From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EE4FC433F5 for ; Fri, 1 Apr 2022 08:05:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244236AbiDAIH3 (ORCPT ); Fri, 1 Apr 2022 04:07:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231421AbiDAIH2 (ORCPT ); Fri, 1 Apr 2022 04:07:28 -0400 Received: from fllv0016.ext.ti.com (fllv0016.ext.ti.com [198.47.19.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5731D1DE5AD; Fri, 1 Apr 2022 01:05:37 -0700 (PDT) Received: from lelv0265.itg.ti.com ([10.180.67.224]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 23185XA6075999; Fri, 1 Apr 2022 03:05:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1648800333; bh=cwZeZOxF+mFqZQssgtMq72BnCfJyu1rh8zRk2NJPysU=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=VSOAz46Qf4omXyZCR6JRphUVOb2BSkVWaoZA1BCD5HVpw4zkoyv8QJnKOcRsm3Nj7 YhTPCGxdEozOUjITz+5FhTBI31X0Ra0u/dZRj5gG3+0K4DjRZNVwIoq5OkcT9vVWB+ FvAWExyemLbiYhAF5aQk0R1IaSrNBq4qyCeR1cjU= Received: from DLEE105.ent.ti.com (dlee105.ent.ti.com [157.170.170.35]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 23185X53002592 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 1 Apr 2022 03:05:33 -0500 Received: from DLEE100.ent.ti.com (157.170.170.30) by DLEE105.ent.ti.com (157.170.170.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14; Fri, 1 Apr 2022 03:05:32 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE100.ent.ti.com (157.170.170.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14 via Frontend Transport; Fri, 1 Apr 2022 03:05:32 -0500 Received: from [10.24.69.236] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 23185SUe081179; Fri, 1 Apr 2022 03:05:29 -0500 Message-ID: <666d230c-73a8-c1a3-2271-f79077705bb5@ti.com> Date: Fri, 1 Apr 2022 13:35:28 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v2 1/2] dt-bindings: usb: Add documentation for AM62 USB Wrapper module Content-Language: en-US To: Krzysztof Kozlowski , Rob Herring CC: , , , Felipe Balbi , Krzysztof Kozlowski , Greg Kroah-Hartman , Roger Quadros , Vignesh Raghavendra , Kishon Vijay Abraham I References: <20220324073425.18607-1-a-govindraju@ti.com> <20220324073425.18607-2-a-govindraju@ti.com> <93fe6a41-3b59-2fbc-6f95-833f337815ee@kernel.org> <41f79aa5-1e04-53f8-ab21-85fe6039e24e@ti.com> <2b33798e-23c2-d4a5-171a-55c28bc40c40@kernel.org> <1fcac9c3-4b84-6572-ebc6-4d6a50f0132a@ti.com> <5139bdb8-11ee-6efe-6c42-acf2f96d9153@linaro.org> From: Aswath Govindraju In-Reply-To: <5139bdb8-11ee-6efe-6c42-acf2f96d9153@linaro.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Krzysztof, Rob, On 01/04/22 13:19, Krzysztof Kozlowski wrote: > On 01/04/2022 07:04, Aswath Govindraju wrote: >> Hi Rob, >> >> On 01/04/22 05:50, Rob Herring wrote: >>> On Thu, Mar 24, 2022 at 12:53:08PM +0100, Krzysztof Kozlowski wrote: >>>> On 24/03/2022 12:40, Aswath Govindraju wrote: >>>>> Hi Krzysztof, >>>>> >>>>> On 24/03/22 16:37, Krzysztof Kozlowski wrote: >>>>>> On 24/03/2022 08:34, Aswath Govindraju wrote: >>>>>>> Add bindings for the TI's AM62 wrapper module for the Synopsys USBSS-DRD >>>>>>> controller. >>>>>>> >>>>>>> Signed-off-by: Aswath Govindraju >>>>>>> --- >>>>>>> >>>>>>> Changes since v1: >>>>>>> - made correction in grammer of clocks property description >>>>>>> and added maxItems in the interrupts property based on comments >>>>>>> received from Roger >>>>>>> - corrected the title, fixed the description of >>>>>>> ti,syscon-phy-pll-refclk, added pattern properties and child node >>>>>>> in the example based on the comments from Krzysztof. >>>>>>> >>>>>>> .../devicetree/bindings/usb/ti,am62-usb.yaml | 117 ++++++++++++++++++ >>>>>>> 1 file changed, 117 insertions(+) >>>>>>> create