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