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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: , 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200803_011851_515589_18656320 X-CRM114-Status: GOOD ( 25.52 ) 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: alexandre.torgue@st.com, linux-kernel@vger.kernel.org, alain.volmat@st.com, linux-i2c@vger.kernel.org, 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+linux-arm-kernel=archiver.kernel.org@lists.infradead.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); -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel