Add support for PMC Time-Aware GPIO (TGPIO) hardware that is present …

…on upcoming Intel platforms. The hardware logic is driven by the ART clock. The current hardware has two GPIO pins. Input interrupts are not implemented in hardware.

The driver implements to the expanded PHC interface. Input requires use of
the user-polling interface. Also, since the ART clock can't be adjusted,
modulating the output frequency uses the edge timestamp interface
(EVENT_COUNT_TSTAMP2) and the PEROUT2 ioctl output frequency adjustment
interface.

Signed-off-by: Christopher Hall <christopher.s.hall@intel.com>

drivers/ptp/Kconfig

@@ -106,6 +106,19 @@ config PTP_1588_CLOCK_PCH
 	  To compile this driver as a module, choose M here: the module
 	  will be called ptp_pch.
 
+config PTP_INTEL_PMC_TGPIO
+	tristate "Intel PMC Timed GPIO"
+	depends on X86
+	depends on ACPI
+	depends on PTP_1588_CLOCK
+	help
+	  This driver adds support for Intel PMC Timed-Aware GPIO (TGPIO)
+	  Controller. The device clock used to drive TGPIO logic is the
+	  Always Running Timer (ART).
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called ptp-intel-pmc-tgpio.
+
 config PTP_1588_CLOCK_KVM
 	tristate "KVM virtual PTP clock"
 	depends on PTP_1588_CLOCK

drivers/ptp/Makefile

@@ -15,3 +15,4 @@ ptp-qoriq-$(CONFIG_DEBUG_FS)		+= ptp_qoriq_debugfs.o
 obj-$(CONFIG_PTP_1588_CLOCK_IDTCM)	+= ptp_clockmatrix.o
 obj-$(CONFIG_PTP_1588_CLOCK_IDT82P33)	+= ptp_idt82p33.o
 obj-$(CONFIG_PTP_1588_CLOCK_VMW)	+= ptp_vmw.o
+obj-$(CONFIG_PTP_INTEL_PMC_TGPIO)	+= ptp-intel-pmc-tgpio.o