linux-kernel - Re: [PATCH v6 1/4] i2c: add a protocol parameter to the alert callback

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Message-ID: <20160318005015.GA31307@roeck-us.net>
Date:	Thu, 17 Mar 2016 17:50:15 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
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 v6 1/4] i2c: add a protocol parameter to the alert
 callback

On Wed, Mar 16, 2016 at 05:39:05PM +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>

For hwmon:

Acked-by: Guenter Roeck <linux@...ck-us.net>

> ---
> 
> new in v2
> 
> changes in v3:
> - added also lm90.c to support the new API
> 
> no changes in v4
> 
> no changes in v5
> 
> changes in v6:
> - made sure lm90 also checks for the type of alert first
> 
>  drivers/char/ipmi/ipmi_ssif.c | 6 +++++-
>  drivers/hwmon/lm90.c          | 6 +++++-
>  drivers/i2c/i2c-smbus.c       | 3 ++-
>  include/linux/i2c.h           | 7 ++++++-
>  4 files changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> index 5f1c3d0..1d67fa3 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 type,
> +		       unsigned int data)
>  {
>  	struct ssif_info *ssif_info = i2c_get_clientdata(client);
>  	unsigned long oflags, *flags;
>  	bool do_get = false;
>  
> +	if (type != 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..a00fd38 100644
> --- a/drivers/hwmon/lm90.c
> +++ b/drivers/hwmon/lm90.c
> @@ -1624,10 +1624,14 @@ 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;
>  
> +	if (type != I2C_PROTOCOL_SMBUS_ALERT)
> +		return;
> +
>  	if (lm90_is_tripped(client, &alarms)) {
>  		/*
>  		 * Disable ALERT# output, because these chips don't implement
> 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
>