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Date: Mon, 18 Nov 2013 14:54:37 +0200
From: "Ivan T. Ivanov" <iivanov@...sol.com>
To: Mark Rutland <mark.rutland@....com>
Cc: "balbi@...com" <balbi@...com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"rob.herring@...xeda.com" <rob.herring@...xeda.com>,
Pawel Moll <Pawel.Moll@....com>,
"swarren@...dotorg.org" <swarren@...dotorg.org>,
"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
"davidb@...eaurora.org" <davidb@...eaurora.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v4 10/15] usb: phy: msm: Add device tree support and
binding information
Hi Mark,
On Fri, 2013-11-15 at 16:38 +0000, Mark Rutland wrote:
> On Tue, Nov 12, 2013 at 02:51:45PM +0000, Ivan T. Ivanov wrote:
> > From: "Ivan T. Ivanov" <iivanov@...sol.com>
> >
> > Allows MSM OTG controller to be specified via device tree.
> >
> > Signed-off-by: Ivan T. Ivanov <iivanov@...sol.com>
> > Cc: devicetree@...r.kernel.org
> > ---
> > .../devicetree/bindings/usb/msm-hsusb.txt | 57 +++++++++++++-
> > drivers/usb/phy/phy-msm-usb.c | 79 +++++++++++++++++---
> > 2 files changed, 124 insertions(+), 12 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/usb/msm-hsusb.txt b/Documentation/devicetree/bindings/usb/msm-hsusb.txt
> > index 0a85eba..f1045e3 100644
> > --- a/Documentation/devicetree/bindings/usb/msm-hsusb.txt
> > +++ b/Documentation/devicetree/bindings/usb/msm-hsusb.txt
> > @@ -30,4 +30,59 @@ Required properties:
> > dr_mode = "peripheral";
> > interrupts = <0 134 0>;
> > usb-phy = <&usb_otg>;
> > - };
> > \ No newline at end of file
> > + };
> > +
> > +USB PHY with optional OTG:
> > +
> > +Required properties:
> > +- compatible: should contain "qcom,usb-otg-ci" for chipsets with
> > + Chipidea 45nm PHY or "qcom,usb-otg-snps" for chipsets
> > + with Synopsys 28nm PHY
>
> To make this easier to read and extend in future, I'd reorganise this
> like so:
>
> compatible: should contain:
> * "qcom,usb-otg-ci" for chipsets with Chipidea 45nm PHY
> * "qcom,usb-otg-snps" for chipsets with Synopsys 28nm PHY
Ok.
>
> > +- regs: offset and length of the register set in the memory map
> > +- interrupts: interrupt-specifier for the OTG interrupt.
> > +
> > +- clocks: A list of phandle + clock-specifier pairs for the
> > + clocks listed in clock-names
> > +- clock-names: Should contain the following:
> > + "phy" USB PHY reference clock
> > + "core" Protocol engine clock
> > + "iface" Interface bus clock
> > + "alt_core" Optional: Protocol engine clock for targets with asynchronous
> > + reset methodology.
>
> I'd rearrange that last entry:
>
> "alt_core": Protocol engine clock for targets with asynchronous
> reset methodology. (optional)
ok.
>
> > +
> > +- dr_mode: One of "host", "peripheral" or "otg". Defaults to "otg"
>
> If this has a default and thus isn't required, it should be listed as
> optional.
This is part of the standard USB bindings, Perhaps I could just
refer to: Documentation/devicetree/bindings/usb/generic.txt
>
> > +
> > +- vdccx-supply: phandle to the regulator for the vdd supply for
> > + digital circuit operation.
> > +- v1p8-supply: phandle to the regulator for the 1.8V supply
> > +- v3p3-supply: phandle to the regulator for the 3.3V supply
> > +
> > +- qcom,otg-control: OTG control (VBUS and ID notifications) can be one of
> > + 1 - PHY control
> > + 2 - PMIC control
> > + 3 - User control (via debugfs)
>
> NAK. This does not seem like a description of the hardware, and given
> the debugfs comment is fundamentally tied to the way Linux functions
> today.
I will remove option 3, but rest are really property of the chipset.
>
> > +
> > +Optional properties:
> > +- qcom,phy-init-sequence: PHY configuration sequence. val, reg pairs
> > + terminate with -1
>
> What is this? I'm really not keen on having arbitrary register/memory
> poking sequences in the dt.
This is related Device Mode Eye Diagram test and values used could be
different between chipsets.
>
> Why does it need to be terminated? Surely the size of the property tells
> you that it's terminated.
Yes. -1 termination could be done in driver.
>
> > +
> > +Example HSUSB OTG controller device node:
> > +
> > + usb@...55000 {
> > + compatible = "qcom,usb-otg-snps";
> > + reg = <0xf9a55000 0x400>;
> > + interrupts = <0 134 0>;;
>
> s/;;/;/
thanks
>
> > + dr_mode = "peripheral";
> > +
> > + clocks = <&gcc GCC_XO_CLK>, <&gcc GCC_USB_HS_SYSTEM_CLK>,
> > + <&gcc GCC_USB_HS_AHB_CLK>;
> > +
> > + clock-names = "phy", "core", "iface";
> > +
> > + vddcx-supply = <&pm8841_s2_corner>;
> > + v1p8-supply = <&pm8941_l6>;
> > + v3p3-supply = <&pm8941_l24>;
> > +
> > + qcom,otg-control = <1>;
> > + qcom,phy-init-sequence = <0x01 0x90 0xffffffff>;
>
> I believe modern dtc versions can handle negative numbers directly.
>
> [...]
>
> > +static int msm_otg_read_dt(struct platform_device *pdev, struct msm_otg *motg)
> > +{
> > + struct msm_otg_platform_data *pdata;
> > + const struct of_device_id *id;
> > + struct device_node *node = pdev->dev.of_node;
> > + int len = 0;
> > + u32 val;
> > +
> > + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> > + if (!pdata)
> > + return -ENOMEM;
> > +
> > + motg->pdata = pdata;
> > +
> > + id = of_match_device(msm_otg_dt_match, &pdev->dev);
> > + pdata->phy_type = (int) id->data;
> > +
> > + pdata->mode = of_usb_get_dr_mode(node);
> > + if (pdata->mode == USB_DR_MODE_UNKNOWN)
> > + pdata->mode = USB_DR_MODE_OTG;
> > +
> > + pdata->otg_control = OTG_PHY_CONTROL;
> > + if (!of_property_read_u32(node, "qcom,otg-control", &val))
> > + pdata->otg_control = val;
>
> Is this validated elsewhere?
No. I will add check.
Thanks.
Ivan
>
> Thanks,
> Mark.
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