Messages in this thread Patch in this message | | | From | Alexandre Belloni <> | Subject | [PATCH 47/58] clocksource/drivers: timer-atmel-tcbclksrc: add clockevent device | Date | Tue, 30 May 2017 23:51:28 +0200 |
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It is possible to compare and get interrupts on the channel that is used for the clocksource. Enable that to have a solution using only one TCB channel.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> --- drivers/clocksource/timer-atmel-tcbclksrc.c | 81 +++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+)
diff --git a/drivers/clocksource/timer-atmel-tcbclksrc.c b/drivers/clocksource/timer-atmel-tcbclksrc.c index f18d177bfdea..462b04e9fed8 100644 --- a/drivers/clocksource/timer-atmel-tcbclksrc.c +++ b/drivers/clocksource/timer-atmel-tcbclksrc.c @@ -12,6 +12,7 @@ static struct atmel_tcb_clksrc { char name[20]; struct clocksource clksrc; + struct clock_event_device clkevt; struct regmap *regmap; struct clk *clk[2]; int channels[2]; @@ -24,6 +25,11 @@ static struct atmel_tcb_clksrc { .mask = CLOCKSOURCE_MASK(32), .flags = CLOCK_SOURCE_IS_CONTINUOUS, }, + .clkevt = { + .features = CLOCK_EVT_FEAT_ONESHOT, + /* Should be lower than at91rm9200's system timer */ + .rating = 125, + }, }; static u64 tc_get_cycles(struct clocksource *cs) @@ -58,6 +64,72 @@ static u64 notrace tc_sched_clock_read32(void) return tc_get_cycles32(&tc.clksrc); } +static int tcb_clkevt_next_event(unsigned long delta, + struct clock_event_device *d) +{ + u32 old, next, cur; + + + regmap_read(tc.regmap, ATMEL_TC_CV(tc.channels[0]), &old); + next = old + delta; + regmap_write(tc.regmap, ATMEL_TC_RC(tc.channels[0]), next); + regmap_read(tc.regmap, ATMEL_TC_CV(tc.channels[0]), &cur); + + /* check whether the delta elapsed while setting the register */ + if ((next < old && cur < old && cur > next) || + (next > old && (cur < old || cur > next))) { + /* + * Clear the CPCS bit in the status register to avoid + * generating a spurious interrupt next time a valid + * timer event is configured. + */ + regmap_read(tc.regmap, ATMEL_TC_SR(tc.channels[0]), &old); + return -ETIME; + } + + regmap_write(tc.regmap, ATMEL_TC_IER(tc.channels[0]), ATMEL_TC_CPCS); + + return 0; +} + +static irqreturn_t tc_clkevt_irq(int irq, void *handle) +{ + unsigned int sr; + + regmap_read(tc.regmap, ATMEL_TC_SR(tc.channels[0]), &sr); + if (sr & ATMEL_TC_CPCS) { + tc.clkevt.event_handler(&tc.clkevt); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int tcb_clkevt_oneshot(struct clock_event_device *dev) +{ + if (clockevent_state_oneshot(dev)) + return 0; + + /* + * Because both clockevent devices may share the same IRQ, we don't want + * the less likely one to stay requested + */ + return request_irq(tc.irq, tc_clkevt_irq, IRQF_TIMER | IRQF_SHARED, + tc.name, &tc); +} + +static int tcb_clkevt_shutdown(struct clock_event_device *dev) +{ + regmap_write(tc.regmap, ATMEL_TC_IDR(tc.channels[0]), 0xff); + if (tc.bits == 16) + regmap_write(tc.regmap, ATMEL_TC_IDR(tc.channels[1]), 0xff); + + if (!clockevent_state_detached(dev)) + free_irq(tc.irq, &tc); + + return 0; +} + static void __init tcb_setup_dual_chan(struct atmel_tcb_clksrc *tc, int mck_divisor_idx) { @@ -188,6 +260,15 @@ static int __init tcb_clksrc_register(struct device_node *node, tc.registered = true; + /* Set up and register clockevents */ + tc.clkevt.name = tc.name; + tc.clkevt.cpumask = cpumask_of(0); + tc.clkevt.set_next_event = tcb_clkevt_next_event; + tc.clkevt.set_state_oneshot = tcb_clkevt_oneshot; + tc.clkevt.set_state_shutdown = tcb_clkevt_shutdown; + clockevents_config_and_register(&tc.clkevt, divided_rate, 1, + BIT(tc.bits) - 1); + return 0; err_disable_t1: -- 2.11.0
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