2 * arch/arm/mach-ox820/rps-time.c
4 * Copyright (C) 2009 Oxford Semiconductor Ltd
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
23 #include <linux/clockchips.h>
24 #include <linux/clk.h>
25 #include <linux/of_irq.h>
26 #include <linux/of_address.h>
27 #include <linux/sched_clock.h>
28 #include <mach/hardware.h>
38 TIMER_MAX_VAL
= (1 << TIMER_BITS
) - 1,
40 TIMER_PERIODIC
= (1 << 6),
41 TIMER_ENABLE
= (1 << 7),
43 TIMER_DIV1
= (0 << 2),
44 TIMER_DIV16
= (1 << 2),
45 TIMER_DIV256
= (2 << 2),
52 static u64 notrace
rps_read_sched_clock(void)
54 return ~readl_relaxed(RPSA_TIMER2_VAL
);
57 static void __init
rps_clocksource_init(void __iomem
*base
, ulong ref_rate
)
62 clock_rate
= ref_rate
/ 16;
64 iowrite32(TIMER_MAX_VAL
, base
+ TIMER_LOAD
);
65 iowrite32(TIMER_PERIODIC
| TIMER_ENABLE
| TIMER_DIV16
,
68 ret
= clocksource_mmio_init(base
+ TIMER_CURR
, "rps_clocksource_timer",
69 clock_rate
, 250, TIMER_BITS
,
70 clocksource_mmio_readl_down
);
72 panic("can't register clocksource\n");
74 sched_clock_register(rps_read_sched_clock
, TIMER_BITS
, clock_rate
);
77 static void __init
rps_timer_init(struct device_node
*np
)
80 unsigned long ref_rate
;
83 refclk
= of_clk_get(np
, 0);
85 if (IS_ERR(refclk
) || clk_prepare_enable(refclk
))
86 panic("rps_timer_init: failed to get refclk\n");
87 ref_rate
= clk_get_rate(refclk
);
89 base
= of_iomap(np
, 0);
91 panic("rps_timer_init: failed to map io\n");
93 rps_clocksource_init(base
+ TIMER2_OFFSET
, ref_rate
);
96 CLOCKSOURCE_OF_DECLARE(nas782x
, "plxtech,nas782x-rps-timer", rps_timer_init
);