From: Steve Longerbeam <slongerbeam@gmail.com>

The input capture API is modelled after request/free irq:

typedef void (*mxc_icap_handler_t)(int, void *, ktime_t);

int mxc_request_input_capture(unsigned int chan,
			      mxc_icap_handler_t handler,
			      unsigned long capflags, void *dev_id);

    - chan: the channel number being requested (0 or 1).

    - handler: a callback when there is an input capture event. The
      handler is given the channel number, the dev_id, and a ktime_t
      marking the input capture event.

    - capflags: IRQF_TRIGGER_RISING and/or IRQF_TRIGGER_FALLING. If
      both are specified, events will be triggered on both rising and
      falling edges of the input capture signal.

    - dev_id: a context pointer given back to the handler.

void mxc_free_input_capture(unsigned int chan, void *dev_id);

    This disables the given input capture channel in the GPT.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
---
 drivers/clocksource/timer-imx-gpt.c | 479 +++++++++++++++++++++++++---
 include/linux/mxc_icap.h            |  16 +
 2 files changed, 445 insertions(+), 50 deletions(-)
 create mode 100644 include/linux/mxc_icap.h

diff --git a/drivers/clocksource/timer-imx-gpt.c b/drivers/clocksource/timer-imx-gpt.c
index 7b2c70f2f353..c6aa1462e441 100644
--- a/drivers/clocksource/timer-imx-gpt.c
+++ b/drivers/clocksource/timer-imx-gpt.c
@@ -5,9 +5,11 @@
 //  Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
 //  Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
 
+#include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/clockchips.h>
+#include <linux/timecounter.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
@@ -16,6 +18,8 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/mxc_icap.h>
 #include <soc/imx/timer.h>
 
 /*
@@ -49,16 +53,52 @@
 #define V2_TCTL_CLK_PER		(2 << 6)
 #define V2_TCTL_CLK_OSC_DIV8	(5 << 6)
 #define V2_TCTL_FRR		(1 << 9)
+#define V2_TCTL_IM1_BIT		16
+#define V2_TCTL_IM2_BIT		18
+#define V2_IM_DISABLE		0
+#define V2_IM_RISING		1
+#define V2_IM_FALLING		2
+#define V2_IM_BOTH		3
 #define V2_TCTL_24MEN		(1 << 10)
 #define V2_TPRER_PRE24M		12
 #define V2_IR			0x0c
+#define V2_IR_OF1		(1 << 0)
+#define V2_IR_IF1		(1 << 3)
+#define V2_IR_IF2		(1 << 4)
 #define V2_TSTAT		0x08
 #define V2_TSTAT_OF1		(1 << 0)
+#define V2_TSTAT_IF1		(1 << 3)
+#define V2_TSTAT_IF2		(1 << 4)
 #define V2_TCN			0x24
 #define V2_TCMP			0x10
+#define V2_TCAP1		0x1c
+#define V2_TCAP2		0x20
 
