From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: [RFT] i2c: algos: bit: prepare/unprepare before sending initial STOP Date: Fri, 15 Jun 2018 14:17:23 +0900 Message-ID: <20180615051723.7193-1-wsa+renesas@sang-engineering.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: linux-i2c@vger.kernel.org, cerg2010cerg2010@mail.ru Cc: linux-renesas-soc@vger.kernel.org, Wolfram Sang , dri-devel@lists.freedesktop.org List-Id: linux-i2c@vger.kernel.org U29tZSBhZGFwdGVycyBuZWVkIHRvIGJlIHByZXBhcmVkL3VucHJlcGFyZWQgYmVmb3JlIGJpdGJh bmdpbmcgdGhlIGJ1cy4KRG8gdGhpcyBmb3IgdGhlIGluaXRpYWwgU1RPUCwgdG9vLgoKU2lnbmVk LW9mZi1ieTogV29sZnJhbSBTYW5nIDx3c2ErcmVuZXNhc0BzYW5nLWVuZ2luZWVyaW5nLmNvbT4K LS0tCgpPaywgYW5vdGhlciBpZGVhIHRvIGZpeCB0aGUgcmVncmVzc2lvbi4gSSdtIG5vdCAxMDAl IHN1cmUgaWYgdGhlIHBsYWNlbWVudCBpcwpwZXJmZWN0LCBidXQgaXQgc2hvdWxkIHNlcnZlIHdl bGwgZW5vdWdoIGFzIGEgcHJvb2Ygb2YgY29uY2VwdCB0byBzZWUgaWYgdGhpcwppcyB0aGUgYWN0 dWFsIGlzc3VlLiBJdCBsb29rcyBwcm9taXNpbmcsIHRob3VnaC4KCiBkcml2ZXJzL2kyYy9hbGdv cy9pMmMtYWxnby1iaXQuYyB8IDkgKysrKysrKysrCiAxIGZpbGUgY2hhbmdlZCwgOSBpbnNlcnRp b25zKCspCgpkaWZmIC0tZ2l0IGEvZHJpdmVycy9pMmMvYWxnb3MvaTJjLWFsZ28tYml0LmMgYi9k cml2ZXJzL2kyYy9hbGdvcy9pMmMtYWxnby1iaXQuYwppbmRleCA0YTM0ZjMxMWUxZmYuLmZhYjQ0 MzdlY2JiNSAxMDA2NDQKLS0tIGEvZHJpdmVycy9pMmMvYWxnb3MvaTJjLWFsZ28tYml0LmMKKysr IGIvZHJpdmVycy9pMmMvYWxnb3MvaTJjLWFsZ28tYml0LmMKQEAgLTY0OCwxMCArNjQ4LDE5IEBA IHN0YXRpYyBpbnQgX19pMmNfYml0X2FkZF9idXMoc3RydWN0IGkyY19hZGFwdGVyICphZGFwLAog CQlhZGFwLT5xdWlya3MgPSAmaTJjX2JpdF9xdWlya19ub19jbGtfc3RyZXRjaDsKIAogCS8qIEJy aW5nIGJ1cyB0byBhIGtub3duIHN0YXRlLiBMb29rcyBsaWtlIFNUT1AgaWYgYnVzIGlzIG5vdCBm cmVlIHlldCAqLworCWlmIChiaXRfYWRhcC0+cHJlX3hmZXIpIHsKKwkJcmV0ID0gYml0X2FkYXAt PnByZV94ZmVyKGFkYXApOworCQlpZiAocmV0IDwgMCkKKwkJCXJldHVybiByZXQ7CisJfQorCiAJ c2V0c2NsKGJpdF9hZGFwLCAxKTsKIAl1ZGVsYXkoYml0X2FkYXAtPnVkZWxheSk7CiAJc2V0c2Rh KGJpdF9hZGFwLCAxKTsKIAorCWlmIChiaXRfYWRhcC0+cG9zdF94ZmVyKQorCQliaXRfYWRhcC0+ cG9zdF94ZmVyKGFkYXApOworCiAJcmV0ID0gYWRkX2FkYXB0ZXIoYWRhcCk7CiAJaWYgKHJldCA8 IDApCiAJCXJldHVybiByZXQ7Ci0tIAoyLjExLjAKCl9fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxp c3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFu L2xpc3RpbmZvL2RyaS1kZXZlbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sauhun.de ([88.99.104.3]:55344 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754165AbeFOFRs (ORCPT ); Fri, 15 Jun 2018 01:17:48 -0400 From: Wolfram Sang To: linux-i2c@vger.kernel.org, cerg2010cerg2010@mail.ru Cc: linux-renesas-soc@vger.kernel.org, dri-devel@lists.freedesktop.org, Wolfram Sang Subject: [RFT] i2c: algos: bit: prepare/unprepare before sending initial STOP Date: Fri, 15 Jun 2018 14:17:23 +0900 Message-Id: <20180615051723.7193-1-wsa+renesas@sang-engineering.com> Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: Some adapters need to be prepared/unprepared before bitbanging the bus. Do this for the initial STOP, too. Signed-off-by: Wolfram Sang --- Ok, another idea to fix the regression. I'm not 100% sure if the placement is perfect, but it should serve well enough as a proof of concept to see if this is the actual issue. It looks promising, though. drivers/i2c/algos/i2c-algo-bit.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 4a34f311e1ff..fab4437ecbb5 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -648,10 +648,19 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap, adap->quirks = &i2c_bit_quirk_no_clk_stretch; /* Bring bus to a known state. Looks like STOP if bus is not free yet */ + if (bit_adap->pre_xfer) { + ret = bit_adap->pre_xfer(adap); + if (ret < 0) + return ret; + } + setscl(bit_adap, 1); udelay(bit_adap->udelay); setsda(bit_adap, 1); + if (bit_adap->post_xfer) + bit_adap->post_xfer(adap); + ret = add_adapter(adap); if (ret < 0) return ret; -- 2.11.0