From c760569d0e9c06b39dd19e82bff0b704d90a73b7 Mon Sep 17 00:00:00 2001 From: Prathyush K Date: Fri, 11 Jul 2014 08:02:15 +0900 Subject: ARM: EXYNOS: Add support for clock handling in power domain While powering on/off a local powerdomain in exynos5 chipsets, the input clocks to each device gets modified. This behaviour is based on the SYSCLK_SYS_PWR_REG registers. E.g. SYSCLK_MFC_SYS_PWR_REG = 0x0, the parent of input clock to MFC (aclk333) gets modified to oscclk = 0x1, no change in clocks. The recommended value of SYSCLK_SYS_PWR_REG before power gating any domain is 0x0. So we must also restore the clocks while powering on a domain everytime. This patch adds the framework for getting the required mux and parent clocks through a power domain device node. With this patch, while powering off a domain, parent is set to oscclk and while powering back on, its re-set to the correct parent which is as per the recommended pd on/off sequence. Signed-off-by: Prathyush K Signed-off-by: Andrew Bresticker Signed-off-by: Arun Kumar K Signed-off-by: Shaik Ameer Basha Reviewed-by: Tomasz Figa Signed-off-by: Kukjin Kim --- .../devicetree/bindings/arm/exynos/power_domain.txt | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt index 5216b419016a..8b4f7b7fe88b 100644 --- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt +++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt @@ -9,6 +9,18 @@ Required Properties: - reg: physical base address of the controller and length of memory mapped region. +Optional Properties: +- clocks: List of clock handles. The parent clocks of the input clocks to the + devices in this power domain are set to oscclk before power gating + and restored back after powering on a domain. This is required for + all domains which are powered on and off and not required for unused + domains. +- clock-names: The following clocks can be specified: + - oscclk: Oscillator clock. + - pclkN, clkN: Pairs of parent of input clock and input clock to the + devices in this power domain. Maximum of 4 pairs (N = 0 to 3) + are supported currently. + Node of a device using power domains must have a samsung,power-domain property defined with a phandle to respective power domain. @@ -19,6 +31,14 @@ Example: reg = <0x10023C00 0x10>; }; + mfc_pd: power-domain@10044060 { + compatible = "samsung,exynos4210-pd"; + reg = <0x10044060 0x20>; + clocks = <&clock CLK_FIN_PLL>, <&clock CLK_MOUT_SW_ACLK333>, + <&clock CLK_MOUT_USER_ACLK333>; + clock-names = "oscclk", "pclk0", "clk0"; + }; + Example of the node using power domain: node { -- cgit v1.2.3