Sigma Designs Tango platforms provide a 27 MHz crystal oscillator.
Use it for clocksource, sched_clock, and delay_timer.
Signed-off-by: Marc Gonzalez <marc_gonza...@sigmadesigns.com>
---
I have a nagging feeling that the QUIT_IF macro will get this patch NAKed ;-)
My rationale: error-handling tends to take the focus away from the normal
path, and put it on the error path. Hiding the details away in a macro
helps to keep the error-handling noise to a minimum.
---
drivers/clocksource/Kconfig | 4 +++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/tango_xtal.c | 61 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+)
create mode 100644 drivers/clocksource/tango_xtal.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4e57730e0be4..63c878d4d9e3 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -275,6 +275,10 @@ config CLKSRC_MIPS_GIC
depends on MIPS_GIC
select CLKSRC_OF
+config CLKSRC_TANGO_XTAL
+ bool
+ select CLKSRC_OF
+
config CLKSRC_PXA
def_bool y if ARCH_PXA || ARCH_SA1100
select CLKSRC_OF if USE_OF
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index f228354961ca..160970a3963b 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o
obj-$(CONFIG_ARCH_INTEGRATOR_AP) += timer-integrator-ap.o
obj-$(CONFIG_CLKSRC_VERSATILE) += versatile.o
obj-$(CONFIG_CLKSRC_MIPS_GIC) += mips-gic-timer.o
+obj-$(CONFIG_CLKSRC_TANGO_XTAL) += tango_xtal.o
obj-$(CONFIG_CLKSRC_IMX_GPT) += timer-imx-gpt.o
obj-$(CONFIG_ASM9260_TIMER) += asm9260_timer.o
obj-$(CONFIG_H8300) += h8300_timer8.o
diff --git a/drivers/clocksource/tango_xtal.c b/drivers/clocksource/tango_xtal.c
new file mode 100644
index 000000000000..a3c265eb7236
--- /dev/null
+++ b/drivers/clocksource/tango_xtal.c
@@ -0,0 +1,61 @@
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/of_address.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+
+#define QUIT_IF(cond, fmt, ...) do if (cond) { \
+ static const char format[] __initconst = fmt; \
+ pr_err(format, ## __VA_ARGS__); \
+ return; \
+} while (0)
+
+static void __iomem *xtal_in_cnt;
+static struct delay_timer delay_timer;
+
+static unsigned long notrace read_xtal_counter(void)
+{
+ return readl_relaxed(xtal_in_cnt);
+}
+
+static u64 notrace read_sched_clock(void)
+{
+ return read_xtal_counter();
+}
+
+static cycle_t read_clocksource(struct clocksource *cs)
+{
+ return read_xtal_counter();
+}
+
+static struct clocksource tango_xtal = {
+ .name = "tango-xtal",
+ .rating = 350,
+ .read = read_clocksource,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init tango_clocksource_init(struct device_node *np)
+{
+ struct clk *clk;
+ int xtal_freq, err;
+
+ xtal_in_cnt = of_iomap(np, 0);
+ QUIT_IF(xtal_in_cnt == NULL, "%s: invalid address\n", np->full_name);
+
+ clk = of_clk_get(np, 0);
+ QUIT_IF(IS_ERR(clk), "%s: invalid clock\n", np->full_name);
+
+ xtal_freq = clk_get_rate(clk);
+ delay_timer.freq = xtal_freq;
+ delay_timer.read_current_timer = read_xtal_counter;
+
+ register_current_timer_delay(&delay_timer);
+ sched_clock_register(read_sched_clock, 32, xtal_freq);
+ err = clocksource_register_hz(&tango_xtal, xtal_freq);
+ QUIT_IF(err, "%s: registration failed\n", np->full_name);
+}
+
+CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);
--
2.4.5
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