clocksource: convert ARM 32-bit down counting clocksources

Convert SP804, MXC, Nomadik and Orion 32-bit down-counting clocksources
to generic mmio clocksource infrastructure.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Alessandro Rubini <rubini@unipv.it>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Lennert Buytenhek <kernel@wantstofly.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 4 insertions, 28 deletions

diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
index 187f4e84bb22..18296ee68802 100644
--- a/arch/arm/plat-nomadik/Kconfig
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -5,6 +5,7 @@
 config PLAT_NOMADIK
         bool
         depends on ARCH_NOMADIK || ARCH_U8500
+        select CLKSRC_MMIO
         default y
         help
           Common platform code for Nomadik and other ST-Ericsson
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
index 41723402006b..ef74e157a9d5 100644
--- a/arch/arm/plat-nomadik/timer.c
+++ b/arch/arm/plat-nomadik/timer.c
@@ -26,29 +26,6 @@
 void __iomem *mtu_base; /* Assigned by machine code */
 
 /*
- * Kernel assumes that sched_clock can be called early
- * but the MTU may not yet be initialized.
- */
-static cycle_t nmdk_read_timer_dummy(struct clocksource *cs)
-{
-        return 0;
-}
-
-/* clocksource: MTU decrements, so we negate the value being read. */
-static cycle_t nmdk_read_timer(struct clocksource *cs)
-{
-        return -readl(mtu_base + MTU_VAL(0));
-}
-
-static struct clocksource nmdk_clksrc = {
-        .name           = "mtu_0",
-        .rating         = 200,
-        .read           = nmdk_read_timer_dummy,
-        .mask           = CLOCKSOURCE_MASK(32),
-        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
-/*
  * Override the global weak sched_clock symbol with this
  * local implementation which uses the clocksource to get some
  * better resolution when scheduling the kernel.
@@ -172,12 +149,10 @@ void __init nmdk_timer_init(void)
         writel(0, mtu_base + MTU_BGLR(0));
         writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0));
 
-        /* Now the clock source is ready */
-        nmdk_clksrc.read = nmdk_read_timer;
-
-        if (clocksource_register_hz(&nmdk_clksrc, rate))
+        if (clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0",
+                        rate, 200, 32, clocksource_mmio_readl_down))
                 pr_err("timer: failed to initialize clock source %s\n",
-                       nmdk_clksrc.name);
+                       "mtu_0");
 
         init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate);