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clocksource: em_sti: Split clock prepare and enable steps 

Currently, the em_sti driver prepares and enables the needed clock in
em_sti_enable(), potentially called through its clockevent device's
->set_state_oneshot().

However, the clk_prepare() step may sleep whereas tick_program_event() and
thus, ->set_state_oneshot(), can be called in atomic context.

Split the clk_prepare_enable() in em_sti_enable() into two steps:
- prepare the clock at device probing via clk_prepare()
- and enable it in em_sti_enable() via clk_enable().
Slightly reorder resource initialization in em_sti_probe() in order to
facilitate error handling in later patches.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Nicolai Stange 2017-02-06 22:12:01 +01:00 committed by John Stultz
parent c3c0a20df9
commit 3814ae092d
1 changed files with 14 additions and 7 deletions
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21
drivers/clocksource/em_sti.c
View File

@ -78,7 +78,7 @@ static int em_sti_enable(struct em_sti_priv *p)
int ret;
/* enable clock */
ret = clk_prepare_enable(p->clk);
ret = clk_enable(p->clk);
if (ret) {
dev_err(&p->pdev->dev, "cannot enable clock\n");
return ret;
@ -107,7 +107,7 @@ static void em_sti_disable(struct em_sti_priv *p)
em_sti_write(p, STI_INTENCLR, 3);
/* stop clock */
clk_disable_unprepare(p->clk);
clk_disable(p->clk);
}
static u64 em_sti_count(struct em_sti_priv *p)
@ -303,6 +303,7 @@ static int em_sti_probe(struct platform_device *pdev)
struct em_sti_priv *p;
struct resource *res;
int irq;
int ret;
p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
if (p == NULL)
@ -323,6 +324,13 @@ static int em_sti_probe(struct platform_device *pdev)
if (IS_ERR(p->base))
return PTR_ERR(p->base);
if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt,
IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
dev_name(&pdev->dev), p)) {
dev_err(&pdev->dev, "failed to request low IRQ\n");
return -ENOENT;
}
/* get hold of clock */
p->clk = devm_clk_get(&pdev->dev, "sclk");
if (IS_ERR(p->clk)) {
@ -330,11 +338,10 @@ static int em_sti_probe(struct platform_device *pdev)
return PTR_ERR(p->clk);
}
if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt,
IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
dev_name(&pdev->dev), p)) {
dev_err(&pdev->dev, "failed to request low IRQ\n");
return -ENOENT;
ret = clk_prepare(p->clk);
if (ret < 0) {
dev_err(&pdev->dev, "cannot prepare clock\n");
return ret;
}
raw_spin_lock_init(&p->lock);