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Mon, 11 May 2020 10:26:22 +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 5A7CA100034; Mon, 11 May 2020 10:26:22 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag5node2.st.com [10.75.127.14]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 2650A2B27B0; Mon, 11 May 2020 10:26:22 +0200 (CEST) Received: from [10.131.226.156] (10.75.127.46) by SFHDAG5NODE2.st.com (10.75.127.14) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 11 May 2020 10:26:20 +0200 Subject: Re: [PATCH 1/4] i2c: smbus: add core function handling SMBus host-notify To: Alain Volmat , , References: <1588657871-14747-1-git-send-email-alain.volmat@st.com> <1588657871-14747-2-git-send-email-alain.volmat@st.com> From: Pierre Yves MORDRET Message-ID: Date: Mon, 11 May 2020 10:26:23 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <1588657871-14747-2-git-send-email-alain.volmat@st.com> Content-Language: en-US X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG6NODE2.st.com (10.75.127.17) To SFHDAG5NODE2.st.com (10.75.127.14) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.676 definitions=2020-05-11_03:2020-05-11, 2020-05-11 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200511_012632_575118_81850C5D X-CRM114-Status: GOOD ( 26.53 ) 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@st.com, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, mcoquelin.stm32@gmail.com, fabrice.gasnier@st.com, 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 Hi all, Reviewed-by: Pierre-Yves MORDRET Thanks On 5/5/20 7:51 AM, 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. > > Signed-off-by: Alain Volmat > --- > drivers/i2c/i2c-core-smbus.c | 105 +++++++++++++++++++++++++++++++++++ > include/linux/i2c-smbus.h | 2 + > 2 files changed, 107 insertions(+) > > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index b34d2ff06931..0c7e135c73e1 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -708,3 +708,108 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) > } > EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); > #endif > + > +struct i2c_smbus_host_notify_status { > + bool notify_start; > + u8 addr; > +}; > + > +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. > + */ > + if (!status->notify_start) > + break; > + status->addr = *val; > + status->notify_start = false; > + break; > + case I2C_SLAVE_STOP: > + 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); > + return ret; > + } > + break; > + default: > + /* Only handle necessary events */ > + break; > + } > + > + return 0; > +} > + > +/** > + * i2c_new_smbus_host_notify_device - get a client for SMBus host-notify support > + * @adapter: the target adapter > + * Context: can sleep > + * > + * Setup handling of the SMBus host-notify protocol on a given I2C bus segment. > + * > + * Handling is done by creating a device and its callback and handling data > + * received via the SMBus host-notify address (0x8) > + * > + * This returns the client, which should be ultimately freed using > + * i2c_free_smbus_host_notify_device(); or an ERRPTR to indicate an error. > + */ > +struct i2c_client *i2c_new_smbus_host_notify_device(struct i2c_adapter *adapter) > +{ > + struct i2c_board_info host_notify_board_info = { > + I2C_BOARD_INFO("smbus_host_notify", 0x08), > + .flags = I2C_CLIENT_SLAVE, > + }; > + struct i2c_smbus_host_notify_status *status; > + struct i2c_client *client; > + int ret; > + > + status = kzalloc(sizeof(struct i2c_smbus_host_notify_status), > + GFP_KERNEL); > + if (!status) > + return ERR_PTR(-ENOMEM); > + > + host_notify_board_info.platform_data = status; > + > + client = i2c_new_client_device(adapter, &host_notify_board_info); > + if (IS_ERR(client)) { > + kfree(status); > + return client; > + } > + > + ret = i2c_slave_register(client, i2c_smbus_host_notify_cb); > + if (ret) { > + i2c_unregister_device(client); > + kfree(status); > + return ERR_PTR(ret); > + } > + > + return client; > +} > +EXPORT_SYMBOL_GPL(i2c_new_smbus_host_notify_device); > + > +/** > + * i2c_free_smbus_host_notify_device - free the client for SMBus host-notify > + * support > + * @client: the client to free > + * Context: can sleep > + * > + * Free the i2c_client allocated via i2c_new_smbus_host_notify_device > + */ > +void i2c_free_smbus_host_notify_device(struct i2c_client *client) > +{ > + i2c_slave_unregister(client); > + kfree(client->dev.platform_data); > + i2c_unregister_device(client); > +} > +EXPORT_SYMBOL_GPL(i2c_free_smbus_host_notify_device); > diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h > index 8c5459034f92..926f6d8ae30d 100644 > --- a/include/linux/i2c-smbus.h > +++ b/include/linux/i2c-smbus.h > @@ -38,5 +38,7 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap) > return 0; > } > #endif > +struct i2c_client *i2c_new_smbus_host_notify_device(struct i2c_adapter *adapter); > +void i2c_free_smbus_host_notify_device(struct i2c_client *client); > > #endif /* _LINUX_I2C_SMBUS_H */ > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel