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Tue, 26 May 2020 12:23:07 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 52FDB10002A; Tue, 26 May 2020 12:23:07 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag3node2.st.com [10.75.127.8]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 2213C21BDB7; Tue, 26 May 2020 12:23:07 +0200 (CEST) Received: from gnbcxd0016.gnb.st.com (10.75.127.44) by SFHDAG3NODE2.st.com (10.75.127.8) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Tue, 26 May 2020 12:23:06 +0200 Date: Tue, 26 May 2020 12:23:01 +0200 From: Alain Volmat To: Wolfram Sang Subject: Re: [PATCH 1/4] i2c: smbus: add core function handling SMBus host-notify Message-ID: <20200526102301.GA14423@gnbcxd0016.gnb.st.com> Mail-Followup-To: Wolfram Sang , Benjamin Tissoires , "robh+dt@kernel.org" , "mark.rutland@arm.com" , Pierre Yves MORDRET , "mcoquelin.stm32@gmail.com" , Alexandre TORGUE , "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-stm32@st-md-mailman.stormreply.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Fabrice GASNIER References: <1588657871-14747-1-git-send-email-alain.volmat@st.com> <1588657871-14747-2-git-send-email-alain.volmat@st.com> <20200523104624.GB3459@ninjato> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200523104624.GB3459@ninjato> X-Disclaimer: ce message est personnel / this message is private X-Originating-IP: [10.75.127.44] X-ClientProxiedBy: SFHDAG7NODE3.st.com (10.75.127.21) To SFHDAG3NODE2.st.com (10.75.127.8) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-05-26_01:2020-05-26, 2020-05-26 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200526_032314_769623_B2CC9005 X-CRM114-Status: GOOD ( 26.41 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , Alexandre TORGUE , "linux-kernel@vger.kernel.org" , Pierre Yves MORDRET , "robh+dt@kernel.org" , Benjamin Tissoires , "linux-i2c@vger.kernel.org" , "mcoquelin.stm32@gmail.com" , Fabrice GASNIER , "linux-stm32@st-md-mailman.stormreply.com" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, May 23, 2020 at 10:46:25AM +0000, Wolfram Sang wrote: > > Adding Benjamin who mainly implemented this. > > On Tue, May 05, 2020 at 07:51:08AM +0200, Alain Volmat wrote: > > SMBus Host-Notify protocol, from the adapter point of view > > consist of receiving a message from a client, including the > > client address and some other data. > > > > It can be simply handled by creating a new slave device > > and registering a callback performing the parsing of the > > message received from the client. > > > > This commit introduces two new core functions > > * i2c_new_smbus_host_notify_device > > * i2c_free_smbus_host_notify_device > > that take care of registration of the new slave device and > > callback and will call i2c_handle_smbus_host_notify once a > > Host-Notify event is received. > > Yay, cool idea to use the slave interface. I like it a lot! > > > +static int i2c_smbus_host_notify_cb(struct i2c_client *client, > > + enum i2c_slave_event event, u8 *val) > > +{ > > + struct i2c_smbus_host_notify_status *status = client->dev.platform_data; > > + int ret; > > + > > + switch (event) { > > + case I2C_SLAVE_WRITE_REQUESTED: > > + status->notify_start = true; > > + break; > > + case I2C_SLAVE_WRITE_RECEIVED: > > + /* We only retrieve the first byte received (addr) > > + * since there is currently no way to retrieve the data > > + * parameter from the client. > > Maybe s/no way/no support/ ? I still wonder if we couldn't add it > somehow. Once we find a device which needs this, of course. Indeed. Such support can be added later on once such device is found. For the time being I will state "no support" > > > + */ > > + if (!status->notify_start) > > + break; > > + status->addr = *val; > > + status->notify_start = false; > > + break; > > + case I2C_SLAVE_STOP: > > What about setting 'notify_start' to false here as well? In the case of > an incomplete write? Ok. I will check that notify_start is false before calling host_notify (since otherwise it will call i2c_handle_smbus_host_notify with a bad addr value) and reset notify_start to false if it is still true. > > > + ret = i2c_handle_smbus_host_notify(client->adapter, > > + status->addr); > > + if (ret < 0) { > > + dev_warn(&client->adapter->dev, "failed to handle host_notify (%d)\n", > > + ret); > > I think we should rather add such error strings to the core if we think > they are needed. I am not convinced they are, though. Agreed, this error can be removed. > > > + return ret; > > + } > > + break; > > + default: > > + /* Only handle necessary events */ > > + break; > > + } > > + > > + return 0; > > +} > > + > > Rest of the code looks good. Maybe we should compile all this only when > I2C_SLAVE is enabled? > Yes, I will enclose that around I2C_SLAVE support check. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel