linux-kernel - Re: [PATCH 1/4] mfd/menf21bmc: remove auto exiting of production mode and add sysfs interface

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Message-ID: <20160111103354.GC14104@x1>
Date:	Mon, 11 Jan 2016 10:33:54 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Andreas Werner <andreas.werner@....de>
Cc:	linux-kernel@...r.kernel.org, sameo@...ux.intel.com
Subject: Re: [PATCH 1/4] mfd/menf21bmc: remove auto exiting of production
 mode and add sysfs interface

When you re-submit this set, with the correct Maintainers CC'ed,
please also update the patch subject lines, so they match the format
of the subsystem.

On Mon, 11 Jan 2016, Lee Jones wrote:
> On Wed, 16 Dec 2015, Andreas Werner wrote:
> 
> > Changed "exit production mode" from automatic exiting to
> > manually using the sysfs interface.
> > 
> > If the driver exit the production mode automatically, the board will
> > not start anymore if the bootloader does not already have the "BIOS life sign"
> > feature.
> > 
> > This patch remove the auto mechanism and add a sysfs interface to manually
> > exiting the production e.g. during the EOL test of the board.
> > 
> > Signed-off-by: Andreas Werner <andreas.werner@....de>
> > ---
> >  drivers/mfd/menf21bmc.c | 65 +++++++++++++++++++++++++++++++++----------------
> >  1 file changed, 44 insertions(+), 21 deletions(-)
> 
> Acked-by: Lee Jones <lee.jones@...aro.org>
> 
> > diff --git a/drivers/mfd/menf21bmc.c b/drivers/mfd/menf21bmc.c
> > index 1c27434..742ffe7 100644
> > --- a/drivers/mfd/menf21bmc.c
> > +++ b/drivers/mfd/menf21bmc.c
> > @@ -27,31 +27,57 @@ static struct mfd_cell menf21bmc_cell[] = {
> >  	{ .name = "menf21bmc_hwmon", }
> >  };
> >  
> > -static int menf21bmc_wdt_exit_prod_mode(struct i2c_client *client)
> > +static ssize_t menf21bmc_mode_show(struct device *dev,
> > +				  struct device_attribute *attr, char *buf)
> >  {
> > -	int val, ret;
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	int val;
> >  
> >  	val = i2c_smbus_read_byte_data(client, BMC_CMD_WDT_PROD_STAT);
> >  	if (val < 0)
> >  		return val;
> >  
> > +	return sprintf(buf, "%d\n", val);
> > +}
> > +
> > +static ssize_t menf21bmc_mode_store(struct device *dev,
> > +				   struct device_attribute *attr,
> > +				   const char *buf, size_t size)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	unsigned long mode_val;
> > +	int ret;
> > +
> > +	if (kstrtoul(buf, 0, &mode_val))
> > +		return -EINVAL;
> > +
> >  	/*
> > -	 * Production mode should be not active after delivery of the Board.
> > -	 * To be sure we check it, inform the user and exit the mode
> > -	 * if active.
> > +	 * We cannot set the production mode (0).
> > +	 * This is the default mode. If exited once,
> > +	 * it cannot be set anymore.
> >  	 */
> > -	if (val == 0x00) {
> > -		dev_info(&client->dev,
> > -			"BMC in production mode. Exit production mode\n");
> > +	if (!mode_val)
> > +		return -EINVAL;
> >  
> > -		ret = i2c_smbus_write_byte(client, BMC_CMD_WDT_EXIT_PROD);
> > -		if (ret < 0)
> > -			return ret;
> > -	}
> > +	ret = i2c_smbus_write_byte(client, BMC_CMD_WDT_EXIT_PROD);
> > +	if (ret < 0)
> > +		return ret;
> >  
> > -	return 0;
> > +	return size;
> >  }
> >  
> > +static DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, menf21bmc_mode_show,
> > +		   menf21bmc_mode_store);
> > +
> > +static struct attribute *menf21bmc_attributes[] = {
> > +	&dev_attr_mode.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group menf21bmc_attr_group = {
> > +	.attrs = menf21bmc_attributes,
> > +};
> > +
> >  static int
> >  menf21bmc_probe(struct i2c_client *client, const struct i2c_device_id *ids)
> >  {
> > @@ -86,20 +112,15 @@ menf21bmc_probe(struct i2c_client *client, const struct i2c_device_id *ids)
> >  	dev_info(&client->dev, "FW Revision: %02d.%02d.%02d\n",
> >  		 rev_major, rev_minor, rev_main);
> >  
> > -	/*
> > -	 * We have to exit the Production Mode of the BMC to activate the
> > -	 * Watchdog functionality and the BIOS life sign monitoring.
> > -	 */
> > -	ret = menf21bmc_wdt_exit_prod_mode(client);
> > -	if (ret < 0) {
> > -		dev_err(&client->dev, "failed to leave production mode\n");
> > +	ret = sysfs_create_group(&client->dev.kobj, &menf21bmc_attr_group);
> > +	if (ret)
> >  		return ret;
> > -	}
> >  
> >  	ret = mfd_add_devices(&client->dev, 0, menf21bmc_cell,
> >  			      ARRAY_SIZE(menf21bmc_cell), NULL, 0, NULL);
> >  	if (ret < 0) {
> >  		dev_err(&client->dev, "failed to add BMC sub-devices\n");
> > +		sysfs_remove_group(&client->dev.kobj, &menf21bmc_attr_group);
> >  		return ret;
> >  	}
> >  
> > @@ -108,7 +129,9 @@ menf21bmc_probe(struct i2c_client *client, const struct i2c_device_id *ids)
> >  
> >  static int menf21bmc_remove(struct i2c_client *client)
> >  {
> > +	sysfs_remove_group(&client->dev.kobj, &menf21bmc_attr_group);
> >  	mfd_remove_devices(&client->dev);
> > +
> >  	return 0;
> >  }
> >  
> 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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