Enhancements for dw_apb_timer:

- use DECLARE_CLOCKSOURCE_OF and convert its users
 - handle the sptimer not being present as sched_clock
 - add optional handling of timer clocks
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Merge tag 'dw_apb_timer_of' of git://github.com/mmind/linux-rockchip into next/drivers

From Heiko Stuebner, enhancements for dw_apb_timer:
- use DECLARE_CLOCKSOURCE_OF and convert its users
- handle the sptimer not being present as sched_clock
- add optional handling of timer clocks

* tag 'dw_apb_timer_of' of git://github.com/mmind/linux-rockchip:
  clocksource: dw_apb_timer_of: use clocksource_of_init
  clocksource: dw_apb_timer_of: select DW_APB_TIMER
  clocksource: dw_apb_timer_of: add clock-handling
  clocksource: dw_apb_timer_of: enable the use the clocksource as sched clock

Documentation/devicetree/bindings/rtc/dw-apb.txt

@@ -5,9 +5,20 @@ Required properties:
 - reg: physical base address of the controller and length of memory mapped
   region.
 - interrupts: IRQ line for the timer.
+- either clocks+clock-names or clock-frequency properties
+
+Optional properties:
+- clocks	: list of clock specifiers, corresponding to entries in
+		  the clock-names property;
+- clock-names	: should contain "timer" and "pclk" entries, matching entries
+		  in the clocks property.
 - clock-frequency: The frequency in HZ of the timer.
 - clock-freq: For backwards compatibility with picoxcell
 
+If using the clock specifiers, the pclk clock is optional, as not all
+systems may use one.
+
+
 Example:
 
 		timer1: timer@ffc09000 {
@@ -23,3 +34,11 @@ Example:
 				clock-frequency = <200000000>;
 				reg = <0xffd00000 0x1000>;
 			};
+
+		timer3: timer@ffe00000 {
+				compatible = "snps,dw-apb-timer-osc";
+				interrupts = <0 170 4>;
+				reg = <0xffe00000 0x1000>;
+				clocks = <&timer_clk>, <&timer_pclk>;
+				clock-names = "timer", "pclk";
+			};

arch/arm/mach-picoxcell/Kconfig

@@ -4,7 +4,6 @@ config ARCH_PICOXCELL
 	select ARM_PATCH_PHYS_VIRT
 	select ARM_VIC
 	select CPU_V6K
-	select DW_APB_TIMER
 	select DW_APB_TIMER_OF
 	select GENERIC_CLOCKEVENTS
 	select HAVE_TCM

arch/arm/mach-picoxcell/common.c

@@ -15,7 +15,6 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
-#include <linux/dw_apb_timer.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
@@ -88,7 +87,6 @@ DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
 	.map_io		= picoxcell_map_io,
 	.nr_irqs	= NR_IRQS_LEGACY,
 	.init_irq	= irqchip_init,
-	.init_time	= dw_apb_timer_init,
 	.init_machine	= picoxcell_init_machine,
 	.dt_compat	= picoxcell_dt_match,
 	.restart	= picoxcell_wdt_restart,

arch/arm/mach-socfpga/Kconfig

@@ -7,7 +7,6 @@ config ARCH_SOCFPGA
 	select CLKDEV_LOOKUP
 	select COMMON_CLK
 	select CPU_V7
-	select DW_APB_TIMER
 	select DW_APB_TIMER_OF
 	select GENERIC_CLOCKEVENTS
 	select GPIO_PL061 if GPIOLIB

arch/arm/mach-socfpga/socfpga.c

@@ -14,7 +14,6 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#include <linux/dw_apb_timer.h>
 #include <linux/clk-provider.h>
 #include <linux/irqchip.h>
 #include <linux/of_address.h>
@@ -120,7 +119,6 @@ DT_MACHINE_START(SOCFPGA, "Altera SOCFPGA")
 	.smp		= smp_ops(socfpga_smp_ops),
 	.map_io		= socfpga_map_io,
 	.init_irq	= socfpga_init_irq,
-	.init_time	= dw_apb_timer_init,
 	.init_machine	= socfpga_cyclone5_init,
 	.restart	= socfpga_cyclone5_restart,
 	.dt_compat	= altera_dt_match,

drivers/clocksource/Kconfig

@@ -21,6 +21,8 @@ config DW_APB_TIMER
 
 config DW_APB_TIMER_OF
 	bool
+	select DW_APB_TIMER
+	select CLKSRC_OF
 
 config ARMADA_370_XP_TIMER
 	bool

drivers/clocksource/dw_apb_timer_of.c

@@ -20,6 +20,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/clk.h>
 
 #include <asm/mach/time.h>
 #include <asm/sched_clock.h>
@@ -27,14 +28,37 @@
 static void timer_get_base_and_rate(struct device_node *np,
 				    void __iomem **base, u32 *rate)
 {
+	struct clk *timer_clk;
+	struct clk *pclk;
+
 	*base = of_iomap(np, 0);
 
 	if (!*base)
 		panic("Unable to map regs for %s", np->name);
 
