From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.perfora.net (mout.perfora.net [74.208.4.196]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F1071E521; Fri, 20 Sep 2024 15:03:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.208.4.196 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726844640; cv=none; b=bdtie4aqx1LtkQjdcD5LYaH3kbp1iJ3OmG8UeFTuQqEOHnigQnfRO20TgvYdXxR33XduD+RPBW3LCQ4jhXgyZwcDltxC21XHZkzSzBh0FQI3GJZCHZGmDL2DgJzwNvhcJ9L4k8udVhTWJo/AyHDeSqg+P6isvfRmw62VphB1CF0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726844640; c=relaxed/simple; bh=X9esZzGOTeQF3OB43MS7uS6NdgofMUQTaJ3qZMAytUQ=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LP9JasFwFdDMOWCS6wMXA8ZcoyOuwZva/jXok1nYuaKhc/uHNkBzyL/RHqjb2xx8iIKT5FiboiS0P5ncVDpBwJ4FFF7pHy7ilxKZGnUWAQ9bbUHIi25Hwnci0sKS5CwUqTqoZm+0DCC5UGzO+Zthf61qNe+4gPq//p1ESTY32u4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=finest.io; spf=pass smtp.mailfrom=finest.io; dkim=pass (2048-bit key) header.d=finest.io header.i=parker@finest.io header.b=KSPtWyPX; arc=none smtp.client-ip=74.208.4.196 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=finest.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=finest.io Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=finest.io header.i=parker@finest.io header.b="KSPtWyPX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=finest.io; s=s1-ionos; t=1726844627; x=1727449427; i=parker@finest.io; bh=BiGXGzW7sTDkHBHRU98fhBYgG2xqKnyjbSiNuAi7zBs=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:Message-ID:In-Reply-To: References:MIME-Version:Content-Type:Content-Transfer-Encoding:cc: content-transfer-encoding:content-type:date:from:message-id: mime-version:reply-to:subject:to; b=KSPtWyPXrhKC5q5NGqGa+2IvDAWnwaRXSXdCvL0QsTruhmrP76qCgYkJVT60pyA7 LsKyTufc16WZAbcWakH+q3jTOBLxEQ0Uc1tahYIyyaLZ+9tajLl3Qp0nW+L3GmZLw Y2SJkAMdvVqjp6RqUM57kzupQEXMFjyq6ZOAf5N4g8diSn08tDS4Y0T2v0Jx7cU1E 0PCmD6RCGsyhNoLRwd82pgsIWaZYGrUoXosp26aXpM5f2eS42Q2MlOa+q1KR0eqBV ZeNrBdhSElVvBpXGMl61p2CuD18wWpCoo5CPi1ZIDXN+H/Eq/0vK0I+1ZxDtpjkw6 PGSBFoScWOHr8xczKg== X-UI-Sender-Class: 55c96926-9e95-11ee-ae09-1f7a4046a0f6 Received: from SWDEV2.connecttech.local ([98.159.241.229]) by mrelay.perfora.net (mreueus002 [74.208.5.2]) with ESMTPSA (Nemesis) id 0MY95y-1sVmhn1nZw-00KC5q; Fri, 20 Sep 2024 17:03:47 +0200 Date: Fri, 20 Sep 2024 11:03:33 -0400 From: Parker Newman To: Andy Shevchenko Cc: Greg Kroah-Hartman , Jiri Slaby , Arnd Bergmann , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Parker Newman Subject: Re: [PATCH v2 1/4] misc: eeprom: eeprom_93cx6: Add quirk for extra read clock cycle Message-ID: <20240920110333.290caae6@SWDEV2.connecttech.local> In-Reply-To: References: Organization: Connect Tech Inc. X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:PBiEFXUH4mF/+GdY+ewzpPsIUKL+hnfiHok9vbItpDYl4pBstM2 2GDT55gdnE+VsuVOOqkyvNie9iEKsNJ7X9K8cx3D1wj7w1iKfUGnc1yID8JC+PmcTjwKRcn bpsxFjINexfovq0WW/wRH3ISrtsajbCM+VVbWJd5JqroymrP5LTFUI4tGkaqrYq7BiK4EQL CcTD/bY7ZkOZSG3VmWDmQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:a8455BJiI6o=;sBGNT1X9cjrPOkpnBrVKYSbORz+ lNUbod1Pu/4LZrh8oMdhG7mj4aeALXWV/Sra3u2alL5TnHoqRb3xKYPBAH5/JcmP/LNDx4pm5 