Re: [PATCH v3 07/19] dt-bindings: memory: factorise LPDDR channel binding into memory channel
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2025-07-23 06:57:14
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On Tue, Jul 22, 2025 at 04:03:24PM +0200, Clément Le Goffic wrote:
LPDDR and DDR channels exist and share the same properties, they have a compatible, ranks, and an io-width.
Maybe it is true for all types of SDRAM, like RDRAM and eDRAM, but I don't think all memory types do. I think this should be renamed to sdram-channel.
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Signed-off-by: Clément Le Goffic <redacted> --- ...pddr-channel.yaml => jedec,memory-channel.yaml} | 26 +++++++++++----------- 1 file changed, 13 insertions(+), 13 deletions(-)diff --git a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-channel.yaml b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,memory-channel.yaml similarity index 82% rename from Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-channel.yaml rename to Documentation/devicetree/bindings/memory-controllers/ddr/jedec,memory-channel.yaml index 34b5bd153f63..3bf3a63466eb 100644 --- a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-channel.yaml +++ b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,memory-channel.yaml@@ -1,16 +1,16 @@ # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2 --- -$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr-channel.yaml# +$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,memory-channel.yaml# $schema: http://devicetree.org/meta-schemas/core.yaml# -title: LPDDR channel with chip/rank topology description +title: Memory channel with chip/rank topology description description: - An LPDDR channel is a completely independent set of LPDDR pins (DQ, CA, CS, - CK, etc.) that connect one or more LPDDR chips to a host system. The main - purpose of this node is to overall LPDDR topology of the system, including the - amount of individual LPDDR chips and the ranks per chip. + A memory channel is a completely independent set of pins (DQ, CA, CS,
A memory channel of SDRAM memory like DDR SDRAM or LPDDR SDRAM is ...
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+ CK, etc.) that connect one or more memory chips to a host system. The main + purpose of this node is to overall memory topology of the system, including the + amount of individual memory chips and the ranks per chip. maintainers: - Julius Werner [off-list ref]@@ -26,14 +26,14 @@ properties: io-width: description: The number of DQ pins in the channel. If this number is different - from (a multiple of) the io-width of the LPDDR chip, that means that + from (a multiple of) the io-width of the memory chip, that means that multiple instances of that type of chip are wired in parallel on this channel (with the channel's DQ pins split up between the different chips, and the CA, CS, etc. pins of the different chips all shorted together). This means that the total physical memory controlled by a channel is equal to the sum of the densities of each rank on the - connected LPDDR chip, times the io-width of the channel divided by - the io-width of the LPDDR chip. + connected memory chip, times the io-width of the channel divided by + the io-width of the memory chip. enum: - 8 - 16@@ -51,8 +51,8 @@ patternProperties: "^rank@[0-9]+$": type: object description: - Each physical LPDDR chip may have one or more ranks. Ranks are - internal but fully independent sub-units of the chip. Each LPDDR bus + Each physical memory chip may have one or more ranks. Ranks are + internal but fully independent sub-units of the chip. Each memory bus transaction on the channel targets exactly one rank, based on the state of the CS pins. Different ranks may have different densities and timing requirements.@@ -107,7 +107,7 @@ additionalProperties: false examples: - | - lpddr-channel0 { + memory-channel0 {
If doing this, then separate commit based on generic node name convention. But then we need to come with generic node name first, sdram-channel? And also '-0', not '0' suffix. Best regards, Krzysztof