clocksource/drivers/tango_xtal: Add new timer for Tango SoCs

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_gonzalez@sigmadesigns.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index a7726db13abbb0e883ec5681fec65a473bc9d29e..50b68bc20720297b3ae4cb3e935c771540b9032f 100644 (file)
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -279,6 +279,10 @@ 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 OF

diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 5c00863c3e33ad8a3061fdf88765cfb4c0770d97..fc9348dc4f92e311315c6c7066da1fd1dd171d5e 100644 (file)
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -56,6 +56,7 @@ 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 (file)
index 0000000..d297b30
--- /dev/null
+++ b/drivers/clocksource/tango_xtal.c
@@ -0,0 +1,66 @@
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/of_address.h>
+#include <linux/printk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+
+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, ret;
+
+       xtal_in_cnt = of_iomap(np, 0);
+       if (xtal_in_cnt == NULL) {
+               pr_err("%s: invalid address\n", np->full_name);
+               return;
+       }
+
+       clk = of_clk_get(np, 0);
+       if (IS_ERR(clk)) {
+               pr_err("%s: invalid clock\n", np->full_name);
+               return;
+       }
+
+       xtal_freq = clk_get_rate(clk);
+       delay_timer.freq = xtal_freq;
+       delay_timer.read_current_timer = read_xtal_counter;
+
+       ret = clocksource_register_hz(&tango_xtal, xtal_freq);
+       if (ret != 0) {
+               pr_err("%s: registration failed\n", np->full_name);
+               return;
+       }
+
+       sched_clock_register(read_sched_clock, 32, xtal_freq);
+       register_current_timer_delay(&delay_timer);
+}
+
+CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);