 #define V2_TIMER_RATE_OSC_DIV8	3000000
 
+struct imx_timer;
+
+struct icap_channel {
+	struct imx_timer *imxtm;
+
+	int chan;
+
+	u32 cnt_reg;
+	u32 irqen_bit;
+	u32 status_bit;
+	u32 mode_bit;
+
+	mxc_icap_handler_t handler;
+	void *dev_id;
+
+	struct cyclecounter cc;
+	struct timecounter tc;
+};
+
+/* FIXME, for now can't find icap unless it's statically allocated */
+static struct icap_channel icap_channel[2];
+static DEFINE_SPINLOCK(icap_lock);
+
 struct imx_timer {
 	enum imx_gpt_type type;
 	void __iomem *base;
@@ -73,12 +113,20 @@ struct imx_gpt_data {
 	int reg_tstat;
 	int reg_tcn;
 	int reg_tcmp;
-	void (*gpt_setup_tctl)(struct imx_timer *imxtm);
-	void (*gpt_irq_enable)(struct imx_timer *imxtm);
-	void (*gpt_irq_disable)(struct imx_timer *imxtm);
-	void (*gpt_irq_acknowledge)(struct imx_timer *imxtm);
+	void (*gpt_oc_setup_tctl)(struct imx_timer *imxtm);
+	void (*gpt_oc_irq_enable)(struct imx_timer *imxtm);
+	void (*gpt_oc_irq_disable)(struct imx_timer *imxtm);
+	void (*gpt_oc_irq_acknowledge)(struct imx_timer *imxtm);
+	bool (*gpt_is_oc_irq)(struct imx_timer *imxtm, unsigned int tstat);
 	int (*set_next_event)(unsigned long evt,
 			      struct clock_event_device *ced);
+
+	void (*gpt_ic_irq_enable)(struct icap_channel *ic);
+	void (*gpt_ic_irq_disable)(struct icap_channel *ic);
+	void (*gpt_ic_irq_acknowledge)(struct icap_channel *ic);
+	bool (*gpt_is_ic_irq)(struct icap_channel *ic, unsigned int tstat);
+	void (*gpt_ic_enable)(struct icap_channel *ic, unsigned int mode);
+	void (*gpt_ic_disable)(struct icap_channel *ic);
 };
 
 static inline struct imx_timer *to_imx_timer(struct clock_event_device *ced)
@@ -86,52 +134,144 @@ static inline struct imx_timer *to_imx_timer(struct clock_event_device *ced)
 	return container_of(ced, struct imx_timer, ced);
 }
 
-static void imx1_gpt_irq_disable(struct imx_timer *imxtm)
+static void imx1_gpt_oc_irq_disable(struct imx_timer *imxtm)
 {
 	unsigned int tmp;
 
 	tmp = readl_relaxed(imxtm->base + MXC_TCTL);
 	writel_relaxed(tmp & ~MX1_2_TCTL_IRQEN, imxtm->base + MXC_TCTL);
 }
-#define imx21_gpt_irq_disable imx1_gpt_irq_disable
+#define imx21_gpt_oc_irq_disable imx1_gpt_oc_irq_disable
 
-static void imx31_gpt_irq_disable(struct imx_timer *imxtm)
+static void imx31_gpt_oc_irq_disable(struct imx_timer *imxtm)
 {
-	writel_relaxed(0, imxtm->base + V2_IR);
+	unsigned int tmp;
+
+	tmp = readl_relaxed(imxtm->base + V2_IR);
+	writel_relaxed(tmp & ~V2_IR_OF1, imxtm->base + V2_IR);
 }
-#define imx6dl_gpt_irq_disable imx31_gpt_irq_disable
+#define imx6dl_gpt_oc_irq_disable imx31_gpt_oc_irq_disable
 
-static void imx1_gpt_irq_enable(struct imx_timer *imxtm)
+static void imx1_gpt_oc_irq_enable(struct imx_timer *imxtm)
 {
 	unsigned int tmp;
 
 	tmp = readl_relaxed(imxtm->base + MXC_TCTL);
 	writel_relaxed(tmp | MX1_2_TCTL_IRQEN, imxtm->base + MXC_TCTL);
 }
-#define imx21_gpt_irq_enable imx1_gpt_irq_enable
+#define imx21_gpt_oc_irq_enable imx1_gpt_oc_irq_enable
 
-static void imx31_gpt_irq_enable(struct imx_timer *imxtm)
+static void imx31_gpt_oc_irq_enable(struct imx_timer *imxtm)
 {
-	writel_relaxed(1<<0, imxtm->base + V2_IR);
+	unsigned int tmp;
+
+	tmp = readl_relaxed(imxtm->base + V2_IR);
+	writel_relaxed(tmp | V2_IR_OF1, imxtm->base + V2_IR);
 }
-#define imx6dl_gpt_irq_enable imx31_gpt_irq_enable
+#define imx6dl_gpt_oc_irq_enable imx31_gpt_oc_irq_enable
 
-static void imx1_gpt_irq_acknowledge(struct imx_timer *imxtm)
+static void imx1_gpt_oc_irq_acknowledge(struct imx_timer *imxtm)
 {
 	writel_relaxed(0, imxtm->base + MX1_2_TSTAT);
 }
 
