[RFC PATCHv4 4/6] clocksource: TI-Nspire timer support
Daniel Tang
dt.tangr at gmail.com
Sat May 25 07:08:05 EDT 2013
Add clocksource and clockevent driver for the TI-Nspire.
Signed-off-by: Daniel Tang <dt.tangr at gmail.com>
---
.../devicetree/bindings/timer/lsi,zevio-timer.txt | 33 +++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/zevio-timer.c | 231 +++++++++++++++++++++
3 files changed, 265 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..c6d7f03
--- /dev/null
+++ b/drivers/clocksource/zevio-timer.c
@@ -0,0 +1,231 @@
+/*
+ * linux/drivers/clocksource/zevio-timer.c
+ *
+ * Copyright (C) 2013 Daniel Tang <tangrs at tangrs.id.au>
+ *
+ * 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_PERIODIC:
+ /* Unsupported */
+ break;
+ 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;
+ }
+
+ 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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