From patchwork Mon Aug 3 05:17:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alain Volmat X-Patchwork-Id: 254938 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=-13.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 82E06C433E1 for ; Mon, 3 Aug 2020 05:18:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65AD7207FB for ; Mon, 3 Aug 2020 05:18:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="RX7vALAl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727978AbgHCFS6 (ORCPT ); Mon, 3 Aug 2020 01:18:58 -0400 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:56759 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728013AbgHCFS4 (ORCPT ); Mon, 3 Aug 2020 01:18:56 -0400 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0735H6eL031639; Mon, 3 Aug 2020 07:18:45 +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=phmgcBwjcV7clYPigq48ZGfYIZjUmWnJrfbPJw1gODw=; b=RX7vALAly2808Hpr3zDVbIQuszCSeqUieC3JZRTF64opqbO0vnOlZlTdShmuJRmy2utf yGi4eZgDYwhc1/d645Gtah0m2j59IXN5eNtQeXBogfQIwsDvhO8H997ahjjqWFQ1Srvo Dh+5y4NpE211BLjGxelKXMPnnCaOchLU5U15D8P6Xt9zazuwV9dZKr9Ck9QfxZ4VgpOl uGtORDRnmCJKI1Tmgc2i1If1fIPCEYNd83zKLZpYHZrTLV2oRnf7MHhN1c4sVeVkrpeU c+oUD6DeiNt0FIqlAYBGFiUaGjOTxCaUv1tmUda3+gI9Ju7cn1CskNyAlDVLZb8N4v+c ug== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 32n6th4vfg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 03 Aug 2020 07:18:45 +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 BA92B100034; Mon, 3 Aug 2020 07:18:43 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag3node2.st.com [10.75.127.8]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 9EA4C20F451; Mon, 3 Aug 2020 07:18:43 +0200 (CEST) Received: from localhost (10.75.127.50) by SFHDAG3NODE2.st.com (10.75.127.8) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 3 Aug 2020 07:18:43 +0200 From: Alain Volmat To: , CC: , , , , , , Subject: [PATCH v3 1/2] i2c: smbus: add core function handling SMBus host-notify Date: Mon, 3 Aug 2020 07:17:55 +0200 Message-ID: <1596431876-24115-2-git-send-email-alain.volmat@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1596431876-24115-1-git-send-email-alain.volmat@st.com> References: <1596431876-24115-1-git-send-email-alain.volmat@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.50] X-ClientProxiedBy: SFHDAG2NODE3.st.com (10.75.127.6) To SFHDAG3NODE2.st.com (10.75.127.8) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-08-03_04:2020-07-31,2020-08-03 signatures=0 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@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_slave_host_notify_device * i2c_free_slave_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 --- v3: move smbus host-notify slave code into i2c-smbus.c file rework slave callback index handling add sanity check in slave free function v2: identical to v1 drivers/i2c/i2c-smbus.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c-smbus.h | 12 ++++++ 2 files changed, 119 insertions(+) diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c index dc0108287ccf..d3d06e3b4f3b 100644 --- a/drivers/i2c/i2c-smbus.c +++ b/drivers/i2c/i2c-smbus.c @@ -197,6 +197,113 @@ EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert); module_i2c_driver(smbalert_driver); +#if IS_ENABLED(CONFIG_I2C_SLAVE) +#define SMBUS_HOST_NOTIFY_LEN 3 +struct i2c_slave_host_notify_status { + u8 index; + u8 addr; +}; + +static int i2c_slave_host_notify_cb(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + struct i2c_slave_host_notify_status *status = client->dev.platform_data; + + switch (event) { + 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->index == 0) + status->addr = *val; + if (status->index < U8_MAX) + status->index++; + break; + case I2C_SLAVE_STOP: + if (status->index == SMBUS_HOST_NOTIFY_LEN) + i2c_handle_smbus_host_notify(client->adapter, + status->addr); + fallthrough; + case I2C_SLAVE_WRITE_REQUESTED: + status->index = 0; + break; + case I2C_SLAVE_READ_REQUESTED: + case I2C_SLAVE_READ_PROCESSED: + *val = 0xff; + break; + } + + return 0; +} + +/** + * i2c_new_slave_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_slave_host_notify_device(); or an ERRPTR to indicate an error. + */ +struct i2c_client *i2c_new_slave_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_slave_host_notify_status *status; + struct i2c_client *client; + int ret; + + status = kzalloc(sizeof(struct i2c_slave_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_slave_host_notify_cb); + if (ret) { + i2c_unregister_device(client); + kfree(status); + return ERR_PTR(ret); + } + + return client; +} +EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device); + +/** + * i2c_free_slave_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_slave_host_notify_device + */ +void i2c_free_slave_host_notify_device(struct i2c_client *client) +{ + if (IS_ERR_OR_NULL(client)) + return; + + i2c_slave_unregister(client); + kfree(client->dev.platform_data); + i2c_unregister_device(client); +} +EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device); +#endif + /* * SPD is not part of SMBus but we include it here for convenience as the * target systems are the same. diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h index 1e4e0de4ef8b..1ef421818d3a 100644 --- a/include/linux/i2c-smbus.h +++ b/include/linux/i2c-smbus.h @@ -38,6 +38,18 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap) return 0; } #endif +#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_I2C_SLAVE) +struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter); +void i2c_free_slave_host_notify_device(struct i2c_client *client); +#else +static inline struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter) +{ + return ERR_PTR(-ENOSYS); +} +static inline void i2c_free_slave_host_notify_device(struct i2c_client *client) +{ +} +#endif #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI) void i2c_register_spd(struct i2c_adapter *adap);