Re: [PATCH 4/5] clk: samsung: Add support for EPLL on exynos5410
From: Krzysztof Kozlowski <hidden>
Date: 2016-08-30 10:36:13
Also in:
linux-samsung-soc
On 08/22/2016 06:31 PM, Sylwester Nawrocki wrote:
This patch adds code instantiating the EPLL, which is used as the audio subsystem's root clock. The requirement to specify the external root clock in clocks property is also added.
I think the requirement was there already but explained little bit differently: 19 External clock: 20 21 There is clock that is generated outside the SoC. It 22 is expected that it is defined using standard clock bindings 23 with following clock-output-name: 24 25 - "fin_pll" - PLL input clock from XXTI so you can just combine them. Driver now will require the fin_pll in two ways: 1. Old lookup by "fin_pll" name. 2. of_clk_get of yours.
quoted hunk ↗ jump to hunk
That ensures proper initialization order by explicitly specifying dependencies in devicetree. It prevents situations when the SoC's clock controller driver has initialized, the external oscillator clock is not yet registered and setting clock frequencies through assigned-clock-rates property doesn't work properly due to unknown external oscillator frequency. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> --- .../devicetree/bindings/clock/exynos5410-clock.txt | 14 +++ drivers/clk/samsung/clk-exynos5410.c | 30 +++++- drivers/clk/samsung/clk-pll.c | 102 +++++++++++++++++++++ drivers/clk/samsung/clk-pll.h | 1 + 4 files changed, 145 insertions(+), 2 deletions(-)diff --git a/Documentation/devicetree/bindings/clock/exynos5410-clock.txt b/Documentation/devicetree/bindings/clock/exynos5410-clock.txt index aeab635..2aefc07 100644 --- a/Documentation/devicetree/bindings/clock/exynos5410-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5410-clock.txt@@ -12,6 +12,9 @@ Required Properties: - #clock-cells: should be 1. +- clocks: should contain an entry specifying the root oscillator clock + on XXTI pin (fin_pll).
Combine with "external clock". Rest looks ok: Reviewed-by: Krzysztof Kozlowski <redacted> Best regards, Krzysztof