[PATCH v5 0/4] i2c-smbus: add support for HOST NOTIFY

[PATCH v5 0/4] i2c-smbus: add support for HOST NOTIFY

[Benjamin Tissoires]

Hi all,

This is a resent of my series sent back in September[1].
The i801 driver has been updated to also match on the skylake chip, which
makes the new Lenovo working with RMI4 too.

The trigger for this series has been that RMI4 (the Synaptics protocol for
their devices) is on its way to v4.6. It would be good if we could have a
review for the smbus part so we can finally switch the Synaptics devices
into a better reporting mode where they report 5 true fingers.

Cheers,
Benjamin


[1] http://thread.gmane.org/gmane.linux.drivers.i2c/23899/focus=2044469

Benjamin Tissoires (4):
  i2c: add a protocol parameter to the alert callback
  i2c-smbus: add SMBus Host Notify support
  i2c: i801: add support of Host Notify
  Input: synaptics-rmi4 - add SMBus support

 Documentation/i2c/smbus-protocol |   3 +
 drivers/char/ipmi/ipmi_ssif.c    |   6 +-
 drivers/hwmon/lm90.c             |   3 +-
 drivers/i2c/busses/i2c-i801.c    |  85 +++++++-
 drivers/i2c/i2c-smbus.c          | 112 ++++++++++-
 drivers/input/rmi4/Kconfig       |  12 ++
 drivers/input/rmi4/Makefile      |   1 +
 drivers/input/rmi4/rmi_bus.h     |  12 ++
 drivers/input/rmi4/rmi_smbus.c   | 416 +++++++++++++++++++++++++++++++++++++++
 include/linux/i2c-smbus.h        |  43 ++++
 include/linux/i2c.h              |  10 +-
 include/uapi/linux/i2c.h         |   1 +
 12 files changed, 694 insertions(+), 10 deletions(-)
 create mode 100644 drivers/input/rmi4/rmi_smbus.c

-- 
2.5.0

[PATCH v5 1/4] i2c: add a protocol parameter to the alert callback

[Benjamin Tissoires]

.alert() is meant to be generic, but there is currently no way
for the device driver to know which protocol generated the alert.
Add a parameter in .alert() to help the device driver to understand
what is given in data.

This patch is required to have the support of SMBus Host Notify protocol
through .alert().

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 drivers/char/ipmi/ipmi_ssif.c | 6 +++++-
 drivers/hwmon/lm90.c          | 3 ++-
 drivers/i2c/i2c-smbus.c       | 3 ++-
 include/linux/i2c.h           | 7 ++++++-
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 5f1c3d0..84d07bc 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -568,12 +568,16 @@ static void retry_timeout(unsigned long data)
 }
 
 
-static void ssif_alert(struct i2c_client *client, unsigned int data)
+static void ssif_alert(struct i2c_client *client,
+		       enum i2c_alert_protocol protocol, unsigned int data)
 {
 	struct ssif_info *ssif_info = i2c_get_clientdata(client);
 	unsigned long oflags, *flags;
 	bool do_get = false;
 
+	if (protocol != I2C_PROTOCOL_SMBUS_ALERT)
+		return;
+
 	ssif_inc_stat(ssif_info, alerts);
 
 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index c9ff08d..2b77dbd 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -1624,7 +1624,8 @@ static int lm90_remove(struct i2c_client *client)
 	return 0;
 }
 
-static void lm90_alert(struct i2c_client *client, unsigned int flag)
+static void lm90_alert(struct i2c_client *client, enum i2c_alert_protocol type,
+		       unsigned int flag)
 {
 	u16 alarms;
 
diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index abb55d3..3b6765a 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -56,7 +56,8 @@ static int smbus_do_alert(struct device *dev, void *addrp)
 	if (client->dev.driver) {
 		driver = to_i2c_driver(client->dev.driver);
 		if (driver->alert)
-			driver->alert(client, data->flag);
+			driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT,
+				      data->flag);
 		else
 			dev_warn(&client->dev, "no driver alert()!\n");
 	} else
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 200cf13b..baae02a 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -126,6 +126,10 @@ i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
 					  u8 command, u8 length, u8 *values);
 #endif /* I2C */
 
+enum i2c_alert_protocol {
+	I2C_PROTOCOL_SMBUS_ALERT,
+};
+
 /**
  * struct i2c_driver - represent an I2C device driver
  * @class: What kind of i2c device we instantiate (for detect)
@@ -181,7 +185,8 @@ struct i2c_driver {
 	 * For the SMBus alert protocol, there is a single bit of data passed
 	 * as the alert response's low bit ("event flag").
 	 */
-	void (*alert)(struct i2c_client *, unsigned int data);
+	void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
+		      unsigned int data);
 
 	/* a ioctl like command that can be used to perform specific functions
 	 * with the device.
-- 
2.5.0

Re: [PATCH v5 1/4] i2c: add a protocol parameter to the alert callback

[Guenter Roeck]

On Tue, Mar 15, 2016 at 03:53:41PM +0100, Benjamin Tissoires wrote:
> .alert() is meant to be generic, but there is currently no way
> for the device driver to know which protocol generated the alert.
> Add a parameter in .alert() to help the device driver to understand
> what is given in data.
> 
> This patch is required to have the support of SMBus Host Notify protocol
> through .alert().
> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
>  drivers/char/ipmi/ipmi_ssif.c | 6 +++++-
>  drivers/hwmon/lm90.c          | 3 ++-
>  drivers/i2c/i2c-smbus.c       | 3 ++-
>  include/linux/i2c.h           | 7 ++++++-
>  4 files changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> index 5f1c3d0..84d07bc 100644
> --- a/drivers/char/ipmi/ipmi_ssif.c
> +++ b/drivers/char/ipmi/ipmi_ssif.c
> @@ -568,12 +568,16 @@ static void retry_timeout(unsigned long data)
>  }
>  
>  
> -static void ssif_alert(struct i2c_client *client, unsigned int data)
> +static void ssif_alert(struct i2c_client *client,
> +		       enum i2c_alert_protocol protocol, unsigned int data)
>  {
>  	struct ssif_info *ssif_info = i2c_get_clientdata(client);
>  	unsigned long oflags, *flags;
>  	bool do_get = false;
>  
> +	if (protocol != I2C_PROTOCOL_SMBUS_ALERT)
> +		return;
> +
>  	ssif_inc_stat(ssif_info, alerts);
>  
>  	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
> index c9ff08d..2b77dbd 100644
> --- a/drivers/hwmon/lm90.c
> +++ b/drivers/hwmon/lm90.c
> @@ -1624,7 +1624,8 @@ static int lm90_remove(struct i2c_client *client)
>  	return 0;
>  }
>  
> -static void lm90_alert(struct i2c_client *client, unsigned int flag)
> +static void lm90_alert(struct i2c_client *client, enum i2c_alert_protocol type,
> +		       unsigned int flag)
>  {

For IPMI you added a check for the alert type. It would seem to be prudent to
add one here as well, unless you expect the driver to be able to handle all
alert types without modification. In that case, though, I would expect some
note that this is the case.

