Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features
@ 2020-06-25  7:39 Alain Volmat
  2020-06-25  7:39 ` [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify Alain Volmat
                   ` (4 more replies)
  0 siblings, 5 replies; 11+ messages in thread
From: Alain Volmat @ 2020-06-25  7:39 UTC (permalink / raw)
  To: wsa, robh+dt
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, alain.volmat, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

This serie adds SMBus Alert and SMBus Host-Notify features for the i2c-stm32f7.

This serie v2 rework comments from the 1st serie and replace the very generic
reg_client / unreg_client callback with HOST_NOTIFY only reg_hnotify_cli
and unreg_hnotify_cli callbacks.

Alain Volmat (4):
  i2c: smbus: add core function handling SMBus host-notify
  i2c: addition of client hnotify reg/unreg callbacks
  dt-bindings: i2c-stm32: add SMBus Alert bindings
  i2c: stm32f7: Add SMBus-specific protocols support

 .../devicetree/bindings/i2c/st,stm32-i2c.yaml      |   4 +
 drivers/i2c/busses/Kconfig                         |   1 +
 drivers/i2c/busses/i2c-stm32f7.c                   | 194 +++++++++++++++++++--
 drivers/i2c/i2c-core-base.c                        |  18 +-
 drivers/i2c/i2c-core-smbus.c                       | 110 ++++++++++++
 include/linux/i2c-smbus.h                          |   2 +
 include/linux/i2c.h                                |   8 +
 7 files changed, 325 insertions(+), 12 deletions(-)


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify
  2020-06-25  7:39 [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
@ 2020-06-25  7:39 ` Alain Volmat
  2020-07-01 10:49   ` Wolfram Sang
  2020-06-25  7:39 ` [PATCH v2 2/4] i2c: addition of client hnotify reg/unreg callbacks Alain Volmat
                   ` (3 subsequent siblings)
  4 siblings, 1 reply; 11+ messages in thread
From: Alain Volmat @ 2020-06-25  7:39 UTC (permalink / raw)
  To: wsa, robh+dt
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, alain.volmat, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

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>
---
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);
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 2/4] i2c: addition of client hnotify reg/unreg callbacks
  2020-06-25  7:39 [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
  2020-06-25  7:39 ` [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify Alain Volmat
@ 2020-06-25  7:39 ` Alain Volmat
  2020-06-25  7:39 ` [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings Alain Volmat
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 11+ messages in thread
From: Alain Volmat @ 2020-06-25  7:39 UTC (permalink / raw)
  To: wsa, robh+dt
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, alain.volmat, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

Addition of two callbacks reg_hnotify_cli and unreg_hnotify_cli
that can be implemented by adapter drivers in order to take action
whenever a client with HOST_NOTIFY flag is being registered to it.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
v2: replace generic client reg/unreg callbacks with host-notify
    client reg/unreg callbacks

 drivers/i2c/i2c-core-base.c | 18 ++++++++++++++++--
 include/linux/i2c.h         |  8 ++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 26f03a14a478..46745e403e98 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -319,6 +319,14 @@ static int i2c_device_probe(struct device *dev)
 	if (!client)
 		return 0;
 
+	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
+		if (client->adapter->algo->reg_hnotify_cli) {
+			status = client->adapter->algo->reg_hnotify_cli(client);
+			if (status)
+				return status;
+		}
+	}
+
 	driver = to_i2c_driver(dev->driver);
 
 	client->irq = client->init_irq;
@@ -415,8 +423,11 @@ static int i2c_device_probe(struct device *dev)
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
 put_sync_adapter:
-	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
+	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 		pm_runtime_put_sync(&client->adapter->dev);
+		if (client->adapter->algo->unreg_hnotify_cli)
+			client->adapter->algo->unreg_hnotify_cli(client);
+	}
 
 	return status;
 }
@@ -442,8 +453,11 @@ static int i2c_device_remove(struct device *dev)
 	device_init_wakeup(&client->dev, false);
 
