[PATCH v2] ARM: clocksource: add support for MOXA ART SoCs
From: Jonas Jensen
Date: Wed Jun 26 2013 - 10:53:43 EST
This patch adds an clocksource driver for the main timer(s)
found on MOXA ART SoCs.
Changes since v2:
1. use clocksource/clockevents infrastructures
2. clock frequency read from system clock
Applies to next-20130619
Signed-off-by: Jonas Jensen <jonas.jensen@xxxxxxxxx>
---
drivers/clocksource/Makefile | 1 +
drivers/clocksource/moxart_timer.c | 184 ++++++++++++++++++++++++++++++++++++
2 files changed, 185 insertions(+), 0 deletions(-)
create mode 100644 drivers/clocksource/moxart_timer.c
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 8d979c7..c93e1a8 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -29,3 +29,4 @@ obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o
obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o
+obj-$(CONFIG_ARCH_MOXART) += moxart_timer.o
diff --git a/drivers/clocksource/moxart_timer.c b/drivers/clocksource/moxart_timer.c
new file mode 100644
index 0000000..376df31
--- /dev/null
+++ b/drivers/clocksource/moxart_timer.c
@@ -0,0 +1,184 @@
+/*
+ * MOXA ART SoCs timer handling.
+ *
+ * Copyright (C) 2013 Jonas Jensen
+ *
+ * Jonas Jensen <jonas.jensen@xxxxxxxxx>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqreturn.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/clocksource.h>
+
+#define MAX_TIMER 2
+#define USED_TIMER 1
+#define APB_CLK 48000000
+
+/* note: timer count is writable */
+
+#define TIMER1_COUNT 0x0
+#define TIMER1_LOAD 0x4
+#define TIMER1_MATCH1 0x8
+#define TIMER1_MATCH2 0xC
+
+#define TIMER2_COUNT 0x10
+#define TIMER2_LOAD 0x14
+#define TIMER2_MATCH1 0x18
+#define TIMER2_MATCH2 0x1C
+
+#define TIMER3_COUNT 0x20
+#define TIMER3_LOAD 0x24
+#define TIMER3_MATCH1 0x28
+#define TIMER3_MATCH2 0x2C
+
+#define TIMER_CR 0x30
+#define TIMER_INTR_STATE 0x34
+#define TIMER_INTR_MASK 0x38
+
+/* TIMER_CR flags:
+ TIMEREG_CR_1_CLOCK 0: PCLK, 1: EXT1CLK
+ TIMEREG_CR_1_INT over flow interrupt enable bit */
+
+#define TIMEREG_CR_1_ENABLE (1 << 0)
+#define TIMEREG_CR_1_CLOCK (1 << 1)
+#define TIMEREG_CR_1_INT (1 << 2)
+#define TIMEREG_CR_2_ENABLE (1 << 3)
+#define TIMEREG_CR_2_CLOCK (1 << 4)
+#define TIMEREG_CR_2_INT (1 << 5)
+#define TIMEREG_CR_3_ENABLE (1 << 6)
+#define TIMEREG_CR_3_CLOCK (1 << 7)
+#define TIMEREG_CR_3_INT (1 << 8)
+#define TIMEREG_CR_COUNT_UP (1 << 9)
+#define TIMEREG_CR_COUNT_DOWN (0 << 9)
+
+static void __iomem *timer_base;
+static unsigned int clock_frequency;
+
+static void moxart_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ u32 u = readl(timer_base + TIMER_CR);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_RESUME:
+ case CLOCK_EVT_MODE_ONESHOT:
+ u |= TIMEREG_CR_1_ENABLE;
+ writel(u, timer_base + TIMER_CR);
+ writel(~0, timer_base + TIMER1_LOAD);
+ pr_debug("%s: CLOCK_EVT_MODE_ONESHOT\n", __func__);
+ break;
+ case CLOCK_EVT_MODE_PERIODIC:
+ u |= TIMEREG_CR_1_ENABLE;
+ writel(u, timer_base + TIMER_CR);
+ writel(clock_frequency / HZ, timer_base + TIMER1_LOAD);
+ pr_debug("%s: CLOCK_EVT_MODE_PERIODIC\n", __func__);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ default:
+ u &= ~TIMEREG_CR_1_ENABLE;
+ writel(u, timer_base + TIMER_CR);
+ break;
+ }
+}
+
+static int moxart_clkevt_next_event(unsigned long cycles,
+ struct clock_event_device *unused)
+{
+ u32 alarm = readl(timer_base + TIMER1_COUNT) - cycles;
+ writel(alarm, timer_base + TIMER1_MATCH1);
+ return 0;
+}
+
+static struct clock_event_device moxart_clockevent = {
+ .name = "moxart_timer",
+ .rating = 300,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_mode = moxart_clkevt_mode,
+ .set_next_event = moxart_clkevt_next_event,
+};
+
+static irqreturn_t moxart_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+static struct irqaction moxart_timer_irq = {
+ .name = "moxart-timer",
+ .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = moxart_timer_interrupt,
+ .dev_id = &moxart_clockevent,
+};
+
+static void __init moxart_timer_init(struct device_node *node)
+{
+ int ret, irq;
+ struct clk *clk;
+
+ timer_base = of_iomap(node, 0);
+ if (!timer_base)
+ panic("%s: failed to map base\n", node->full_name);
+
+ irq = irq_of_parse_and_map(node, 0);
+ if (irq <= 0)
+ panic("%s: can't parse IRQ\n", node->full_name);
+
+ ret = setup_irq(irq, &moxart_timer_irq);
+ if (ret) {
+ pr_err("%s: failed to setup IRQ %d\n", node->full_name, irq);
+ return;
+ }
+
+ clock_frequency = APB_CLK;
+ /* it might be a good idea to have a default other than 0 for
+ clock_frequency, should any attempt at getting a valid
+ frequency fail, not that i see how it could, it probably could..
+ having it APB_CLK can certainly be wrong on some hardware,
+ why it is set again with the DT specific property: */
+
+ ret = of_property_read_u32(node, "clock-frequency", &clock_frequency);
+ if (ret)
+ pr_err("%s: can't read clock-frequency DT property\n",
+ node->full_name);
+
+ clk = of_clk_get(node, 0);
+ if (IS_ERR(clk))
+ pr_err("%s: of_clk_get failed\n", __func__);
+ else {
+ clock_frequency = clk_get_rate(clk);
+ pr_debug("%s: clk_get_rate=%u success\n", __func__,
+ clock_frequency);
+ }
+
+ writel(~0, timer_base + TIMER2_LOAD);
+
+ writel(TIMEREG_CR_1_ENABLE | TIMEREG_CR_2_ENABLE |
+ TIMEREG_CR_COUNT_DOWN, timer_base + TIMER_CR);
+
+ if (clocksource_mmio_init(timer_base + TIMER2_COUNT, "moxart_timer",
+ clock_frequency, 200, 32, clocksource_mmio_readl_down))
+ pr_err("%s: clocksource_mmio_init failed\n", __func__);
+
+ moxart_clockevent.cpumask = cpumask_of(0);
+
+ clockevents_config_and_register(&moxart_clockevent, clock_frequency,
+ 0x4, 0xf0000000);
+
+ pr_info("%s: %s finished clock_frequency=%d HZ=%d IRQ=%d\n",
+ node->full_name, __func__, clock_frequency, HZ, irq);
+}
+CLOCKSOURCE_OF_DECLARE(moxart, "moxa,moxart-timer", moxart_timer_init);
+
--
1.7.2.5
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