Thnaks,
Guenter

>  	u16 alarms;
>  
> diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> index abb55d3..3b6765a 100644
> --- a/drivers/i2c/i2c-smbus.c
> +++ b/drivers/i2c/i2c-smbus.c
> @@ -56,7 +56,8 @@ static int smbus_do_alert(struct device *dev, void *addrp)
>  	if (client->dev.driver) {
>  		driver = to_i2c_driver(client->dev.driver);
>  		if (driver->alert)
> -			driver->alert(client, data->flag);
> +			driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT,
> +				      data->flag);
>  		else
>  			dev_warn(&client->dev, "no driver alert()!\n");
>  	} else
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 200cf13b..baae02a 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -126,6 +126,10 @@ i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
>  					  u8 command, u8 length, u8 *values);
>  #endif /* I2C */
>  
> +enum i2c_alert_protocol {
> +	I2C_PROTOCOL_SMBUS_ALERT,
> +};
> +
>  /**
>   * struct i2c_driver - represent an I2C device driver
>   * @class: What kind of i2c device we instantiate (for detect)
> @@ -181,7 +185,8 @@ struct i2c_driver {
>  	 * For the SMBus alert protocol, there is a single bit of data passed
>  	 * as the alert response's low bit ("event flag").
>  	 */
> -	void (*alert)(struct i2c_client *, unsigned int data);
> +	void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
> +		      unsigned int data);
>  
>  	/* a ioctl like command that can be used to perform specific functions
>  	 * with the device.
> -- 
> 2.5.0
> 

Re: [PATCH v5 1/4] i2c: add a protocol parameter to the alert callback

[Benjamin Tissoires]

On Mar 15 2016 or thereabouts, Guenter Roeck wrote:
> On Tue, Mar 15, 2016 at 03:53:41PM +0100, Benjamin Tissoires wrote:
> > .alert() is meant to be generic, but there is currently no way
> > for the device driver to know which protocol generated the alert.
> > Add a parameter in .alert() to help the device driver to understand
> > what is given in data.
> > 
> > This patch is required to have the support of SMBus Host Notify protocol
> > through .alert().
> > 
> > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > ---
> >  drivers/char/ipmi/ipmi_ssif.c | 6 +++++-
> >  drivers/hwmon/lm90.c          | 3 ++-
> >  drivers/i2c/i2c-smbus.c       | 3 ++-
> >  include/linux/i2c.h           | 7 ++++++-
> >  4 files changed, 15 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> > index 5f1c3d0..84d07bc 100644
> > --- a/drivers/char/ipmi/ipmi_ssif.c
> > +++ b/drivers/char/ipmi/ipmi_ssif.c
> > @@ -568,12 +568,16 @@ static void retry_timeout(unsigned long data)
> >  }
> >  
> >  
> > -static void ssif_alert(struct i2c_client *client, unsigned int data)
> > +static void ssif_alert(struct i2c_client *client,
> > +		       enum i2c_alert_protocol protocol, unsigned int data)
> >  {
> >  	struct ssif_info *ssif_info = i2c_get_clientdata(client);
> >  	unsigned long oflags, *flags;
> >  	bool do_get = false;
> >  
> > +	if (protocol != I2C_PROTOCOL_SMBUS_ALERT)
> > +		return;
> > +
> >  	ssif_inc_stat(ssif_info, alerts);
> >  
> >  	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
> > diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
> > index c9ff08d..2b77dbd 100644
> > --- a/drivers/hwmon/lm90.c
> > +++ b/drivers/hwmon/lm90.c
> > @@ -1624,7 +1624,8 @@ static int lm90_remove(struct i2c_client *client)
> >  	return 0;
> >  }
> >  
> > -static void lm90_alert(struct i2c_client *client, unsigned int flag)
> > +static void lm90_alert(struct i2c_client *client, enum i2c_alert_protocol type,
> > +		       unsigned int flag)
> >  {
> 
> For IPMI you added a check for the alert type. It would seem to be prudent to
> add one here as well, unless you expect the driver to be able to handle all
> alert types without modification. In that case, though, I would expect some
> note that this is the case.

Hi Guenter,

yes, this is a miss from my side. I'll update the series tomorrow.
Hopefully by then, the kbuild bot will find the remaining issues (2 in a
row is kind of shameful).

Cheers,
Benjamin

> 
> Thnaks,
> Guenter
> 
> >  	u16 alarms;
> >  
> > diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> > index abb55d3..3b6765a 100644
> > --- a/drivers/i2c/i2c-smbus.c
> > +++ b/drivers/i2c/i2c-smbus.c
> > @@ -56,7 +56,8 @@ static int smbus_do_alert(struct device *dev, void *addrp)
> >  	if (client->dev.driver) {
> >  		driver = to_i2c_driver(client->dev.driver);
> >  		if (driver->alert)
> > -			driver->alert(client, data->flag);
> > +			driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT,
> > +				      data->flag);
> >  		else
> >  			dev_warn(&client->dev, "no driver alert()!\n");
> >  	} else
> > diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> > index 200cf13b..baae02a 100644
> > --- a/include/linux/i2c.h
> > +++ b/include/linux/i2c.h
> > @@ -126,6 +126,10 @@ i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
> >  					  u8 command, u8 length, u8 *values);
> >  #endif /* I2C */
> >  
> > +enum i2c_alert_protocol {
> > +	I2C_PROTOCOL_SMBUS_ALERT,
> > +};
> > +
> >  /**
> >   * struct i2c_driver - represent an I2C device driver
> >   * @class: What kind of i2c device we instantiate (for detect)
> > @@ -181,7 +185,8 @@ struct i2c_driver {
> >  	 * For the SMBus alert protocol, there is a single bit of data passed
> >  	 * as the alert response's low bit ("event flag").
> >  	 */
> > -	void (*alert)(struct i2c_client *, unsigned int data);
> > +	void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
> > +		      unsigned int data);
> >  
> >  	/* a ioctl like command that can be used to perform specific functions
> >  	 * with the device.
> > -- 
> > 2.5.0
> > 

