Received-SPF: pass (google.com: domain of linux-kernel+bounces-42684-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Message-ID: <da864300-ae0a-43fc-84bd-94e985d8ac73@theobroma-systems.com>
Date: Mon, 29 Jan 2024 13:26:51 +0100
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v4 3/6] dt-bindings: serial: add binding for rs485
 rx-enable state when rs485 is disabled
Content-Language: en-US
To: Conor Dooley <conor@kernel.org>,
 Farouk Bouabid <farouk.bouabid@theobroma-systems.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 Jiri Slaby <jirislaby@kernel.org>, Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, Heiko Stuebner <heiko@sntech.de>,
 Rob Herring <robh@kernel.org>, linux-kernel@vger.kernel.org,
 linux-serial@vger.kernel.org, devicetree@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org
References: <20240126-dev-rx-enable-v4-0-45aaf4d96328@theobroma-systems.com>
 <20240126-dev-rx-enable-v4-3-45aaf4d96328@theobroma-systems.com>
 <20240128-vagabond-mutilator-cf8dc6ac8a41@spud>
From: Quentin Schulz <quentin.schulz@theobroma-systems.com>
In-Reply-To: <20240128-vagabond-mutilator-cf8dc6ac8a41@spud>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?amY0U0hvZFR5WC9WcVhudmNYeE50bExHSE1vR1dmTmRJbzBxMFlWbXg2OEky?=
 =?utf-8?B?SG9QVlM1bVhSQXhjWXRWV0MwQ2VXM285V0JhZUxqSXBZejBBWE5pSEJJZ0I5?=
 =?utf-8?B?cFFKZXdOaitWcEp5ajJLQ0EwcXlvUSt5VTYwdDdsVDdHbVlJam4rbHJTMklD?=
 =?utf-8?B?Nmk2eTVaWnllS2lOQ2c5K2RWUm1QODJtS05EaytBUUdSdG0vV1RoOVdtSHZz?=
 =?utf-8?B?RHBuSWJwY25hTCtBZWlFcE9FdjJoVlMzMzNhZG1Ob0g0SkdkNitIMXdmTTVB?=
 =?utf-8?B?RmZtaGhFejh6a0FSWmJYZzF0SDcwMllxSzZSU3draHJ1TFJ1Ly82N2JQUmZJ?=
 =?utf-8?B?ZllzRXplOWFpMDNyemlEMGg1UnVOMkFEa0VqOWVGRmlIZEM0SW9wMG5YS2VH?=
 =?utf-8?B?YnM5clBtdG5jOWpMV1grcUllWDB0V0wrSjBQYlEvZGVkZmpuWHZyS1BpK0Z4?=
 =?utf-8?B?MitXNVliWlBocmRwdFNVRVRCMnZydERVNjUvS2Q3cXRqOUt6a0lMMlBES0Rk?=
 =?utf-8?B?c3VlRFpDOFBuc1lCelJsYWc0V3JxOUQxZW50Nmg3UmFHQ3laR2tmSEhRQnZi?=
 =?utf-8?B?UStLalZBRGl6S0lGNmdDRWpPb1luTTBRdytxZUp0ZVFnYzZpMHBxREgwTFUy?=
 =?utf-8?B?SVhHL1M3R2lWd0FDM1ozQWovcnMvK200aTYvMGNubnB0aUtFY2VwYWNwaE1h?=
 =?utf-8?B?U3NYbFJpU2ZiM0ZWWUZYMzlCSXN4YVZ0WDhyTkhPQktDREM3V3JFdDZTWTEx?=
 =?utf-8?B?dktxQkY2UUNRbXJZbUN0TDhHOTJFbC9YdUN3VkJUdDVZVzI4QllEWUxpVDc0?=
 =?utf-8?B?WkxMQ3AxMXBLWGNPaTBubysrRCswVUczOEp1eHN6SEVBOVdOSWdxQWZJZGc3?=
 =?utf-8?B?VmRkUngxV0hQa0NrUlhaSlFKc3hwUzl0cEpoUGt0SHBaWGVUM2w0b1U3ZVdL?=
 =?utf-8?B?eHBkZ2xSYUdsUlJrd0YxcURvaHZwZ0E3d1lUN2NlZjRtd0M1NFNBNjhXU1dq?=
 =?utf-8?B?SHluNmFjRGVzUy9SZllBK1JKeGFKUHhZR21YZlBFV0JHTzkrL0N1OE9qNklM?=
 =?utf-8?B?Qmk0eFBKclBVaFNiaVRENkVvTnFaY213cEYwMjk4Rjd2ZUloYXdrNDNsUmtw?=
 =?utf-8?B?Y1pBMEdPb3I3Wi9Dam4rbWsyZ2dzR1huTlh3Y2hZRDVrTlY2ZjBlZVk2dzlW?=
 =?utf-8?B?M0xJbVk5UDhSdWo4eGw0Mi8yUFlERWZ0YVFJamFHZTUvelVxL1dkdUFMT2pY?=
