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[66.90.144.107]) by smtp.gmail.com with ESMTPSA id y13-20020a4a650d000000b00329a5250c77sm616167ooc.6.2022.04.14.05.34.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Apr 2022 05:34:08 -0700 (PDT) Received: (nullmailer pid 1718363 invoked by uid 1000); Thu, 14 Apr 2022 12:34:07 -0000 Date: Thu, 14 Apr 2022 07:34:07 -0500 From: Rob Herring To: Drew Fustini Cc: Krzysztof Kozlowski , Dave Gerlach , Tony Lindgren , Nishanth Menon , Santosh Shilimkar , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] dt-bindings: wkup-m3-ipc: Add ti,io-isolation property Message-ID: References: <20220413020641.2789408-1-dfustini@baylibre.com> <20220413020641.2789408-2-dfustini@baylibre.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220413020641.2789408-2-dfustini@baylibre.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, Apr 12, 2022 at 07:06:40PM -0700, Drew Fustini wrote: > Add documentation for the ti,io-isolation DT property on the wkup_m3_ipc > node which tells the wkup_m3_ipc driver to use the wkup_m3 to enable > IO Isolation during low power mode transitions on am43xx platforms. > > Signed-off-by: Dave Gerlach > [dfustini: convert to YAML, make DTS example that passes check] > Signed-off-by: Drew Fustini > --- > .../bindings/soc/ti/wkup-m3-ipc.yaml | 68 +++++++++++++++++-- > 1 file changed, 63 insertions(+), 5 deletions(-) > > diff --git a/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml b/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml > index 7f4a75c5fcaa..30a65b75c024 100644 > --- a/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml > +++ b/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml > @@ -24,14 +24,22 @@ description: |+ > A wkup_m3_ipc device node is used to represent the IPC registers within an > SoC. > > - Support for VTT Toggle > - ================================== > + Support for VTT Toggle with GPIO pin > + ==================================== > On some boards like the AM335x EVM-SK and the AM437x GP EVM, a GPIO pin is > connected to the enable pin on the DDR VTT regulator. This allows the > regulator to be disabled upon suspend and enabled upon resume. Please note > that the GPIO pin must be part of the GPIO0 module as only this GPIO module > is in the wakeup power domain. > > + Support for IO Isolation > + ======================== > + On AM437x SoCs, certain pins can be forced into an alternate state when IO > + isolation is activated. Those pins have pad control registers prefixed by > + 'CTRL_CONF_' that contain DS0 (e.g. deep sleep) configuration bits that can > + override the pin's existing bias (pull-up/pull-down) and value (high/low) when > + IO isolation is active. Can't this feature be implied from the compatible string? > + > properties: > compatible: > enum: > @@ -63,6 +71,14 @@ properties: > $ref: /schemas/types.yaml#/definitions/uint32 > description: GPIO pin connected to enable pin on VTT regulator > > + ti,set-io-isolation: > + type: boolean > + description: > + If this property is present, then the wkup_m3_ipc driver will instruct > + the CM3 firmware to activate IO isolation when suspending to deep sleep. > + This can be leveraged by a board design to put other devices on the board > + into a low power state. > + > required: > - compatible > - reg > @@ -74,21 +90,63 @@ additionalProperties: false > > examples: > - | > + /* Example for AM335x SoC */ > soc { > #address-cells = <1>; > #size-cells = <1>; > > - mailbox: mailbox { > + am335x_mailbox: mailbox { > #mbox-cells = <1>; > }; > > - wkup_m3_ipc: wkup_m3_ipc@1324 { > + wkup_m3_ipc@1324 { > compatible = "ti,am3352-wkup-m3-ipc"; > reg = <0x1324 0x24>; > interrupts = <78>; > ti,rproc = <&wkup_m3>; > - mboxes = <&mailbox &mbox_wkupm3>; > + mboxes = <&am335x_mailbox &mbox_wkupm3>; > ti,vtt-gpio-pin = <7>; > }; > }; > + > + - | > + /* > + * Example for AM473x SoC: > + * On the AM437x-GP-EVM board, gpio5_7 is wired to enable pin of the DDR VTT > + * regulator. The 'ddr_vtt_toggle_default' pinmux node configures gpio5_7 > + * for pull-up during normal system operation. However, the DS0 (deep sleep) > + * state of the pin is configured for pull-down and thus the VTT regulator > + * will be disabled to save power when IO isolation is active. Note that > + * this method is an alternative to using the 'ti,vtt-gpio-pin' property. > + */ > + #include > + soc { > + #address-cells = <1>; > + #size-cells = <1>; > + > + am437x_mailbox: mailbox { > + #mbox-cells = <1>; > + }; > + > + am43xx_pinmux { > + pinctrl-names = "default"; > + pinctrl-0 = <&ddr3_vtt_toggle_default>; > + > + ddr3_vtt_toggle_default: ddr_vtt_toggle_default { > + pinctrl-single,pins = < > + 0x25C (DS0_PULL_UP_DOWN_EN | PIN_OUTPUT_PULLUP | DS0_FORCE_OFF_MODE | MUX_MODE7) > + >; > + }; > + }; > + > + wkup_m3_ipc@1324 { > + compatible = "ti,am4372-wkup-m3-ipc"; > + reg = <0x1324 0x24>; > + interrupts = <78>; > + ti,rproc = <&wkup_m3>; > + mboxes = <&am437x_mailbox &mbox_wkupm3>; > + ti,set-io-isolation; > + }; > + }; > + > ... > -- > 2.32.0 > >