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 bilhuang@nvidia.com --- 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); mutex_unlock(&prepare_lock);
return ret; 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)
/** * struct clk_notifier - associate a clk with a notifier
On Thu, 2013-03-14 at 17:31 +0800, Bill Huang wrote:
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 bilhuang@nvidia.com
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);return ret; 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) /**
- struct clk_notifier - associate a clk with a notifier
Sorry, I'll send v3 since this bread build.
On Thu, Mar 14, 2013 at 02:31:04AM -0700, Bill Huang wrote:
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 bilhuang@nvidia.com
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
?
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?
On 03/15/2013 11:45 AM, Russell King - ARM Linux wrote:
On Thu, Mar 14, 2013 at 02:31:04AM -0700, Bill Huang wrote:
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 bilhuang@nvidia.com
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
Yes, these should be stacked/nested better for consistency.
But for DVFS, the voltage needs to be raised before the prepare body is run, so that if clk_prepare actually enables the clock, the voltage is already at the safe level required by that clock. Similarly, for unprepare, you can only lower the voltage after having turned off the clock, which is guaranteed after the unprepare body. So, I think you want to move the notifier for prepare in the code above (and rename it to pre/before_prepare?), rather than the notifier for unprepare.
In order to cover more cases, you might have both {pre,post}_{un,}prepare notifiers, although I'm not sure when you'd use the other two options.
diff --git a/include/linux/clk.h b/include/linux/clk.h
+#define CLK_PREPARED BIT(3) +#define CLK_UNPREPARED BIT(4)
On Sat, 2013-03-16 at 03:51 +0800, Stephen Warren wrote:
On 03/15/2013 11:45 AM, Russell King - ARM Linux wrote:
On Thu, Mar 14, 2013 at 02:31:04AM -0700, Bill Huang wrote:
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 bilhuang@nvidia.com
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
Yes, these should be stacked/nested better for consistency.
But for DVFS, the voltage needs to be raised before the prepare body is run, so that if clk_prepare actually enables the clock, the voltage is already at the safe level required by that clock. Similarly, for unprepare, you can only lower the voltage after having turned off the clock, which is guaranteed after the unprepare body. So, I think you want to move the notifier for prepare in the code above (and rename it to pre/before_prepare?), rather than the notifier for unprepare.
Oh yes I should raised notify before prepare body is run.
In order to cover more cases, you might have both {pre,post}_{un,}prepare notifiers, although I'm not sure when you'd use the other two options.
Right, maybe {pre,post}_{un,}prepare will be useful.
diff --git a/include/linux/clk.h b/include/linux/clk.h
+#define CLK_PREPARED BIT(3) +#define CLK_UNPREPARED BIT(4)
-
Bill Huang -
Russell King - ARM Linux -
Stephen Warren