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 shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8A105EC874B for ; Thu, 7 Sep 2023 18:01:36 +0000 (UTC) Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.96) (envelope-from ) id 1qeJJS-0001yp-07; Thu, 07 Sep 2023 14:01:06 -0400 Received: from [2001:4d48:ad52:32c8:5054:ff:fe00:142] (helo=pandora.armlinux.org.uk) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qeJJQ-0001yD-0j for kernelnewbies@kernelnewbies.org; Thu, 07 Sep 2023 14:01:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=X4xUKnQy5Cuyq/hlcTvI9PdWU+bO5LlG1WNNbVR8IrU=; b=lleRes3stqKrEVBIpyWoQv1a+r gcuk3LwaMYPqCntIqfD62zX3R9U/uxNscQhd1wwd7tn7UfdE112nDjujBeGXAVKSObqviG4BNYL2K q3BmwOaKa5OjDUdO6MCFf6uOx+jUfqPrrh2Y9xzHwhJ2Q5ubd3NUDgyWey8OW2Z+b7CDu3zkE1E7s WrQjNXU1jxJZ30sKuLMPjb4dd8R7BuNjxvjpg1PNctN6zBnCBn/iIv74WZJSNsz9W/TXCS692xvxk GpoZnI9Csrhw6/ExpTYX1kHfafdv2PaGIhuQGz7qWsqqVik+dlGjAtgpA54Ro/eVtauQY/r8FIIBx e24awPug==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:36672) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qeJJ7-0004BF-0b; Thu, 07 Sep 2023 19:00:45 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qeJJ6-000639-R6; Thu, 07 Sep 2023 19:00:44 +0100 Date: Thu, 7 Sep 2023 19:00:44 +0100 From: "Russell King (Oracle)" To: Raul Piper Subject: Re: Debugging i2c : i2cdetect cant detect a device on i2c line Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Cc: Linux Devicetree , Conor Dooley , Andi Shyti , Krzysztof Kozlowski , kernelnewbies , Linus Walleij , LKML , tanure@linux.com, Rob Herring , Linux I2C , Bagas Sanjaya , Linux ARM X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: kernelnewbies-bounces@kernelnewbies.org T24gVGh1LCBTZXAgMDcsIDIwMjMgYXQgMTA6Mzg6MTBQTSArMDUzMCwgUmF1bCBQaXBlciB3cm90 ZToKPiBPbiBUaHUsIFNlcCA3LCAyMDIzIGF0IDk6NDfigK9QTSBMdWNhcyBUYW51cmUgPHRhbnVy ZUBsaW51eC5jb20+IHdyb3RlOgo+ID4KPiA+Cj4gPgo+ID4gT24gVGh1LCA3IFNlcHQgMjAyMywg MTQ6NTYgUnVzc2VsbCBLaW5nIChPcmFjbGUpLCA8bGludXhAYXJtbGludXgub3JnLnVrPiB3cm90 ZToKPiA+Pgo+ID4+IE9uIFRodSwgU2VwIDA3LCAyMDIzIGF0IDA4OjM2OjMyUE0gKzA3MDAsIEJh Z2FzIFNhbmpheWEgd3JvdGU6Cj4gPj4gPiBbYWxzbyBDYzogZGV2aWNldHJlZSBhbmQgQVJNIGZv bGtzXQo+ID4+ID4KPiA+PiA+IE9uIFRodSwgU2VwIDA3LCAyMDIzIGF0IDA4OjIxOjQ0QU0gKzA1 MzAsIFJhdWwgUGlwZXIgd3JvdGU6Cj4gPj4gPiA+IEhlbGxvICwKPiA+PiA+ID4gSSBhbSB0cnlp bmcgdG8gZGV0ZWN0IGFuIGkyYyBkZXZpY2UgQSBvbiBpMmMxIGxpbmUgb24gIG9uZSBvZiB0aGUg QXJtCj4gPj4gPiA+IENvcnRleCBBNyBwbGF0Zm9ybSBidXQgbm90IGFibGUgdG8gc2VlIGFueSBk ZXZpY2Ugb24gYSBnaXZlbiBhZGRyZXNzICgKPiA+PiA+ID4gMHgzZCkgLgo+ID4+ID4gPgo+ID4+ ID4gPiBJcyB0aGVyZSBhbnkgcGFyYW1ldGVycyBvZiBpMmMgd2hpY2ggaSBjYW4gY2hhbmdlIGxp a2UgcmlzZS9mYWxsIHRpbWUKPiA+PiA+ID4gLCB0aW1lb3V0IGV0YyBpbiBhIGRldmljZSB0cmVl IG9yIGtlcm5lbCBzb3VyY2UgYW5kIHJlIHRlc3QgaXQ/Cj4gPj4gPiA+IEkgaGF2ZSB0cmllZCBj aGFuZ2luZyB0aGUgaTJjIHNwZWVkIGZyb20gMTAwS0h6IHRvIDQwMCBLSHogIGJ1dCBubyBzdWNj