_device *dev)
                        phy_remove_link_mode(phydev,
                                             
ETHTOOL_LINK_MODE_1000baseT_Full_BIT);
        }
+
+       ret = ksz9477_ptp_init(dev);
+       if (ret)
+               goto error_switch_unregister;
+
+       return 0;
+
+error_switch_unregister:
+       ksz_switch_remove(dev);
        return ret;
 }
 EXPORT_SYMBOL(ksz9477_switch_register);
 
+void ksz9477_switch_remove(struct ksz_device *dev)
+{
+       ksz9477_ptp_deinit(dev);
+       ksz_switch_remove(dev);
+}
+EXPORT_SYMBOL(ksz9477_switch_remove);
+
 MODULE_AUTHOR("Woojung Huh <woojung....@microchip.com>");
 MODULE_DESCRIPTION("Microchip KSZ9477 Series Switch DSA Driver");
 MODULE_LICENSE("GPL");
diff --git a/drivers/net/dsa/microchip/ksz9477_ptp.c 
b/drivers/net/dsa/microchip/ksz9477_ptp.c
new file mode 100644
index 000000000000..0ffc4504a290
--- /dev/null
+++ b/drivers/net/dsa/microchip/ksz9477_ptp.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Microchip KSZ9477 switch driver PTP routines
+ *
+ * Author: Christian Eggers <cegg...@arri.de>
+ *
+ * Copyright (c) 2020 ARRI Lighting
+ */
+
+#include <linux/ptp_clock_kernel.h>
+
+#include "ksz_common.h"
+#include "ksz9477_reg.h"
+
+#include "ksz9477_ptp.h"
+
+#define KSZ_PTP_INC_NS 40  /* HW clock is incremented every 40 ns (by 40) */
+#define KSZ_PTP_SUBNS_BITS 32  /* Number of bits in sub-nanoseconds counter */
+
+/* Posix clock support */
+
+static int ksz9477_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+       struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+       u16 data16;
+       int ret;
+
+       mutex_lock(&dev->ptp_mutex);
+
+       if (scaled_ppm) {
+               s64 ppb, adj;
+               u32 data32;
+
+               /* basic calculation:
+                * s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
+                * s64 adj = div_s64(((s64)ppb * KSZ_PTP_INC_NS) << 
KSZ_PTP_SUBNS_BITS,
+                *                   NSEC_PER_SEC);
+                */
+
+               /* More precise calculation (avoids shifting out precision).
+                * See scaled_ppm_to_ppb() in ptp_clock.c for details.
+                */
+               ppb = 1 + scaled_ppm;
+               ppb *= 125;
+               ppb *= KSZ_PTP_INC_NS;
+               ppb <<= KSZ_PTP_SUBNS_BITS - 13;
+               adj = div_s64(ppb, NSEC_PER_SEC);
+
+               data32 = abs(adj);
+               data32 &= BIT_MASK(30) - 1;
+               if (adj >= 0)
+                       data32 |= PTP_RATE_DIR;
+
+               ret = ksz_write32(dev, REG_PTP_SUBNANOSEC_RATE, data32);
+               if (ret)
+                       goto error_return;
+       }
+
+       ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+       if (ret)
+               goto error_return;
+
+       if (scaled_ppm)
+               data16 |= PTP_CLK_ADJ_ENABLE;
+       else
+               data16 &= ~PTP_CLK_ADJ_ENABLE;
+
+       ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+       if (ret)
+               goto error_return;
+
+error_return:
+       mutex_unlock(&dev->ptp_mutex);
+       return ret;
+}
+
+static int ksz9477_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+       struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+       s32 sec, nsec;
+       u16 data16;
+       int ret;
+
+       mutex_lock(&dev->ptp_mutex);
+
+       /* Do not use ns_to_timespec64(), both sec and nsec are subtracted by
+        * hardware.
+        */
+       sec = div_s64_rem(delta, NSEC_PER_SEC, &nsec);
+
+       ret = ksz_write32(dev, REG_PTP_RTC_NANOSEC, abs(nsec));
+       if (ret)
+               goto error_return;
+
+       /* Contradictory to the data sheet, seconds are also considered.  */
+       ret = ksz_write32(dev, REG_PTP_RTC_SEC, abs(sec));
+       if (ret)
+               goto error_return;
+
+       ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+       if (ret)
+               goto error_return;
+
+       data16 |= PTP_STEP_ADJ;
+       if (delta < 0)
+               data16 &= ~PTP_STEP_DIR;  /* 0: subtract */
+       else
+               data16 |= PTP_STEP_DIR;   /* 1: add */
+
+       ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+       if (ret)
+               goto error_return;
+
+error_return:
+       mutex_unlock(&dev->ptp_mutex);
+       return ret;
+}
+
+static int _ksz9477_ptp_gettime(struct ksz_device *dev, struct timespec64 *ts)
+{
+       u32 nanoseconds;
+       u32 seconds;
+       u16 data16;
+       u8 phase;
+       int ret;
+
+       /* Copy current PTP clock into shadow registers */
+       ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+       if (ret)
+               return ret;
+
+       data16 |= PTP_READ_TIME;
+
+       ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+       if (ret)
+               return ret;
+
+       /* Read from shadow registers */
+       ret = ksz_read8(dev, REG_PTP_RTC_SUB_NANOSEC__2, &phase);
+       if (ret)
+               return ret;
+       ret = ksz_read32(dev, REG_PTP_RTC_NANOSEC, &nanoseconds);
+       if (ret)
+               return ret;
+       ret = ksz_read32(dev, REG_PTP_RTC_SEC, &seconds);
+       if (ret)
+               return ret;
+
+       ts->tv_sec = seconds;
+       ts->tv_nsec = nanoseconds + phase * 8;
+
+       return 0;
+}
+
+static int ksz9477_ptp_gettime(struct ptp_clock_info *ptp,
+                              struct timespec64 *ts)