[PATCH v5 2/4] i2c-smbus: add SMBus Host Notify support

[Benjamin Tissoires]

SMBus Host Notify allows a slave device to act as a master on a bus to
notify the host of an interrupt. On Intel chipsets, the functionality
is directly implemented in the firmware. We just need to export a
function to call .alert() on the proper device driver.

i2c_handle_smbus_host_notify() behaves like i2c_handle_smbus_alert().
When called, it schedules a task that will be able to sleep to go through
the list of devices attached to the adapter.

The current implementation allows one Host Notification to be scheduled
while an other is running.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 Documentation/i2c/smbus-protocol |   3 ++
 drivers/i2c/i2c-smbus.c          | 113 +++++++++++++++++++++++++++++++++++++--
 include/linux/i2c-smbus.h        |  43 +++++++++++++++
 include/linux/i2c.h              |   3 ++
 include/uapi/linux/i2c.h         |   1 +
 5 files changed, 158 insertions(+), 5 deletions(-)

diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol
index 6012b12..4e07848 100644
--- a/Documentation/i2c/smbus-protocol
+++ b/Documentation/i2c/smbus-protocol
@@ -199,6 +199,9 @@ alerting device's address.
 
 [S] [HostAddr] [Wr] A [DevAddr] A [DataLow] A [DataHigh] A [P]
 
+I2C drivers for devices which can trigger SMBus Host Notify should implement
+the optional alert() callback.
+
 
 Packet Error Checking (PEC)
 ===========================
diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 3b6765a..1de7ee5 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -33,7 +33,8 @@ struct i2c_smbus_alert {
 
 struct alert_data {
 	unsigned short		addr;
-	u8			flag:1;
+	enum i2c_alert_protocol	type;
+	unsigned int		data;
 };
 
 /* If this is the alerting device, notify its driver */
@@ -56,8 +57,7 @@ static int smbus_do_alert(struct device *dev, void *addrp)
 	if (client->dev.driver) {
 		driver = to_i2c_driver(client->dev.driver);
 		if (driver->alert)
-			driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT,
-				      data->flag);
+			driver->alert(client, data->type, data->data);
 		else
 			dev_warn(&client->dev, "no driver alert()!\n");
 	} else
@@ -97,8 +97,9 @@ static void smbus_alert(struct work_struct *work)
 		if (status < 0)
 			break;
 
-		data.flag = status & 1;
+		data.data = status & 1;
 		data.addr = status >> 1;
+		data.type = I2C_PROTOCOL_SMBUS_ALERT;
 
 		if (data.addr == prev_addr) {
 			dev_warn(&ara->dev, "Duplicate SMBALERT# from dev "
@@ -106,7 +107,7 @@ static void smbus_alert(struct work_struct *work)
 			break;
 		}
 		dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n",
-			data.addr, data.flag);
+			data.addr, data.data);
 
 		/* Notify driver for the device which issued the alert */
 		device_for_each_child(&ara->adapter->dev, &data,
@@ -240,6 +241,108 @@ int i2c_handle_smbus_alert(struct i2c_client *ara)
 }
 EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
 
+static void smbus_host_notify_work(struct work_struct *work)
+{
+	struct alert_data alert;
+	struct i2c_adapter *adapter;
+	unsigned long flags;
+	u16 payload;
+	u8 addr;
+	struct smbus_host_notify *data;
+
+	data = container_of(work, struct smbus_host_notify, work);
+
+	spin_lock_irqsave(&data->lock, flags);
+	payload = data->payload;
+	addr = data->addr;
+	adapter = data->adapter;
+
+	/* clear the pending bit and release the spinlock */
+	data->pending = false;
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	if (!adapter || !addr)
+		return;
+
+	alert.type = I2C_PROTOCOL_SMBUS_HOST_NOTIFY;
+	alert.addr = addr;
+	alert.data = payload;
+
+	device_for_each_child(&adapter->dev, &alert, smbus_do_alert);
+}
+
+/**
+ * i2c_setup_smbus_host_notify - Allocate a new smbus_host_notify for the given
+ * I2C adapter.
+ * @adapter: the adapter we want to associate a Host Notify function
+ *
+ * Returns a struct smbus_host_notify pointer on success, and NULL on failure.
+ * The resulting smbus_host_notify must not be freed afterwards, it is a
+ * managed resource already.
+ */
+struct smbus_host_notify *i2c_setup_smbus_host_notify(struct i2c_adapter *adap)
+{
+	struct smbus_host_notify *host_notify;
+
+	host_notify = devm_kzalloc(&adap->dev, sizeof(struct smbus_host_notify),
+				   GFP_KERNEL);
+	if (!host_notify)
+		return NULL;
+
+	host_notify->adapter = adap;
+
+	spin_lock_init(&host_notify->lock);
+	INIT_WORK(&host_notify->work, smbus_host_notify_work);
+
+	return host_notify;
+}
+EXPORT_SYMBOL_GPL(i2c_setup_smbus_host_notify);
+
+/**
+ * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
+ * I2C client.
+ * @host_notify: the struct host_notify attached to the relevant adapter
+ * @data: the Host Notify data which contains the payload and address of the
+ * client
+ * Context: can't sleep
+ *
+ * Helper function to be called from an I2C bus driver's interrupt
+ * handler. It will schedule the Host Notify work, in turn calling the
+ * corresponding I2C device driver's alert function.
+ *
+ * host_notify should be a valid pointer previously returned by
+ * i2c_setup_smbus_host_notify().
+ */
+int i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify,
+				 unsigned short addr, unsigned int data)
+{
+	unsigned long flags;
+	struct i2c_adapter *adapter;
+
+	if (!host_notify || !host_notify->adapter)
+		return -EINVAL;
+
+	adapter = host_notify->adapter;
+
+	spin_lock_irqsave(&host_notify->lock, flags);
+
+	if (host_notify->pending) {
+		spin_unlock_irqrestore(&host_notify->lock, flags);
+		dev_warn(&adapter->dev, "Host Notify already scheduled\n.");
+		return -EFAULT;
+	}
+
+	host_notify->payload = data;
+	host_notify->addr = addr;
+
+	/* Mark that there is a pending notification and release the lock */
+	host_notify->pending = true;
+	spin_unlock_irqrestore(&host_notify->lock, flags);
+
+	return schedule_work(&host_notify->work);
+}
+EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
+
 module_i2c_driver(smbalert_driver);
 