ZXNzLgo+ID4+ID4gPiBJIGhhdmUgZXZlbiB0cmllZCByZW1vdmluZyB0aGUgMS41SyBwdWxsIHVw cyBvbiB0aGUgaTJjIGxpbmVzIGJ1dCBubyByZXN1bHQuCj4gPj4KPiA+PiBIb25lc3RseSwgZnJv bSB0aGlzIGRlc2NyaXB0aW9uLCBJJ20gd29uZGVyaW5nIGlmIHRoaXMgcG9zdGluZyBpcyBhIGpv a2UuCj4gPj4KPiA+PiBJMkMgaXMgZW50aXJlbHkgX3JlbGlhbnRfIG9uIHB1bGwtdXBzLiBJdCdz IGEgd2lyZS1vciBidXMsIGFuZCB0aGUKPiA+PiBsb2dpYyAxIHN0YXRlIGlzIGNyZWF0ZWQgYnkg bm8gZGV2aWNlIHB1bGxpbmcgdGhlIHNpZ25hbCBsb3csIHRoZXJlYnkKPiA+PiBhbGxvd2luZyB0 aGUgcHVsbC11cCByZXNpc3RvciB0byBwdWxsIHRoZSBsaW5lIHRvIHRoZSBsb2dpYyAxIHN0YXRl Lgo+ID4+Cj4gPj4gVGhlIHB1bGwtdXAgbXVzdCBiZSB0aGUgY29ycmVjdCBzdHJlbmd0aCBmb3Ig dGhlIGRldmljZXMgb24gdGhlIGJ1cy4KPiA+PiBJZiBpdCBpcyB0b28gc3Ryb25nLCB0aGVuIGEg ZHJpdmVyIG1heSBub3QgYmUgYWJsZSB0byBwdWxsIHRoZSBzaWduYWwKPiA+PiBzdWZmaWNpZW50 bHkgbG93IGZvciBvdGhlciBkZXZpY2VzIHRvIHJlZ2lzdGVyIGl0IGFzIGEgbG9naWMgMC4KPiA+ Pgo+ID4+IENvbnZlcnNlbHksIHRoZSBwdWxsLXVwIG11c3QgYmUgc3Ryb25nIGVub3VnaCBzbyB0 aGF0IHRoZSByaXNlLXRpbWUKPiA+PiBvZiB0aGUgc2lnbmFsIGlzIHN1ZmZpY2llbnQgdG8gcmVn aXN0ZXIgYXMgYSBsb2dpYyAxLgo+ID4+Cj4gPj4gSWYgaXQncyBhIHByb2JsZW0gd2l0aCB0aGUg cmlzZSB0aW1lLCB0aGVuIGluY3JlYXNpbmcgdGhlIGNsb2NrIHJhdGUKPiA+PiB3aWxsIGp1c3Qg bWFrZSB0aGUgc2l0dWF0aW9uIHdvcnNlLgo+IAo+IFdoZXJlIGNhbiBJIGNoYW5nZSB0aGlzIHRp bWU/IENhbiB5b3UgcGxlYXNlIHByb3ZpZGUgZXhhbXBsZSBvZiBzb21lCj4gZGV2aWNlL2Rldmlj ZSB0cmVlPwoKWW91IGNhbid0IGRpcmVjdGx5LiBUaGUgcmlzZSB0aW1lIGlzIGEgZnVuY3Rpb24g b2YgdGhlIGNhcGFjaXRpdmUKbG9hZGluZyBvbiB0aGUgbGluZXMgYW5kIHRoZSBwdWxsLXVwIHJl c2lzdG9yLiBJdCdzIG5vdCBhIHNvZnR3YXJlCnBhcmFtZXRlci4KCj4gPj4gU28sIGlmIG90aGVy IGRldmljZXMgd29yayBvbiB0aGUgYnVzLCBpdCBjb3VsZCBiZSB0aGF0IHRoZSBWaWwKPiA+PiB0 aHJlc2hvbGQgb2YgdGhpcyBkZXZpY2UgaXMgbm90IGJlaW5nIGFjaGlldmVkLCB3aGVyZWFzIHRo ZSBvdGhlcgo+ID4+IGRldmljZXMgYXJlIGhhcHB5LiBUaGVyZWZvcmUsIEkgd291bGQgc3VnZ2Vz dCB5b3Ugc3R1ZHkgdGhlIGRhdGEKPiA+PiBzaGVldHMgb2YgdGhlIGRldmljZSB0aGF0IGlzbid0 IGJlaW5nIGRldGVjdGVkLgo+IFdoYXQgVmlsIHRocmVzaG9sZD8gSSBjaGVja2VkIHRoZSBwb3dl ciBzdXBwbHkgdG8gdGhpcyBkZXZpY2UgYW5kIGl0Cj4gaXMgfjMuMyBWIGFzIGV4cGVjdGVkLgoK VGhpcyBtYWtlcyBtZSBjb252aW5jZWQgdGhhdCB5b3UncmUgbm90IGZhbWlsaWFyIHdpdGggZWxl Y3Ryb25pY3MuCgpWaWwgaXMgYSBwcmV0dHkgc3RhbmRhcmQgcGFyYW1ldGVyIGluIGFsbCBkaWdp dGFsIGxvZ2ljIGZvciAiVm9sdGFnZSwKaW5wdXQsIGxvdyIgLSB0aGUgdm9sdGFnZSBhdCB3aGlj aCBpdCBpcyBndWFyYW50ZWVkIHRoYXQgdGhlIGRldmljZQp3aWxsIHNlZSBhIGxvZ2ljIDAgc2ln bmFsIG9uIGl0cyBpbnB1dC4KCklmIEkgZHJhdyBhIGRpYWdyYW0gaWxsdXN0cmF0aW5nIHRoZSB2 b2x0YWdlIGxldmVscyBvbiBhbiBpbnB1dCwKdG9wIGlzIHRoZSBzdXBwbHkgdm9sdGFnZSwgYm90 dG9tIGlzIGdyb3VuZCwgdGhlbiBtb3N0IGFyZToKCgkrLS0tLS0tKwk8LS0tIFZjYyAoc3VwcGx5 IHZvbHRhZ2UpCgl8ICAgICAgfAk8LS0tIFdpdGhpbiB0aGlzIHJlZ2lvbiwgaXQgaXMgZ3VhcmFu dGVlZCB0aGF0Cgl8ICAgICAgfAkgICAgIHRoZSBkZXZpY2Ugd2lsbCBzZWUgYSBsb2dpYyAxCgkr LS0tLS0tKwk8LS0tIFZpaCAoaW5wdXQgaGlnaCkKCXwvLy8vLy98Cgl8XFxcXFxcfAk8LS0tIFdp dGhpbiB0aGlzIHJlZ2lvbiwgdGhlIHZhbHVlIHRoYXQgdGhlCgl8Ly8vLy8vfAkgICAgIGRldmlj ZSBzZWVzIGlzIGluZGV0ZXJtaW5hbnQKCXxcXFxcXFx8CgkrLS0tLS0tKwk8LS0tIFZpbCAoaW5w dXQgbG93KQoJfCAgICAgIHwKCXwgICAgICB8CgkrLS0tLS0tKwk8LS0tIEdyb3VuZCAoMFYpCgpT bywgaWYgdGhlIHZvbHRhZ2Ugb24gdGhlIFNEQSBhbmQgU0NMIHBpbnMgZG9lcyBub3QgcmVhY2gg VmlsIG9yIGJlbG93LAp0aGVyZSBpcyBubyBndWFyYW50ZWUgdGhhdCB0aGUgZGV2aWNlIHdpbGwg c2VlIGEgbG9naWMgMCBvbiBpdHMgaW5wdXQsCmFuZCBpdCBlaXRoZXIgd29uJ3Qgd29yaywgaXQg bWF5IHNwb3JhZGljYWxseSB3b3JrLiBCYXNpY2FsbHksIFZpbCBpcwp0aGUgdGhyZXNob2xkIHZv bHRhZ2UgYXQgd2hpY2ggdGhlIG1hbnVmYWN0dXJlciBfZ3VhcmFudGVlc18gdGhhdCB0aGUKZGV2 aWNlIHdpbGwgc2VlIGEgbG9naWMgMCwgYW5kIFZpaCBpcyB0aGUgdGhyZXNob2xkIHZvbHRhZ2Ug YXQgd2hpY2gKdGhlIG1hbnVmYWN0dXJlciBfZ3VhcmFudGVlc18gdGhhdCB0aGUgZGV2aWNlIHdp bGwgc2VlIGEgbG9naWMgMS4KCkJvdGggdGhlc2UgcGFyYW1ldGVycyB3aWxsIGJlIHNwZWNpZmll ZCBpbiB0aGUgZGF0YSBzaGVldCwgcG9zc2libHkKYXMgYSBmdW5jdGlvbiBvZiBzdXBwbHkgdm9s dGFnZS4KCj4gPj4gTGFzdGx5LCBpZiB0aGUgdW5kZXRlY3RhYmxlIGRldmljZSBoYXMgYSByZXNl dCBsaW5lLCBpdCdzIHBvc3NpYmxlCj4gPj4gdGhhdCB0aGUgZGV2aWNlIGlzbid0IHJlc3BvbmRp bmcgYmVjYXVzZSBpdCdzIGJlaW5nIGhlbGQgaW4gcmVzZXQuCj4gVGhlIGRldmljZSBpcyBmaW5l LCBJIGFtIHN1cmUgYWJvdXQgaXQuIEFzIHRoZSBkZXZpY2UgcHJvdmlkZXMgZGF0YSBvbgo+IFVT QVJUIGFzIHdlbGwgYW5kIEkgYW0gZ2V0dGluZyBpdC4KPiA+Cj4gPiBQbGVhc2UgdHJ5IHRvIHVz ZSBhbiBsb2dpYyBhbmFseXNlciBsaWtlIHNhbGVhZSBsb2dpYy4KPiA+IFByb2JlIHRoZSBpMmMg YnVzLCByZXNldCBsaW5lLCBwb3dlciBsaW5lcywgcGlucyB0aGF0IHNldCB0aGUgaTJjIGFkZHJl c3MgZm9yIHRoZSBkZXZpY2UuCj4gPiBDYW4gdGVsbCB1cyB3aGljaCBkZXZpY2UgaXQgaXM/Cj4g Cj4gSXRzIGEgR1BTIHNlbnNvcihzdGlsbCB1bmRlciBkZXZlbG9wbWVudCkgLkxvZ2ljIEFuYWx5 c2VyIGdpdmVzIE5BQ0sKPiBvbiB0aGUgZ2l2ZW4gYWRkcmVzcy4KCldoaWNoIG1lYW5zIGVpdGhl ciB0aGUgZGV2aWNlIGlzIG5vdCBzZWVpbmcgdGhlIGxvZ2ljIGxldmVscyBuZWNlc3NhcnkKdG8g cmVjZWl2ZSB0aGUgYWRkcmVzcywgb3IgbWF5YmUgaWYgdGhpcyBpcyBhIHByb3RvdHlwZSBJMkMg ZGV2aWNlLAptYXliZSBpdCBoYXMgYSBidWcgaW4gaXRzIGFkZHJlc3MgbWF0Y2hpbmcgbG9naWMs IG9yIHRoZSBhZGRyZXNzIGlzCmluY29ycmVjdGx5IHNldC4KCkknZCBmaXJzdCBiZSBjaGVja2lu ZyB0aGF0IHRoZSBWaWggYW5kIFZpbCBmb3IgdGhpcyBkZXZpY2UgYXJlIGJlaW5nCmFjaGlldmVk IGJ5IHB1dHRpbmcgYW4gb3NjaWxsb3Njb3BlIG9uIGl0cyBpbnB1dCBwaW4gYW5kIGNvbXBhcmlu Zwp0aGF0IHdpdGggdGhlIGRldmljZSBzcGVjaWZpY2F0aW9uLgoKLS0gClJNSydzIFBhdGNoIHN5 c3RlbTogaHR0cHM6Ly93d3cuYXJtbGludXgub3JnLnVrL2RldmVsb3Blci9wYXRjaGVzLwpGVFRQ IGlzIGhlcmUhIDgwTWJwcyBkb3duIDEwTWJwcyB1cC4gRGVjZW50IGNvbm5lY3Rpdml0eSBhdCBs YXN0IQoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KS2Vy bmVsbmV3YmllcyBtYWlsaW5nIGxpc3QKS2VybmVsbmV3Ymllc0BrZXJuZWxuZXdiaWVzLm9yZwpo dHRwczovL2xpc3RzLmtlcm5lbG5ld2JpZXMub3JnL21haWxtYW4vbGlzdGluZm8va2VybmVsbmV3 Ymllcwo= 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 A8208EC8743 for ; Thu, 7 Sep 2023 18:01:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235420AbjIGSBS (ORCPT ); Thu, 7 Sep 2023 14:01:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244058AbjIGSBR (ORCPT ); Thu, 7 Sep 2023 14:01:17 -0400 Received: from pandora.armlinux.org.uk (unknown [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 050801FCF; Thu, 7 Sep 2023 11:00:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=X4xUKnQy5Cuyq/hlcTvI9PdWU+bO5LlG1WNNbVR8IrU=; b=lleRes3stqKrEVBIpyWoQv1a+r gcuk3LwaMYPqCntIqfD62zX3R9U/uxNscQhd1wwd7tn7UfdE112nDjujBeGXAVKSObqviG4BNYL2K q3BmwOaKa5OjDUdO6MCFf6uOx+jUfqPrrh2Y9xzHwhJ2Q5ubd3NUDgyWey8OW2Z+b7CDu3zkE1E7s WrQjNXU1jxJZ30sKuLMPjb4dd8R7BuNjxvjpg1PNctN6zBnCBn/iIv74WZJSNsz9W/TXCS692xvxk GpoZnI9Csrhw6/ExpTYX1kHfafdv2PaGIhuQGz7qWsqqVik+dlGjAtgpA54Ro/eVtauQY/r8FIIBx e24awPug==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:36672) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qeJJ7-0004BF-0b; Thu, 07 Sep 2023 19:00:45 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qeJJ6-000639-R6; Thu, 07 Sep 2023 19:00:44 +0100 Date: Thu, 7 Sep 2023 19:00:44 +0100 From: "Russell King (Oracle)" To: Raul Piper Cc: tanure@linux.com, Bagas Sanjaya , Linux Devicetree , Conor Dooley , Andi Shyti , kernelnewbies , Linus Walleij , LKML , Rob Herring , Linux I2C , Krzysztof Kozlowski , Linux ARM Subject: Re: Debugging i2c : i2cdetect cant detect a device on i2c line Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On Thu, Sep 07, 2023 at 10:38:10PM +0530, Raul Piper wrote: > On Thu, Sep 7, 2023 at 9:47 PM Lucas Tanure wrote: > > > > > > > > On Thu, 7 Sept 2023, 14:56 Russell King (Oracle), wrote: > >> > >> On Thu, Sep 07, 2023 at 08:36:32PM +0700, Bagas Sanjaya wrote: > >> > [also Cc: devicetree and ARM folks] > >> > > >> > On Thu, Sep 07, 2023 at 08:21:44AM +0530, Raul Piper wrote: > >> > > Hello , > >> > > I am trying to detect an i2c device A on i2c1 line on one of the Arm > >> > > Cortex A7 platform but not able to see any device on a given address ( > >> > > 0x3d) . > >> > > > >> > > Is there any parameters of i2c which i can change like rise/fall time > >> > > , timeout etc in a device tree or kernel source and re test it? > >> > > I have tried changing the i2c speed from 100KHz to 400 KHz but no success. > >> > > I have even tried removing the 1.5K pull ups on the i2c lines but no result. > >> > >> Honestly, from this description, I'm wondering if this posting is a joke. > >> > >> I2C is entirely _reliant_ on pull-ups. It's a wire-or bus, and the > >> logic 1 state is created by no device pulling the signal low, thereby > >> allowing the pull-up resistor to pull the line to the logic 1 state. > >> > >> The pull-up must be the correct strength for the devices on the bus. > >> If it is too strong, then a driver may not be able to pull the signal > >> sufficiently low for other devices to register it as a logic 0. > >> > >> Conversely, the pull-up must be strong enough so that the rise-time > >> of the signal is sufficient to register as a logic 1. > >> > >> If it's a problem with the rise time, then