-static void imx21_gpt_irq_acknowledge(struct imx_timer *imxtm)
+static void imx21_gpt_oc_irq_acknowledge(struct imx_timer *imxtm)
 {
 	writel_relaxed(MX2_TSTAT_CAPT | MX2_TSTAT_COMP,
 				imxtm->base + MX1_2_TSTAT);
 }
 
-static void imx31_gpt_irq_acknowledge(struct imx_timer *imxtm)
+static bool imx1_gpt_is_oc_irq(struct imx_timer *imxtm, unsigned int tstat)
+{
+	return true;
+}
+
+static bool imx21_gpt_is_oc_irq(struct imx_timer *imxtm, unsigned int tstat)
+{
+	return (tstat & MX2_TSTAT_COMP) != 0;
+}
+
+static bool imx31_gpt_is_oc_irq(struct imx_timer *imxtm, unsigned int tstat)
+{
+	return (tstat & V2_TSTAT_OF1) != 0;
+}
+#define imx6dl_gpt_is_oc_irq imx31_gpt_is_oc_irq
+
+static void imx31_gpt_oc_irq_acknowledge(struct imx_timer *imxtm)
 {
 	writel_relaxed(V2_TSTAT_OF1, imxtm->base + V2_TSTAT);
 }
-#define imx6dl_gpt_irq_acknowledge imx31_gpt_irq_acknowledge
+#define imx6dl_gpt_oc_irq_acknowledge imx31_gpt_oc_irq_acknowledge
+
+static void imx31_gpt_ic_irq_disable(struct icap_channel *ic)
+{
+	struct imx_timer *imxtm = ic->imxtm;
+	unsigned int tmp;
+
+	tmp = readl_relaxed(imxtm->base + V2_IR);
+	tmp &= ~ic->irqen_bit;
+	writel_relaxed(tmp, imxtm->base + V2_IR);
+}
+#define imx6dl_gpt_ic_irq_disable imx31_gpt_ic_irq_disable
+
+static void imx31_gpt_ic_irq_enable(struct icap_channel *ic)
+{
+	struct imx_timer *imxtm = ic->imxtm;
+	unsigned int tmp;
+
+	tmp = readl_relaxed(imxtm->base + V2_IR);
+	tmp |= ic->irqen_bit;
+	writel_relaxed(tmp, imxtm->base + V2_IR);
+}
+#define imx6dl_gpt_ic_irq_enable imx31_gpt_ic_irq_enable
+
+static void imx31_gpt_ic_irq_acknowledge(struct icap_channel *ic)
+{
+	struct imx_timer *imxtm = ic->imxtm;
+
+	writel_relaxed(ic->status_bit, imxtm->base + V2_TSTAT);
+}
+#define imx6dl_gpt_ic_irq_acknowledge imx31_gpt_ic_irq_acknowledge
+
+static bool imx1_gpt_is_ic_irq(struct icap_channel *ic, unsigned int tstat)
+{
+	return false;
+}
+#define imx21_gpt_is_ic_irq imx1_gpt_is_ic_irq
+
+static bool imx31_gpt_is_ic_irq(struct icap_channel *ic, unsigned int tstat)
+{
+	return (tstat & ic->status_bit) != 0;
+}
+#define imx6dl_gpt_is_ic_irq imx31_gpt_is_ic_irq
+
+static void imx31_gpt_ic_enable(struct icap_channel *ic, unsigned int mode)
+{
+	struct imx_timer *imxtm = ic->imxtm;
+	unsigned int tctl, mask;
+
+	mask = 0x3 << ic->mode_bit;
+	mode <<= ic->mode_bit;
+
+	tctl = readl_relaxed(imxtm->base + MXC_TCTL);
+	tctl &= ~mask;
+	tctl |= mode;
+	writel_relaxed(tctl, imxtm->base + MXC_TCTL);
+}
+#define imx6dl_gpt_ic_enable imx31_gpt_ic_enable
+
+static void imx31_gpt_ic_disable(struct icap_channel *ic)
+{
+	struct imx_timer *imxtm = ic->imxtm;
+	unsigned int tctl, mask;
+
+	mask = 0x3 << ic->mode_bit;
+
+	tctl = readl_relaxed(imxtm->base + MXC_TCTL);
+	tctl &= ~mask;
+	writel_relaxed(tctl, imxtm->base + MXC_TCTL);
+}
+#define imx6dl_gpt_ic_disable imx31_gpt_ic_disable
 
 static void __iomem *sched_clock_reg;
 
