From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Kepplinger Subject: Re: [PATCH v2 1/9] serial: uapi: add SER_RS485_DELAY_IN_USEC flag to struct serial_rs485 Date: Fri, 8 Mar 2019 08:36:39 +0100 Message-ID: <64024432-55f7-57e4-78cd-8f43c8bea521@ginzinger.com> References: <20190221171758.10322-1-martin.kepplinger@ginzinger.com> Mime-Version: 1.0 Content-Type: multipart/signed; protocol="application/x-pkcs7-signature"; micalg="sha-256"; boundary="----2536A47B892EED563B7786C5F41D57D8" Return-path: In-Reply-To: <20190221171758.10322-1-martin.kepplinger@ginzinger.com> Sender: linux-kernel-owner@vger.kernel.org To: gregkh@linuxfoundation.org, robh+dt@kernel.org, mark.rutland@arm.com, jslaby@suse.com, corbet@lwn.net, richard.genoud@gmail.com, nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com, ludovic.desroches@microchip.com, mcoquelin.stm32@gmail.com, alexandre.torgue@st.com, linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com Cc: linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org This is an S/MIME signed message ------2536A47B892EED563B7786C5F41D57D8 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit On 21.02.19 18:17, Martin Kepplinger wrote: > This extends the user interface for rs485 communication: > > We add a new flag, SER_RS485_DELAY_IN_USEC, to struct serial_rs485 that > indicates that delay_rts_before_send and delay_rts_after_send values are > interpreted in microsecond units. > > Up until now, the code comment defined these values to hold the delays in > millisecond units. Especially with fast data rates (1Mbaut or more) that > are not too uncommon for RS485, 1ms become quite long. Users need to be > able to set shorter delays than 1 ms in order not to slow down the channel > unnecessarily. > > So when delays are needed, but not as long as 1ms, this enables faster > communication channels without changing the baudrate. > > Signed-off-by: Martin Kepplinger > --- > > revision history > ---------------- > v2: re-send as a proper series after fixing my mailserver > v1: initial implementation idea > > > So have this totally quirky patch that uses udelay() in our tree > for a looong time now because of the above reasons - and because we are lazy. > This is an attempt to get rid of said patch on our side and fix this properly. > > What do you thing about adding a flag in general? > > The following patches should integrate this idea in devicetree and drivers. > These changes are NOT tested on hardware but should behave predictably > enough. I use the delays in a driver that doesn't implement them yet at > all. I'll do that after this (or something similar) is merged - it's a 2-liner > then. > > Also, a patch to the rs485conf tool, that is sometimes used instead of > ioctl() directly, will be prepared as well. > any objections of questions about having microsecond delays and this series of changes? thanks martin ------2536A47B892EED563B7786C5F41D57D8 Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" MIIOHAYJKoZIhvcNAQcCoIIODTCCDgkCAQExDzANBglghkgBZQMEAgEFADALBgkq hkiG9w0BBwGgggshMIIF5jCCA86gAwIBAgIQapvhODv/K2ufAdXZuKdSVjANBgkq hkiG9w0BAQwFADCBhTELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFu Y2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExp bWl0ZWQxKzApBgNVBAMTIkNPTU9ETyBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3Jp dHkwHhcNMTMwMTEwMDAwMDAwWhcNMjgwMTA5MjM1OTU5WjCBlzELMAkGA1UEBhMC R0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9y ZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBS U0EgQ2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwggEi MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC+s55XrCh2dUAWxzgDmNPGGHYh UPMleQtMtaDRfTpYPpynMS6n9jR22YRq2tA9NEjk6vW7rN/5sYFLIP1of3l0NKZ6 fLWfF2VgJ5cijKYy/qlAckY1wgOkUMgzKlWlVJGyK+UlNEQ1/5ErCsHq9x9aU/x1 KwTdF/LCrT03Rl/FwFrf1XTCwa2QZYL55AqLPikFlgqOtzk06kb2qvGlnHJvijjI 03BOrNpo+kZGpcHsgyO1/u1OZTaOo8wvEU17VVeP1cHWse9tGKTDyUGg2hJZjrqc k39UIm/nKbpDSZ0JsMoIw/JtOOg0JC56VzQgBo7ictReTQE5LFLG3yQK+xS1AgMB AAGjggE8MIIBODAfBgNVHSMEGDAWgBS7r34CPfqm8TyEjq3uOJjs2TIy1DAdBgNV HQ4EFgQUgq9sjPjF/pZhfOgfPStxSF7Ei8AwDgYDVR0PAQH/BAQDAgGGMBIGA1Ud EwEB/wQIMAYBAf8CAQAwEQYDVR0gBAowCDAGBgRVHSAAMEwGA1UdHwRFMEMwQaA/ oD2GO2h0dHA6Ly9jcmwuY29tb2RvY2EuY29tL0NPTU9ET1JTQUNlcnRpZmljYXRp b25BdXRob3JpdHkuY3JsMHEGCCsGAQUFBwEBBGUwYzA7BggrBgEFBQcwAoYvaHR0 cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQWRkVHJ1c3RDQS5jcnQwJAYI KwYBBQUHMAGGGGh0dHA6Ly9vY3NwLmNvbW9kb2NhLmNvbTANBgkqhkiG9w0BAQwF AAOCAgEAeFyygSg0TzzuX1bOn5dW7I+iaxf28/ZJCAbU2C81zd9A/tNx4+jsQgwR GiHjZrAYayZrrm78hOx7aEpkfNPQIHGG6Fvq3EzWf/Lvx7/hk6zSPwIal9v5IkDc ZoFD7f3iT7PdkHJY9B51csvU50rxpEg1OyOT8fk2zvvPBuM4qQNqbGWlnhMpIMwp WZT89RY0wpJO+2V6eXEGGHsROs3njeP9DqqqAJaBa4wBeKOdGCWn1/Jp2oY6dyNm NppI4ZNMUH4Tam85S1j6E95u4+1Nuru84OrMIzqvISE2HN/56ebTOWlcrurffade 2022O/tUU1gb4jfWCcyvB8czm12FgX/y/lRjmDbEA08QJNB2729Y+io1IYO3ztve BdvUCIYZojTq/OCR6MvnzS6X72HP0PRLRTiOSEmIDsS5N5w/8IW1Hva5hEFy6fDA fd9yI+O+IMMAj1KcL/Zo9jzJ16HO5m60ttl1Enk8MQkz/W3JlHaeI5iKFn4UJu1/ cP2YHXYPiWf2JyBzsLBrGk1II+3yL8aorYew6CQvdVifC3HtwlSam9V1niiCfOBe 2C12TdKGu05LWIA3ZkFcWJGaNXOZ6Ggyh/TqvXG5v7zmEVDNXFnHn9tFpMpOUvxh csjycBtH0dZ0WrNw6gH+HF8TIhCnH3+zzWuDN0Rk6h9KVkfKehIwggUzMIIEG6AD AgECAhBNQrEzGzrZ6FVYh1EEYH4+MA0GCSqGSIb3DQEBCwUAMIGXMQswCQYDVQQG EwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxm b3JkMRowGAYDVQQKExFDT01PRE8gQ0EgTGltaXRlZDE9MDsGA1UEAxM0Q09NT0RP IFJTQSBDbGllbnQgQXV0aGVudGljYXRpb24gYW5kIFNlY3VyZSBFbWFpbCBDQTAe Fw0xODA3MTgwMDAwMDBaFw0yMTA3MTcyMzU5NTlaMDAxLjAsBgkqhkiG9w0BCQEW H21hcnRpbi5rZXBwbGluZ2VyQGdpbnppbmdlci5jb20wggEiMA0GCSqGSIb3DQEB AQUAA4IBDwAwggEKAoIBAQDsMC77L0D+2D8I8X5ubnBhADLgU+HtlwMTFt/WJIhc kgbvnawYXWrCIpk8F6BJ0R/iFCykPdG7741EmlcHRKOJfhVxjXhwnoGFqnYmurCt fvZLR3+mT3FWnVv2RAdrXscXH3BpijqqWabdtTbiTvmcl86Zc6mNlVhYZSbDul/E voIGZotGcGIWrgZxN+8MQJQHKb0KHyWlPVPkrjvEfOJHKKLFsBNSnNMR95Ijg3Sp h8/8RG490/zRHflGzUlxDSlLyY9YJGzSdDzcFKoYcc4oaaUY5N3uhRna43TLUIQh 6ybt3DKVz1Pw/ikwYJrOsulJrVr3D8KVHdGxq7HYl7jnAgMBAAGjggHfMIIB2zAf BgNVHSMEGDAWgBSCr2yM+MX+lmF86B89K3FIXsSLwDAdBgNVHQ4EFgQU/GtSUbHg 14sPDlmo27eQYwtjaS0wDgYDVR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAwHQYD VR0lBBYwFAYIKwYBBQUHAwQGCCsGAQUFBwMCMEYGA1UdIAQ/MD0wOwYMKwYBBAGy MQECAQMFMCswKQYIKwYBBQUHAgEWHWh0dHBzOi8vc2VjdXJlLmNvbW9kby5uZXQv Q1BTMFoGA1UdHwRTMFEwT6BNoEuGSWh0dHA6Ly9jcmwuY29tb2RvY2EuY29tL0NP TU9ET1JTQUNsaWVudEF1dGhlbnRpY2F0aW9uYW5kU2VjdXJlRW1haWxDQS5jcmww gYsGCCsGAQUFBwEBBH8wfTBVBggrBgEFBQcwAoZJaHR0cDovL2NydC5jb21vZG9j YS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1cmVFbWFp bENBLmNydDAkBggrBgEFBQcwAYYYaHR0cDovL29jc3AuY29tb2RvY2EuY29tMCoG A1UdEQQjMCGBH21hcnRpbi5rZXBwbGluZ2VyQGdpbnppbmdlci5jb20wDQYJKoZI hvcNAQELBQADggEBAGEuG01K1tt5i3gUdQkYem/KpbJUYBZd43QwmoTa0TGXUiYq b+g/TeGG9QQ1yq+73xOr8fu6oT2608C7EiJc6JmjTs485/OZmTqgYkrLfs71F1kB 3Z59WPf5aoR/pnn5vdfkkoO29V1cKPJR4z+iOG2hOlcK/dXrX8i6mnL5DGIe8l5n udUPvIbUhbMavrDd6kwhs0oCjylwdKGlFkCpKMn3HPflfDeHuV9Z8Nrpeq/7+Pm0 I/fLPkaYlULASJoJCucMYcedY9rmuro9JhV+NuVXaqLIrQPc1vyKFeRuLHh84M6c 1h1DArdGTykXZUwjXnnHtuOtzjIAzkx2Ns43vEsxggK/MIICuwIBATCBrDCBlzEL MAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UE BxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMT NENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1h aWwgQ0ECEE1CsTMbOtnoVViHUQRgfj4wDQYJYIZIAWUDBAIBBQCggeQwGAYJKoZI hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTkwMzA4MDczNjUy WjAvBgkqhkiG9w0BCQQxIgQgPi0/A/FGPZLJ0Kwybmi0bIrpJPJfARNB7/eCxOTG o1YweQYJKoZIhvcNAQkPMWwwajALBglghkgBZQMEASowCwYJYIZIAWUDBAEWMAsG CWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcN AwICAUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwDQYJKoZIhvcNAQEBBQAEggEA wuhHke5K5io9iK6UNOlMXfSDGysSAovsjouAMCejw5DiJZxqd8nwbZJGgemy7yu9 NQV51vyzbwRwTLyZtnHKpQluVA/o+NU/7I9tlo4M2lXsOqglkaaKyDPAp6xELtai wOc2FomCjHOjK8xspRadKCzE2YJDs1bAzFEsDPhF+SIw+THXV7Ayua/K8tblGzbC B2WxySiaeveBYWyENB2pfbB56uUwh/N6uhlACalUQSFA1IFI2XCWjLn5O8ogaNY6 4U0uxJwcm/lUqVWl97BCBZ1Qi0EX7aKrEAsmd4AUnfTKD595FbrUpCJ9oYpgo8PP YlNfBLs9UwWgQSaJDfTBAw== ------2536A47B892EED563B7786C5F41D57D8--