increasing the clock rate > >> will just make the situation worse. > > Where can I change this time? Can you please provide example of some > device/device tree? You can't directly. The rise time is a function of the capacitive loading on the lines and the pull-up resistor. It's not a software parameter. > >> So, if other devices work on the bus, it could be that the Vil > >> threshold of this device is not being achieved, whereas the other > >> devices are happy. Therefore, I would suggest you study the data > >> sheets of the device that isn't being detected. > What Vil threshold? I checked the power supply to this device and it > is ~3.3 V as expected. This makes me convinced that you're not familiar with electronics. Vil is a pretty standard parameter in all digital logic for "Voltage, input, low" - the voltage at which it is guaranteed that the device will see a logic 0 signal on its input. If I draw a diagram illustrating the voltage levels on an input, top is the supply voltage, bottom is ground, then most are: +------+ <--- Vcc (supply voltage) | | <--- Within this region, it is guaranteed that | | the device will see a logic 1 +------+ <--- Vih (input high) |//////| |\\\\\\| <--- Within this region, the value that the |//////| device sees is indeterminant |\\\\\\| +------+ <--- Vil (input low) | | | | +------+ <--- Ground (0V) So, if the voltage on the SDA and SCL pins does not reach Vil or below, there is no guarantee that the device will see a logic 0 on its input, and it either won't work, it may sporadically work. Basically, Vil is the threshold voltage at which the manufacturer _guarantees_ that the device will see a logic 0, and Vih is the threshold voltage at which the manufacturer _guarantees_ that the device will see a logic 1. Both these parameters will be specified in the data sheet, possibly as a function of supply voltage. > >> Lastly, if the undetectable device has a reset line, it's possible > >> that the device isn't responding because it's being held in reset. > The device is fine, I am sure about it. As the device provides data on > USART as well and I am getting it. > > > > Please try to use an logic analyser like saleae logic. > > Probe the i2c bus, reset line, power lines, pins that set the i2c address for the device. > > Can tell us which device it is? > > Its a GPS sensor(still under development) .Logic Analyser gives NACK > on the given address. Which means either the device is not seeing the logic levels necessary to receive the address, or maybe if this is a prototype I2C device, maybe it has a bug in its address matching logic, or the address is incorrectly set. I'd first be checking that the Vih and Vil for this device are being achieved by putting an oscilloscope on its input pin and comparing that with the device specification. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9A92CEC874C for ; Thu, 7 Sep 2023 18:01:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aY7DeMcsHAhPFh56MtbDkFZx2ygPEKzup1B6+rkotWo=; b=iaSOFU8haolsbG G9M2tpR9y9mDVo1iDnhM6khTFzf+Xw4qT8ZOpuuWMk7iuAsquKxm7bNahLOiqvspj02StRjXZMczC +WR6GYUQIVZNAI7KX5a6O5nc1eD25eh47av+vkzqjttj61il9RZwVwWefo3+ID6jfb6ICwYZoQCqk R4cxaz6LbIVgt/XCUDHXaT82R5aDXT5xmpJPRVjndieiRDldpGArVgleEc/Es35sod0Tjkp1iE+nx zAUKGzer7twYmthvnzwXRSGbZLmU8EOvIU5Xr5/UcpUfYJ8CsU5Vas4KsXfwukVSFvhd5vrKZnVkB DpK2vkpBvqOhXAgKIEgQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qeJJP-00CWCL-2V; Thu, 07 Sep 2023 18:01:03 +0000 Received: from [2001:4d48:ad52:32c8:5054:ff:fe00:142] (helo=pandora.armlinux.org.uk) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qeJJM-00CWBO-1o for linux-arm-kernel@lists.infradead.org; Thu, 07 Sep 2023 18:01:02 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=X4xUKnQy5Cuyq/hlcTvI9PdWU+bO5LlG1WNNbVR8IrU=; b=lleRes3stqKrEVBIpyWoQv1a+r gcuk3LwaMYPqCntIqfD62zX3R9U/uxNscQhd1wwd7tn7UfdE112nDjujBeGXAVKSObqviG4BNYL2K q3BmwOaKa5OjDUdO6MCFf6uOx+jUfqPrrh2Y9xzHwhJ2Q5ubd3NUDgyWey8OW2Z+b7CDu3zkE1E7s WrQjNXU1jxJZ30sKuLMPjb4dd8R7BuNjxvjpg1PNctN6zBnCBn/iIv74WZJSNsz9W/TXCS692xvxk GpoZnI9Csrhw6/ExpTYX1kHfafdv2PaGIhuQGz7qWsqqVik+dlGjAtgpA54Ro/eVtauQY/r8FIIBx e24awPug==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:36672) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qeJJ7-0004BF-0b; Thu, 07 Sep 2023 19:00:45 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qeJJ6-000639-R6; Thu, 07 Sep 2023 19:00:44 +0100 Date: Thu, 7 Sep 2023 19:00:44 +0100 From: "Russell King (Oracle)" To: Raul Piper Cc: tanure@linux.com, Bagas Sanjaya , Linux Devicetree , Conor Dooley , Andi Shyti , kernelnewbies , Linus Walleij , LKML , Rob Herring , Linux I2C , Krzysztof Kozlowski , Linux ARM Subject: Re: Debugging i2c : i2cdetect cant detect a device on i2c line Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230907_110100_604458_BB1E1179 X-CRM114-Status: GOOD ( 44.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gVGh1LCBTZXAgMDcsIDIwMjMgYXQgMTA6Mzg6MTBQTSArMDUzMCwgUmF1bCBQaXBlciB3cm90 ZToKPiBPbiBUaHUsIFNlcCA3LCAyMDIzIGF0IDk6NDfigK9QTSBMdWNhcyBUYW51cmUgPHRhbnVy ZUBsaW51eC5jb20+IHdyb3RlOgo+ID4KPiA+Cj4gPgo+ID4gT24gVGh1LCA3IFNlcHQgMjAyMywg MTQ6NTYgUnVzc2VsbCBLaW5nIChPcmFjbGUpLCA8bGludXhAYXJtbGludXgub3JnLnVrPiB3cm90 ZToKPiA+Pgo+ID4+IE9uIFRodSwgU2VwIDA3LCAyMDIzIGF0IDA4OjM2OjMyUE0gKzA3MDAsIEJh Z2FzIFNhbmpheWEgd3JvdGU6Cj4gPj4gPiBbYWxzbyBDYzogZGV2aWNldHJlZSBhbmQgQVJNIGZv bGtzXQo+ID4+ID4KPiA+PiA+IE9uIFRodSwgU2VwIDA3LCAyMDIzIGF0IDA4OjIxOjQ0QU0gKzA1 MzAsIFJhdWwgUGlwZXIgd3JvdGU6Cj4gPj4gPiA+IEhlbGxvICwKPiA+PiA+ID4gSSBhbSB0cnlp bmcgdG8gZGV0ZWN0IGFuIGkyYyBkZXZpY2UgQSBvbiBpMmMxIGxpbmUgb24gIG9uZSBvZiB0aGUg QXJtCj4gPj4gPiA+IENvcnRleCBBNyBwbGF0Zm9ybSBidXQgbm90IGFibGUgdG8gc2VlIGFueSBk ZXZpY2Ugb24gYSBnaXZlbiBhZGRyZXNzICgKPiA+PiA+ID4gMHgzZCkgLgo+ID4+ID4gPgo+ID4+ ID4gPiBJcyB0aGVyZSBhbnkgcGFyYW1ldGVycyBvZiBpMmMgd2hpY2ggaSBjYW4gY2hhbmdlIGxp a2UgcmlzZS9mYWxsIHRpbWUKPiA+PiA+ID4gLCB0aW1lb3V0IGV0YyBpbiBhIGRldmljZSB0cmVl IG9yIGtlcm5lbCBzb3VyY2UgYW5kIHJlIHRlc3QgaXQ/Cj4gPj4gPiA+IEkgaGF2ZSB0cmllZCBj aGFuZ2luZyB0aGUgaTJjIHNwZWVkIGZyb20gMTAwS0h6IHRvIDQwMCBLSHogIGJ1dCBubyBzdWNj ZXNzLgo+ID4+ID4gPiBJIGhhdmUgZXZlbiB0cmllZCByZW1vdmluZyB0aGUgMS41SyBwdWxsIHVw cyBvbiB0aGUgaTJjIGxpbmVzIGJ1dCBubyByZXN1bHQuCj4gPj4KPiA+PiBIb25lc3RseSwgZnJv bSB0aGlzIGRlc2NyaXB0aW9uLCBJJ20gd29uZGVyaW5nIGlmIHRoaXMgcG9zdGluZyBpcyBhIGpv a2UuCj4gPj4KPiA+PiBJMkMgaXMgZW50aXJlbHkgX3JlbGlhbnRfIG9uIHB1bGwtdXBzLiBJdCdz IGEgd2lyZS1vciBidXMsIGFuZCB0aGUKPiA+PiBsb2dpYyAxIHN0YXRlIGlzIGNyZWF0ZWQgYnkg bm8gZGV2aWNlIHB1bGxpbmcgdGhlIHNpZ25hbCBsb3csIHRoZXJlYnkKPiA+PiBhbGxvd2luZyB0 aGUgcHVsbC11cCByZXNpc3RvciB0byBwdWxsIHRoZSBsaW5lIHRvIHRoZSBsb2dpYyAxIHN0YXRl Lgo+ID4+Cj4gPj4gVGhlIHB1bGwtdXAgbXVzdCBiZSB0aGUgY29ycmVjdCBzdHJlbmd0aCBmb3Ig dGhlIGRldmljZXMgb24gdGhlIGJ1cy4KPiA+PiBJZiBpdCBpcyB0b28gc3Ryb25nLCB0aGVuIGEg ZHJpdmVyIG1heSBub3QgYmUgYWJsZSB0byBwdWxsIHRoZSBzaWduYWwKPiA+PiBzdWZmaWNpZW50 bHkgbG93IGZvciBvdGhlciBkZXZpY2VzIHRvIHJlZ2lzdGVyIGl0IGFzIGEgbG9naWMgMC4KPiA+ Pgo+ID4+IENvbnZlcnNlbHksIHRoZSBwdWxsLXVwIG11c3QgYmUgc3Ryb25nIGVub3VnaCBzbyB0 aGF0IHRoZSByaXNlLXRpbWUKPiA+PiBvZiB0aGUgc2lnbmFsIGlzIHN1ZmZpY2llbnQgdG8gcmVn aXN0ZXIgYXMgYSBsb2dpYyAxLgo+ID4+Cj4gPj4gSWYgaXQncyBhIHByb2JsZW0gd2l0aCB0aGUg cmlzZSB0aW1lLCB0aGVuIGluY3JlYXNpbmcgdGhlIGNsb2NrIHJhdGUKPiA+PiB3aWxsIGp1c3Qg bWFrZSB0aGUgc2l0dWF0aW9uIHdvcnNlLgo+IAo+IFdoZXJlIGNhbiBJIGNoYW5nZSB0aGlzIHRp bWU/IENhbiB5b3UgcGxlYXNlIHByb3ZpZGUgZXhhbXBsZSBvZiBzb21lCj4gZGV2aWNlL2Rldmlj ZSB0cmVlPwoKWW91IGNhbid0IGRpcmVjdGx5LiBUaGUgcmlzZSB0aW1lIGlzIGEgZnVuY3Rpb24g b2YgdGhlIGNhcGFjaXRpdmUKbG9hZGluZyBvbiB0aGUgbGluZXMgYW5kIHRoZSBwdWxsLXVwIHJl c2lzdG9yLiBJdCdzIG5vdCBhIHNvZnR3YXJlCnBhcmFtZXRlci4KCj4gPj4gU28sIGlmIG90aGVy IGRldmljZXMgd29yayBvbiB0aGUgYnVzLCBpdCBjb3VsZCBiZSB0aGF0IHRoZSBWaWwKPiA+PiB0 aHJlc2hvbGQgb2YgdGhpcyBkZXZpY2UgaXMgbm90IGJlaW5nIGFjaGlldmVkLCB3aGVyZWFzIHRo ZSBvdGhlcgo+ID4+IGRldmljZXMgYXJlIGhhcHB5LiBUaGVyZWZvcmUsIEkgd291bGQgc3VnZ2Vz dCB5b3Ugc3R1ZHkgdGhlIGRhdGEKPiA+PiBzaGVldHMgb2YgdGhlIGRldmljZSB0aGF0IGlzbid0 IGJlaW5nIGRldGVjdGVkLgo+IFdoYXQgVmlsIHRocmVzaG9sZD8gSSBjaGVja2VkIHRoZSBwb3dl ciBzdXBwbHkgdG8gdGhpcyBkZXZpY2UgYW5kIGl0Cj4gaXMgfjMuMyBWIGFzIGV4cGVjdGVkLgoK VGhpcyBtYWtlcyBtZSBjb252aW5jZWQgdGhhdCB5b3UncmUgbm90IGZhbWlsaWFyIHdpdGggZWxl Y3Ryb25pY3MuCgpWaWwgaXMgYSBwcmV0dHkgc3RhbmRhcmQgcGFyYW1ldGVyIGluIGFsbCBkaWdp dGFsIGxvZ2ljIGZvciAiVm9sdGFnZSwKaW5wdXQsIGxvdyIgLSB0aGUgdm9sdGFnZSBhdCB3aGlj aCBpdCBpcyBndWFyYW50ZWVkIHRoYXQgdGhlIGRldmljZQp3aWxsIHNlZSBhIGxvZ2ljIDAgc2ln bmFsIG9uIGl0cyBpbnB1dC4KCklmIEkgZHJhdyBhIGRpYWdyYW0gaWxsdXN0cmF0aW5nIHRoZSB2 b2x0YWdlIGxldmVscyBvbiBhbiBpbnB1dCwKdG9wIGlzIHRoZSBzdXBwbHkgdm9sdGFnZSwgYm90 dG9tIGlzIGdyb3VuZCwgdGhlbiBtb3N0IGFyZToKCgkrLS0tLS0tKwk8LS0tIFZjYyAoc3VwcGx5 