@@ -149,6 +289,19 @@ static unsigned long imx_read_current_timer(void)
 }
 #endif
 
+static u64 mxc_clocksource_read(struct clocksource *cs)
+{
+	return mxc_read_sched_clock();
+}
+
+static struct clocksource clocksource_mxc = {
+	.name = "mxc_timer1",
+	.rating = 200,
+	.mask = CLOCKSOURCE_MASK(32),
+	.read = mxc_clocksource_read,
+	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
 static int __init mxc_clocksource_init(struct imx_timer *imxtm)
 {
 	unsigned int c = clk_get_rate(imxtm->clk_per);
@@ -163,8 +316,7 @@ static int __init mxc_clocksource_init(struct imx_timer *imxtm)
 	sched_clock_reg = reg;
 
 	sched_clock_register(mxc_read_sched_clock, 32, c);
-	return clocksource_mmio_init(reg, "mxc_timer1", c, 200, 32,
-			clocksource_mmio_readl_up);
+	return clocksource_register_hz(&clocksource_mxc, c);
 }
 
 /* clock event */
@@ -204,14 +356,14 @@ static int mxc_shutdown(struct clock_event_device *ced)
 	u32 tcn;
 
 	/* Disable interrupt in GPT module */
-	imxtm->gpt->gpt_irq_disable(imxtm);
+	imxtm->gpt->gpt_oc_irq_disable(imxtm);
 
 	tcn = readl_relaxed(imxtm->base + imxtm->gpt->reg_tcn);
 	/* Set event time into far-far future */
 	writel_relaxed(tcn - 3, imxtm->base + imxtm->gpt->reg_tcmp);
 
 	/* Clear pending interrupt */
-	imxtm->gpt->gpt_irq_acknowledge(imxtm);
+	imxtm->gpt->gpt_oc_irq_acknowledge(imxtm);
 
 #ifdef DEBUG
 	printk(KERN_INFO "%s: changing mode\n", __func__);
@@ -225,7 +377,7 @@ static int mxc_set_oneshot(struct clock_event_device *ced)
 	struct imx_timer *imxtm = to_imx_timer(ced);
 
 	/* Disable interrupt in GPT module */
-	imxtm->gpt->gpt_irq_disable(imxtm);
+	imxtm->gpt->gpt_oc_irq_disable(imxtm);
 
 	if (!clockevent_state_oneshot(ced)) {
 		u32 tcn = readl_relaxed(imxtm->base + imxtm->gpt->reg_tcn);
@@ -233,7 +385,7 @@ static int mxc_set_oneshot(struct clock_event_device *ced)
 		writel_relaxed(tcn - 3, imxtm->base + imxtm->gpt->reg_tcmp);
 
 		/* Clear pending interrupt */
-		imxtm->gpt->gpt_irq_acknowledge(imxtm);
+		imxtm->gpt->gpt_oc_irq_acknowledge(imxtm);
 	}
 
 #ifdef DEBUG
@@ -246,7 +398,7 @@ static int mxc_set_oneshot(struct clock_event_device *ced)
 	 * to call mxc_set_next_event() or shutdown clock after
 	 * mode switching
 	 */
-	imxtm->gpt->gpt_irq_enable(imxtm);
+	imxtm->gpt->gpt_oc_irq_enable(imxtm);
 
 	return 0;
 }
@@ -259,12 +411,29 @@ static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id)
 	struct clock_event_device *ced = dev_id;
 	struct imx_timer *imxtm = to_imx_timer(ced);
 	uint32_t tstat;
+	int i;
 
 	tstat = readl_relaxed(imxtm->base + imxtm->gpt->reg_tstat);
 
