diff options
author | Dong Aisheng <aisheng.dong@nxp.com> | 2016-06-30 09:31:14 (GMT) |
---|---|---|
committer | Stephen Boyd <sboyd@codeaurora.org> | 2016-07-02 00:42:56 (GMT) |
commit | fc8726a2c021b5525151ff6482f8f9a863c56d8d (patch) | |
tree | 2914b8e4323084d09d30037b71f4c26ba2ee28eb | |
parent | a4b3518d146f150d633f7dc815bb8ee2fbc162e9 (diff) | |
download | linux-fc8726a2c021b5525151ff6482f8f9a863c56d8d.tar.xz |
clk: core: support clocks which requires parents enable (part 2)
On Freescale i.MX7D platform, all clocks operations, including
enable/disable, rate change and re-parent, requires its parent clock on.
Current clock core can not support it well.
This patch adding flag CLK_OPS_PARENT_ENABLE to handle this special case in
clock core that enable its parent clock firstly for each operation and
disable it later after operation complete.
The patch part 2 fixes set clock rate and set parent while its parent
is off. The most special case is for set_parent() operation which requires
all parents including both old and new one to be enabled at the same time
during the operation.
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
[sboyd@codeaurora.org: Move set_rate tracepoint after prepare_enable]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
-rw-r--r-- | drivers/clk/clk.c | 48 |
1 files changed, 33 insertions, 15 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index e3bd28c..820a939 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1172,7 +1172,9 @@ static struct clk_core *__clk_set_parent_before(struct clk_core *core, struct clk_core *old_parent = core->parent; /* - * Migrate prepare state between parents and prevent race with + * 1. enable parents for CLK_OPS_PARENT_ENABLE clock + * + * 2. Migrate prepare state between parents and prevent race with * clk_enable(). * * If the clock is not prepared, then a race with @@ -1188,12 +1190,17 @@ static struct clk_core *__clk_set_parent_before(struct clk_core *core, * * See also: Comment for clk_set_parent() below. */ + + /* enable old_parent & parent if CLK_OPS_PARENT_ENABLE is set */ + if (core->flags & CLK_OPS_PARENT_ENABLE) { + clk_core_prepare_enable(old_parent); + clk_core_prepare_enable(parent); + } + + /* migrate prepare count if > 0 */ if (core->prepare_count) { - clk_core_prepare(parent); - flags = clk_enable_lock(); - clk_core_enable(parent); - clk_core_enable(core); - clk_enable_unlock(flags); + clk_core_prepare_enable(parent); + clk_core_enable_lock(core); } /* update the clk tree topology */ @@ -1208,18 +1215,19 @@ static void __clk_set_parent_after(struct clk_core *core, struct clk_core *parent, struct clk_core *old_parent) { - unsigned long flags; - /* * Finish the migration of prepare state and undo the changes done * for preventing a race with clk_enable(). */ if (core->prepare_count) { - flags = clk_enable_lock(); - clk_core_disable(core); - clk_core_disable(old_parent); - clk_enable_unlock(flags); - clk_core_unprepare(old_parent); + clk_core_disable_lock(core); + clk_core_disable_unprepare(old_parent); + } + + /* re-balance ref counting if CLK_OPS_PARENT_ENABLE is set */ + if (core->flags & CLK_OPS_PARENT_ENABLE) { + clk_core_disable_unprepare(parent); + clk_core_disable_unprepare(old_parent); } } @@ -1466,13 +1474,17 @@ static void clk_change_rate(struct clk_core *core) unsigned long best_parent_rate = 0; bool skip_set_rate = false; struct clk_core *old_parent; + struct clk_core *parent = NULL; old_rate = core->rate; - if (core->new_parent) + if (core->new_parent) { + parent = core->new_parent; best_parent_rate = core->new_parent->rate; - else if (core->parent) + } else if (core->parent) { + parent = core->parent; best_parent_rate = core->parent->rate; + } if (core->flags & CLK_SET_RATE_UNGATE) { unsigned long flags; @@ -1500,6 +1512,9 @@ static void clk_change_rate(struct clk_core *core) __clk_set_parent_after(core, core->new_parent, old_parent); } + if (core->flags & CLK_OPS_PARENT_ENABLE) + clk_core_prepare_enable(parent); + trace_clk_set_rate(core, core->new_rate); if (!skip_set_rate && core->ops->set_rate) @@ -1518,6 +1533,9 @@ static void clk_change_rate(struct clk_core *core) clk_core_unprepare(core); } + if (core->flags & CLK_OPS_PARENT_ENABLE) + clk_core_disable_unprepare(parent); + if (core->notifier_count && old_rate != core->rate) __clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate); |