Support LAN743x PTP periodic output on any GPIO

The LAN743x Ethernet controller provides two independent PTP event
channels. Each one can be used to generate a periodic output from
the PTP clock. The output can be routed to any one of the available
GPIO pins on the device.

The PTP clock API can now be used to:
- select any LAN743x GPIO pin to function as a periodic output
- select either LAN743x PTP event channel to generate the output

The LAN7430 has 4 GPIO pins that are multiplexed with its internal
PHY LED control signals. A pin assigned to the LED control function
will be assigned to the GPIO function if selected for PTP periodic
output.
Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/lan743x_ptp.h

@@ -7,6 +7,18 @@
 #include "linux/ptp_clock_kernel.h"
 #include "linux/netdevice.h"
 
+#define LAN7430_N_LED			4
+#define LAN7430_N_GPIO			4	/* multiplexed with PHY LEDs */
+#define LAN7431_N_GPIO			12
+
+#define LAN743X_PTP_N_GPIO		LAN7431_N_GPIO
+
+/* the number of periodic outputs is limited by number of
+ * PTP clock event channels
+ */
+#define LAN743X_PTP_N_EVENT_CHAN	2
+#define LAN743X_PTP_N_PEROUT		LAN743X_PTP_N_EVENT_CHAN
+
 struct lan743x_adapter;
 
 /* GPIO */
@@ -43,6 +55,11 @@ int lan743x_ptp_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd);
 #define PTP_FLAG_PTP_CLOCK_REGISTERED		BIT(1)
 #define PTP_FLAG_ISR_ENABLED			BIT(2)
 
+struct lan743x_ptp_perout {
+	int  event_ch;	/* PTP event channel (0=channel A, 1=channel B) */
+	int  gpio_pin;	/* GPIO pin where output appears */
+};
+
 struct lan743x_ptp {
 	int flags;
 
@@ -51,13 +68,13 @@ struct lan743x_ptp {
 
 	struct ptp_clock *ptp_clock;
 	struct ptp_clock_info ptp_clock_info;
-	struct ptp_pin_desc pin_config[1];
+	struct ptp_pin_desc pin_config[LAN743X_PTP_N_GPIO];
 
-#define LAN743X_PTP_NUMBER_OF_EVENT_CHANNELS (2)
 	unsigned long used_event_ch;
+	struct lan743x_ptp_perout perout[LAN743X_PTP_N_PEROUT];
 
-	int perout_event_ch;
-	int perout_gpio_bit;
+	bool leds_multiplexed;
+	bool led_enabled[LAN7430_N_LED];
 
 	/* tx_ts_lock: used to prevent concurrent access to timestamp arrays */
 	spinlock_t	tx_ts_lock;