From 20ac628bdcdd48828bdca10e91a8ef29a9aae527 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Jul 2012 15:12:03 -0500 Subject: [PATCH] ARM: OMAP2+: Fix dmtimer set source clock failure commit 54f32a35f4d3a653a18a2c8c239f19ae060bd803 upstream. Calling the dmtimer function omap_dm_timer_set_source() fails if following a call to pm_runtime_put() to disable the timer. For example the following sequence would fail to set the parent clock ... omap_dm_timer_stop(gptimer); omap_dm_timer_set_source(gptimer, OMAP_TIMER_SRC_32_KHZ); The following error message would be seen ... omap_dm_timer_set_source: failed to set timer_32k_ck as parent The problem is that, by design, pm_runtime_put() simply decrements the usage count and returns before the timer has actually been disabled. Therefore, setting the parent clock failed because the timer was still active when the trying to set the parent clock. Setting a parent clock will fail if the clock you are setting the parent of has a non-zero usage count. To ensure that this does not fail use pm_runtime_put_sync() when disabling the timer. Note that this will not be seen on OMAP1 devices, because these devices do not use the clock framework for dmtimers. Signed-off-by: Jon Hunter Acked-by: Kevin Hilman Signed-off-by: Tony Lindgren Signed-off-by: Ben Hutchings --- arch/arm/plat-omap/dmtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c index af3b92be8459..f9adbbb077ff 100644 --- a/arch/arm/plat-omap/dmtimer.c +++ b/arch/arm/plat-omap/dmtimer.c @@ -236,7 +236,7 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_enable); void omap_dm_timer_disable(struct omap_dm_timer *timer) { - pm_runtime_put(&timer->pdev->dev); + pm_runtime_put_sync(&timer->pdev->dev); } EXPORT_SYMBOL_GPL(omap_dm_timer_disable); -- 2.39.5