From mboxrd@z Thu Jan 1 00:00:00 1970 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,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 44B93C433DF for ; Tue, 4 Aug 2020 14:24:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F77722B42 for ; Tue, 4 Aug 2020 14:24:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="Qm5g9VHz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728928AbgHDOYI (ORCPT ); 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Tue, 04 Aug 2020 16:03:58 +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 54FBC100034; Tue, 4 Aug 2020 16:03:56 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag5node2.st.com [10.75.127.14]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 1FA6F2BC7A0; Tue, 4 Aug 2020 16:03:56 +0200 (CEST) Received: from lmecxl1060.lme.st.com (10.75.127.44) by SFHDAG5NODE2.st.com (10.75.127.14) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 4 Aug 2020 16:03:55 +0200 Subject: Re: [PATCH v3 1/2] i2c: smbus: add core function handling SMBus host-notify To: Alain Volmat , CC: , , , , , References: <1596431876-24115-1-git-send-email-alain.volmat@st.com> <1596431876-24115-2-git-send-email-alain.volmat@st.com> From: Pierre Yves MORDRET Message-ID: <46f8ab6e-e53d-dadc-1031-425757fb9a4f@st.com> Date: Tue, 4 Aug 2020 16:03:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1596431876-24115-2-git-send-email-alain.volmat@st.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.44] X-ClientProxiedBy: SFHDAG1NODE1.st.com (10.75.127.1) To SFHDAG5NODE2.st.com (10.75.127.14) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-04_04:2020-08-03,2020-08-04 signatures=0 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Hi Alain Look good for me Reviewed-by: Pierre-Yves MORDRET Best Regards On 8/3/20 7:17 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_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); >