[PATCH v3] ARM: clocksource: add support for MOXA ART SoCs
Jonas Jensen
jonas.jensen at gmail.com
Thu Jun 27 07:23:23 EDT 2013
This patch adds an clocksource driver for the main timer(s)
found on MOXA ART SoCs.
Signed-off-by: Jonas Jensen <jonas.jensen at gmail.com>
---
Notes:
Applies to next-20130619
Changes since v2:
1. remove unused defines: MAX_TIMER, USED_TIMER, APB_CLK
2. split register defines so each timer has a base
3. use standard multiline comments
4. replace whitespaces with tabs
5. rename "timer_base" "base"
6. rename "clock_frequency" "clock_count_per_tick"
7. disable TIMER1 in CLOCK_EVT_MODE_ONESHOT
8. remove pr_debug:s
9. in CLOCK_EVT_MODE_PERIODIC, switch order, write clock_count_per_tick
to TIMER1 LOAD and enable it
10. enable TIMER1 in moxart_clkevt_next_event
11. remove IRQF_DISABLED, IRQF_IRQPOLL from irqaction flags
12. set clock_frequency exclusively from system clock
13. bail if of_clk_get fails
14. assign clock_count_per_tick to DIV_ROUND_CLOSEST(pclk, HZ)
15. align continuation lines with matching opening brace
drivers/clocksource/Makefile | 1 +
drivers/clocksource/moxart_timer.c | 166 +++++++++++++++++++++++++++++++++++++
2 files changed, 167 insertions(+)
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..4678b30
--- /dev/null
+++ b/drivers/clocksource/moxart_timer.c
@@ -0,0 +1,166 @@
+/*
+ * MOXA ART SoCs timer handling.
+ *
+ * Copyright (C) 2013 Jonas Jensen
+ *
+ * Jonas Jensen <jonas.jensen at gmail.com>
+ *
+ * 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 TIMER1_BASE 0x00
+#define TIMER2_BASE 0x10
+#define TIMER3_BASE 0x20
+
+#define REG_COUNT 0x0 /* writable */
+#define REG_LOAD 0x4
+#define REG_MATCH1 0x8
+#define REG_MATCH2 0xC
+
+#define TIMER_CR 0x30
+#define TIMER_INTR_STATE 0x34
+#define TIMER_INTR_MASK 0x38
+
+/*
+ * TIMER_CR flags:
+ *
+ * TIMEREG_CR_*_CLOCK 0: PCLK, 1: EXT1CLK
+ * TIMEREG_CR_*_INT overflow 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 *base;
+static unsigned int clock_count_per_tick;
+
+static void moxart_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ u32 u = readl(base + TIMER_CR);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_RESUME:
+ case CLOCK_EVT_MODE_ONESHOT:
+ u &= ~TIMEREG_CR_1_ENABLE;
+ writel(u, base + TIMER_CR);
+ writel(~0, base + TIMER1_BASE + REG_LOAD);
+ break;
+ case CLOCK_EVT_MODE_PERIODIC:
+ writel(clock_count_per_tick, base + TIMER1_BASE + REG_LOAD);
+ u |= TIMEREG_CR_1_ENABLE;
+ writel(u, base + TIMER_CR);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ default:
+ u &= ~TIMEREG_CR_1_ENABLE;
+ writel(u, base + TIMER_CR);
+ break;
+ }
+}
+
+static int moxart_clkevt_next_event(unsigned long cycles,
+ struct clock_event_device *unused)
+{
+ u32 u;
+ u = readl(base + TIMER1_BASE + REG_COUNT) - cycles;
+ writel(u, base + TIMER1_BASE + REG_MATCH1);
+ u = readl(base + TIMER_CR) | TIMEREG_CR_1_ENABLE;
+ writel(u, base + TIMER_CR);
+ return 0;
+}
+
+static struct clock_event_device moxart_clockevent = {
+ .name = "moxart_timer",
+ .rating = 200,
+ .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 = dev_id;
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+static struct irqaction moxart_timer_irq = {
+ .name = "moxart-timer",
+ .flags = IRQF_TIMER,
+ .handler = moxart_timer_interrupt,
+ .dev_id = &moxart_clockevent,
+};
+
+static void __init moxart_timer_init(struct device_node *node)
+{
+ int ret, irq;
+ unsigned long pclk;
+ struct clk *clk;
+
+ base = of_iomap(node, 0);
+ if (!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;
+ }
+
+ clk = of_clk_get(node, 0);
+ if (IS_ERR(clk)) {
+ pr_err("%s: of_clk_get failed\n", __func__);
+ return;
+ }
+
+ pclk = clk_get_rate(clk);
+ clock_count_per_tick = DIV_ROUND_CLOSEST(pclk, HZ);
+
+ writel(~0, base + TIMER2_BASE + REG_LOAD);
+
+ writel(TIMEREG_CR_2_ENABLE, base + TIMER_CR);
+
+ if (clocksource_mmio_init(base + TIMER2_BASE + REG_COUNT,
+ "moxart_timer", pclk, 200, 32,
+ clocksource_mmio_readl_down)) {
+ pr_err("%s: clocksource_mmio_init failed\n", __func__);
+ return;
+ }
+
+ moxart_clockevent.cpumask = cpumask_of(0);
+
+ clockevents_config_and_register(&moxart_clockevent, pclk,
+ 0x4, 0xf0000000);
+
+ pr_info("%s: %s finished pclk=%lu HZ=%d IRQ=%d\n",
+ node->full_name, __func__, pclk, HZ, irq);
+}
+CLOCKSOURCE_OF_DECLARE(moxart, "moxa,moxart-timer", moxart_timer_init);
+
--
1.8.2.1
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