 	client->irq = 0;
-	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
+	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 		pm_runtime_put(&client->adapter->dev);
+		if (client->adapter->algo->unreg_hnotify_cli)
+			client->adapter->algo->unreg_hnotify_cli(client);
+	}
 
 	return status;
 }
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index b8b8963f8bb9..35ad108adc68 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -507,6 +507,10 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info,
  *   so e.g. PMICs can be accessed very late before shutdown. Optional.
  * @functionality: Return the flags that this algorithm/adapter pair supports
  *   from the ``I2C_FUNC_*`` flags.
+ * @reg_hnotify_cli: Callback informing that a new client with HOST_NOTIFY flag
+ *   is being registered
+ * @unreg_hnotify_cli: Callback informing that a client with HOST_NOTIFY flag
+ *   is being removed
  * @reg_slave: Register given client to I2C slave mode of this adapter
  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
  *
@@ -543,6 +547,10 @@ struct i2c_algorithm {
 	/* To determine what the adapter supports */
 	u32 (*functionality)(struct i2c_adapter *adap);
 
+	/* To inform the adapter of the probe/remove of a HOST_NOTIFY client */
+	int (*reg_hnotify_cli)(struct i2c_client *client);
+	void (*unreg_hnotify_cli)(struct i2c_client *client);
+
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 	int (*reg_slave)(struct i2c_client *client);
 	int (*unreg_slave)(struct i2c_client *client);
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings
  2020-06-25  7:39 [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
  2020-06-25  7:39 ` [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify Alain Volmat
  2020-06-25  7:39 ` [PATCH v2 2/4] i2c: addition of client hnotify reg/unreg callbacks Alain Volmat
@ 2020-06-25  7:39 ` Alain Volmat
  2020-06-30 19:41   ` Wolfram Sang
  2020-06-25  7:39 ` [PATCH v2 4/4] i2c: stm32f7: Add SMBus-specific protocols support Alain Volmat
  2020-06-30 16:05 ` [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Wolfram Sang
  4 siblings, 1 reply; 11+ messages in thread
From: Alain Volmat @ 2020-06-25  7:39 UTC (permalink / raw)
  To: wsa, robh+dt
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, alain.volmat, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

Add a new binding of the i2c-stm32f7 driver to enable the handling
of the SMBUS-Alert.

The I2C/SMBUS framework already provides a mechanism to enable SMBus-Alert
by naming an IRQ line "smbus_alert". However, on stm32, the SMBus-Alert is
part of the i2c IRQ. Using the smbus_alert naming here would lead to having
2 handlers (the handler of the driver and the smbus_alert handler
from I2C/SMBUS framework) on the unique i2c IRQ of the stm32. Meaning that
the smbus_alert handler would get called for all IRQ generated by the stm32
I2C controller.

For that reason, the smbus_alert IRQ naming cannot be used and a dedicated
binding is introduced.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
v2: Clarify commit message

 Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
index f2fcbb361180..6fde046fae5e 100644
--- a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
@@ -36,6 +36,10 @@ allOf:
             minItems: 3
             maxItems: 3
 
+        st,smbus-alert:
+          description: Enable the SMBus Alert feature
+          $ref: /schemas/types.yaml#/definitions/flag
+
   - if:
       properties:
         compatible:
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 4/4] i2c: stm32f7: Add SMBus-specific protocols support
  2020-06-25  7:39 [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
                   ` (2 preceding siblings ...)
  2020-06-25  7:39 ` [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings Alain Volmat
@ 2020-06-25  7:39 ` Alain Volmat
  2020-06-30 16:05 ` [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Wolfram Sang
  4 siblings, 0 replies; 11+ messages in thread
From: Alain Volmat @ 2020-06-25  7:39 UTC (permalink / raw)
  To: wsa, robh+dt
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, alain.volmat, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

This patch adds the support for SMBus Host notify and SMBus Alert
extensions protocols