-	imxtm->gpt->gpt_irq_acknowledge(imxtm);
+	for (i = 0; i < 2; i++) {
+		struct icap_channel *ic = &icap_channel[i];
+		ktime_t timestamp;
 
-	ced->event_handler(ced);
+		if (!imxtm->gpt->gpt_is_ic_irq(ic, tstat))
+			continue;
+
+		imxtm->gpt->gpt_ic_irq_acknowledge(ic);
+
+		timestamp = ns_to_ktime(timecounter_read(&ic->tc));
+
+		if (ic->handler)
+			ic->handler(ic->chan, ic->dev_id, timestamp);
+	}
+
+	if (imxtm->gpt->gpt_is_oc_irq(imxtm, tstat)) {
+		imxtm->gpt->gpt_oc_irq_acknowledge(imxtm);
+		ced->event_handler(ced);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -289,16 +458,16 @@ static int __init mxc_clockevent_init(struct imx_timer *imxtm)
 			   IRQF_TIMER | IRQF_IRQPOLL, "i.MX Timer Tick", ced);
 }
 
-static void imx1_gpt_setup_tctl(struct imx_timer *imxtm)
+static void imx1_gpt_oc_setup_tctl(struct imx_timer *imxtm)
 {
 	u32 tctl_val;
 
 	tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN;
 	writel_relaxed(tctl_val, imxtm->base + MXC_TCTL);
 }
-#define imx21_gpt_setup_tctl imx1_gpt_setup_tctl
+#define imx21_gpt_oc_setup_tctl imx1_gpt_oc_setup_tctl
 
-static void imx31_gpt_setup_tctl(struct imx_timer *imxtm)
+static void imx31_gpt_oc_setup_tctl(struct imx_timer *imxtm)
 {
 	u32 tctl_val;
 
@@ -311,7 +480,7 @@ static void imx31_gpt_setup_tctl(struct imx_timer *imxtm)
 	writel_relaxed(tctl_val, imxtm->base + MXC_TCTL);
 }
 
-static void imx6dl_gpt_setup_tctl(struct imx_timer *imxtm)
+static void imx6dl_gpt_oc_setup_tctl(struct imx_timer *imxtm)
 {
 	u32 tctl_val;
 
@@ -332,10 +501,12 @@ static const struct imx_gpt_data imx1_gpt_data = {
 	.reg_tstat = MX1_2_TSTAT,
 	.reg_tcn = MX1_2_TCN,
 	.reg_tcmp = MX1_2_TCMP,
-	.gpt_irq_enable = imx1_gpt_irq_enable,
-	.gpt_irq_disable = imx1_gpt_irq_disable,
-	.gpt_irq_acknowledge = imx1_gpt_irq_acknowledge,
-	.gpt_setup_tctl = imx1_gpt_setup_tctl,
+	.gpt_oc_irq_enable = imx1_gpt_oc_irq_enable,
+	.gpt_oc_irq_disable = imx1_gpt_oc_irq_disable,
+	.gpt_oc_irq_acknowledge = imx1_gpt_oc_irq_acknowledge,
+	.gpt_is_oc_irq = imx1_gpt_is_oc_irq,
+	.gpt_is_ic_irq = imx1_gpt_is_ic_irq,
+	.gpt_oc_setup_tctl = imx1_gpt_oc_setup_tctl,
 	.set_next_event = mx1_2_set_next_event,
 };
 