+	/*
+	 * Not all implementations use a periphal clock, so don't panic
+	 * if it's not present
+	 */
+	pclk = of_clk_get_by_name(np, "pclk");
+	if (!IS_ERR(pclk))
+		if (clk_prepare_enable(pclk))
+			pr_warn("pclk for %s is present, but could not be activated\n",
+				np->name);
+
+	timer_clk = of_clk_get_by_name(np, "timer");
+	if (IS_ERR(timer_clk))
+		goto try_clock_freq;
+
+	if (!clk_prepare_enable(timer_clk)) {
+		*rate = clk_get_rate(timer_clk);
+		return;
+	}
+
+try_clock_freq:
 	if (of_property_read_u32(np, "clock-freq", rate) &&
 		of_property_read_u32(np, "clock-frequency", rate))
-		panic("No clock-frequency property for %s", np->name);
+		panic("No clock nor clock-frequency property for %s", np->name);
 }
 
 static void add_clockevent(struct device_node *event_timer)
@@ -57,6 +81,9 @@ static void add_clockevent(struct device_node *event_timer)
 	dw_apb_clockevent_register(ced);
 }
 
+static void __iomem *sched_io_base;
+static u32 sched_rate;
+
 static void add_clocksource(struct device_node *source_timer)
 {
 	void __iomem *iobase;
@@ -71,9 +98,15 @@ static void add_clocksource(struct device_node *source_timer)
 
 	dw_apb_clocksource_start(cs);
 	dw_apb_clocksource_register(cs);
-}
 
-static void __iomem *sched_io_base;
+	/*
+	 * Fallback to use the clocksource as sched_clock if no separate
+	 * timer is found. sched_io_base then points to the current_value
+	 * register of the clocksource timer.
+	 */
+	sched_io_base = iobase + 0x04;
+	sched_rate = rate;
+}
 
 static u32 read_sched_clock(void)
 {
@@ -89,39 +122,37 @@ static const struct of_device_id sptimer_ids[] __initconst = {
 static void init_sched_clock(void)
 {
 	struct device_node *sched_timer;
-	u32 rate;
 
 	sched_timer = of_find_matching_node(NULL, sptimer_ids);
-	if (!sched_timer)
-		panic("No RTC for sched clock to use");
+	if (sched_timer) {
+		timer_get_base_and_rate(sched_timer, &sched_io_base,
+					&sched_rate);
+		of_node_put(sched_timer);
+	}
 
-	timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
-	of_node_put(sched_timer);
-
-	setup_sched_clock(read_sched_clock, 32, rate);
+	setup_sched_clock(read_sched_clock, 32, sched_rate);
 }
 
-static const struct of_device_id osctimer_ids[] __initconst = {
-	{ .compatible = "picochip,pc3x2-timer" },
-	{ .compatible = "snps,dw-apb-timer-osc" },
-	{},
-};
-
-void __init dw_apb_timer_init(void)
+static int num_called;
+static void __init dw_apb_timer_init(struct device_node *timer)
 {
-	struct device_node *event_timer, *source_timer;
+	switch (num_called) {
+	case 0:
+		pr_debug("%s: found clockevent timer\n", __func__);
+		add_clockevent(timer);
+		of_node_put(timer);
+		break;
+	case 1:
+		pr_debug("%s: found clocksource timer\n", __func__);
+		add_clocksource(timer);
+		of_node_put(timer);
+		init_sched_clock();
+		break;
+	default:
+		break;
+	}
 
-	event_timer = of_find_matching_node(NULL, osctimer_ids);
-	if (!event_timer)
-		panic("No timer for clockevent");
-	add_clockevent(event_timer);
-
-	source_timer = of_find_matching_node(event_timer, osctimer_ids);
-	if (!source_timer)
-		panic("No timer for clocksource");
-	add_clocksource(source_timer);
-
-	of_node_put(source_timer);
-
-	init_sched_clock();
+	num_called++;
 }
+CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer-osc", dw_apb_timer_init);

include/linux/dw_apb_timer.h

@@ -53,5 +53,4 @@ void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs);
 cycle_t dw_apb_clocksource_read(struct dw_apb_clocksource *dw_cs);
 void dw_apb_clocksource_unregister(struct dw_apb_clocksource *dw_cs);
 
-extern void dw_apb_timer_init(void);
 #endif /* __DW_APB_TIMER_H__ */