This patch introduces the st,smbus-alert binding in order to enable
SMBus-Alert handling. Indeed, while the I2C/SMBUS framework already
provide a mechanism to enable SMBus-Alert by naming an IRQ line
"smbus_alert", on stm32 the SMBus-Alert is part of the i2c IRQ.
Using the smbus_alert naming here would lead to having 2 handlers
(the handler of the driver and the smbus_alert handler from I2C/SMBUS
framework) on the unique i2c IRQ of the stm32. Meaning that the
smbus_alert handler would get called for all IRQ generated by the stm32
I2C controller.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
v2: adapt code to use reg_hnotify_cli / unreg_hnotify_cli instead
    of reg_client / unreg_client
    clarify commit message

 drivers/i2c/busses/Kconfig       |   1 +
 drivers/i2c/busses/i2c-stm32f7.c | 194 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 185 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 735bf31a3fdf..ae8671727a4c 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1036,6 +1036,7 @@ config I2C_STM32F7
 	tristate "STMicroelectronics STM32F7 I2C support"
 	depends on ARCH_STM32 || COMPILE_TEST
 	select I2C_SLAVE
+	select I2C_SMBUS
 	help
 	  Enable this option to add support for STM32 I2C controller embedded
 	  in STM32F7 SoCs.
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index bff3479fe122..d8f483ceeabb 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -14,10 +14,12 @@
  * This driver is based on i2c-stm32f4.c
  *
  */
+#include <linux/atomic.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
@@ -50,6 +52,8 @@
 
 /* STM32F7 I2C control 1 */
 #define STM32F7_I2C_CR1_PECEN			BIT(23)
+#define STM32F7_I2C_CR1_ALERTEN			BIT(22)
+#define STM32F7_I2C_CR1_SMBHEN			BIT(20)
 #define STM32F7_I2C_CR1_WUPEN			BIT(18)
 #define STM32F7_I2C_CR1_SBC			BIT(16)
 #define STM32F7_I2C_CR1_RXDMAEN			BIT(15)
@@ -121,6 +125,7 @@
 				(((n) & STM32F7_I2C_ISR_ADDCODE_MASK) >> 17)
 #define STM32F7_I2C_ISR_DIR			BIT(16)
 #define STM32F7_I2C_ISR_BUSY			BIT(15)
+#define STM32F7_I2C_ISR_ALERT			BIT(13)
 #define STM32F7_I2C_ISR_PECERR			BIT(11)
 #define STM32F7_I2C_ISR_ARLO			BIT(9)
 #define STM32F7_I2C_ISR_BERR			BIT(8)
@@ -134,6 +139,7 @@
 #define STM32F7_I2C_ISR_TXE			BIT(0)
 
 /* STM32F7 I2C Interrupt Clear */
+#define STM32F7_I2C_ICR_ALERTCF			BIT(13)
 #define STM32F7_I2C_ICR_PECCF			BIT(11)
 #define STM32F7_I2C_ICR_ARLOCF			BIT(9)
 #define STM32F7_I2C_ICR_BERRCF			BIT(8)
@@ -150,7 +156,7 @@
 
 #define STM32F7_I2C_MAX_LEN			0xff
 #define STM32F7_I2C_DMA_LEN_MIN			0x16
-#define STM32F7_I2C_MAX_SLAVE			0x2
+#define STM32F7_I2C_MAX_SLAVE			0x3
 
 #define STM32F7_I2C_DNF_DEFAULT			0
 #define STM32F7_I2C_DNF_MAX			16
@@ -275,6 +281,29 @@ struct stm32f7_i2c_msg {
 };
 