@@ -343,10 +514,12 @@ static const struct imx_gpt_data imx21_gpt_data = {
 	.reg_tstat = MX1_2_TSTAT,
 	.reg_tcn = MX1_2_TCN,
 	.reg_tcmp = MX1_2_TCMP,
-	.gpt_irq_enable = imx21_gpt_irq_enable,
-	.gpt_irq_disable = imx21_gpt_irq_disable,
-	.gpt_irq_acknowledge = imx21_gpt_irq_acknowledge,
-	.gpt_setup_tctl = imx21_gpt_setup_tctl,
+	.gpt_oc_irq_enable = imx21_gpt_oc_irq_enable,
+	.gpt_oc_irq_disable = imx21_gpt_oc_irq_disable,
+	.gpt_oc_irq_acknowledge = imx21_gpt_oc_irq_acknowledge,
+	.gpt_is_oc_irq = imx21_gpt_is_oc_irq,
+	.gpt_is_ic_irq = imx21_gpt_is_ic_irq,
+	.gpt_oc_setup_tctl = imx21_gpt_oc_setup_tctl,
 	.set_next_event = mx1_2_set_next_event,
 };
 
@@ -354,27 +527,160 @@ static const struct imx_gpt_data imx31_gpt_data = {
 	.reg_tstat = V2_TSTAT,
 	.reg_tcn = V2_TCN,
 	.reg_tcmp = V2_TCMP,
-	.gpt_irq_enable = imx31_gpt_irq_enable,
-	.gpt_irq_disable = imx31_gpt_irq_disable,
-	.gpt_irq_acknowledge = imx31_gpt_irq_acknowledge,
-	.gpt_setup_tctl = imx31_gpt_setup_tctl,
+	.gpt_oc_irq_enable = imx31_gpt_oc_irq_enable,
+	.gpt_oc_irq_disable = imx31_gpt_oc_irq_disable,
+	.gpt_oc_irq_acknowledge = imx31_gpt_oc_irq_acknowledge,
+	.gpt_is_oc_irq = imx31_gpt_is_oc_irq,
+	.gpt_oc_setup_tctl = imx31_gpt_oc_setup_tctl,
 	.set_next_event = v2_set_next_event,
+
+	/* input capture methods */
+	.gpt_ic_irq_enable = imx31_gpt_ic_irq_enable,
+	.gpt_ic_irq_disable = imx31_gpt_ic_irq_disable,
+	.gpt_ic_irq_acknowledge = imx31_gpt_ic_irq_acknowledge,
+	.gpt_is_ic_irq = imx31_gpt_is_ic_irq,
+	.gpt_ic_enable = imx31_gpt_ic_enable,
+	.gpt_ic_disable = imx31_gpt_ic_disable,
 };
 
 static const struct imx_gpt_data imx6dl_gpt_data = {
 	.reg_tstat = V2_TSTAT,
 	.reg_tcn = V2_TCN,
 	.reg_tcmp = V2_TCMP,
-	.gpt_irq_enable = imx6dl_gpt_irq_enable,
-	.gpt_irq_disable = imx6dl_gpt_irq_disable,
-	.gpt_irq_acknowledge = imx6dl_gpt_irq_acknowledge,
-	.gpt_setup_tctl = imx6dl_gpt_setup_tctl,
+	.gpt_oc_irq_enable = imx6dl_gpt_oc_irq_enable,
+	.gpt_oc_irq_disable = imx6dl_gpt_oc_irq_disable,
+	.gpt_oc_irq_acknowledge = imx6dl_gpt_oc_irq_acknowledge,
+	.gpt_is_oc_irq = imx6dl_gpt_is_oc_irq,
+	.gpt_oc_setup_tctl = imx6dl_gpt_oc_setup_tctl,
 	.set_next_event = v2_set_next_event,
+
+	/* input capture methods */
+	.gpt_ic_irq_enable = imx6dl_gpt_ic_irq_enable,
+	.gpt_ic_irq_disable = imx6dl_gpt_ic_irq_disable,
+	.gpt_ic_irq_acknowledge = imx6dl_gpt_ic_irq_acknowledge,
+	.gpt_is_ic_irq = imx6dl_gpt_is_ic_irq,
+	.gpt_ic_enable = imx6dl_gpt_ic_enable,
+	.gpt_ic_disable = imx6dl_gpt_ic_disable,
 };
 