zo4Azz+i75+XVkiDWMb8FR4qzwoh4b162jypvJflYJIekxklScBzZWt0g072l2w6hpnUUuw9I uqCOzMEtHJe9Z4VdV5Uc57SQllFuDA9FqaqPu+phoG8kYdtiA1r291iYuPn43S/A8n5bDs62C UKgOhflxj0wLTXEa8TvQEvLrJoaaCRKqmsWMp4SIjVQtgYXXk7GgIZ0bVKzucSmIdQjJj8U8i X6nsPmNbvuKGiXUb5MsSLqzz9rKvP5kB3f5gtB3654nocSWzSlE62qY8VQn0P5YegmNY5/8LF Zr/6CUHB/a7XI21CpWJ4YW8yM1FtlrOGzGtmw5CLe94RgTSF5PxOVtARsE4tHHohYR4o2fhIN 7pDAMWvv1SOzU9Yxv+DYwsHsQniz7wbuIMjZ7WZc4Mv/Eq4yN5jUwjAHOPftPIFS+FlbVap8c Fe1qEkzshF2g/s1s2wy7lbtwvHJ91aBlWTd7uByZfFinDDEt9NxCiHLCZFC5hchJccHjMjalY jZTm3L4KxgvFAWeKoBjbLmq/K3KIPjvk+LeFcKrNYJ+5Ay3muCtzmNg4iiMNvm21JYu87rocD tTR5PQPAmfjTxp3jye+EVt5TNuavJz/eXWGqeNonbwgNzWOQL1Z4s8F8uZQFBFpeuGJbF5PQY 8mK5EbH2VZFWEneWHL7OKWAKkmsuvtFLw== On Fri, 20 Sep 2024 17:45:15 +0300 Andy Shevchenko wrote: > On Fri, Sep 20, 2024 at 10:03:21AM -0400, Parker Newman wrote: > > From: Parker Newman > >=20 > > This patch adds a quirk similar to eeprom_93xx46 to add an extra clock > > cycle before reading data from the EEPROM. > >=20 > > The 93Cx6 family of EEPROMs output a "dummy 0 bit" between the writing > > of the op-code/address from the host to the EEPROM and the reading of > > the actual data from the EEPROM. > >=20 > > More info can be found on page 6 of the AT93C46 datasheet (linked below= ). > > Similar notes are found in other 93xx6 datasheets. > >=20 > > In summary the read operation for a 93Cx6 EEPROM is: > > Write to EEPROM: 110[A5-A0] (9 bits) > > Read from EEPROM: 0[D15-D0] (17 bits) > >=20 > > Where: > > 110 is the start bit and READ OpCode > > [A5-A0] is the address to read from > > 0 is a "dummy bit" preceding the actual data > > [D15-D0] is the actual data. > >=20 > > Looking at the READ timing diagrams in the 93Cx6 datasheets the dummy > > bit should be clocked out on the last address bit clock cycle meaning it > > should be discarded naturally. > >=20 > > However, depending on the hardware configuration sometimes this dummy > > bit is not discarded. This is the case with Exar PCI UARTs which require > > an extra clock cycle between sending the address and reading the data. > >=20 > > Link: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-5193-SEEPR= OM-AT93C46D-Datasheet.pdf =20 >=20 > JFYI: You may also convert this to Datasheet: tag (we have a history of it > mostly in IIO subsystem), basically replacing word Link by Datasheet in t= he > above line. >=20 Sounds good, I will change in v3. > > Signed-off-by: Parker Newman =20 >=20 > Code wise LGTM now, > Reviewed-by: Andy Shevchenko >=20 > (Do not forget to embed this tag into a new version. With this the `b4` t= ool > is quite helpful, so the workflow is to checkout a new branch in your lo= cal > Git tree, like `git checkout -b exar-93xx46 v6.12-rc1` then taking a mes= sage > ID from email of this thread =E2=80=94 any should succeed, but cover let= ter's one > for sure =E2=80=94 run the following `b4 am $`. It will prin= t the hints > what to do next, something like `git am $.mbx`. Then you can > continue with `git rebase --interactive v6.12-rc1` if the code or other > stuff in the commit message needs to be updated.) >=20 Thanks! This is very helpful. =20