mode 100644 Documentation/devicetree/bindings/usb/ti,am62-usb.yaml >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml >>>>>>> new file mode 100644 >>>>>>> index 000000000000..452bfdc6fb09 >>>>>>> --- /dev/null >>>>>>> +++ b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml >>>>>>> @@ -0,0 +1,117 @@ >>>>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause >>>>>>> +%YAML 1.2 >>>>>>> +--- >>>>>>> +$id: http://devicetree.org/schemas/usb/ti,am62-usb.yaml# >>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>>>>>> + >>>>>>> +title: TI's AM62 wrapper module for the Synopsys USBSS-DRD controller >>>>>>> + >>>>>>> +maintainers: >>>>>>> + - Aswath Govindraju >>>>>>> + >>>>>>> +properties: >>>>>>> + compatible: >>>>>>> + const: ti,am62-usb >>>>>>> + >>>>>>> + reg: >>>>>>> + maxItems: 1 >>>>>>> + >>>>>>> + ranges: true >>>>>>> + >>>>>>> + power-domains: >>>>>>> + description: >>>>>>> + PM domain provider node and an args specifier containing >>>>>>> + the USB ISO device id value. See, >>>>>>> + Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml >>>>>>> + maxItems: 1 >>>>>>> + >>>>>>> + clocks: >>>>>>> + description: Clock phandle to usb2_refclk >>>>>>> + maxItems: 1 >>>>>>> + >>>>>>> + clock-names: >>>>>>> + items: >>>>>>> + - const: ref >>>>>>> + >>>>>>> + id-gpio: >>>>>>> + description: >>>>>>> + GPIO to be used as ID pin >>>>>>> + maxItems: 1 >>>>>> >>>>>> I have doubts about this. If you USB controller handles the ID pin, then >>>>>> probably this should be moved to usb-connector.yaml. I did not see >>>>>> id-gpio in any other USB controller blocks. >>>>>> >>>>> >>>>> Yes, the USB wrapper handles the ID pin operation only. It also reads >>>>> the status of VBUS by reading a register from its MMR and not using a >>>>> gpio. After evaluating the role the based on the states if id pin and >>>>> VBUS, this role is communicated to the dwc3 core driver using extcon. >>>>> There is no way for the dwc3 driver to detect the role on its own. >>>>> >>>>> >>>>> The usb-connector(drivers/usb/common/usb-conn-gpio.c) driver, seems to >>>>> be implemented for driving the VBUS, based on ID and VBUS pin status. >>>>> However, in case of the above implementation we need to communicate the >>>>> detected role to the dwc3 core driver. Also, the wrapper does not >>>>> control VBUS but it is the dwc3 core driver that drives the VBUS. >>>>> Therefore, I think the usb-connector implementation cannot be used here. >>>> >>>> I don't think about usb-conn-gpio.c but using the binding generic >>>> binding for usb-X-connector and define a connector with ID. >>>> >>>> Actually Rob could help here. >>>> >>>> Rob, >>>> Should the id-gpio be modeled as a property in this glue/wrapper driver >>>> or rather as part of usb-connector child node? >>> >>> That's a simple question. Where does the ID GPIO signal go to? The >>> connector, so it goes in the connector node. >>> >> >> Thank you for the clarification. Here ID-gpio is directly read by the >> wrapper and hence, I have modeled it as a property in the wrapper dt >> node. May I know if this wrong and should the modelling be looked at >> differently? > > What do you mean here by "read"? If you refer to the driver reading the > pin value, it is less related to the hardware, right? > > Thank you for clarification. Now I understood, I was looking at it in the wrong way and when looking at in in terms hardware I understood the mistake that I have been doing. So, the id-gpio is actually not an inherent part of the wrapper but rather something that it gets from the connector. So, there needs to be different node describing this. Thanks, Aswath > Best regards, > Krzysztof