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authorLeonard Crestez <leonard.crestez@nxp.com>2019-11-23 00:45:02 +0300
committerChanwoo Choi <cw00.choi@samsung.com>2019-12-30 03:59:05 +0300
commitc49a5d0968690a08378fd14371678c3479f269aa (patch)
tree4d8fb51c08a6482bc4a3d9957ff2b501b7deb015 /Documentation/devicetree
parentd96c60b48a0b51e4711f9cf88b8da520b521b432 (diff)
downloadlinux-c49a5d0968690a08378fd14371678c3479f269aa.tar.xz
dt-bindings: memory: Add bindings for imx8m ddr controller
Add devicetree bindings for the i.MX DDR Controller on imx8m series chips. It supports dynamic frequency switching between multiple data rates and this is exposed to Linux via the devfreq subsystem. Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Acked-by: Chanwoo Choi <cw00.choi@samsung.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml72
1 files changed, 72 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml b/Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml
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+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/fsl/imx8m-ddrc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: i.MX8M DDR Controller
+
+maintainers:
+ - Leonard Crestez <leonard.crestez@nxp.com>
+
+description:
+ The DDRC block is integrated in i.MX8M for interfacing with DDR based
+ memories.
+
+ It supports switching between different frequencies at runtime but during
+ this process RAM itself becomes briefly inaccessible so actual frequency
+ switching is implemented by TF-A code which runs from a SRAM area.
+
+ The Linux driver for the DDRC doesn't even map registers (they're included
+ for the sake of "describing hardware"), it mostly just exposes firmware
+ capabilities through standard Linux mechanism like devfreq and OPP tables.
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - fsl,imx8mn-ddrc
+ - fsl,imx8mm-ddrc
+ - fsl,imx8mq-ddrc
+ - const: fsl,imx8m-ddrc
+
+ reg:
+ maxItems: 1
+ description:
+ Base address and size of DDRC CTL area.
+ This is not currently mapped by the imx8m-ddrc driver.
+
+ clocks:
+ maxItems: 4
+
+ clock-names:
+ items:
+ - const: core
+ - const: pll
+ - const: alt
+ - const: apb
+
+ operating-points-v2: true
+ opp-table: true
+
+required:
+ - reg
+ - compatible
+ - clocks
+ - clock-names
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/imx8mm-clock.h>
+ ddrc: memory-controller@3d400000 {
+ compatible = "fsl,imx8mm-ddrc", "fsl,imx8m-ddrc";
+ reg = <0x3d400000 0x400000>;
+ clock-names = "core", "pll", "alt", "apb";
+ clocks = <&clk IMX8MM_CLK_DRAM_CORE>,
+ <&clk IMX8MM_DRAM_PLL>,
+ <&clk IMX8MM_CLK_DRAM_ALT>,
+ <&clk IMX8MM_CLK_DRAM_APB>;
+ operating-points-v2 = <&ddrc_opp_table>;
+ };