 /**
+ * struct stm32f7_i2c_host - SMBus host specific data
+ * @client: I2C slave device that represents SMBus host
+ * @notify_start: indicate that this is the start of the notify transaction
+ * @addr: device address of SMBus device that initiate SMBus host protocol
+ */
+struct stm32f7_i2c_host {
+	struct i2c_client *client;
+	bool notify_start;
+	u8 addr;
+};
+
+/**
+ * struct stm32f7_i2c_alert - SMBus alert specific data
+ * @setup: platform data for the smbus_alert i2c client
+ * @ara: I2C slave device used to respond to the SMBus Alert with Alert
+ * Response Address
+ */
+struct stm32f7_i2c_alert {
+	struct i2c_smbus_alert_setup setup;
+	struct i2c_client *ara;
+};
+
+/**
  * struct stm32f7_i2c_dev - private data of the controller
  * @adap: I2C adapter for this controller
  * @dev: device for this controller
@@ -301,6 +330,9 @@ struct stm32f7_i2c_msg {
  * @fmp_creg: register address for clearing Fast Mode Plus bits
  * @fmp_mask: mask for Fast Mode Plus bits in set register
  * @wakeup_src: boolean to know if the device is a wakeup source
+ * @host_notify_cnt: atomic to know number of host_notify enabled clients
+ * @host_notify_client: SMBus host-notify client
+ * @alert: SMBus alert specific data
  */
 struct stm32f7_i2c_dev {
 	struct i2c_adapter adap;
@@ -327,6 +359,9 @@ struct stm32f7_i2c_dev {
 	u32 fmp_creg;
 	u32 fmp_mask;
 	bool wakeup_src;
+	atomic_t host_notify_cnt;
+	struct i2c_client *host_notify_client;
+	struct stm32f7_i2c_alert *alert;
 };
 
 /*
@@ -1321,10 +1356,20 @@ static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
 	int i;
 
 	/*
-	 * slave[0] supports 7-bit and 10-bit slave address
-	 * slave[1] supports 7-bit slave address only
+	 * slave[0] support only SMBus Host address (0x8)
+	 * slave[1] supports 7-bit and 10-bit slave address
+	 * slave[2] supports 7-bit slave address only
 	 */
-	for (i = STM32F7_I2C_MAX_SLAVE - 1; i >= 0; i--) {
+	if (atomic_read(&i2c_dev->host_notify_cnt)) {
+		if (slave->addr == 0x08) {
+			if (i2c_dev->slave[0])
+				goto fail;
+			*id = 0;
+			return 0;
+		}
+	}
+
+	for (i = STM32F7_I2C_MAX_SLAVE - 1; i > 0; i--) {
 		if (i == 1 && (slave->flags & I2C_CLIENT_TEN))
 			continue;
 		if (!i2c_dev->slave[i]) {
@@ -1333,6 +1378,7 @@ static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
 		}
 	}
 
+fail:
 	dev_err(dev, "Slave 0x%x could not be registered\n", slave->addr);
 
 	return -EINVAL;
@@ -1586,6 +1632,13 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
 		f7_msg->result = -EINVAL;
 	}
 
+	if (status & STM32F7_I2C_ISR_ALERT) {
+		dev_dbg(dev, "<%s>: SMBus alert received\n", __func__);
+		writel_relaxed(STM32F7_I2C_ICR_ALERTCF, base + STM32F7_I2C_ICR);
+		i2c_handle_smbus_alert(i2c_dev->alert->ara);
+		return IRQ_HANDLED;
+	}
+
 	if (!i2c_dev->slave_running) {
 		u32 mask;
 		/* Disable interrupts */
@@ -1776,7 +1829,13 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
 	if (!stm32f7_i2c_is_slave_registered(i2c_dev))
 		stm32f7_i2c_enable_wakeup(i2c_dev, true);
 