 =?utf-8?B?OFVwTmJORVVTaEhDZ3k0WWw3SW5jdzZFSEtFckZDYytOcFZ3WWNVVENWRnpa?=
 =?utf-8?B?REdYc2JWU3MxdHN2TnNlNEFVRGFEQnZFOXJWZkRXZURKZUo5OENjMUk2V2to?=
 =?utf-8?B?MDQ3MUtVTGdWUTVDL20vNFUyZDhGTzBvSU5INVorVGNXZjJ6MnhZNWZaZjFQ?=
 =?utf-8?B?V0FyZHpTVVdqZnZJUkV5OFM1NXNhc2Q5eDZqaEJJUktNaFN2NHI1alVFd2dE?=
 =?utf-8?B?WDlmRGQ2WkNweVJ3aFhYRUR0TjBmV1UwTWUzVGw2ZHJBQlhITVNNb1B1akx4?=
 =?utf-8?B?Z2Qybm9qVTRCNFMwdS96YnFLV2VmajVialZZL1IxWWdQQlJuVE9tcDNOdUV0?=
 =?utf-8?B?YmNXRVhLSGlhS1ZEOHluL1BpYVBjcjE3SmxySjFsWHhGNGswNVp4QTBRQXhU?=
 =?utf-8?B?ekxxcWl2d0JQQ1VVSHB3aTh3cTRnVEM0MXo2aTNOYkh5bXhxYWVnSjFjNThw?=
 =?utf-8?B?UUE0Y1luN2VIc0NNWlkrM0p6d1Y3b2llSTBtMW9WQVdBbmg5bG1DT21MWmtC?=
 =?utf-8?B?ckQrR1RKckZKZmJFQW9YcEppWjdZSXB0TSt5YnJYT1FqUGx3Skp4QTF1d2dR?=
 =?utf-8?B?bDRSL3Q4ZnNieTNXbkFRTUx2TDFWaXlBVGRZU2MzSThUbXdjNzZLVmtHVEdD?=
 =?utf-8?B?LzQ0SHJnUzhjVUxYcXlCdW9kRElrYXVjRkpWZ0U0eGhJb21xdi9WSS9yVG9P?=
 =?utf-8?B?R3ZEOWJPVnJONFBiK3ZPRkFaYTl0OCtPeS9lY1ZNQjNheVJJM0oxYkxSczdX?=
 =?utf-8?B?WEZFNzZ4VGRrQ29MdmwyNmdyUGNhL2VnS0c3UENXVkEvbVAwZXJocGVVdnAv?=
 =?utf-8?B?QU1MdEJ6MUlpclpwSU90RDdlUVkwdjFSVER4UlN5Q1lNaGlrZVJvRklYQmJp?=
 =?utf-8?Q?5CM3cAwbr+OphoHE+HETifo=3D?=
X-OriginatorOrg: theobroma-systems.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 932af928-0637-44b3-746f-08dc20c5944c
X-MS-Exchange-CrossTenant-AuthSource: DU2PR04MB8536.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Jan 2024 12:26:55.0444
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 5e0e1b52-21b5-4e7b-83bb-514ec460677e
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: Smjx7S3sfsfokiRbSVaLp3WxSOyZFZHz48HMIn/Bo0fbSA8qzAxEHq4mBcL2Mqsu1m58YRbo92NnoldtjwUuu8l5+CD3JPrftzs7B5FEdehPxVlmJ6VPCm3O0B4cpv/a
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAXPR04MB9256

Hi Conor,

On 1/28/24 18:38, Conor Dooley wrote:
> On Fri, Jan 26, 2024 at 03:55:12PM +0100, Farouk Bouabid wrote:
>> RS485 can have a receiver-enable gpio (rx-enable-gpios). When rs485 is
>> enabled, this gpio, if provided, must be driven active while receiving.
>> However when RS485 is disabled this gpio should not have an undefined
>> state. In that case, as DE and RE pins can be connected both to this gpio,
>> if its state is not properly defined, can cause unexpected transceiver
>> behavior.
>> This binding depend on rx-enable-gpios to be implemented.
> 
> Why do you need a dedicated property for this when there exists a device
> specific compatible for the uart on both of the affected rockchip
> systems?
> 

This has nothing to do with Rockchip's IP but the HW design of our 
carrierboard, so using the "rockchip,px30-uart" for that (which I assume 
is what was suggested here?) is incorrect since it'll also apply to 
PX30, RK3399 and RK3588-based Q7 SoCs we manufacture.

Did I understand the suggestion correctly?

Cheers,
Quentin