+{
+       struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+       int ret;
+
+       mutex_lock(&dev->ptp_mutex);
+       ret = _ksz9477_ptp_gettime(dev, ts);
+       mutex_unlock(&dev->ptp_mutex);
+
+       return ret;
+}
+
+static int ksz9477_ptp_settime(struct ptp_clock_info *ptp,
+                              struct timespec64 const *ts)
+{
+       struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+       u16 data16;
+       int ret;
+
+       mutex_lock(&dev->ptp_mutex);
+
+       /* Write to shadow registers */
+
+       /* clock phase */
+       ret = ksz_read16(dev, REG_PTP_RTC_SUB_NANOSEC__2, &data16);
+       if (ret)
+               goto error_return;
+
+       data16 &= ~PTP_RTC_SUB_NANOSEC_M;
+
+       ret = ksz_write16(dev, REG_PTP_RTC_SUB_NANOSEC__2, data16);
+       if (ret)
+               goto error_return;
+
+       /* nanoseconds */
+       ret = ksz_write32(dev, REG_PTP_RTC_NANOSEC, ts->tv_nsec);
+       if (ret)
+               goto error_return;
+
+       /* seconds */
+       ret = ksz_write32(dev, REG_PTP_RTC_SEC, ts->tv_sec);
+       if (ret)
+               goto error_return;
+
+       /* Load PTP clock from shadow registers */
+       ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+       if (ret)
+               goto error_return;
+
+       data16 |= PTP_LOAD_TIME;
+
+       ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+       if (ret)
+               goto error_return;
+
+error_return:
+       mutex_unlock(&dev->ptp_mutex);
+       return ret;
+}
+
+static int ksz9477_ptp_enable(struct ptp_clock_info *ptp,
+                             struct ptp_clock_request *req, int on)
+{
+       return -EOPNOTSUPP;
+}
+
+static int ksz9477_ptp_start_clock(struct ksz_device *dev)
+{
+       u16 data;
+       int ret;
+
+       ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data);
+       if (ret)
+               return ret;
+
+       /* Perform PTP clock reset */
+       data |= PTP_CLK_RESET;
+       ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data);
+       if (ret)
+               return ret;
+       data &= ~PTP_CLK_RESET;
+
+       /* Enable PTP clock */
+       data |= PTP_CLK_ENABLE;
+       ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+static int ksz9477_ptp_stop_clock(struct ksz_device *dev)
+{
+       u16 data;
+       int ret;
+
+       ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data);
+       if (ret)
+               return ret;
+
+       /* Disable PTP clock */
+       data &= ~PTP_CLK_ENABLE;
+       return ksz_write16(dev, REG_PTP_CLK_CTRL, data);
+}
+
+int ksz9477_ptp_init(struct ksz_device *dev)
+{
+       int ret;
+
+       mutex_init(&dev->ptp_mutex);
+
+       /* PTP clock properties */
+
+       dev->ptp_caps.owner = THIS_MODULE;
+       snprintf(dev->ptp_caps.name, sizeof(dev->ptp_caps.name),
+                dev_name(dev->dev));
+
+       /* Sub-nanoseconds-adj,max * sub-nanoseconds / 40ns * 1ns
+        * = (2^30-1) * (2 ^ 32) / 40 ns * 1 ns = 6249999
+        */
+       dev->ptp_caps.max_adj     = 6249999;
+       dev->ptp_caps.n_alarm     = 0;
+       dev->ptp_caps.n_ext_ts    = 0;  /* currently not implemented */
+       dev->ptp_caps.n_per_out   = 0;
+       dev->ptp_caps.pps         = 0;
+       dev->ptp_caps.adjfine     = ksz9477_ptp_adjfine;
+       dev->ptp_caps.adjtime     = ksz9477_ptp_adjtime;
+       dev->ptp_caps.gettime64   = ksz9477_ptp_gettime;
+       dev->ptp_caps.settime64   = ksz9477_ptp_settime;
+       dev->ptp_caps.enable      = ksz9477_ptp_enable;
+
+       /* Start hardware counter (will overflow after 136 years) */
+       ret = ksz9477_ptp_start_clock(dev);
+       if (ret)
+               return ret;
+
+       dev->ptp_clock = ptp_clock_register(&dev->ptp_caps, dev->dev);
+       if (IS_ERR(dev->ptp_clock)) {
+               ret = PTR_ERR(dev->ptp_clock);
+               goto error_stop_clock;
+       }
+
+       return 0;
+
+error_stop_clock:
+       ksz9477_ptp_stop_clock(dev);
+       return ret;
+}
+
+void ksz9477_ptp_deinit(struct ksz_device *dev)
+{
+       ptp_clock_unregister(dev->ptp_clock);
+       ksz9477_ptp_stop_clock(dev);
+}
diff --git a/drivers/net/dsa/microchip/ksz9477_ptp.h 
b/drivers/net/dsa/microchip/ksz9477_ptp.h
new file mode 100644
index 000000000000..0076538419fa
--- /dev/null
+++ b/drivers/net/dsa/microchip/ksz9477_ptp.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Microchip KSZ9477 switch driver PTP routines
+ *
+ * Author: Christian Eggers <cegg...@arri.de>
+ *
+ * Copyright (c) 2020 ARRI Lighting
+ */
+
+#ifndef DRIVERS_NET_DSA_MICROCHIP_KSZ9477_PTP_H_
+#define DRIVERS_NET_DSA_MICROCHIP_KSZ9477_PTP_H_
+
+#include "ksz_common.h"
+
+#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ9477_PTP)
+
+int ksz9477_ptp_init(struct ksz_device *dev);
+void ksz9477_ptp_deinit(struct ksz_device *dev);
+
+#else
+
+static inline int ksz9477_ptp_init(struct ksz_device *dev) { return 0; }
+static inline void ksz9477_ptp_deinit(struct ksz_device *dev) {}
+
+#endif
+
+#endif /* DRIVERS_NET_DSA_MICROCHIP_KSZ9477_PTP_H_ */
diff --git a/drivers/net/dsa/microchip/ksz9477_spi.c 
b/drivers/net/dsa/microchip/ksz9477_spi.c
index fc0ac9e2c56d..8cd825a02bba 100644
--- a/drivers/net/dsa/microchip/ksz9477_spi.c
+++ b/drivers/net/dsa/microchip/ksz9477_spi.c
@@ -72,7 +72,7 @@ static int ksz9477_spi_remove(struct spi_device *spi)
        struct ksz_device *dev = spi_get_drvdata(spi);
 
