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path: root/drivers/clocksource/clps711x-timer.c
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Diffstat (limited to 'drivers/clocksource/clps711x-timer.c')
-rw-r--r--drivers/clocksource/clps711x-timer.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/clocksource/clps711x-timer.c b/drivers/clocksource/clps711x-timer.c
new file mode 100644
index 0000000000..e95fdc49c2
--- /dev/null
+++ b/drivers/clocksource/clps711x-timer.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Cirrus Logic CLPS711X clocksource driver
+ *
+ * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+
+enum {
+ CLPS711X_CLKSRC_CLOCKSOURCE,
+ CLPS711X_CLKSRC_CLOCKEVENT,
+};
+
+static void __iomem *tcd;
+
+static u64 notrace clps711x_sched_clock_read(void)
+{
+ return ~readw(tcd);
+}
+
+static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base)
+{
+ unsigned long rate = clk_get_rate(clock);
+
+ tcd = base;
+
+ clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
+ clocksource_mmio_readw_down);
+
+ sched_clock_register(clps711x_sched_clock_read, 16, rate);
+}
+
+static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
+ unsigned int irq)
+{
+ struct clock_event_device *clkevt;
+ unsigned long rate;
+
+ clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
+ if (!clkevt)
+ return -ENOMEM;
+
+ rate = clk_get_rate(clock);
+
+ /* Set Timer prescaler */
+ writew(DIV_ROUND_CLOSEST(rate, HZ), base);
+
+ clkevt->name = "clps711x-clockevent";
+ clkevt->rating = 300;
+ clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
+ clkevt->cpumask = cpumask_of(0);
+ clockevents_config_and_register(clkevt, HZ, 0, 0);
+
+ return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
+ "clps711x-timer", clkevt);
+}
+
+static int __init clps711x_timer_init(struct device_node *np)
+{
+ unsigned int irq = irq_of_parse_and_map(np, 0);
+ struct clk *clock = of_clk_get(np, 0);
+ void __iomem *base = of_iomap(np, 0);
+
+ if (!base)
+ return -ENOMEM;
+ if (!irq)
+ return -EINVAL;
+ if (IS_ERR(clock))
+ return PTR_ERR(clock);
+
+ switch (of_alias_get_id(np, "timer")) {
+ case CLPS711X_CLKSRC_CLOCKSOURCE:
+ clps711x_clksrc_init(clock, base);
+ break;
+ case CLPS711X_CLKSRC_CLOCKEVENT:
+ return _clps711x_clkevt_init(clock, base, irq);
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);