Given a hirarchy of clk1 -> [div] -> clk2, when the rate of clk1 gets changed, clk2 changes as well as the divider stays the same. There may be cases where a user of clk2 needs it at a specific rate, so clk2 needs to be readjusted for the changed rate of clk1. So if a rate was requested for the clock, and its rate changed during the underlying rate-change, with this change the clock framework now tries to readjust the rate back to/near the requested one. The whole process is protected by a new clock-flag to not force this behaviour change onto every clock defined in the ccf. Signed-off-by: Heiko Stuebner <heiko at sntech.de> --- drivers/clk/clk.c | 13 +++++++++++-- include/linux/clk-provider.h | 1 + 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 65e0aad..22be369 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1410,6 +1410,9 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core, return fail_clk; } +static int clk_core_set_rate_nolock(struct clk_core *core, + unsigned long req_rate); + /* * walk down a subtree and set the new rates notifying the rate * change on the way @@ -1494,6 +1497,12 @@ static void clk_change_rate(struct clk_core *core) /* handle the new child who might not be in core->children yet */ if (core->new_child) clk_change_rate(core->new_child); + + /* handle a changed clock that needs to readjust its rate */ + if (core->flags & CLK_KEEP_REQ_RATE && core->req_rate + && core->new_rate != old_rate + && core->new_rate != core->req_rate) + clk_core_set_rate_nolock(core, core->req_rate); } static int clk_core_set_rate_nolock(struct clk_core *core, @@ -1529,11 +1538,11 @@ static int clk_core_set_rate_nolock(struct clk_core *core, return -EBUSY; } + core->req_rate = req_rate; + /* change the rates */ clk_change_rate(top); - core->req_rate = req_rate; - return ret; } diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 0c72204..06f189e 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -33,6 +33,7 @@ #define CLK_RECALC_NEW_RATES BIT(9) /* recalc rates after notifications */ #define CLK_SET_RATE_UNGATE BIT(10) /* clock needs to run to set rate */ #define CLK_IS_CRITICAL BIT(11) /* do not gate, ever */ +#define CLK_KEEP_REQ_RATE BIT(12) /* keep reqrate on parent rate change */ struct clk; struct clk_hw; -- 2.8.0.rc3