-	if (id == 0) {
+	switch (id) {
+	case 0:
+		/* Slave SMBus Host */
+		i2c_dev->slave[id] = slave;
+		break;
+
+	case 1:
 		/* Configure Own Address 1 */
 		oar1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR1);
 		oar1 &= ~STM32F7_I2C_OAR1_MASK;
@@ -1789,7 +1848,9 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
 		oar1 |= STM32F7_I2C_OAR1_OA1EN;
 		i2c_dev->slave[id] = slave;
 		writel_relaxed(oar1, i2c_dev->base + STM32F7_I2C_OAR1);
-	} else if (id == 1) {
+		break;
+
+	case 2:
 		/* Configure Own Address 2 */
 		oar2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR2);
 		oar2 &= ~STM32F7_I2C_OAR2_MASK;
@@ -1802,7 +1863,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
 		oar2 |= STM32F7_I2C_OAR2_OA2EN;
 		i2c_dev->slave[id] = slave;
 		writel_relaxed(oar2, i2c_dev->base + STM32F7_I2C_OAR2);
-	} else {
+		break;
+
+	default:
+		dev_err(dev, "I2C slave id not supported\n");
 		ret = -ENODEV;
 		goto pm_free;
 	}
@@ -1843,10 +1907,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
 	if (ret < 0)
 		return ret;
 
-	if (id == 0) {
+	if (id == 1) {
 		mask = STM32F7_I2C_OAR1_OA1EN;
 		stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR1, mask);
-	} else {
+	} else if (id == 2) {
 		mask = STM32F7_I2C_OAR2_OA2EN;
 		stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR2, mask);
 	}
@@ -1911,6 +1975,99 @@ static int stm32f7_i2c_setup_fm_plus_bits(struct platform_device *pdev,
 					  &i2c_dev->fmp_mask);
 }
 
+static int stm32f7_i2c_enable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct i2c_adapter *adap = &i2c_dev->adap;
+	void __iomem *base = i2c_dev->base;
+	struct i2c_client *client;
+
+	client = i2c_new_smbus_host_notify_device(adap);
+	if (IS_ERR(client))
+		return PTR_ERR(client);
+
+	i2c_dev->host_notify_client = client;
+
+	/* Enable SMBus Host address */
+	stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, STM32F7_I2C_CR1_SMBHEN);
+
+	return 0;
+}
+
+static void stm32f7_i2c_disable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
+{
+	void __iomem *base = i2c_dev->base;
+
+	if (i2c_dev->host_notify_client) {
+		/* Disable SMBus Host address */
+		stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1,
+				     STM32F7_I2C_CR1_SMBHEN);
+		i2c_free_smbus_host_notify_device(i2c_dev->host_notify_client);
+	}
+}
+
+static int stm32f7_i2c_reg_hnotify_client(struct i2c_client *client)
+{
+	struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(client->adapter);
+	int ret;
+
+	/* Only enable on the first device registration */
+	if (atomic_inc_return(&i2c_dev->host_notify_cnt) == 1) {
+		ret = stm32f7_i2c_enable_smbus_host(i2c_dev);
+		if (ret) {
+			dev_err(i2c_dev->dev,
+				"failed to enable SMBus host notify (%d)\n",
+				ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void stm32f7_i2c_unreg_hnotify_client(struct i2c_client *client)
+{
+	struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(client->adapter);
+
+	if (atomic_dec_return(&i2c_dev->host_notify_cnt) == 0)
+		stm32f7_i2c_disable_smbus_host(i2c_dev);
+}
+
+static int stm32f7_i2c_enable_smbus_alert(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct stm32f7_i2c_alert *alert;
+	struct i2c_adapter *adap = &i2c_dev->adap;
+	struct device *dev = i2c_dev->dev;
+	void __iomem *base = i2c_dev->base;
+
+	alert = devm_kzalloc(dev, sizeof(*alert), GFP_KERNEL);
+	if (!alert)
+		return -ENOMEM;
+
+	alert->ara = i2c_new_smbus_alert_device(adap, &alert->setup);
+	if (IS_ERR(alert->ara))
+		return PTR_ERR(alert->ara);
+
+	i2c_dev->alert = alert;
+
+	/* Enable SMBus Alert */
+	stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, STM32F7_I2C_CR1_ALERTEN);
+
+	return 0;
+}
+
+static void stm32f7_i2c_disable_smbus_alert(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct stm32f7_i2c_alert *alert = i2c_dev->alert;
+	void __iomem *base = i2c_dev->base;
+
+	if (alert) {
+		/* Disable SMBus Alert */
+		stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1,
+				     STM32F7_I2C_CR1_ALERTEN);
+		i2c_unregister_device(alert->ara);
+	}
+}
+
 static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE |
@@ -1918,7 +2075,7 @@ static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
 		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 		I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
 		I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC |
-		I2C_FUNC_SMBUS_I2C_BLOCK;
+		I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_HOST_NOTIFY;
 }
 
 static const struct i2c_algorithm stm32f7_i2c_algo = {
@@ -1927,6 +2084,8 @@ static const struct i2c_algorithm stm32f7_i2c_algo = {
 	.functionality = stm32f7_i2c_func,
 	.reg_slave = stm32f7_i2c_reg_slave,
 	.unreg_slave = stm32f7_i2c_unreg_slave,
+	.reg_hnotify_cli = stm32f7_i2c_reg_hnotify_client,
+	.unreg_hnotify_cli = stm32f7_i2c_unreg_hnotify_client,
 };
 
 static int stm32f7_i2c_probe(struct platform_device *pdev)
@@ -2088,6 +2247,16 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
 	if (ret)
 		goto pm_disable;
 
+	if (device_property_read_bool(&pdev->dev, "st,smbus-alert")) {
+		ret = stm32f7_i2c_enable_smbus_alert(i2c_dev);
+		if (ret) {
+			dev_err(i2c_dev->dev,
+				"failed to enable SMBus alert protocol (%d)\n",
+				ret);
+			goto i2c_adapter_remove;
+		}
+	}
+
 	dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
 
 	pm_runtime_mark_last_busy(i2c_dev->dev);
@@ -2095,6 +2264,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
 
 	return 0;
 
+i2c_adapter_remove:
+	i2c_del_adapter(adap);
+
 pm_disable:
 	pm_runtime_put_noidle(i2c_dev->dev);
 	pm_runtime_disable(i2c_dev->dev);
@@ -2126,6 +2298,8 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
 {
 	struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 
+	stm32f7_i2c_disable_smbus_alert(i2c_dev);
+
 	i2c_del_adapter(&i2c_dev->adap);
 	pm_runtime_get_sync(i2c_dev->dev);
 
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features
  2020-06-25  7:39 [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
                   ` (3 preceding siblings ...)
  2020-06-25  7:39 ` [PATCH v2 4/4] i2c: stm32f7: Add SMBus-specific protocols support Alain Volmat
@ 2020-06-30 16:05 ` Wolfram Sang
  2020-07-01  9:21   ` Alain Volmat
  4 siblings, 1 reply; 11+ messages in thread
From: Wolfram Sang @ 2020-06-30 16:05 UTC (permalink / raw)
  To: Alain Volmat
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, robh+dt, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

[-- Attachment #1.1: Type: text/plain, Size: 273 bytes --]

On Thu, Jun 25, 2020 at 09:39:25AM +0200, Alain Volmat wrote:
> This serie adds SMBus Alert and SMBus Host-Notify features for the i2c-stm32f7.

If it is not too much work for you, I think it makes sense to split the
series into two, i.e. HostNotify and SMBusAlert parts.


[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings
  2020-06-25  7:39 ` [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings Alain Volmat
@ 2020-06-30 19:41   ` Wolfram Sang
  0 siblings, 0 replies; 11+ messages in thread
From: Wolfram Sang @ 2020-06-30 19:41 UTC (permalink / raw)
  To: Alain Volmat
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, robh+dt, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

[-- Attachment #1.1: Type: text/plain, Size: 1112 bytes --]

On Thu, Jun 25, 2020 at 09:39:28AM +0200, Alain Volmat wrote:
> Add a new binding of the i2c-stm32f7 driver to enable the handling
> of the SMBUS-Alert.
> 
> The I2C/SMBUS framework already provides a mechanism to enable SMBus-Alert
> by naming an IRQ line "smbus_alert". However, on stm32, the SMBus-Alert is
> part of the i2c IRQ. Using the smbus_alert naming here would lead to having
> 2 handlers (the handler of the driver and the smbus_alert handler
> from I2C/SMBUS framework) on the unique i2c IRQ of the stm32. Meaning that
> the smbus_alert handler would get called for all IRQ generated by the stm32
> I2C controller.
> 
> For that reason, the smbus_alert IRQ naming cannot be used and a dedicated
> binding is introduced.

