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author | Amit Kucheria <amit.kucheria@verdurent.com> | 2010-05-28 11:29:09 +0300 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2010-07-26 14:17:57 +0200 |
commit | 9b839ec0a880977d05ec4d25028ca4a0c3216c61 (patch) | |
tree | 261d1f3be890592d6cd229e2d4251d2b9024a1ec /arch/arm/plat-mxc/clock.c | |
parent | c45dd814008f8842f854aa6960dfd6c610a01873 (diff) | |
download | op-kernel-dev-9b839ec0a880977d05ec4d25028ca4a0c3216c61.zip op-kernel-dev-9b839ec0a880977d05ec4d25028ca4a0c3216c61.tar.gz |
arm: mxc: utilise usecount field in clock operations
This patch fixes the clock refcounting when reparenting is used.
Boot-tested on imx51 babbage board.
Sascha pointed out a good explanation of refcounting here:
http://www.spinics.net/lists/arm-kernel/msg85879.html
Signed-off-by: Amit Kucheria <amit.kucheria@canonical.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/arm/plat-mxc/clock.c')
-rw-r--r-- | arch/arm/plat-mxc/clock.c | 37 |
1 files changed, 25 insertions, 12 deletions
diff --git a/arch/arm/plat-mxc/clock.c b/arch/arm/plat-mxc/clock.c index 323ff8c..2ed3ab1 100644 --- a/arch/arm/plat-mxc/clock.c +++ b/arch/arm/plat-mxc/clock.c @@ -52,13 +52,14 @@ static void __clk_disable(struct clk *clk) { if (clk == NULL || IS_ERR(clk)) return; - - __clk_disable(clk->parent); - __clk_disable(clk->secondary); - WARN_ON(!clk->usecount); - if (!(--clk->usecount) && clk->disable) - clk->disable(clk); + + if (!(--clk->usecount)) { + if (clk->disable) + clk->disable(clk); + __clk_disable(clk->parent); + __clk_disable(clk->secondary); + } } static int __clk_enable(struct clk *clk) @@ -66,12 +67,13 @@ static int __clk_enable(struct clk *clk) if (clk == NULL || IS_ERR(clk)) return -EINVAL; - __clk_enable(clk->parent); - __clk_enable(clk->secondary); - - if (clk->usecount++ == 0 && clk->enable) - clk->enable(clk); + if (clk->usecount++ == 0) { + __clk_enable(clk->parent); + __clk_enable(clk->secondary); + if (clk->enable) + clk->enable(clk); + } return 0; } @@ -160,17 +162,28 @@ EXPORT_SYMBOL(clk_set_rate); int clk_set_parent(struct clk *clk, struct clk *parent) { int ret = -EINVAL; + struct clk *old; if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent) || clk->set_parent == NULL) return ret; + if (clk->usecount) + clk_enable(parent); + mutex_lock(&clocks_mutex); ret = clk->set_parent(clk, parent); - if (ret == 0) + if (ret == 0) { + old = clk->parent; clk->parent = parent; + } else { + old = parent; + } mutex_unlock(&clocks_mutex); + if (clk->usecount) + clk_disable(old); + return ret; } EXPORT_SYMBOL(clk_set_parent); |