+static u64 gpt_ic_read(const struct cyclecounter *cc)
+{
+	struct icap_channel *ic = container_of(cc, struct icap_channel, cc);
+	struct imx_timer *imxtm = ic->imxtm;
+
+	return readl_relaxed(imxtm->base + ic->cnt_reg);
+}
+
+int mxc_request_input_capture(unsigned int chan, mxc_icap_handler_t handler,
+			      unsigned long capflags, void *dev_id)
+{
+	struct imx_timer *imxtm;
+	struct icap_channel *ic;
+	unsigned long flags;
+	u64 start_cycles;
+	int ret = 0;
+	u32 mode;
+
+	/* we only care about rising and falling flags */
+	capflags &= (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING);
+
+	if (chan > 1 || !handler || !capflags)
+		return -EINVAL;
+
+	ic = &icap_channel[chan];
+	imxtm = ic->imxtm;
+
+	if (!imxtm->gpt->gpt_ic_enable)
+		return -ENODEV;
+
+	spin_lock_irqsave(&icap_lock, flags);
+
+	if (ic->handler) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ic->handler = handler;
+	ic->dev_id = dev_id;
+
+	switch (capflags) {
+	case IRQF_TRIGGER_RISING:
+		mode = V2_IM_RISING;
+		break;
+	case IRQF_TRIGGER_FALLING:
+		mode = V2_IM_FALLING;
+		break;
+	default:
+		mode = V2_IM_BOTH;
+		break;
+	}
+
+	/* ack any pending input capture interrupt before enabling */
+	imxtm->gpt->gpt_ic_irq_acknowledge(ic);
+
+	/*
+	 * initialize the cyclecounter. The input capture is capturing
+	 * from the mxc clocksource, so it has the same mask/shift/mult.
+	 */
+	memset(&ic->cc, 0, sizeof(ic->cc));
+	ic->cc.read = gpt_ic_read;
+	ic->cc.mask = clocksource_mxc.mask;
+	ic->cc.shift = clocksource_mxc.shift;
+	ic->cc.mult = clocksource_mxc.mult;
+
+	/* initialize a timecounter for the input capture */
+	start_cycles = mxc_read_sched_clock();
+	timecounter_init(&ic->tc, &ic->cc, ktime_get_ns());
+	/*
+	 * timecounter_init() read the last captured timer count, but
+	 * that's not the start cycle counter, so update it with the
+	 * real start cycles.
+	 */
+	ic->tc.cycle_last = start_cycles;
+
+	imxtm->gpt->gpt_ic_enable(ic, mode);
+	imxtm->gpt->gpt_ic_irq_enable(ic);
+
+out:
+	spin_unlock_irqrestore(&icap_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mxc_request_input_capture);
+
+void mxc_free_input_capture(unsigned int chan, void *dev_id)
+{
+	struct imx_timer *imxtm;
+	struct icap_channel *ic;
+	unsigned long flags;
+
+	if (chan > 1)
+		return;
+
+	ic = &icap_channel[chan];
+	imxtm = ic->imxtm;
+
+	if (!imxtm->gpt->gpt_ic_disable)
+		return;
+
+	spin_lock_irqsave(&icap_lock, flags);
+
+	if (!ic->handler || dev_id != ic->dev_id)
+		goto out;
+
+	imxtm->gpt->gpt_ic_irq_disable(ic);
+	imxtm->gpt->gpt_ic_disable(ic);
+
+	ic->handler = NULL;
+	ic->dev_id = NULL;
+out:
+	spin_unlock_irqrestore(&icap_lock, flags);
+}
+EXPORT_SYMBOL_GPL(mxc_free_input_capture);
+
 static int __init _mxc_timer_init(struct imx_timer *imxtm)
 {
-	int ret;
+	struct icap_channel *ic;
+	int i, ret;
 
 	switch (imxtm->type) {
 	case GPT_TYPE_IMX1:
@@ -410,14 +716,23 @@ static int __init _mxc_timer_init(struct imx_timer *imxtm)
 	writel_relaxed(0, imxtm->base + MXC_TCTL);
 	writel_relaxed(0, imxtm->base + MXC_TPRER); /* see datasheet note */
 