 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h
index 8f1b086..d2fbd19 100644
--- a/include/linux/i2c-smbus.h
+++ b/include/linux/i2c-smbus.h
@@ -23,6 +23,8 @@
 #define _LINUX_I2C_SMBUS_H
 
 #include <linux/i2c.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
 
 
 /**
@@ -48,4 +50,45 @@ struct i2c_client *i2c_setup_smbus_alert(struct i2c_adapter *adapter,
 					 struct i2c_smbus_alert_setup *setup);
 int i2c_handle_smbus_alert(struct i2c_client *ara);
 
+/**
+ * smbus_host_notify - internal structure used by the Host Notify mechanism.
+ * @adapter: the I2C adapter associated with this struct
+ * @work: worker used to schedule the IRQ in the slave device
+ * @lock: spinlock to check if a notification is already pending
+ * @pending: flag set when a notification is pending (any new notification will
+ *		be rejected if pending is true)
+ * @payload: the actual payload of the Host Notify event
+ * @addr: the address of the slave device which raised the notification
+ *
+ * This struct needs to be allocated by i2c_setup_smbus_host_notify() and does
+ * not need to be freed. Internally, i2c_setup_smbus_host_notify() uses a
+ * managed resource to clean this up when the adapter get released.
+ */
+struct smbus_host_notify {
+	struct i2c_adapter	*adapter;
+	struct work_struct	work;
+	spinlock_t		lock;
+	bool			pending;
+	u16			payload;
+	u8			addr;
+};
+
+#if defined(CONFIG_I2C_SMBUS) || defined(CONFIG_I2C_SMBUS_MODULE)
+struct smbus_host_notify *i2c_setup_smbus_host_notify(struct i2c_adapter *adap);
+int i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify,
+				 unsigned short addr, unsigned int data);
+#else
+static inline struct smbus_host_notify *
+i2c_setup_smbus_host_notify(struct i2c_adapter *adap)
+{
+	return NULL;
+}
+
+static inline int i2c_handle_smbus_host_notify(struct i2c_adapter *adapter,
+				     unsigned short addr, unsigned int data)
+{
+	return 0;
+}
+#endif /* I2C_SMBUS */
+
 #endif /* _LINUX_I2C_SMBUS_H */
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index baae02a..056f800 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -128,6 +128,7 @@ i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
 
 enum i2c_alert_protocol {
 	I2C_PROTOCOL_SMBUS_ALERT,
+	I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
 };
 
 /**
@@ -184,6 +185,8 @@ struct i2c_driver {
 	 * The format and meaning of the data value depends on the protocol.
 	 * For the SMBus alert protocol, there is a single bit of data passed
 	 * as the alert response's low bit ("event flag").
+	 * For the SMBus Host Notify protocol, the data corresponds to the
+	 * 16-bit payload data reported by the slave device acting as master.
 	 */
 	void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
 		      unsigned int data);
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index b0a7dd6..83ec8ae 100644
--- a/include/uapi/linux/i2c.h
+++ b/include/uapi/linux/i2c.h
@@ -101,6 +101,7 @@ struct i2c_msg {
 #define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
 #define I2C_FUNC_SMBUS_READ_I2C_BLOCK	0x04000000 /* I2C-like block xfer  */
 #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK	0x08000000 /* w/ 1-byte reg. addr. */
+#define I2C_FUNC_SMBUS_HOST_NOTIFY	0x10000000
 
 #define I2C_FUNC_SMBUS_BYTE		(I2C_FUNC_SMBUS_READ_BYTE | \
 					 I2C_FUNC_SMBUS_WRITE_BYTE)
-- 
2.5.0

[PATCH v5 3/4] i2c: i801: add support of Host Notify

[Benjamin Tissoires]

The i801 chip can handle the Host Notify feature since ICH 3 as mentioned
in http://www.intel.com/content/dam/doc/datasheet/82801ca-io-controller-hub-3-datasheet.pdf

Enable the functionality unconditionally and propagate the alert
on each notification.

With a T440s and a Synaptics touchpad that implements Host Notify, the
payload data is always 0x0000, so I am not sure if the device actually
sends the payload or if there is a problem regarding the implementation.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 drivers/i2c/busses/i2c-i801.c | 85 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 82 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 585a3b7..b244aa40 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -72,6 +72,7 @@
  * Block process call transaction	no
  * I2C block read transaction		yes (doesn't use the block buffer)
  * Slave mode				no
+ * SMBus Host Notify			yes
  * Interrupt processing			yes
  *
  * See the file Documentation/i2c/busses/i2c-i801 for details.
@@ -86,6 +87,7 @@
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/acpi.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
@@ -112,6 +114,10 @@
 #define SMBPEC(p)	(8 + (p)->smba)		/* ICH3 and later */
 #define SMBAUXSTS(p)	(12 + (p)->smba)	/* ICH4 and later */
 #define SMBAUXCTL(p)	(13 + (p)->smba)	/* ICH4 and later */
+#define SMBSLVSTS(p)	(16 + (p)->smba)	/* ICH3 and later */
+#define SMBSLVCMD(p)	(17 + (p)->smba)	/* ICH3 and later */
+#define SMBNTFDADD(p)	(20 + (p)->smba)	/* ICH3 and later */
+#define SMBNTFDDAT(p)	(22 + (p)->smba)	/* ICH3 and later */
 
 /* PCI Address Constants */
 #define SMBBAR		4
@@ -176,6 +182,12 @@
 #define SMBHSTSTS_INTR		0x02
 #define SMBHSTSTS_HOST_BUSY	0x01
 
