[PATCH] Add TI-Nspire timer support

[Daniel Tang]

Hi,

This patch adds a clocksource/clockevent driver for the TI-Nspire calculator series.

Cheers,
Daniel Tang


Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Daniel Tang <dt.tangr@xxxxxxxxx>
---
 .../devicetree/bindings/timer/lsi,zevio-timer.txt  |  33 +++
 drivers/clocksource/Makefile                       |   1 +
 drivers/clocksource/zevio-timer.c                  | 232 +++++++++++++++++++++
 3 files changed, 266 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/lsi,zevio-timer.txt
 create mode 100644 drivers/clocksource/zevio-timer.c

diff --git a/Documentation/devicetree/bindings/timer/lsi,zevio-timer.txt b/Documentation/devicetree/bindings/timer/lsi,zevio-timer.txt
new file mode 100644
index 0000000..b2d07ad
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/lsi,zevio-timer.txt
@@ -0,0 +1,33 @@
+TI-NSPIRE timer
+
+Required properties:
+
+- compatible : should be "lsi,zevio-timer".
+- reg : The physical base address and size of the timer (always first).
+- clocks: phandle to the source clock.
+
+Optional properties:
+
+- interrupts : The interrupt number of the first timer.
+- reg : The interrupt acknowledgement registers
+	(always after timer base address)
+
+If any of the optional properties are not given, the timer is added as a
+clock-source only.
+
+Example:
+
+timer {
+	compatible = "lsi,zevio-timer";
+	reg = <0x900D0000 0x1000>, <0x900A0020 0x8>;
+	interrupts = <19>;
+	clocks = <&timer_clk>;
+};
+
+Example (no clock-events):
+
+timer {
+	compatible = "lsi,zevio-timer";
+	reg = <0x900D0000 0x1000>;
+	clocks = <&timer_clk>;
+};
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 8d979c7..293f86e 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_ARCH_PRIMA2)	+= timer-prima2.o
 obj-$(CONFIG_SUN4I_TIMER)	+= sun4i_timer.o
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra20_timer.o
 obj-$(CONFIG_VT8500_TIMER)	+= vt8500_timer.o
+obj-$(CONFIG_ARCH_NSPIRE)	+= zevio-timer.o
 obj-$(CONFIG_ARCH_BCM)		+= bcm_kona_timer.o
 obj-$(CONFIG_CADENCE_TTC_TIMER)	+= cadence_ttc_timer.o
 obj-$(CONFIG_CLKSRC_EXYNOS_MCT)	+= exynos_mct.o
diff --git a/drivers/clocksource/zevio-timer.c b/drivers/clocksource/zevio-timer.c
new file mode 100644
index 0000000..5f213d9
--- /dev/null
+++ b/drivers/clocksource/zevio-timer.c
@@ -0,0 +1,232 @@
+/*
+ *  linux/drivers/clocksource/zevio-timer.c
+ *
+ *  Copyright (C) 2013 Daniel Tang <tangrs@xxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/cpumask.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+
+#define IO_CURRENT_VAL	0x00
+#define IO_DIVIDER	0x04
+#define IO_CONTROL	0x08
+
+#define IO_TIMER1	0x00
+#define IO_TIMER2	0x0C
+
+#define IO_MATCH_BEGIN	0x18
+#define IO_MATCH(x)	(IO_MATCH_BEGIN + ((x)<<2))
+
+#define IO_INTR_STS	0x00
+#define IO_INTR_ACK	0x00
+#define IO_INTR_MSK	0x04
+
+#define CNTL_STOP_TIMER	(1<<4)
+#define CNTL_RUN_TIMER	(0<<4)
+
+#define CNTL_INC	(1<<3)
+#define CNTL_DEC	(0<<3)
+
+#define CNTL_TOZERO	0
+#define CNTL_MATCH(x)	((x) + 1)
+#define CNTL_FOREVER	7
+
+/* There are 6 match registers but we only use one. */
+#define TIMER_MATCH	0
+
+#define TIMER_INTR_MSK	(1<<(TIMER_MATCH))
+#define TIMER_INTR_ALL	0x3F
+
+struct zevio_timer {
+	void __iomem *base;
+	void __iomem *timer1, *timer2;
+	void __iomem *interrupt_regs;
+
+	int irqnr;
+
+	struct clk *clk;
+	struct clock_event_device clkevt;
+	struct irqaction clkevt_irq;
+
+	char clocksource_name[64];
+	char clockevent_name[64];
+};
+
+static int zevio_timer_set_event(unsigned long delta,
+		struct clock_event_device *dev)
+{
+	unsigned long flags;
+	struct zevio_timer *timer = container_of(dev,
+			struct zevio_timer,
+			clkevt);
+
+	local_irq_save(flags);
+
+	writel(delta, timer->timer1 + IO_CURRENT_VAL);
+	writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH),
+			timer->timer1 + IO_CONTROL);
+
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+static void zevio_timer_set_mode(enum clock_event_mode mode,
+		struct clock_event_device *dev)
+{
+	unsigned long flags;
+	struct zevio_timer *timer = container_of(dev,
+			struct zevio_timer,
