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clocksource/drivers/sun5i: Add clock notifiers

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The parent clock of the sun5i timer is the AHB clock, which rate
might change because of other devices requirements.

This is for example the case on the Allwinner A31, where the DMA
controller needs a minimum rate higher than the default, that is
enforced after the timer driver has probed.

Add clock notifiers to make sure we reflect the clock rate
changes in the timer rates.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1427796746-373-5-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Maxime Ripard 2015-03-31 12:12:26 +02:00 committed by Ingo Molnar
parent 4a59058f0b
commit 3071efa466
1 changed files with 64 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
drivers/clocksource/timer-sun5i.c
View File

@ -40,9 +40,13 @@
struct sun5i_timer {
void __iomem *base;
struct clk *clk;
struct notifier_block clk_rate_cb;
u32 ticks_per_jiffy;
};
#define to_sun5i_timer(x) \
container_of(x, struct sun5i_timer, clk_rate_cb)
struct sun5i_timer_clksrc {
struct sun5i_timer timer;
struct clocksource clksrc;
@ -151,6 +155,29 @@ static cycle_t sun5i_clksrc_read(struct clocksource *clksrc)
return ~readl(cs->timer.base + TIMER_CNTVAL_LO_REG(1));
}
static int sun5i_rate_cb_clksrc(struct notifier_block *nb,
unsigned long event, void *data)
{
struct clk_notifier_data *ndata = data;
struct sun5i_timer *timer = to_sun5i_timer(nb);
struct sun5i_timer_clksrc *cs = container_of(timer, struct sun5i_timer_clksrc, timer);
switch (event) {
case PRE_RATE_CHANGE:
clocksource_unregister(&cs->clksrc);
break;
case POST_RATE_CHANGE:
clocksource_register_hz(&cs->clksrc, ndata->new_rate);
break;
default:
break;
}
return NOTIFY_DONE;
}
static int __init sun5i_setup_clocksource(struct device_node *node,
void __iomem *base,
struct clk *clk, int irq)
@ -173,6 +200,14 @@ static int __init sun5i_setup_clocksource(struct device_node *node,
cs->timer.base = base;
cs->timer.clk = clk;
cs->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clksrc;
cs->timer.clk_rate_cb.next = NULL;
ret = clk_notifier_register(clk, &cs->timer.clk_rate_cb);
if (ret) {
pr_err("Unable to register clock notifier.\n");
goto err_disable_clk;
}
writel(~0, base + TIMER_INTVAL_LO_REG(1));
writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
@ -187,11 +222,13 @@ static int __init sun5i_setup_clocksource(struct device_node *node,
ret = clocksource_register_hz(&cs->clksrc, rate);
if (ret) {
pr_err("Couldn't register clock source.\n");
goto err_disable_clk;
goto err_remove_notifier;
}
return 0;
err_remove_notifier:
clk_notifier_unregister(clk, &cs->timer.clk_rate_cb);
err_disable_clk:
clk_disable_unprepare(clk);
err_free:
@ -199,6 +236,21 @@ err_free:
return ret;
}
static int sun5i_rate_cb_clkevt(struct notifier_block *nb,
unsigned long event, void *data)
{
struct clk_notifier_data *ndata = data;
struct sun5i_timer *timer = to_sun5i_timer(nb);
struct sun5i_timer_clkevt *ce = container_of(timer, struct sun5i_timer_clkevt, timer);
if (event == POST_RATE_CHANGE) {
clockevents_update_freq(&ce->clkevt, ndata->new_rate);
ce->timer.ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
}
return NOTIFY_DONE;
}
static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem *base,
struct clk *clk, int irq)
{
@ -222,6 +274,14 @@ static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem
ce->timer.base = base;
ce->timer.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
ce->timer.clk = clk;
ce->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clkevt;
ce->timer.clk_rate_cb.next = NULL;
ret = clk_notifier_register(clk, &ce->timer.clk_rate_cb);
if (ret) {
pr_err("Unable to register clock notifier.\n");
goto err_disable_clk;
}
ce->clkevt.name = node->name;
ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
@ -242,11 +302,13 @@ static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem
"sun5i_timer0", ce);
if (ret) {
pr_err("Unable to register interrupt\n");
goto err_disable_clk;
goto err_remove_notifier;
}
return 0;
err_remove_notifier:
clk_notifier_unregister(clk, &ce->timer.clk_rate_cb);
err_disable_clk:
clk_disable_unprepare(clk);
err_free: