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

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Date:	Tue, 15 Mar 2016 21:08:48 +0100
From:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	Wolfram Sang <wsa@...-dreams.de>, Jonathan Corbet <corbet@....net>,
	Corey Minyard <minyard@....org>,
	Jean Delvare <jdelvare@...e.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Andrew Duggan <aduggan@...aptics.com>,
	Christopher Heiny <cheiny@...aptics.com>,
	linux-i2c@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH v5 1/4] i2c: add a protocol parameter to the alert
 callback

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@...hat.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
> >