| Message ID | 1396623201-26000-2-git-send-email-t.stanislaws@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On 04.04.2014 16:53, Tomasz Stanislawski wrote: > This patch adds support for propagation of setup of clock's parent one level > up. > > This feature is helpful when a driver changes topology of its clocks using > clk_set_parent(). The problem occurs when on one platform/SoC driver's clock > is located at MUX output but on the other platform/SoC there is a gated proxy > clock between the MUX and driver's clock. In such a case, driver's code has to > be modified to use one clock for enabling and the other clock for setup of a > parent. > > The code updates are avoided by propagating setup of a parent up one level. > > Additionally, this patch adds CLK_SET_PARENT_PARENT (sorry for naming) flag to > inform clk-core that clk_set_parent() should be propagated. > > Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> > --- > drivers/clk/clk.c | 6 ++++++ > include/linux/clk-provider.h | 1 + > 2 files changed, 7 insertions(+) > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index dff0373..53bbfda 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -1737,6 +1737,12 @@ int clk_set_parent(struct clk *clk, struct clk *parent) > > /* try finding the new parent index */ > if (parent) { > + if ((clk->flags & CLK_SET_PARENT_PARENT) > + && clk->num_parents == 1) { > + ret = clk_set_parent(clk->parent, parent); > + goto out; > + } > + > p_index = clk_fetch_parent_index(clk, parent); > p_rate = parent->rate; > if (p_index < 0) { > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h > index 5119174..daa0b03 100644 > --- a/include/linux/clk-provider.h > +++ b/include/linux/clk-provider.h > @@ -30,6 +30,7 @@ > #define CLK_GET_RATE_NOCACHE BIT(6) /* do not use the cached clk rate */ > #define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */ > #define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */ > +#define CLK_SET_PARENT_PARENT BIT(9) /* propagate parent change up one level */ > > struct clk_hw; > struct dentry; > This would be very useful, at least on Exynos platforms, with mux-div-gate clock paths. PARENT_PARENT sounds a bit funny, though. Reviewed-by: Tomasz Figa <t.figa@samsung.com> Best regards, Tomasz
Mike, On 08.04.2014 17:45, Tomasz Figa wrote: > Hi, > > On 04.04.2014 16:53, Tomasz Stanislawski wrote: >> This patch adds support for propagation of setup of clock's parent one >> level >> up. >> >> This feature is helpful when a driver changes topology of its clocks >> using >> clk_set_parent(). The problem occurs when on one platform/SoC >> driver's clock >> is located at MUX output but on the other platform/SoC there is a >> gated proxy >> clock between the MUX and driver's clock. In such a case, driver's >> code has to >> be modified to use one clock for enabling and the other clock for >> setup of a >> parent. >> >> The code updates are avoided by propagating setup of a parent up one >> level. >> >> Additionally, this patch adds CLK_SET_PARENT_PARENT (sorry for naming) >> flag to >> inform clk-core that clk_set_parent() should be propagated. >> >> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> >> --- >> drivers/clk/clk.c | 6 ++++++ >> include/linux/clk-provider.h | 1 + >> 2 files changed, 7 insertions(+) >> >> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c >> index dff0373..53bbfda 100644 >> --- a/drivers/clk/clk.c >> +++ b/drivers/clk/clk.c >> @@ -1737,6 +1737,12 @@ int clk_set_parent(struct clk *clk, struct clk >> *parent) >> >> /* try finding the new parent index */ >> if (parent) { >> + if ((clk->flags & CLK_SET_PARENT_PARENT) >> + && clk->num_parents == 1) { >> + ret = clk_set_parent(clk->parent, parent); >> + goto out; >> + } >> + >> p_index = clk_fetch_parent_index(clk, parent); >> p_rate = parent->rate; >> if (p_index < 0) { >> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h >> index 5119174..daa0b03 100644 >> --- a/include/linux/clk-provider.h >> +++ b/include/linux/clk-provider.h >> @@ -30,6 +30,7 @@ >> #define CLK_GET_RATE_NOCACHE BIT(6) /* do not use the cached clk >> rate */ >> #define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate >> change */ >> #define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk >> accuracy */ >> +#define CLK_SET_PARENT_PARENT BIT(9) /* propagate parent change up >> one level */ >> >> struct clk_hw; >> struct dentry; >> > > This would be very useful, at least on Exynos platforms, with > mux-div-gate clock paths. PARENT_PARENT sounds a bit funny, though. > > Reviewed-by: Tomasz Figa <t.figa@samsung.com> Your opinion on this would be greatly appreciated. Best regards, Tomasz
