From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregory.clement@bootlin.com (Gregory CLEMENT) Date: Mon, 05 Mar 2018 16:48:54 +0100 Subject: [PATCH 1/2] ARM: dts: armada388-clearfog: increase speed of i2c0 to 400kHz In-Reply-To: (Russell King's message of "Tue, 27 Feb 2018 16:01:57 +0000") References: <20180227160135.GU9418@n2100.armlinux.org.uk> Message-ID: <87d10i5xqx.fsf@bootlin.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Russell, On mar., f?vr. 27 2018, Russell King wrote: > All the devices on I2C0 support fast mode, so increase the bus speed > to match. I agree with this part. I didn't pay attention to it in the initial submission but now I've checked it, and indeed according to the datasheet the MCP3021 support "standard (100 kHz) and Fast (400 kHz) I2C Compatible modes" > The Armada 388 is known to have a timing issue when in > standard mode, which we believe causes the ficticious device at 0x64 > to appear. This errata "FE-8471889 I2C Repeated Start is not supported in standard mode (up to 100K)" was supposed to be fixed with the commit c1d15b68aab8 ("i2c: mv64xxx: Fix timing issue on Armada XP (errata FE-8471889)"). And it was used on the Armada 38x SoCs since fbffee74986c ("ARM: dts: Fix I2C repeated start issue on Armada-38x") in 4.14. So I think that now even at 100kHz the ficticious device should not appear any more. If it is still the case then there might be an issue with the fix in the 2c driver. Gregory > > Signed-off-by: Russell King > --- > arch/arm/boot/dts/armada-388-clearfog.dtsi | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/boot/dts/armada-388-clearfog.dtsi b/arch/arm/boot/dts/armada-388-clearfog.dtsi > index 68acfc968706..0e3b1f140e6d 100644 > --- a/arch/arm/boot/dts/armada-388-clearfog.dtsi > +++ b/arch/arm/boot/dts/armada-388-clearfog.dtsi > @@ -143,8 +143,7 @@ > }; > > &i2c0 { > - /* Is there anything on this? */ > - clock-frequency = <100000>; > + clock-frequency = <400000>; > pinctrl-0 = <&i2c0_pins>; > pinctrl-names = "default"; > status = "okay"; > @@ -239,13 +238,11 @@ > }; > }; > > - /* The MCP3021 is 100kHz clock only */ > + /* The MCP3021 supports standard and fast modes */ > mikrobus_adc: mcp3021 at 4c { > compatible = "microchip,mcp3021"; > reg = <0x4c>; > }; > - > - /* Also something at 0x64 */ > }; > > &i2c1 { > -- > 2.7.4 > -- Gregory Clement, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering http://bootlin.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gregory CLEMENT Subject: Re: [PATCH 1/2] ARM: dts: armada388-clearfog: increase speed of i2c0 to 400kHz Date: Mon, 05 Mar 2018 16:48:54 +0100 Message-ID: <87d10i5xqx.fsf@bootlin.com> References: <20180227160135.GU9418@n2100.