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| author | Prathyush K <prathyush.k@samsung.com> | 2014-07-11 08:02:15 +0900 |
|---|---|---|
| committer | Kukjin Kim <kgene.kim@samsung.com> | 2014-07-11 08:03:19 +0900 |
| commit | c760569d0e9c06b39dd19e82bff0b704d90a73b7 (patch) | |
| tree | f0e69210b658804b75f39a650c36bb867f732cc0 /Documentation | |
| parent | be0b420ad6123e587738a67a9eff3ec213a57604 (diff) | |
| download | linux-c760569d0e9c06b39dd19e82bff0b704d90a73b7.tar.bz2 | |
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 <prathyush.k@samsung.com>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Arun Kumar K <arun.kk@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/arm/exynos/power_domain.txt | 20 |
1 files changed, 20 insertions, 0 deletions
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 { |