[PATCH v2 0/2] rockchip pcie3-phy separate refclk support

From: Niklas Cassel <cassel@kernel.org>
To: Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>
Cc: devicetree@vger.kernel.org,
	Sebastian Reichel <sebastian.reichel@collabora.com>,
	Michal Tomek <mtdev79b@gmail.com>,
	Damien Le Moal <dlemoal@kernel.org>,
	Jon Lin <jon.lin@rock-chips.com>,
	Niklas Cassel <cassel@kernel.org>,
	linux-phy@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org
Subject: [PATCH v2 0/2] rockchip pcie3-phy separate refclk support
Date: Fri, 12 Apr 2024 14:58:14 +0200	[thread overview]
Message-ID: <20240412125818.17052-1-cassel@kernel.org> (raw)

This series is based on: linux-phy phy/next

Hello all,

The rockchip,pcie3-phy PHY in rk3588 is by default configured to run in
"common reference clock" mode. (Which is a sensible default, as the most
commonly used clock configuration is "common reference clock".)

However, PCIe also defines two other configurations where the Root Complex
and Endpoint uses separate reference clocks: SRNS and SRIS.

Having the Root Complex PHY configured in "common reference clock mode"
while having an Endpoint connected which is supplying its own reference
clock (i.e. SRNS or SRIS configuration), will either result in the link
training failing, or a highly unstable link that continuously jumps
between link states L0 and recovery.

Add a rockchip specific device tree property that can be added to the
rk3588 Root Complex device tree PHY node, if the connected Endpoint device
is using a separate refererence clock. This way we will get a stable link
when using an Endpoint configured in SRNS or SRIS mode.

Kind regards,
Niklas

Changes since V1:
-Picked up tags
-Rebased on phy/next

Niklas Cassel (2):
  dt-bindings: phy: rockchip,pcie3-phy: add
    rockchip,rx-common-refclk-mode
  phy: rockchip-snps-pcie3: add support for
    rockchip,rx-common-refclk-mode

 .../bindings/phy/rockchip,pcie3-phy.yaml      | 10 +++++
 .../phy/rockchip/phy-rockchip-snps-pcie3.c    | 37 +++++++++++++++++++
 2 files changed, 47 insertions(+)

-- 
2.44.0

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