        if (dev)
-               ksz_switch_remove(dev);
+               ksz9477_switch_remove(dev);
 
        return 0;
 }
diff --git a/drivers/net/dsa/microchip/ksz_common.h 
b/drivers/net/dsa/microchip/ksz_common.h
index ac6914d361c8..f70a45c591d8 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/mutex.h>
 #include <linux/phy.h>
+#include <linux/ptp_clock_kernel.h>
 #include <linux/regmap.h>
 #include <net/dsa.h>
 
@@ -90,6 +91,12 @@ struct ksz_device {
        u32 overrides;                  /* chip functions set by user */
        u16 host_mask;
        u16 port_mask;
+
+#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ9477_PTP)
+       struct ptp_clock *ptp_clock;
+       struct ptp_clock_info ptp_caps;
+       struct mutex ptp_mutex;         /* protects PTP related hardware */
+#endif
 };
 
 struct alu_struct {
@@ -145,6 +152,7 @@ void ksz_switch_remove(struct ksz_device *dev);
 
 int ksz8795_switch_register(struct ksz_device *dev);
 int ksz9477_switch_register(struct ksz_device *dev);
+void ksz9477_switch_remove(struct ksz_device *dev);
 
 void ksz_update_port_member(struct ksz_device *dev, int port);
 void ksz_init_mib_timer(struct ksz_device *dev);
-- 
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: 
HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: 
HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; 
Markus Zeiler

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