+			clkevt);
+
+	local_irq_save(flags);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_RESUME:
+	case CLOCK_EVT_MODE_ONESHOT:
+		/* Enable timer interrupts */
+		writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK);
+		writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
+		dev->mode = mode;
+		break;
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_UNUSED:
+		/* Disable timer interrupts */
+		writel(0, timer->interrupt_regs + IO_INTR_MSK);
+		writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
+		/* Stop timer */
+		writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
+		dev->mode = mode;
+		break;
+	case CLOCK_EVT_MODE_PERIODIC:
+	default:
+		/* Unsupported */
+		break;
+	}
+
+	local_irq_restore(flags);
+}
+
+static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id)
+{
+	struct zevio_timer *timer = dev_id;
+	u32 intr;
+
+	intr = readl(timer->interrupt_regs + IO_INTR_ACK);
+	if (!(intr & TIMER_INTR_MSK))
+		return IRQ_NONE;
+
+	writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK);
+	writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
+
+	if (timer->clkevt.event_handler)
+		timer->clkevt.event_handler(&timer->clkevt);
+
+	return IRQ_HANDLED;
+}
+
+static int __init zevio_timer_add(struct device_node *node)
+{
+	struct zevio_timer *timer;
+	struct resource res;
+	int ret;
+
+	timer = kzalloc(sizeof(*timer), GFP_ATOMIC);
+	if (!timer)
+		return -ENOMEM;
+
+	timer->base = of_iomap(node, 0);
+	if (!timer->base) {
+		ret = -EINVAL;
+		goto error_free;
+	}
+	timer->timer1 = timer->base + IO_TIMER1;
+	timer->timer2 = timer->base + IO_TIMER2;
+
+	timer->clk = of_clk_get(node, 0);
+	if (IS_ERR(timer->clk)) {
+		ret = PTR_ERR(timer->clk);
+		pr_err("Timer clock not found! (error %d)\n", ret);
+		goto error_unmap;
+	}
+
+	timer->interrupt_regs = of_iomap(node, 1);
+	timer->irqnr = irq_of_parse_and_map(node, 0);
+
+	of_address_to_resource(node, 0, &res);
+	scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name),
+			"%llx.%s_clocksource",
+			(unsigned long long)res.start, node->name);
+
+	scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name),
+			"%llx.%s_clockevent",
+			(unsigned long long)res.start, node->name);
+
+	if (timer->interrupt_regs && timer->irqnr) {
+		timer->clkevt.name	= timer->clockevent_name;
+		timer->clkevt.set_next_event = zevio_timer_set_event;
+		timer->clkevt.set_mode	= zevio_timer_set_mode;
+		timer->clkevt.rating	= 200;
+		timer->clkevt.cpumask	= cpu_all_mask;
+		timer->clkevt.features	=
+			CLOCK_EVT_FEAT_ONESHOT;
+
+		writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL);
+		writel(0, timer->timer1 + IO_DIVIDER);
+
+		/* Start with timer interrupts disabled */
+		writel(0, timer->interrupt_regs + IO_INTR_MSK);
+		writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK);
+
+		/* Interrupt to occur when timer value matches 0 */
+		writel(0, timer->base + IO_MATCH(TIMER_MATCH));
+
+		timer->clkevt_irq.name	= timer->clockevent_name;
+		timer->clkevt_irq.handler = zevio_timer_interrupt;
+		timer->clkevt_irq.dev_id = timer;
+		timer->clkevt_irq.flags	=
+			IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL;
+
+		setup_irq(timer->irqnr, &timer->clkevt_irq);
+
+		clockevents_config_and_register(&timer->clkevt,
+				clk_get_rate(timer->clk), 0x0001, 0xffff);
+		pr_info("Added %s as clockevent\n", timer->clockevent_name);
+	}
+
+	writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL);
+	writel(0, timer->timer2 + IO_CURRENT_VAL);
+	writel(0, timer->timer2 + IO_DIVIDER);
+	writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC,
+			timer->timer2 + IO_CONTROL);
+
+	clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL,
+			timer->clocksource_name,
+			clk_get_rate(timer->clk),
+			200, 16,
+			clocksource_mmio_readw_up);
+
+	pr_info("Added %s as clocksource\n", timer->clocksource_name);
+
+	return 0;
+error_unmap:
+	iounmap(timer->base);
+error_free:
+	kfree(timer);
+	return ret;
+}
+
+CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_add);
-- 
1.8.1.3--
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