IHZvbHRhZ2UpCgl8ICAgICAgfAk8LS0tIFdpdGhpbiB0aGlzIHJlZ2lvbiwgaXQgaXMgZ3VhcmFu dGVlZCB0aGF0Cgl8ICAgICAgfAkgICAgIHRoZSBkZXZpY2Ugd2lsbCBzZWUgYSBsb2dpYyAxCgkr LS0tLS0tKwk8LS0tIFZpaCAoaW5wdXQgaGlnaCkKCXwvLy8vLy98Cgl8XFxcXFxcfAk8LS0tIFdp dGhpbiB0aGlzIHJlZ2lvbiwgdGhlIHZhbHVlIHRoYXQgdGhlCgl8Ly8vLy8vfAkgICAgIGRldmlj ZSBzZWVzIGlzIGluZGV0ZXJtaW5hbnQKCXxcXFxcXFx8CgkrLS0tLS0tKwk8LS0tIFZpbCAoaW5w dXQgbG93KQoJfCAgICAgIHwKCXwgICAgICB8CgkrLS0tLS0tKwk8LS0tIEdyb3VuZCAoMFYpCgpT bywgaWYgdGhlIHZvbHRhZ2Ugb24gdGhlIFNEQSBhbmQgU0NMIHBpbnMgZG9lcyBub3QgcmVhY2gg VmlsIG9yIGJlbG93LAp0aGVyZSBpcyBubyBndWFyYW50ZWUgdGhhdCB0aGUgZGV2aWNlIHdpbGwg c2VlIGEgbG9naWMgMCBvbiBpdHMgaW5wdXQsCmFuZCBpdCBlaXRoZXIgd29uJ3Qgd29yaywgaXQg bWF5IHNwb3JhZGljYWxseSB3b3JrLiBCYXNpY2FsbHksIFZpbCBpcwp0aGUgdGhyZXNob2xkIHZv bHRhZ2UgYXQgd2hpY2ggdGhlIG1hbnVmYWN0dXJlciBfZ3VhcmFudGVlc18gdGhhdCB0aGUKZGV2 aWNlIHdpbGwgc2VlIGEgbG9naWMgMCwgYW5kIFZpaCBpcyB0aGUgdGhyZXNob2xkIHZvbHRhZ2Ug YXQgd2hpY2gKdGhlIG1hbnVmYWN0dXJlciBfZ3VhcmFudGVlc18gdGhhdCB0aGUgZGV2aWNlIHdp bGwgc2VlIGEgbG9naWMgMS4KCkJvdGggdGhlc2UgcGFyYW1ldGVycyB3aWxsIGJlIHNwZWNpZmll ZCBpbiB0aGUgZGF0YSBzaGVldCwgcG9zc2libHkKYXMgYSBmdW5jdGlvbiBvZiBzdXBwbHkgdm9s dGFnZS4KCj4gPj4gTGFzdGx5LCBpZiB0aGUgdW5kZXRlY3RhYmxlIGRldmljZSBoYXMgYSByZXNl dCBsaW5lLCBpdCdzIHBvc3NpYmxlCj4gPj4gdGhhdCB0aGUgZGV2aWNlIGlzbid0IHJlc3BvbmRp bmcgYmVjYXVzZSBpdCdzIGJlaW5nIGhlbGQgaW4gcmVzZXQuCj4gVGhlIGRldmljZSBpcyBmaW5l LCBJIGFtIHN1cmUgYWJvdXQgaXQuIEFzIHRoZSBkZXZpY2UgcHJvdmlkZXMgZGF0YSBvbgo+IFVT QVJUIGFzIHdlbGwgYW5kIEkgYW0gZ2V0dGluZyBpdC4KPiA+Cj4gPiBQbGVhc2UgdHJ5IHRvIHVz ZSBhbiBsb2dpYyBhbmFseXNlciBsaWtlIHNhbGVhZSBsb2dpYy4KPiA+IFByb2JlIHRoZSBpMmMg YnVzLCByZXNldCBsaW5lLCBwb3dlciBsaW5lcywgcGlucyB0aGF0IHNldCB0aGUgaTJjIGFkZHJl c3MgZm9yIHRoZSBkZXZpY2UuCj4gPiBDYW4gdGVsbCB1cyB3aGljaCBkZXZpY2UgaXQgaXM/Cj4g Cj4gSXRzIGEgR1BTIHNlbnNvcihzdGlsbCB1bmRlciBkZXZlbG9wbWVudCkgLkxvZ2ljIEFuYWx5 c2VyIGdpdmVzIE5BQ0sKPiBvbiB0aGUgZ2l2ZW4gYWRkcmVzcy4KCldoaWNoIG1lYW5zIGVpdGhl ciB0aGUgZGV2aWNlIGlzIG5vdCBzZWVpbmcgdGhlIGxvZ2ljIGxldmVscyBuZWNlc3NhcnkKdG8g cmVjZWl2ZSB0aGUgYWRkcmVzcywgb3IgbWF5YmUgaWYgdGhpcyBpcyBhIHByb3RvdHlwZSBJMkMg ZGV2aWNlLAptYXliZSBpdCBoYXMgYSBidWcgaW4gaXRzIGFkZHJlc3MgbWF0Y2hpbmcgbG9naWMs IG9yIHRoZSBhZGRyZXNzIGlzCmluY29ycmVjdGx5IHNldC4KCkknZCBmaXJzdCBiZSBjaGVja2lu ZyB0aGF0IHRoZSBWaWggYW5kIFZpbCBmb3IgdGhpcyBkZXZpY2UgYXJlIGJlaW5nCmFjaGlldmVk IGJ5IHB1dHRpbmcgYW4gb3NjaWxsb3Njb3BlIG9uIGl0cyBpbnB1dCBwaW4gYW5kIGNvbXBhcmlu Zwp0aGF0IHdpdGggdGhlIGRldmljZSBzcGVjaWZpY2F0aW9uLgoKLS0gClJNSydzIFBhdGNoIHN5 c3RlbTogaHR0cHM6Ly93d3cuYXJtbGludXgub3JnLnVrL2RldmVsb3Blci9wYXRjaGVzLwpGVFRQ IGlzIGhlcmUhIDgwTWJwcyBkb3duIDEwTWJwcyB1cC4gRGVjZW50IGNvbm5lY3Rpdml0eSBhdCBs YXN0IQoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbGlu dXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5pbmZyYWRl YWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgt YXJtLWtlcm5lbAo=