From mboxrd@z Thu Jan 1 00:00:00 1970 From: jacopo mondi Subject: Re: [RFT] i2c: sh_mobile: avoid unnecessary register read Date: Tue, 14 Nov 2017 10:10:47 +0100 Message-ID: <20171114091047.GG19070@w540> References: <20171109222053.27093-1-wsa+renesas@sang-engineering.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20171109222053.27093-1-wsa+renesas@sang-engineering.com> Sender: linux-renesas-soc-owner@vger.kernel.org To: Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Yoshihiro Shimoda List-Id: linux-i2c@vger.kernel.org Hi Wolfram, On Thu, Nov 09, 2017 at 11:20:53PM +0100, Wolfram Sang wrote: > There is no data when the first WAIT interrupt arrives. No need to read > something then. > > Signed-off-by: Wolfram Sang > --- > > I am not super happy with (real pos >= 0) done twice, but I didn't find a > better solution yet. The compiler will make this cheap anyhow, I guess. > > Jacopo: can you please test this on top of all other patches? No regressions on Migo-R during image capture. Tested-by: Jacopo Mondi Thanks j > > drivers/i2c/busses/i2c-sh_mobile.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c > index 80561ffbcf7b46..40a66d466c3c49 100644 > --- a/drivers/i2c/busses/i2c-sh_mobile.c > +++ b/drivers/i2c/busses/i2c-sh_mobile.c > @@ -433,8 +433,9 @@ static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) > break; > } > data = i2c_op(pd, OP_RX_STOP_DATA, 0); > - } else > + } else if (real_pos >= 0) { > data = i2c_op(pd, OP_RX, 0); > + } > > if (real_pos >= 0) > pd->msg->buf[real_pos] = data; > -- > 2.11.0 >