What if we update the core to not register another irq handler if the
"smbus_alert" and main irq are the same?

I think it could work. However, while trying to make a proof-of-concept,
I found that irq descriptions in the generic i2c binding document are
probably mixed up. And before fixing that, I'd like to get HostNotify
done first.

Makes sense?


[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features
  2020-06-30 16:05 ` [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Wolfram Sang
@ 2020-07-01  9:21   ` Alain Volmat
  2020-07-01  9:28     ` Wolfram Sang
  0 siblings, 1 reply; 11+ messages in thread
From: Alain Volmat @ 2020-07-01  9:21 UTC (permalink / raw)
  To: Wolfram Sang
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, robh+dt, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

On Tue, Jun 30, 2020 at 06:05:00PM +0200, Wolfram Sang wrote:
> On Thu, Jun 25, 2020 at 09:39:25AM +0200, Alain Volmat wrote:
> > This serie adds SMBus Alert and SMBus Host-Notify features for the i2c-stm32f7.
> 
> If it is not too much work for you, I think it makes sense to split the
> series into two, i.e. HostNotify and SMBusAlert parts.
> 

I've just prepared the 1st new serie with only the HostNotify bits in it.
(basically, the core part, the dt-bindings with the enable-host-notify, and
the usage within i2c-stm32f7).
You mentioned in the other thread that you still have some more review comment
I believe. Is that right ? If that is so, I'll wait for those comment and
then push that new serie for review.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features
  2020-07-01  9:21   ` Alain Volmat
@ 2020-07-01  9:28     ` Wolfram Sang
  0 siblings, 0 replies; 11+ messages in thread
From: Wolfram Sang @ 2020-07-01  9:28 UTC (permalink / raw)
  To: robh+dt, mark.rutland, pierre-yves.mordret, mcoquelin.stm32,
	alexandre.torgue, linux-i2c, devicetree, linux-stm32,
	linux-arm-kernel, linux-kernel, fabrice.gasnier

[-- Attachment #1.1: Type: text/plain, Size: 458 bytes --]


> I've just prepared the 1st new serie with only the HostNotify bits in it.
> (basically, the core part, the dt-bindings with the enable-host-notify, and
> the usage within i2c-stm32f7).

Cool, thanks!

> You mentioned in the other thread that you still have some more review comment
> I believe. Is that right ? If that is so, I'll wait for those comment and
> then push that new serie for review.

Yes, for the core part. Please wait for these comments.


[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify
  2020-06-25  7:39 ` [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify Alain Volmat
@ 2020-07-01 10:49   ` Wolfram Sang
  2020-07-02 11:23     ` Alain Volmat
  0 siblings, 1 reply; 11+ messages in thread
From: Wolfram Sang @ 2020-07-01 10:49 UTC (permalink / raw)
  To: Alain Volmat
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, robh+dt, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

[-- Attachment #1.1: Type: text/plain, Size: 4192 bytes --]

On Thu, Jun 25, 2020 at 09:39:26AM +0200, 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_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>
> ---
> v2: remove useless dev_err message in case of hnotify handling error
>     prevent handling hnotify in case of a incomplete write

Okay, now I got it to work, I also noted a few more issues.

First, I'd suggest s/i2c_smbus_host_notify/i2c_slave_host_notify/g for
all occurences in this patch. This makes a stronger distinction between
the generic HostNotify support and the slave specific one.

Also, I wonder if this shouldn't go to i2c-smbus.c instead but I haven't
checked if we end up in dependency hell then. Second best thought: at
least move to i2c-core-slave.c, then we could save the #ifdeffery in the
c-file?

