From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] i2c/mips: Fix error return codes from Sibyte i2c bus driver Date: Sat, 26 Jun 2010 18:29:15 +0200 Message-ID: <20100626182915.46ab3ecd@hyperion.delvare> References: <1277056673-4305-1-git-send-email-guenter.roeck@ericsson.com> <20100621190252.2adc6bd8@hyperion.delvare> <20100622115417.GA14418@ericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: "Maciej W. Rozycki" Cc: Guenter Roeck , "ben-linux@fluff.org" , "hsweeten@visionengravers.com" , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" List-Id: linux-i2c@vger.kernel.org On Sat, 26 Jun 2010 17:14:59 +0100 (BST), Maciej W. Rozycki wrote: > On Tue, 22 Jun 2010, Guenter Roeck wrote: > > > > > @@ -104,7 +104,7 @@ static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr, > > > > if (error & M_SMB_ERROR) { > > > > /* Clear error bit by writing a 1 */ > > > > csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS)); > > > > - return -1; /* XXXKW better error code? */ > > > > + return -ENXIO; > > > > } > > > > > > > > if (data_bytes == 1) > > > > > > Definitely an improvement. However, returning -ENXIO on all errors > > > seems wrong. This error value should only be returned on missing ack > > > from the slave on address byte. Isn't it possible to distinguish > > > between different error kinds? M_SMB_ERROR_TYPE seems promising, but > > > one would need to look up the datasheet (which I don't have) to > > > discover its meaning. > > > > > Makes sense. I'll dig up a copy of the datasheet and see if I can improve it. > > The M_SMB_ERROR_TYPE bit is cleared if an expected ackonwledgement has > not been seen and set if the transfer has failed after 15 retries. So > that's probably ENXIO for the former and EIO for the latter. Exactly what Guenter did. Good. -- Jean Delvare