Hi Mike, Do you have any comments about this patch? The patch is needed to provide a clean fix for recently broken support for HDMI on Exynos4210 SoC in mainline. Regards, Tomasz Stanislawski On 05/01/2014 12:19 AM, Tomasz Figa wrote: > Mike, > > On 08.04.2014 17:45, Tomasz Figa wrote: >> Hi, >> >> On 04.04.2014 16:53, Tomasz Stanislawski wrote: >>> This patch adds support for propagation of setup of clock's parent one >>> level >>> up. >>> >>> This feature is helpful when a driver changes topology of its clocks >>> using >>> clk_set_parent(). The problem occurs when on one platform/SoC >>> driver's clock >>> is located at MUX output but on the other platform/SoC there is a >>> gated proxy >>> clock between the MUX and driver's clock. In such a case, driver's >>> code has to >>> be modified to use one clock for enabling and the other clock for >>> setup of a >>> parent. >>> >>> The code updates are avoided by propagating setup of a parent up one >>> level. >>> >>> Additionally, this patch adds CLK_SET_PARENT_PARENT (sorry for naming) >>> flag to >>> inform clk-core that clk_set_parent() should be propagated. >>> >>> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> >>> --- >>> drivers/clk/clk.c | 6 ++++++ >>> include/linux/clk-provider.h | 1 + >>> 2 files changed, 7 insertions(+) >>> >>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c >>> index dff0373..53bbfda 100644 >>> --- a/drivers/clk/clk.c >>> +++ b/drivers/clk/clk.c >>> @@ -1737,6 +1737,12 @@ int clk_set_parent(struct clk *clk, struct clk >>> *parent) >>> >>> /* try finding the new parent index */ >>> if (parent) { >>> + if ((clk->flags & CLK_SET_PARENT_PARENT) >>> + && clk->num_parents == 1) { >>> + ret = clk_set_parent(clk->parent, parent); >>> + goto out; >>> + } >>> + >>> p_index = clk_fetch_parent_index(clk, parent); >>> p_rate = parent->rate; >>> if (p_index < 0) { >>> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h >>> index 5119174..daa0b03 100644 >>> --- a/include/linux/clk-provider.h >>> +++ b/include/linux/clk-provider.h >>> @@ -30,6 +30,7 @@ >>> #define CLK_GET_RATE_NOCACHE BIT(6) /* do not use the cached clk >>> rate */ >>> #define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate >>> change */ >>> #define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk >>> accuracy */ >>> +#define CLK_SET_PARENT_PARENT BIT(9) /* propagate parent change up >>> one level */ >>> >>> struct clk_hw; >>> struct dentry; >>> >> >> This would be very useful, at least on Exynos platforms, with >> mux-div-gate clock paths. PARENT_PARENT sounds a bit funny, though. >> >> Reviewed-by: Tomasz Figa <t.figa@samsung.com> > > Your opinion on this would be greatly appreciated. > > Best regards, > Tomasz
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index dff0373..53bbfda 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1737,6 +1737,12 @@ int clk_set_parent(struct clk *clk, struct clk *parent) /* try finding the new parent index */ if (parent) { + if ((clk->flags & CLK_SET_PARENT_PARENT) + && clk->num_parents == 1) { + ret = clk_set_parent(clk->parent, parent); + goto out; + } + p_index = clk_fetch_parent_index(clk, parent); p_rate = parent->rate; if (p_index < 0) { diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 5119174..daa0b03 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -30,6 +30,7 @@ #define CLK_GET_RATE_NOCACHE BIT(6) /* do not use the cached clk rate */ #define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */ #define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */ +#define CLK_SET_PARENT_PARENT BIT(9) /* propagate parent change up one level */ struct clk_hw; struct dentry;
This patch adds support for propagation of setup of clock's parent one level up. This feature is helpful when a driver changes topology of its clocks using clk_set_parent(). The problem occurs when on one platform/SoC driver's clock is located at MUX output but on the other platform/SoC there is a gated proxy clock between the MUX and driver's clock. In such a case, driver's code has to be modified to use one clock for enabling and the other clock for setup of a parent. The code updates are avoided by propagating setup of a parent up one level. Additionally, this patch adds CLK_SET_PARENT_PARENT (sorry for naming) flag to inform clk-core that clk_set_parent() should be propagated. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> --- drivers/clk/clk.c | 6 ++++++ include/linux/clk-provider.h | 1 + 2 files changed, 7 insertions(+)