net: microchip: lan743x: add support for PTP pulse width (duty cycle)

If the PTP_PEROUT_DUTY_CYCLE flag is set, then check if the
request_on value in ptp_perout_request matches the pre-defined
values or a toggle option.
Return a failure if the value is not supported.

Preserve the old behaviors if the PTP_PEROUT_DUTY_CYCLE flag is not
set.

Tested with an oscilloscope on EVB-LAN7430:
e.g., to output PPS 1sec period 500mS on (high) to GPIO 2.
 ./testptp -L 2,2
 ./testptp -p 1000000000 -w 500000000

Signed-off-by: Yuiko Oshino <yuiko.oshino@microchip.com>
Link: https://lore.kernel.org/r/1634046593-64312-1-git-send-email-yuiko.oshino@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h
index 6080028..34c22ee 100644 (file)
--- a/drivers/net/ethernet/microchip/lan743x_main.h
+++ b/drivers/net/ethernet/microchip/lan743x_main.h
@@ -279,6 +279,7 @@
 #define PTP_GENERAL_CONFIG_CLOCK_EVENT_1MS_    (3)
 #define PTP_GENERAL_CONFIG_CLOCK_EVENT_10MS_   (4)
 #define PTP_GENERAL_CONFIG_CLOCK_EVENT_200MS_  (5)
+#define PTP_GENERAL_CONFIG_CLOCK_EVENT_TOGGLE_ (6)
 #define PTP_GENERAL_CONFIG_CLOCK_EVENT_X_SET_(channel, value) \
        (((value) & 0x7) << (1 + ((channel) << 2)))
 #define PTP_GENERAL_CONFIG_RELOAD_ADD_X_(channel)      (BIT((channel) << 2))

diff --git a/drivers/net/ethernet/microchip/lan743x_ptp.c b/drivers/net/ethernet/microchip/lan743x_ptp.c
index ab6d719..9380e39 100644 (file)
--- a/drivers/net/ethernet/microchip/lan743x_ptp.c
+++ b/drivers/net/ethernet/microchip/lan743x_ptp.c
@@ -491,9 +491,10 @@ static int lan743x_ptp_perout(struct lan743x_adapter *adapter, int on,
        int perout_pin = 0;
        unsigned int index = perout_request->index;
        struct lan743x_ptp_perout *perout = &ptp->perout[index];
+       int ret = 0;
 
        /* Reject requests with unsupported flags */
-       if (perout_request->flags)
+       if (perout_request->flags & ~PTP_PEROUT_DUTY_CYCLE)
                return -EOPNOTSUPP;
 
        if (on) {
@@ -518,6 +519,7 @@ static int lan743x_ptp_perout(struct lan743x_adapter *adapter, int on,
                netif_warn(adapter, drv, adapter->netdev,
                           "Failed to reserve event channel %d for PEROUT\n",
                           index);
+               ret = -EBUSY;
                goto failed;
        }
 
@@ -529,6 +531,7 @@ static int lan743x_ptp_perout(struct lan743x_adapter *adapter, int on,
                netif_warn(adapter, drv, adapter->netdev,
                           "Failed to reserve gpio %d for PEROUT\n",
                           perout_pin);
+               ret = -EBUSY;
                goto failed;
        }
 
@@ -540,27 +543,93 @@ static int lan743x_ptp_perout(struct lan743x_adapter *adapter, int on,
        period_sec += perout_request->period.nsec / 1000000000;
        period_nsec = perout_request->period.nsec % 1000000000;
 
-       if (period_sec == 0) {
-               if (period_nsec >= 400000000) {
+       if (perout_request->flags & PTP_PEROUT_DUTY_CYCLE) {
+               struct timespec64 ts_on, ts_period;
+               s64 wf_high, period64, half;
+               s32 reminder;
+
+               ts_on.tv_sec = perout_request->on.sec;
+               ts_on.tv_nsec = perout_request->on.nsec;
+               wf_high = timespec64_to_ns(&ts_on);
+               ts_period.tv_sec = perout_request->period.sec;
+               ts_period.tv_nsec = perout_request->period.nsec;
+               period64 = timespec64_to_ns(&ts_period);
+
+               if (period64 < 200) {
+                       netif_warn(adapter, drv, adapter->netdev,
+                                  "perout period too small, minimum is 200nS\n");
+                       ret = -EOPNOTSUPP;
+                       goto failed;
+               }
+               if (wf_high >= period64) {
+                       netif_warn(adapter, drv, adapter->netdev,
+                                  "pulse width must be smaller than period\n");
+                       ret = -EINVAL;
+                       goto failed;
+               }
+
+               /* Check if we can do 50% toggle on an even value of period.
+                * If the period number is odd, then check if the requested
+                * pulse width is the same as one of pre-defined width values.
+                * Otherwise, return failure.
+                */
+               half = div_s64_rem(period64, 2, &reminder);
+               if (!reminder) {
+                       if (half == wf_high) {
+                               /* It's 50% match. Use the toggle option */
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_TOGGLE_;
+                               /* In this case, devide period value by 2 */
+                               ts_period = ns_to_timespec64(div_s64(period64, 2));
+                               period_sec = ts_period.tv_sec;
+                               period_nsec = ts_period.tv_nsec;
+
+                               goto program;
+                       }
+               }
+               /* if we can't do toggle, then the width option needs to be the exact match */
+               if (wf_high == 200000000) {
                        pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_200MS_;
-               } else if (period_nsec >= 20000000) {
+               } else if (wf_high == 10000000) {
                        pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_10MS_;
-               } else if (period_nsec >= 2000000) {
+               } else if (wf_high == 1000000) {
                        pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_1MS_;
-               } else if (period_nsec >= 200000) {
+               } else if (wf_high == 100000) {
                        pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_100US_;
-               } else if (period_nsec >= 20000) {
+               } else if (wf_high == 10000) {
                        pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_10US_;
-               } else if (period_nsec >= 200) {
+               } else if (wf_high == 100) {
                        pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_100NS_;
                } else {
                        netif_warn(adapter, drv, adapter->netdev,
-                                  "perout period too small, minimum is 200nS\n");
+                                  "duty cycle specified is not supported\n");
+                       ret = -EOPNOTSUPP;
                        goto failed;
                }
        } else {
-               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_200MS_;
+               if (period_sec == 0) {
+                       if (period_nsec >= 400000000) {
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_200MS_;
+                       } else if (period_nsec >= 20000000) {
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_10MS_;
+                       } else if (period_nsec >= 2000000) {
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_1MS_;
+                       } else if (period_nsec >= 200000) {
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_100US_;
+                       } else if (period_nsec >= 20000) {
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_10US_;
+                       } else if (period_nsec >= 200) {
+                               pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_100NS_;
+                       } else {
+                               netif_warn(adapter, drv, adapter->netdev,
+                                          "perout period too small, minimum is 200nS\n");
+                               ret = -EOPNOTSUPP;
+                               goto failed;
+                       }
+               } else {
+                       pulse_width = PTP_GENERAL_CONFIG_CLOCK_EVENT_200MS_;
+               }
        }
+program:
 
        /* turn off by setting target far in future */
        lan743x_csr_write(adapter,
@@ -599,7 +668,7 @@ static int lan743x_ptp_perout(struct lan743x_adapter *adapter, int on,
 
 failed:
        lan743x_ptp_perout_off(adapter, index);
-       return -ENODEV;
+       return ret;
 }
 
 static int lan743x_ptpci_enable(struct ptp_clock_info *ptpci,