+/* Host Notify Status registers bits */
+#define SMBSLVSTS_HST_NTFY_STS	1
+
+/* Host Notify Command registers bits */
+#define SMBSLVCMD_HST_NTFY_INTREN	0x01
+
 #define STATUS_ERROR_FLAGS	(SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
 				 SMBHSTSTS_DEV_ERR)
 
@@ -244,13 +256,18 @@ struct i801_priv {
 	struct platform_device *mux_pdev;
 #endif
 	struct platform_device *tco_pdev;
+
+	struct smbus_host_notify *host_notify;
 };
 
+#define SMBHSTNTFY_SIZE		8
+
 #define FEATURE_SMBUS_PEC	(1 << 0)
 #define FEATURE_BLOCK_BUFFER	(1 << 1)
 #define FEATURE_BLOCK_PROC	(1 << 2)
 #define FEATURE_I2C_BLOCK_READ	(1 << 3)
 #define FEATURE_IRQ		(1 << 4)
+#define FEATURE_HOST_NOTIFY	(1 << 5)
 /* Not really a feature, but it's convenient to handle it as such */
 #define FEATURE_IDF		(1 << 15)
 #define FEATURE_TCO		(1 << 16)
@@ -261,6 +278,7 @@ static const char *i801_feature_names[] = {
 	"Block process call",
 	"I2C block read",
 	"Interrupt",
+	"SMBus Host Notify",
 };
 
 static unsigned int disable_features;
@@ -269,7 +287,8 @@ MODULE_PARM_DESC(disable_features, "Disable selected driver features:\n"
 	"\t\t  0x01  disable SMBus PEC\n"
 	"\t\t  0x02  disable the block buffer\n"
 	"\t\t  0x08  disable the I2C block read functionality\n"
-	"\t\t  0x10  don't use interrupts ");
+	"\t\t  0x10  don't use interrupts\n"
+	"\t\t  0x20  disable SMBus Host Notify ");
 
 /* Make sure the SMBus host is ready to start transmitting.
    Return 0 if it is, -EBUSY if it is not. */
@@ -503,8 +522,23 @@ static void i801_isr_byte_done(struct i801_priv *priv)
 	outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
 }
 
+static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
+{
+	unsigned short addr;
+	unsigned int data;
+
+	addr = inb_p(SMBNTFDADD(priv)) >> 1;
+	data = inw_p(SMBNTFDDAT(priv));
+
+	i2c_handle_smbus_host_notify(priv->host_notify, addr, data);
+
+	/* clear Host Notify bit and return */
+	outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
+	return IRQ_HANDLED;
+}
+
 /*
- * There are two kinds of interrupts:
+ * There are three kinds of interrupts:
  *
  * 1) i801 signals transaction completion with one of these interrupts:
  *      INTR - Success
@@ -516,6 +550,8 @@ static void i801_isr_byte_done(struct i801_priv *priv)
  *
  * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
  *    occurs for each byte of a byte-by-byte to prepare the next byte.
+ *
+ * 3) Host Notify interrupts
  */
 static irqreturn_t i801_isr(int irq, void *dev_id)
 {
@@ -528,6 +564,12 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
 	if (!(pcists & SMBPCISTS_INTS))
 		return IRQ_NONE;
 
+	if (priv->features & FEATURE_HOST_NOTIFY) {
+		status = inb_p(SMBSLVSTS(priv));
+		if (status & SMBSLVSTS_HST_NTFY_STS)
+			return i801_host_notify_isr(priv);
+	}
+
 	status = inb_p(SMBHSTSTS(priv));
 	if (status & SMBHSTSTS_BYTE_DONE)
 		i801_isr_byte_done(priv);
@@ -825,7 +867,29 @@ static u32 i801_func(struct i2c_adapter *adapter)
 	       I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK |
 	       ((priv->features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0) |
 	       ((priv->features & FEATURE_I2C_BLOCK_READ) ?
-		I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0);
+		I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0) |
+	       ((priv->features & FEATURE_HOST_NOTIFY) ?
+		I2C_FUNC_SMBUS_HOST_NOTIFY : 0);
+}
+
+static int i801_enable_host_notify(struct i2c_adapter *adapter)
+{
+	struct i801_priv *priv = i2c_get_adapdata(adapter);
+
+	if (!(priv->features & FEATURE_HOST_NOTIFY))
+		return -ENOTSUPP;
+
+	if (!priv->host_notify)
+		priv->host_notify = i2c_setup_smbus_host_notify(adapter);
+
+	if (!priv->host_notify)
+		return -ENOMEM;
+
+	outb_p(SMBSLVCMD_HST_NTFY_INTREN, SMBSLVCMD(priv));
+	/* clear Host Notify bit to allow a new notification */
+	outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
+
+	return 0;
 }
 
 static const struct i2c_algorithm smbus_algorithm = {
@@ -1279,6 +1343,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		priv->features |= FEATURE_SMBUS_PEC;
 		priv->features |= FEATURE_BLOCK_BUFFER;
 		priv->features |= FEATURE_TCO;
+		priv->features |= FEATURE_HOST_NOTIFY;
 		break;
 
 	case PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF0:
@@ -1298,6 +1363,8 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		priv->features |= FEATURE_BLOCK_BUFFER;
 		/* fall through */
 	case PCI_DEVICE_ID_INTEL_82801CA_3:
+		priv->features |= FEATURE_HOST_NOTIFY;
+		/* fall through */
 	case PCI_DEVICE_ID_INTEL_82801BA_2:
 	case PCI_DEVICE_ID_INTEL_82801AB_3:
 	case PCI_DEVICE_ID_INTEL_82801AA_3:
@@ -1407,6 +1474,15 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return err;
 	}
 
+	/*
+	 * Enable Host Notify for chips that supports it.
+	 * It is done after i2c_add_adapter() so that we are sure the work queue
+	 * is not used if i2c_add_adapter() fails.
+	 */
+	err = i801_enable_host_notify(&priv->adapter);
+	if (err && err != -ENOTSUPP)
+		dev_warn(&dev->dev, "Unable to enable SMBus Host Notify\n");
+
 	i801_probe_optional_slaves(priv);
 	/* We ignore errors - multiplexing is optional */
 	i801_add_mux(priv);
@@ -1445,8 +1521,11 @@ static int i801_suspend(struct pci_dev *dev, pm_message_t mesg)
 
 static int i801_resume(struct pci_dev *dev)
 {
+	struct i801_priv *priv = pci_get_drvdata(dev);
+
 	pci_set_power_state(dev, PCI_D0);
 	pci_restore_state(dev);
+	i801_enable_host_notify(&priv->adapter);
 	return 0;
 }
 #else
-- 
2.5.0