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: (Russell King's message of "Tue, 27 Feb 2018 16:01:57 +0000") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Russell King Cc: Mark Rutland , Andrew Lunn , Jason Cooper , devicetree@vger.kernel.org, Rob Herring , Gregory Clement , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth List-Id: devicetree@vger.kernel.org SGkgUnVzc2VsbCwKIAogT24gbWFyLiwgZsOpdnIuIDI3IDIwMTgsIFJ1c3NlbGwgS2luZyA8cm1r K2tlcm5lbEBhcm1saW51eC5vcmcudWs+IHdyb3RlOgoKPiBBbGwgdGhlIGRldmljZXMgb24gSTJD MCBzdXBwb3J0IGZhc3QgbW9kZSwgc28gaW5jcmVhc2UgdGhlIGJ1cyBzcGVlZAo+IHRvIG1hdGNo LgoKSSBhZ3JlZSB3aXRoIHRoaXMgcGFydC4gSSBkaWRuJ3QgcGF5IGF0dGVudGlvbiB0byBpdCBp biB0aGUgaW5pdGlhbApzdWJtaXNzaW9uIGJ1dCBub3cgSSd2ZSBjaGVja2VkIGl0LCBhbmQgaW5k ZWVkIGFjY29yZGluZyB0byB0aGUKZGF0YXNoZWV0IHRoZSBNQ1AzMDIxIHN1cHBvcnQgInN0YW5k YXJkICgxMDAga0h6KSBhbmQgRmFzdCAoNDAwIGtIeikgSTJDCkNvbXBhdGlibGUgbW9kZXMiCgo+ IFRoZSBBcm1hZGEgMzg4IGlzIGtub3duIHRvIGhhdmUgYSB0aW1pbmcgaXNzdWUgd2hlbiBpbgo+ IHN0YW5kYXJkIG1vZGUsIHdoaWNoIHdlIGJlbGlldmUgY2F1c2VzIHRoZSBmaWN0aWNpb3VzIGRl dmljZSBhdCAweDY0Cj4gdG8gYXBwZWFyLgoKVGhpcyBlcnJhdGEgIkZFLTg0NzE4ODkgSTJDIFJl cGVhdGVkIFN0YXJ0IGlzIG5vdCBzdXBwb3J0ZWQgaW4gc3RhbmRhcmQKbW9kZSAodXAgdG8gMTAw SykiIHdhcyBzdXBwb3NlZCB0byBiZSBmaXhlZCB3aXRoIHRoZSBjb21taXQgYzFkMTViNjhhYWI4 CigiaTJjOiBtdjY0eHh4OiBGaXggdGltaW5nIGlzc3VlIG9uIEFybWFkYSBYUCAoZXJyYXRhIEZF LTg0NzE4ODkpIikuIEFuZAppdCB3YXMgdXNlZCBvbiB0aGUgQXJtYWRhIDM4eCBTb0NzIHNpbmNl IGZiZmZlZTc0OTg2YyAoIkFSTTogZHRzOiBGaXggSTJDCnJlcGVhdGVkIHN0YXJ0IGlzc3VlIG9u IEFybWFkYS0zOHgiKSBpbiA0LjE0LgoKU28gSSB0aGluayB0aGF0IG5vdyBldmVuIGF0IDEwMGtI eiB0aGUgZmljdGljaW91cyBkZXZpY2Ugc2hvdWxkIG5vdAphcHBlYXIgYW55IG1vcmUuIElmIGl0 IGlzIHN0aWxsIHRoZSBjYXNlIHRoZW4gdGhlcmUgbWlnaHQgYmUgYW4gaXNzdWUKd2l0aCB0aGUg Zml4IGluIHRoZSAyYyBkcml2ZXIuCgpHcmVnb3J5Cgo+Cj4gU2lnbmVkLW9mZi1ieTogUnVzc2Vs bCBLaW5nIDxybWsra2VybmVsQGFybWxpbnV4Lm9yZy51az4KPiAtLS0KPiAgYXJjaC9hcm0vYm9v dC9kdHMvYXJtYWRhLTM4OC1jbGVhcmZvZy5kdHNpIHwgNyArKy0tLS0tCj4gIDEgZmlsZSBjaGFu Z2VkLCAyIGluc2VydGlvbnMoKyksIDUgZGVsZXRpb25zKC0pCj4KPiBkaWZmIC0tZ2l0IGEvYXJj aC9hcm0vYm9vdC9kdHMvYXJtYWRhLTM4OC1jbGVhcmZvZy5kdHNpIGIvYXJjaC9hcm0vYm9vdC9k dHMvYXJtYWRhLTM4OC1jbGVhcmZvZy5kdHNpCj4gaW5kZXggNjhhY2ZjOTY4NzA2Li4wZTNiMWYx NDBlNmQgMTAwNjQ0Cj4gLS0tIGEvYXJjaC9hcm0vYm9vdC9kdHMvYXJtYWRhLTM4OC1jbGVhcmZv Zy5kdHNpCj4gKysrIGIvYXJjaC9hcm0vYm9vdC9kdHMvYXJtYWRhLTM4OC1jbGVhcmZvZy5kdHNp Cj4gQEAgLTE0Myw4ICsxNDMsNyBAQAo+ICB9Owo+ICAKPiAgJmkyYzAgewo+IC0JLyogSXMgdGhl cmUgYW55dGhpbmcgb24gdGhpcz8gKi8KPiAtCWNsb2NrLWZyZXF1ZW5jeSA9IDwxMDAwMDA+Owo+ ICsJY2xvY2stZnJlcXVlbmN5ID0gPDQwMDAwMD47Cj4gIAlwaW5jdHJsLTAgPSA8JmkyYzBfcGlu cz47Cj4gIAlwaW5jdHJsLW5hbWVzID0gImRlZmF1bHQiOwo+ICAJc3RhdHVzID0gIm9rYXkiOwo+ IEBAIC0yMzksMTMgKzIzOCwxMSBAQAo+ICAJCX07Cj4gIAl9Owo+ICAKPiAtCS8qIFRoZSBNQ1Az MDIxIGlzIDEwMGtIeiBjbG9jayBvbmx5ICovCj4gKwkvKiBUaGUgTUNQMzAyMSBzdXBwb3J0cyBz dGFuZGFyZCBhbmQgZmFzdCBtb2RlcyAqLwo+ICAJbWlrcm9idXNfYWRjOiBtY3AzMDIxQDRjIHsK PiAgCQljb21wYXRpYmxlID0gIm1pY3JvY2hpcCxtY3AzMDIxIjsKPiAgCQlyZWcgPSA8MHg0Yz47 Cj4gIAl9Owo+IC0KPiAtCS8qIEFsc28gc29tZXRoaW5nIGF0IDB4NjQgKi8KPiAgfTsKPiAgCj4g ICZpMmMxIHsKPiAtLSAKPiAyLjcuNAo+CgotLSAKR3JlZ29yeSBDbGVtZW50LCBCb290bGluIChm b3JtZXJseSBGcmVlIEVsZWN0cm9ucykKRW1iZWRkZWQgTGludXggYW5kIEtlcm5lbCBlbmdpbmVl cmluZwpodHRwOi8vYm9vdGxpbi5jb20KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFpbGluZyBsaXN0CmxpbnV4LWFybS1r ZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWls bWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK