clocksource: convert MXS timrotv2 to 32-bit down counting clocksource

Convert the MXS timrotv2 32-bit down counting clocksource to the
generic clocksource infrastructure.

Cc: Sascha Hauer <kernel@pengutronix.de>
Acked-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 8 insertions, 13 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cbc27fb1256..43f003a5a0f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -376,6 +376,7 @@ config ARCH_MXS
         select GENERIC_CLOCKEVENTS
         select ARCH_REQUIRE_GPIOLIB
         select CLKDEV_LOOKUP
+        select CLKSRC_MMIO
         help
           Support for Freescale MXS-based family of processors
 
diff --git a/arch/arm/mach-mxs/timer.c b/arch/arm/mach-mxs/timer.c
index 13647f30186..cace0d2e5a5 100644
--- a/arch/arm/mach-mxs/timer.c
+++ b/arch/arm/mach-mxs/timer.c
@@ -101,11 +101,6 @@ static cycle_t timrotv1_get_cycles(struct clocksource *cs)
                         & 0xffff0000) >> 16);
 }
 
-static cycle_t timrotv2_get_cycles(struct clocksource *cs)
-{
-        return ~__raw_readl(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
-}
-
 static int timrotv1_set_next_event(unsigned long evt,
                                         struct clock_event_device *dev)
 {
@@ -230,8 +225,8 @@ static int __init mxs_clockevent_init(struct clk *timer_clk)
 static struct clocksource clocksource_mxs = {
         .name           = "mxs_timer",
         .rating         = 200,
-        .read           = timrotv2_get_cycles,
-        .mask           = CLOCKSOURCE_MASK(32),
+        .read           = timrotv1_get_cycles,
+        .mask           = CLOCKSOURCE_MASK(16),
         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
@@ -239,12 +234,11 @@ static int __init mxs_clocksource_init(struct clk *timer_clk)
 {
         unsigned int c = clk_get_rate(timer_clk);
 
-        if (timrot_is_v1()) {
-                clocksource_mxs.read = timrotv1_get_cycles;
-                clocksource_mxs.mask = CLOCKSOURCE_MASK(16);
-        }
-
-        clocksource_register_hz(&clocksource_mxs, c);
+        if (timrot_is_v1())
+                clocksource_register_hz(&clocksource_mxs, c);
+        else
+                clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
+                        "mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
 
         return 0;
 }