Re: [PATCH v5 3/4] i2c: i801: add support of Host Notify

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2284 bytes --]

Hi Benjamin,

[auto build test WARNING on input/next]
[also build test WARNING on v4.5 next-20160315]
[cannot apply to wsa/i2c/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Benjamin-Tissoires/i2c-smbus-add-support-for-HOST-NOTIFY/20160315-230340
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git next
config: x86_64-randconfig-x006-201611 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   drivers/i2c/busses/i2c-i801.c: In function 'i801_host_notify_isr':
>> drivers/i2c/busses/i2c-i801.c:533:31: warning: passing argument 1 of 'i2c_handle_smbus_host_notify' from incompatible pointer type [-Wincompatible-pointer-types]
     i2c_handle_smbus_host_notify(priv->host_notify, addr, data);
                                  ^
   In file included from drivers/i2c/busses/i2c-i801.c:90:0:
   include/linux/i2c-smbus.h:87:19: note: expected 'struct i2c_adapter *' but argument is of type 'struct smbus_host_notify *'
    static inline int i2c_handle_smbus_host_notify(struct i2c_adapter *adapter,
                      ^

vim +/i2c_handle_smbus_host_notify +533 drivers/i2c/busses/i2c-i801.c

   517			/* Write next byte, except for IRQ after last byte */
   518			outb_p(priv->data[++priv->count], SMBBLKDAT(priv));
   519		}
   520	
   521		/* Clear BYTE_DONE to continue with next byte */
   522		outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
   523	}
   524	
   525	static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
   526	{
   527		unsigned short addr;
   528		unsigned int data;
   529	
   530		addr = inb_p(SMBNTFDADD(priv)) >> 1;
   531		data = inw_p(SMBNTFDDAT(priv));
   532	
 > 533		i2c_handle_smbus_host_notify(priv->host_notify, addr, data);
   534	
   535		/* clear Host Notify bit and return */
   536		outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
   537		return IRQ_HANDLED;
   538	}
   539	
   540	/*
   541	 * There are three kinds of interrupts:

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 22724 bytes --]

Re: [PATCH v5 3/4] i2c: i801: add support of Host Notify

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1049 bytes --]

Hi Benjamin,

[auto build test ERROR on input/next]
[also build test ERROR on v4.5 next-20160315]
[cannot apply to wsa/i2c/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Benjamin-Tissoires/i2c-smbus-add-support-for-HOST-NOTIFY/20160315-230340
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git next
config: x86_64-rhel (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   drivers/built-in.o: In function `i801_enable_host_notify':
>> i2c-i801.c:(.text+0x2d57cb): undefined reference to `i2c_setup_smbus_host_notify'
   drivers/built-in.o: In function `i801_isr':
>> i2c-i801.c:(.text+0x2d69ef): undefined reference to `i2c_handle_smbus_host_notify'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 35654 bytes --]

[PATCH v5 4/4] Input: synaptics-rmi4 - add SMBus support

[Benjamin Tissoires]

Code obtained from https://raw.githubusercontent.com/mightybigcar/synaptics-rmi4/jf/drivers/input/rmi4/rmi_smbus.c
and updated to match upstream. And fixed to make it work.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
---
 drivers/input/rmi4/Kconfig     |  12 ++
 drivers/input/rmi4/Makefile    |   1 +
 drivers/input/rmi4/rmi_bus.h   |  12 ++
 drivers/input/rmi4/rmi_smbus.c | 416 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 441 insertions(+)
 create mode 100644 drivers/input/rmi4/rmi_smbus.c

diff --git a/drivers/input/rmi4/Kconfig b/drivers/input/rmi4/Kconfig
index f73df24..86a180b 100644
--- a/drivers/input/rmi4/Kconfig
+++ b/drivers/input/rmi4/Kconfig
@@ -27,6 +27,18 @@ config RMI4_SPI
 
 	  If unsure, say N.
 
+config RMI4_SMB
+	tristate "RMI4 SMB Support"
+	depends on RMI4_CORE && I2C
+	help
+	  Say Y here if you want to support RMI4 devices connected to an SMB
+	  bus.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called rmi_smbus.
+
 config RMI4_2D_SENSOR
 	bool
 	depends on RMI4_CORE
diff --git a/drivers/input/rmi4/Makefile b/drivers/input/rmi4/Makefile
index 95c00a7..3c8ebf2 100644
--- a/drivers/input/rmi4/Makefile
+++ b/drivers/input/rmi4/Makefile
@@ -11,3 +11,4 @@ rmi_core-$(CONFIG_RMI4_F30) += rmi_f30.o
 # Transports
 obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o
 obj-$(CONFIG_RMI4_SPI) += rmi_spi.o
+obj-$(CONFIG_RMI4_SMB) += rmi_smbus.o
diff --git a/drivers/input/rmi4/rmi_bus.h b/drivers/input/rmi4/rmi_bus.h
index 8995798..b7625a9 100644
--- a/drivers/input/rmi4/rmi_bus.h
+++ b/drivers/input/rmi4/rmi_bus.h
@@ -105,6 +105,18 @@ rmi_get_platform_data(struct rmi_device *d)
 bool rmi_is_physical_device(struct device *dev);
 