> 
>  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;

So, we are safe if the message is too short. Otherwise, we capture the
first byte (== address) only, right. Further bytes until STOP are
discarded. So, we don't check if the message is too long and contains
more than the status word. Maybe we should add that?

> +		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:

The missing cases are mandatory. From my testunit driver:

        case I2C_SLAVE_READ_REQUESTED:
        case I2C_SLAVE_READ_PROCESSED:
                *val = 0xff;
                break;

> +		/* Only handle necessary events */
> +		break;
> +	}
> +
> +	return 0;
> +}
> +

...

> --- 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);

Those need to be guarded with I2C_SLAVE as well. And an #else branch
with empty/successful placeholders.

>  
>  #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI)
>  void i2c_register_spd(struct i2c_adapter *adap);
> -- 
> 2.7.4
> 

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify
  2020-07-01 10:49   ` Wolfram Sang
@ 2020-07-02 11:23     ` Alain Volmat
  0 siblings, 0 replies; 11+ messages in thread
From: Alain Volmat @ 2020-07-02 11:23 UTC (permalink / raw)
  To: Wolfram Sang
  Cc: mark.rutland, devicetree, alexandre.torgue, linux-kernel,
	pierre-yves.mordret, robh+dt, linux-i2c, mcoquelin.stm32,
	fabrice.gasnier, linux-stm32, linux-arm-kernel

Hi Wolfram,

> Okay, now I got it to work, I also noted a few more issues.
> 
> First, I'd suggest s/i2c_smbus_host_notify/i2c_slave_host_notify/g for
> all occurences in this patch. This makes a stronger distinction between
> the generic HostNotify support and the slave specific one.

Ok with that.

> Also, I wonder if this shouldn't go to i2c-smbus.c instead but I haven't
> checked if we end up in dependency hell then. Second best thought: at
> least move to i2c-core-slave.c, then we could save the #ifdeffery in the
> c-file?

I have actually difficulties to understand clearly what should go within
i2c-smbus.c vs i2c-core-smbus or i2c-core-slave. My feeling is that
i2c-core-slave is more about the registering of a slave rather than one usage
of the slave mechanism. Hence I am not sure those functions/cb belong there.
But at the same time, I don't know about i2c-smbus vs i2c-core-smbus. I putted
it within i2c-core-smbus considering that the creation of the alert device
is also done there.

....

> > +{
> > +	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;
> 
> So, we are safe if the message is too short. Otherwise, we capture the
> first byte (== address) only, right. Further bytes until STOP are
> discarded. So, we don't check if the message is too long and contains
> more than the status word. Maybe we should add that?

Yes I modified that.

> > +		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:
> 
> The missing cases are mandatory. From my testunit driver:
> 
>         case I2C_SLAVE_READ_REQUESTED:
>         case I2C_SLAVE_READ_PROCESSED:
>                 *val = 0xff;
>                 break;

Ok, done as well.

> > --- 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);
> 
> Those need to be guarded with I2C_SLAVE as well. And an #else branch
> with empty/successful placeholders.

Ok understood.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, back to index

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-25  7:39 [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Alain Volmat
2020-06-25  7:39 ` [PATCH v2 1/4] i2c: smbus: add core function handling SMBus host-notify Alain Volmat
2020-07-01 10:49   ` Wolfram Sang
2020-07-02 11:23     ` Alain Volmat
2020-06-25  7:39 ` [PATCH v2 2/4] i2c: addition of client hnotify reg/unreg callbacks Alain Volmat
2020-06-25  7:39 ` [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings Alain Volmat
2020-06-30 19:41   ` Wolfram Sang
2020-06-25  7:39 ` [PATCH v2 4/4] i2c: stm32f7: Add SMBus-specific protocols support Alain Volmat
2020-06-30 16:05 ` [PATCH v2 0/4] stm32-f7: Addition of SMBus Alert / Host-notify features Wolfram Sang
2020-07-01  9:21   ` Alain Volmat
2020-07-01  9:28     ` Wolfram Sang

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git