-	imxtm->gpt->gpt_setup_tctl(imxtm);
+	imxtm->gpt->gpt_oc_setup_tctl(imxtm);
 
 	/* init and register the timer to the framework */
 	ret = mxc_clocksource_init(imxtm);
 	if (ret)
 		return ret;
 
-	return mxc_clockevent_init(imxtm);
+	ret = mxc_clockevent_init(imxtm);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < 2; i++) {
+		ic = &icap_channel[i];
+		ic->imxtm = imxtm;
+	}
+
+	return 0;
 }
 
 void __init mxc_timer_init(unsigned long pbase, int irq, enum imx_gpt_type type)
@@ -439,6 +754,70 @@ void __init mxc_timer_init(unsigned long pbase, int irq, enum imx_gpt_type type)
 	_mxc_timer_init(imxtm);
 }
 
+/*
+ * a platform driver is needed in order to acquire pinmux
+ * for input capture pins. The probe call is also useful
+ * for setting up the input capture channel structures.
+ */
+static int mxc_timer_probe(struct platform_device *pdev)
+{
+	struct icap_channel *ic;
+	int i;
+
+	/* setup the input capture channels */
+	for (i = 0; i < 2; i++) {
+		ic = &icap_channel[i];
+		ic->chan = i;
+		if (i == 0) {
+			ic->cnt_reg = V2_TCAP1;
+			ic->irqen_bit = V2_IR_IF1;
+			ic->status_bit = V2_TSTAT_IF1;
+			ic->mode_bit = V2_TCTL_IM1_BIT;
+		} else {
+			ic->cnt_reg = V2_TCAP2;
+			ic->irqen_bit = V2_IR_IF2;
+			ic->status_bit = V2_TSTAT_IF2;
+			ic->mode_bit = V2_TCTL_IM2_BIT;
+		}
+	}
+
+	return 0;
+}
+
+static int mxc_timer_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static const struct of_device_id timer_of_match[] = {
+	{ .compatible = "fsl,imx1-gpt" },
+	{ .compatible = "fsl,imx21-gpt" },
+	{ .compatible = "fsl,imx27-gpt" },
+	{ .compatible = "fsl,imx31-gpt" },
+	{ .compatible = "fsl,imx25-gpt" },
+	{ .compatible = "fsl,imx50-gpt" },
+	{ .compatible = "fsl,imx51-gpt" },
+	{ .compatible = "fsl,imx53-gpt" },
+	{ .compatible = "fsl,imx6q-gpt" },
+	{ .compatible = "fsl,imx6dl-gpt" },
+	{ .compatible = "fsl,imx6sl-gpt" },
+	{ .compatible = "fsl,imx6sx-gpt" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, timer_of_match);
+
+static struct platform_driver mxc_timer_pdrv = {
+	.probe		= mxc_timer_probe,
+	.remove		= mxc_timer_remove,
+	.driver		= {
+		.name	= "mxc-timer",
+		.owner	= THIS_MODULE,
+		.of_match_table	= timer_of_match,
+	},
+};
+
+module_platform_driver(mxc_timer_pdrv);
+
 static int __init mxc_timer_init_dt(struct device_node *np,  enum imx_gpt_type type)
 {
 	struct imx_timer *imxtm;
diff --git a/include/linux/mxc_icap.h b/include/linux/mxc_icap.h
new file mode 100644
index 000000000000..fa5ffdf3b589
--- /dev/null
+++ b/include/linux/mxc_icap.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * i.MX GPT Input Capture support.
+ *
+ * Copyright (C) 2015 Mentor Graphics, Inc. All Rights Reserved.
+ */
+#ifndef __MXC_ICAP_H__
+#define __MXC_ICAP_H__
+
+typedef void (*mxc_icap_handler_t)(int, void *, ktime_t);
+
+int mxc_request_input_capture(unsigned int chan, mxc_icap_handler_t handler,
+			      unsigned long capflags, void *dev_id);
+void mxc_free_input_capture(unsigned int chan, void *dev_id);
+
+#endif
-- 
2.25.1