From patchwork Thu Jun 25 07:39:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alain Volmat X-Patchwork-Id: 198505 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 573E1C433DF for ; Thu, 25 Jun 2020 07:40:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E1C720663 for ; Thu, 25 Jun 2020 07:40:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="zm/c0HYq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390205AbgFYHkR (ORCPT ); Thu, 25 Jun 2020 03:40:17 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:56303 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390040AbgFYHkH (ORCPT ); Thu, 25 Jun 2020 03:40:07 -0400 Received: from pps.filterd (m0046037.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05P7UEwY010950; Thu, 25 Jun 2020 09:39:51 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=STMicroelectronics; bh=xW18aHqVXh3iPSEvqhWN2VsRtt/LE3Q5T8UGXbk88qw=; b=zm/c0HYq+umt+SXTY4acvb77ohuOD30gJplhbCgOB339cPLj1dpjSkE08gklVliDa/S7 /Vjappn8VMeVLXL2js7K3RiyiBTMAqY2AVx75uv3ndfocqQbLf0u02lIzquAp3jj2fJY kiEmEkxK9pqgo6dYEd7SVgU798516JUUdpGXCpVntm91A9CEMnAr/0g7GiOXqu/zBxWm rqY49RniM9WHJRbhP0uIaslvce35yh8im9yf5GF6hufkGUjQSAsICzjcj+jAjtlpM/i9 bAfYPOZ4yBsz7j8THg/x+WrA1UAgT6FDzJhfHgRUbHSHEJ3BUl71O94XLHq9QaWgkq+q Sw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 31uuus0kee-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 25 Jun 2020 09:39:51 +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 CACB6100034; Thu, 25 Jun 2020 09:39:50 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag3node2.st.com [10.75.127.8]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id B73932A82E2; Thu, 25 Jun 2020 09:39:50 +0200 (CEST) Received: from localhost (10.75.127.48) by SFHDAG3NODE2.st.com (10.75.127.8) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 25 Jun 2020 09:39:50 +0200 From: Alain Volmat To: , CC: , , , , , , , , , , Subject: [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify Date: Thu, 25 Jun 2020 09:39:26 +0200 Message-ID: <1593070769-9106-2-git-send-email-alain.volmat@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1593070769-9106-1-git-send-email-alain.volmat@st.com> References: <1593070769-9106-1-git-send-email-alain.volmat@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.48] X-ClientProxiedBy: SFHDAG4NODE3.st.com (10.75.127.12) 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=2020-06-25_03:2020-06-25,2020-06-25 signatures=0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 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 --- v2: remove useless dev_err message in case of hnotify handling error prevent handling hnotify in case of a incomplete write drivers/i2c/i2c-core-smbus.c | 110 +++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c-smbus.h | 2 + 2 files changed, 112 insertions(+) diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index 56bb840142e3..3a37664fb5f6 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -708,3 +708,113 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) } EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); #endif + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +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 support 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: + /* In case of incomplete write, don't handle host-notify */ + if (status->notify_start) { + status->notify_start = false; + break; + } + + ret = i2c_handle_smbus_host_notify(client->adapter, + status->addr); + if (ret < 0) + 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); +#endif diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h index 1e4e0de4ef8b..974038a684ed 100644 --- a/include/linux/i2c-smbus.h +++ b/include/linux/i2c-smbus.h @@ -38,6 +38,8 @@ 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); #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI) void i2c_register_spd(struct i2c_adapter *adap);