 /**
+ * rmi_reset - reset a RMI4 device
+ * @d: Pointer to an RMI device
+ *
+ * Calls for a reset of each function implemented by a specific device.
+ * Returns 0 on success or a negative error code.
+ */
+static inline int rmi_reset(struct rmi_device *d)
+{
+	return d->driver->reset_handler(d);
+}
+
+/**
  * rmi_read - read a single byte
  * @d: Pointer to an RMI device
  * @addr: The address to read from
diff --git a/drivers/input/rmi4/rmi_smbus.c b/drivers/input/rmi4/rmi_smbus.c
new file mode 100644
index 0000000..eed6821
--- /dev/null
+++ b/drivers/input/rmi4/rmi_smbus.c
@@ -0,0 +1,416 @@
+/*
+ * Copyright (c) 2015 - 2016 Red Hat, Inc
+ * Copyright (c) 2011, 2012 Synaptics Incorporated
+ * Copyright (c) 2011 Unixphere
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kconfig.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/rmi.h>
+#include <linux/slab.h>
+#include "rmi_driver.h"
+
+#define SMB_PROTOCOL_VERSION_ADDRESS	0xfd
+#define SMB_MAX_COUNT			32
+#define RMI_SMB2_MAP_SIZE		8 /* 8 entry of 4 bytes each */
+#define RMI_SMB2_MAP_FLAGS_WE		0x01
+
+struct mapping_table_entry {
+	u16 rmiaddr;
+	u8 readcount;
+	u8 flags;
+};
+
+struct rmi_smb_xport {
+	struct rmi_transport_dev xport;
+	struct i2c_client *client;
+
+	struct mutex page_mutex;
+	int page;
+	u8 table_index;
+	struct mutex mappingtable_mutex;
+	struct mapping_table_entry mapping_table[RMI_SMB2_MAP_SIZE];
+};
+
+static int rmi_smb_get_version(struct rmi_smb_xport *rmi_smb)
+{
+	struct i2c_client *client = rmi_smb->client;
+	int retval;
+
+	/* Check if for SMBus new version device by reading version byte. */
+	retval = i2c_smbus_read_byte_data(client, SMB_PROTOCOL_VERSION_ADDRESS);
+	if (retval < 0) {
+		dev_err(&client->dev, "failed to get SMBus version number!\n");
+		return retval;
+	}
+	return retval + 1;
+}
+
+/* SMB block write - wrapper over ic2_smb_write_block */
+static int smb_block_write(struct rmi_transport_dev *xport,
+			      u8 commandcode, const void *buf, size_t len)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	struct i2c_client *client = rmi_smb->client;
+	int retval;
+
+	retval = i2c_smbus_write_block_data(client, commandcode, len, buf);
+
+	rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
+		"wrote %zd bytes at %#04x: %d (%*ph)\n",
+		len, commandcode, retval, (int)len, buf);
+
+	return retval;
+}
+
+/*
+ * The function to get command code for smbus operations and keeps
+ * records to the driver mapping table
+ */
+static int rmi_smb_get_command_code(struct rmi_transport_dev *xport,
+		u16 rmiaddr, int bytecount, bool isread, u8 *commandcode)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	int i;
+	int retval;
+	struct mapping_table_entry mapping_data[1];
+
+	mutex_lock(&rmi_smb->mappingtable_mutex);
+	for (i = 0; i < RMI_SMB2_MAP_SIZE; i++) {
+		if (rmi_smb->mapping_table[i].rmiaddr == rmiaddr) {
+			if (isread) {
+				if (rmi_smb->mapping_table[i].readcount
+							== bytecount) {
+					*commandcode = i;
+					retval = 0;
+					goto exit;
+				}
+			} else {
+				if (rmi_smb->mapping_table[i].flags &
+							RMI_SMB2_MAP_FLAGS_WE) {
+					*commandcode = i;
+					retval = 0;
+					goto exit;
+				}
+			}
+		}
+	}
+	i = rmi_smb->table_index;
+	rmi_smb->table_index = (i + 1) % RMI_SMB2_MAP_SIZE;
+
+	/* constructs mapping table data entry. 4 bytes each entry */
+	memset(mapping_data, 0, sizeof(mapping_data));
+
+	mapping_data[0].rmiaddr = cpu_to_le16(rmiaddr);
+	mapping_data[0].readcount = bytecount;
+	mapping_data[0].flags = !isread ? RMI_SMB2_MAP_FLAGS_WE : 0;
+
+	retval = smb_block_write(xport, i + 0x80, mapping_data,
+				 sizeof(mapping_data));
+
+	if (retval < 0) {
+		/*
+		 * if not written to device mapping table
+		 * clear the driver mapping table records
+		 */
+		rmi_smb->mapping_table[i].rmiaddr = 0x0000;
+		rmi_smb->mapping_table[i].readcount = 0;
+		rmi_smb->mapping_table[i].flags = 0;
+		goto exit;
+	}
+	/* save to the driver level mapping table */
+	rmi_smb->mapping_table[i].rmiaddr = rmiaddr;
+	rmi_smb->mapping_table[i].readcount = bytecount;
+	rmi_smb->mapping_table[i].flags = !isread ? RMI_SMB2_MAP_FLAGS_WE : 0;
+	*commandcode = i;
+
+exit:
+	mutex_unlock(&rmi_smb->mappingtable_mutex);
+
+	return retval;
+}
+
+static int rmi_smb_write_block(struct rmi_transport_dev *xport, u16 rmiaddr,
+				const void *databuff, size_t len)
+{
+	int retval = 0;
+	u8 commandcode;
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	int cur_len = (int)len;
+
+	mutex_lock(&rmi_smb->page_mutex);
+
+	while (cur_len > 0) {
+		/*
+		 * break into 32 butes chunks to write get command code
+		 */
+		int block_len = min_t(int, len, SMB_MAX_COUNT);
+
+		retval = rmi_smb_get_command_code(xport, rmiaddr, block_len,
+						  false, &commandcode);
+		if (retval < 0)
+			goto exit;
+
+		/* write to smb device */
+		retval = smb_block_write(xport, commandcode,
+					 databuff, block_len);
+		if (retval < 0)
+			goto exit;
+
+		/* prepare to write next block of bytes */
+		cur_len -= SMB_MAX_COUNT;
+		databuff += SMB_MAX_COUNT;
+		rmiaddr += SMB_MAX_COUNT;
+	}
+exit:
+	mutex_unlock(&rmi_smb->page_mutex);
+	return retval;
+}
+
+/* SMB block read - wrapper over ic2_smb_read_block */
+static int smb_block_read(struct rmi_transport_dev *xport,
+			     u8 commandcode, void *buf, size_t len)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	struct i2c_client *client = rmi_smb->client;
+	int retval;
+
+	retval = i2c_smbus_read_block_data(client, commandcode, buf);
+	if (retval < 0)
+		return retval;
+
+	return retval;
+}
+
+static int rmi_smb_read_block(struct rmi_transport_dev *xport, u16 rmiaddr,
+			      void *databuff, size_t len)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	int retval;
+	u8 commandcode;
+	int cur_len = (int)len;
+
+	mutex_lock(&rmi_smb->page_mutex);
+	memset(databuff, 0, len);
+
+	while (cur_len > 0) {
+		/* break into 32 bytes chunks to write get command code */
+		int block_len =  min_t(int, cur_len, SMB_MAX_COUNT);
+
+		retval = rmi_smb_get_command_code(xport, rmiaddr, block_len,
+						  true, &commandcode);
+		if (retval < 0)
+			goto exit;
+
+		/* read to smb device */
+		retval = smb_block_read(xport, commandcode,
+					databuff, block_len);
+		if (retval < 0)
+			goto exit;
+
+		/* prepare to read next block of bytes */
+		cur_len -= SMB_MAX_COUNT;
+		databuff += SMB_MAX_COUNT;
+		rmiaddr += SMB_MAX_COUNT;
+	}
+
+	retval = 0;
+
+exit:
+	mutex_unlock(&rmi_smb->page_mutex);
+	return retval;
+}
+
+static void rmi_smb_clear_state(struct rmi_smb_xport *rmi_smb)
+{
+	/* the mapping table has been flushed, discard the current one */
+	mutex_lock(&rmi_smb->mappingtable_mutex);
+	memset(rmi_smb->mapping_table, 0, sizeof(rmi_smb->mapping_table));
+	mutex_unlock(&rmi_smb->mappingtable_mutex);
+}
+
+static int rmi_smb_enable_smbus_mode(struct rmi_smb_xport *rmi_smb)
+{
+	int retval;
+
+	/* we need to get the smbus version to activate the touchpad */
+	retval = rmi_smb_get_version(rmi_smb);
+	if (retval < 0)
+		return retval;
+
+	return 0;
+}
+
+static int rmi_smb_reset(struct rmi_transport_dev *xport, u16 reset_addr)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+
+	rmi_smb_clear_state(rmi_smb);
+
+	/*
+	 * we do not call the actual reset command, it has to be handled in
+	 * PS/2 or there will be races between PS/2 and SMBus.
+	 * PS/2 should ensure that a psmouse_reset is called before
+	 * intializing the device and after it has been removed to be in a known
+	 * state.
+	 */
+	return rmi_smb_enable_smbus_mode(rmi_smb);
+}
+
+static const struct rmi_transport_ops rmi_smb_ops = {
+	.write_block	= rmi_smb_write_block,
+	.read_block	= rmi_smb_read_block,
+	.reset		= rmi_smb_reset,
+};
+
+static void rmi_smb_alert(struct i2c_client *client,
+			  enum i2c_alert_protocol type, unsigned int data)
+{
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+	struct rmi_device *rmi_dev = rmi_smb->xport.rmi_dev;
+	struct rmi_driver_data *drv_data = dev_get_drvdata(&rmi_dev->dev);
+
+	if (type != I2C_PROTOCOL_SMBUS_HOST_NOTIFY)
+		return;
+
+	if (!drv_data) {
+		dev_err(&client->dev,
+			"Something went wrong, driver data is NULL.\n");
+		return;
+	}
+
+	rmi_process_interrupt_requests(rmi_dev);
+}
+
+static struct i2c_driver rmi_smb_driver;
+
+static int rmi_smb_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct rmi_device_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct rmi_smb_xport *rmi_smb;
+	int retval;
+	int smbus_version;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+				     I2C_FUNC_SMBUS_HOST_NOTIFY)) {
+		dev_err(&client->dev,
+			"adapter does not support required functionality.\n");
+		return -ENODEV;
+	}
+
+	rmi_smb = devm_kzalloc(&client->dev, sizeof(struct rmi_smb_xport),
+				GFP_KERNEL);
+	if (!rmi_smb)
+		return -ENOMEM;
+
+	if (!pdata) {
+		dev_err(&client->dev, "no platform data, aborting\n");
+		return -ENOMEM;
+	}
+
+	rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",
+		dev_name(&client->dev));
+
+	rmi_smb->client = client;
+	mutex_init(&rmi_smb->page_mutex);
+	mutex_init(&rmi_smb->mappingtable_mutex);
+
+	rmi_smb->xport.dev = &client->dev;
+	rmi_smb->xport.pdata = *pdata;
+	rmi_smb->xport.proto_name = "smb2";
+	rmi_smb->xport.ops = &rmi_smb_ops;
+
+	/* Check if for SMBus new version device by reading version byte. */
+	retval = rmi_smb_get_version(rmi_smb);
+	if (retval < 0)
+		return retval;
+
+	smbus_version = retval;
+	rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Smbus version is %d",
+		smbus_version);
+
+	if (smbus_version != 2) {
+		dev_err(&client->dev, "Unrecognized SMB version %d.\n",
+				smbus_version);
+		return -ENODEV;
+	}
+
+	i2c_set_clientdata(client, rmi_smb);
+
+	retval = rmi_register_transport_device(&rmi_smb->xport);
+	if (retval) {
+		dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",
+			client->addr);
+		i2c_set_clientdata(client, NULL);
+		return retval;
+	}
+
+	dev_info(&client->dev, "registered rmi smb driver at %#04x.\n",
+			client->addr);
+	return 0;
+
+}
+
+static int rmi_smb_remove(struct i2c_client *client)
+{
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+
+	rmi_unregister_transport_device(&rmi_smb->xport);
+
+	return 0;
+}
+
+static int rmi_smb_resume(struct device *dev)
+{
+	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+	struct rmi_device *rmi_dev = rmi_smb->xport.rmi_dev;
+
+	rmi_smb_reset(&rmi_smb->xport, 0);
+
+	rmi_reset(rmi_dev);
+	return 0;
+}
+
+static const struct i2c_device_id rmi_id[] = {
+	{ "rmi4_smbus", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rmi_id);
+
+static struct i2c_driver rmi_smb_driver = {
+	.driver = {
+		.owner	= THIS_MODULE,
+		.name	= "rmi4_smbus",
+		.resume	= rmi_smb_resume,
+	},
+	.id_table	= rmi_id,
+	.probe		= rmi_smb_probe,
+	.remove		= rmi_smb_remove,
+	.alert		= rmi_smb_alert,
+};
+
+module_i2c_driver(rmi_smb_driver);
+
+MODULE_AUTHOR("Allie Xiong <axiong@synaptics.com>");
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
+MODULE_DESCRIPTION("RMI4 SMBus driver");
+MODULE_LICENSE("GPL");
-- 
2.5.0