From: Alain Volmat <alain.volmat@st.com>
To: <wsa@kernel.org>, <robh+dt@kernel.org>
Cc: <mark.rutland@arm.com>, <pierre-yves.mordret@st.com>,
<mcoquelin.stm32@gmail.com>, <alexandre.torgue@st.com>,
<linux-i2c@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-stm32@st-md-mailman.stormreply.com>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <fabrice.gasnier@st.com>,
<alain.volmat@st.com>
Subject: [PATCH 1/4] i2c: smbus: add core function handling SMBus host-notify
Date: Tue, 5 May 2020 07:51:08 +0200 [thread overview]
Message-ID: <1588657871-14747-2-git-send-email-alain.volmat@st.com> (raw)
In-Reply-To: <1588657871-14747-1-git-send-email-alain.volmat@st.com>
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 <alain.volmat@st.com>
---
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 */
--
2.17.1
next prev parent reply other threads:[~2020-05-05 5:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 5:51 [PATCH 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
2020-05-05 5:51 ` Alain Volmat [this message]
2020-05-11 8:26 ` [PATCH 1/4] i2c: smbus: add core function handling SMBus host-notify Pierre Yves MORDRET
2020-05-23 10:46 ` Wolfram Sang
2020-05-26 10:23 ` Alain Volmat
2020-05-05 5:51 ` [PATCH 2/4] i2c: addition of client reg/unreg callbacks Alain Volmat
2020-05-11 8:28 ` Pierre Yves MORDRET
2020-05-23 10:49 ` Wolfram Sang
2020-05-05 5:51 ` [PATCH 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings Alain Volmat
2020-05-13 2:19 ` Rob Herring
2020-05-13 5:42 ` Alain Volmat
2020-05-18 10:53 ` Alain Volmat
2020-05-23 10:36 ` wsa
2020-05-26 10:31 ` Alain Volmat
2020-05-05 5:51 ` [PATCH 4/4] i2c: stm32f7: Add SMBus-specific protocols support Alain Volmat
2020-05-11 8:27 ` Pierre Yves MORDRET
2020-05-23 11:01 ` Wolfram Sang
2020-05-26 10:39 ` Alain Volmat
2020-06-30 6:40 ` Wolfram Sang
2020-06-30 9:31 ` Alain Volmat
2020-06-30 15:11 ` Wolfram Sang
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