[RFC v2 1/1] clk: Add notifier support in clk_prepare/clk_unprepare
From: Russell King - ARM Linux <hidden>
Date: 2013-03-15 17:46:16
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On Thu, Mar 14, 2013 at 02:31:04AM -0700, Bill Huang wrote:
quoted hunk ↗ jump to hunk
Add the below two notifier events so drivers which are interested in knowing the clock status can act accordingly. This is extremely useful in some of the DVFS (Dynamic Voltage Frequency Scaling) design. CLK_PREPARED CLK_UNPREPARED Signed-off-by: Bill Huang <redacted> --- drivers/clk/clk.c | 3 +++ include/linux/clk.h | 2 ++ 2 files changed, 5 insertions(+)diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index ed87b24..3292cec 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c@@ -550,6 +550,7 @@ void clk_unprepare(struct clk *clk) { mutex_lock(&prepare_lock); __clk_unprepare(clk); + __clk_notify(clk, CLK_UNPREPARED, clk->rate, clk->rate); mutex_unlock(&prepare_lock); } EXPORT_SYMBOL_GPL(clk_unprepare);@@ -598,6 +599,8 @@ int clk_prepare(struct clk *clk) mutex_lock(&prepare_lock); ret = __clk_prepare(clk); + if (!ret) + __clk_notify(clk, CLK_PREPARED, clk->rate, clk->rate);
So, on prepare, we notify after we've prepared the clock. On unprepare, we notify after the clock has been shut down. Are you sure that's the correct ordering? Would it not be better to view it in a stack-like fashion, iow: get prepare notify-prepare enable disable notify-unprepare unprepare put ?
quoted hunk ↗ jump to hunk
diff --git a/include/linux/clk.h b/include/linux/clk.h index b3ac22d..16c1d92 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h@@ -43,6 +43,8 @@ struct clk; #define PRE_RATE_CHANGE BIT(0) #define POST_RATE_CHANGE BIT(1) #define ABORT_RATE_CHANGE BIT(2) +#define CLK_PREPARED BIT(3) +#define CLK_UNPREPARED BIT(4)
This implies that we're only going to have a maximum of 32 reason codes here. Is that enough?