From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David.Wu" Subject: Re: [PATCH v7 4/9] i2c: rk3x: Move setting STATE_START and add STATE_SETUP Date: Fri, 6 May 2016 11:20:41 +0800 Message-ID: <572C0D89.9050708@rock-chips.com> References: <1462371194-5809-1-git-send-email-david.wu@rock-chips.com> <1462371194-5809-5-git-send-email-david.wu@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-i2c-owner@vger.kernel.org To: Doug Anderson Cc: =?UTF-8?Q?Heiko_St=c3=bcbner?= , Wolfram Sang , Mark Rutland , Tao Huang , Jianqun Xu , Lin Huang , Pawel Moll , Ian Campbell , "devicetree@vger.kernel.org" , "open list:ARM/Rockchip SoC..." , "linux-kernel@vger.kernel.org" , Eddie Cai , Andy Shevchenko , Rob Herring , "linux-i2c@vger.kernel.org" , Kumar Gala , Chris , Brian Norris , David Riley , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org Hi Doug, =E5=9C=A8 2016/5/6 6:56, Doug Anderson =E5=86=99=E9=81=93: > David, > > On Wed, May 4, 2016 at 7:13 AM, David Wu wr= ote: >> Signed-off-by: David Wu >> --- >> Change in v7: >> - none >> >> drivers/i2c/busses/i2c-rk3x.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) > > Probably this change could be dropped now. Switching the location of > setting START_START was much more important when you were supporting > HIGH SPEED mode. I don't think we need it anymore, right? > Yes, I would drop it next version=EF=BC=8CSTATE_SETUP didn't make sense= , it was not much more important, because there was a error printk for=20 rk3x_i2c_setup() called failed. > ...if we want to keep this change, I'd say: > > 1. Add a description, like maybe: > > To help with debugging add a STATE_SETUP between STATE_IDLE and > STATE_START to make it more obvious that we're not actually idle but = we > also haven't initiated the start bit. This change is not expected to > have any impact but it does delay the changing of state to STATE_STAR= T. > If previously we were getting an erroneous interrupt before we actual= ly > sent the start bit we'll now be treating that differently. The new > behavior (catching the erroneous interrupt) should be better. > > 2. Change "i2c->state =3D STATE_SETUP" to the _start_ of > rk3x_i2c_setup(). That would have a better chance of catching a > spurious interrupt. > > 3. Add an error check at the start of rk3x_i2c_irq() similar to the > check for STATE_IDLE (or use the same check and modify the printk). > Specifically the justification for adding STATE_SETUP is to help with > debugging (catch interrupts that were unexpected and print more info > about our state), so we should make it useful for this. > > > -Doug > > >