diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/timer-atmel-tcb.c | 63 |
1 files changed, 33 insertions, 30 deletions
diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c index 423af2f9835f..7a6474acc774 100644 --- a/drivers/clocksource/timer-atmel-tcb.c +++ b/drivers/clocksource/timer-atmel-tcb.c @@ -27,9 +27,10 @@ * - Some chips support 32 bit counter. A single channel is used for * this 32 bit free-running counter. the second channel is not used. * - * - The third channel may be used to provide a 16-bit clockevent - * source, used in either periodic or oneshot mode. This runs - * at 32 KiHZ, and can handle delays of up to two seconds. + * - The third channel may be used to provide a clockevent source, used in + * either periodic or oneshot mode. For 16-bit counter its runs at 32 KiHZ, + * and can handle delays of up to two seconds. For 32-bit counters, it runs at + * the same rate as the clocksource * * REVISIT behavior during system suspend states... we should disable * all clocks and save the power. Easily done for clockevent devices, @@ -47,6 +48,8 @@ static struct } tcb_cache[3]; static u32 bmr_cache; +static const u8 atmel_tcb_divisors[] = { 2, 8, 32, 128 }; + static u64 tc_get_cycles(struct clocksource *cs) { unsigned long flags; @@ -143,6 +146,7 @@ static unsigned long notrace tc_delay_timer_read32(void) struct tc_clkevt_device { struct clock_event_device clkevt; struct clk *clk; + u32 rate; void __iomem *regs; }; @@ -151,13 +155,6 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt) return container_of(clkevt, struct tc_clkevt_device, clkevt); } -/* For now, we always use the 32K clock ... this optimizes for NO_HZ, - * because using one of the divided clocks would usually mean the - * tick rate can never be less than several dozen Hz (vs 0.5 Hz). - * - * A divided clock could be good for high resolution timers, since - * 30.5 usec resolution can seem "low". - */ static u32 timer_clock; static int tc_shutdown(struct clock_event_device *d) @@ -183,7 +180,7 @@ static int tc_set_oneshot(struct clock_event_device *d) clk_enable(tcd->clk); - /* slow clock, count up to RC, then irq and stop */ + /* count up to RC, then irq and stop */ writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR)); writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER)); @@ -205,10 +202,10 @@ static int tc_set_periodic(struct clock_event_device *d) */ clk_enable(tcd->clk); - /* slow clock, count up to RC, then irq and restart */ + /* count up to RC, then irq and restart */ writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR)); - writel((32768 + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC)); + writel((tcd->rate + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC)); /* Enable clock and interrupts on RC compare */ writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER)); @@ -256,47 +253,55 @@ static irqreturn_t ch2_irq(int irq, void *handle) return IRQ_NONE; } -static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) +static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx) { int ret; struct clk *t2_clk = tc->clk[2]; int irq = tc->irq[2]; - - ret = clk_prepare_enable(tc->slow_clk); - if (ret) - return ret; + int bits = tc->tcb_config->counter_width; /* try to enable t2 clk to avoid future errors in mode change */ ret = clk_prepare_enable(t2_clk); - if (ret) { - clk_disable_unprepare(tc->slow_clk); + if (ret) return ret; - } - - clk_disable(t2_clk); clkevt.regs = tc->regs; clkevt.clk = t2_clk; - timer_clock = clk32k_divisor_idx; + if (bits == 32) { + timer_clock = divisor_idx; + clkevt.rate = clk_get_rate(t2_clk) / atmel_tcb_divisors[divisor_idx]; + } else { + ret = clk_prepare_enable(tc->slow_clk); + if (ret) { + clk_disable_unprepare(t2_clk); + return ret; + } + + clkevt.rate = clk_get_rate(tc->slow_clk); + timer_clock = ATMEL_TC_TIMER_CLOCK5; + } + + clk_disable(t2_clk); clkevt.clkevt.cpumask = cpumask_of(0); ret = request_irq(irq, ch2_irq, IRQF_TIMER, "tc_clkevt", &clkevt); if (ret) { clk_unprepare(t2_clk); - clk_disable_unprepare(tc->slow_clk); + if (bits != 32) + clk_disable_unprepare(tc->slow_clk); return ret; } - clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff); + clockevents_config_and_register(&clkevt.clkevt, clkevt.rate, 1, BIT(bits) - 1); return ret; } #else /* !CONFIG_GENERIC_CLOCKEVENTS */ -static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) +static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx) { /* NOTHING */ return 0; @@ -346,8 +351,6 @@ static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_id writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR); } -static const u8 atmel_tcb_divisors[] = { 2, 8, 32, 128 }; - static struct atmel_tcb_config tcb_rm9200_config = { .counter_width = 16, }; @@ -472,7 +475,7 @@ static int __init tcb_clksrc_init(struct device_node *node) goto err_disable_t1; /* channel 2: periodic and oneshot timer support */ - ret = setup_clkevents(&tc, ATMEL_TC_TIMER_CLOCK5); + ret = setup_clkevents(&tc, best_divisor_idx); if (ret) goto err_unregister_clksrc; |