[PATCH linux dev-4.10 v4 2/2] hwmon: (ucd9000) Add debugfs for mfr_status info

Andrew Jeffery andrew at aj.id.au
Tue Aug 22 12:01:19 AEST 2017


On Mon, 2017-08-21 at 17:09 -0500, Christopher Bostic wrote:
> Add debugfs to list the mfr_status register and its gpiN_fault
> fields.
> 
> > Signed-off-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>
> ---
> v2 - Remove mfr_status directory in debugfs and place the files
>      up in the parent ucd9000 directory.
> ---
>  drivers/hwmon/pmbus/ucd9000.c | 122 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 122 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index 5cea5f6..f906d8e 100644
> --- a/drivers/hwmon/pmbus/ucd9000.c
> +++ b/drivers/hwmon/pmbus/ucd9000.c
> @@ -19,6 +19,7 @@
>   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
>   */
>  
> +#include <linux/debugfs.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/init.h>
> @@ -38,6 +39,7 @@
> >  #define UCD9000_FAN_CONFIG_INDEX	0xe7
> >  #define UCD9000_FAN_CONFIG		0xe8
> >  #define UCD9000_LOGGED_FAULTS		0xea
> > +#define UCD9000_MFR_STATUS		0xf3
> >  #define UCD9000_GPIO_SELECT		0xfa
> >  #define UCD9000_GPIO_CONFIG		0xfb
> >  #define UCD9000_DEVICE_ID		0xfd
> @@ -56,16 +58,25 @@
> >  #define UCD9000_MON_VOLTAGE_HW	4
>  
> >  #define UCD9000_NUM_FAN		4
> > +#define UCD9000_NAME_SIZE	24
>  
> >  #define UCD90160_NUM_GPIOS	26
> > +#define UCD90160_GPI_COUNT	8
> > +#define UCD90160_GPI_FAULT_BASE	16
>  
>  struct ucd9000_data {
> >  	u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
> >  	struct pmbus_driver_info info;
> >  	struct gpio_chip gpio;
> > > +	struct dentry *debugfs;	/* debugfs device directory */
>  };
>  #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
>  
> +struct ucd9000_debugfs_entry {
> > +	struct i2c_client *client;
> > +	u8 index;
> +};
> +
>  static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
>  {
> >  	int fan_config = 0;
> @@ -143,6 +154,7 @@ static int ucd9000_gpio_read_config(struct i2c_client *client,
> >  	if (ret < 0) {
> >  		dev_err(&client->dev, "Failed to select GPIO %d: %d\n", offset,
> >  			ret);
> +

Can we fold the whitespace cleanups into the appropriate patch? Please audit
the rest of the patch for similar issues.

> >  		return ret;
> >  	}
>  
> @@ -157,6 +169,7 @@ static int ucd9000_gpio_get(struct gpio_chip *gc, unsigned int offset)
> >  	ret = ucd9000_gpio_read_config(client, offset);
> >  	if (ret < 0) {
> >  		dev_err(&client->dev, "failed to read GPIO config\n");
> +
> >  		return ret;
> >  	}
>  
> @@ -185,6 +198,108 @@ static int ucd9000_gpio_direction_input(struct gpio_chip *gc,
> >  	return 0;
>  }
>  
> +static struct dentry *ucd9000_debugfs_dir;
> +
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +static int ucd9000_get_mfr_status(struct i2c_client *client, u32 *buffer)
> +{
> > +	int ret;
> +
> > +	ret = pmbus_set_page(client, 0);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev, "pmbus_set_page failed. rc:%d\n", ret);
> > +		return ret;
> > +	}
> > +	return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS,
> > +					(u8 *)buffer);

I know you don't intend to support the device but this will cause stack
corruption on the ucd90240. Maybe it's not worth fixing at the moment, but it's
probably worth a comment. From the command reference, page 81:

	With the UCD90120 and UCD90124 devices, this command [MFR_STATUS] is 2
	bytes long (bits 0-15). With the UCD90240, this command is 5 bytes
	long. With all other devices, it is 4 bytes long.

> +}
> +
> +static int ucd9000_debugfs_get_mfr_status_bit(void *data, u64 *val)
> +{
> > +	struct ucd9000_debugfs_entry *entry = data;
> > +	struct i2c_client *client = entry->client;
> > +	int nr = entry->index;
> > +	u32 buffer;
> > +	int ret;
> +
> > +	ret = ucd9000_get_mfr_status(client, &buffer);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev,
> > +			"Failed to read mfr status. rc:%d\n", ret);
> > +		return ret;
> > +	}
> +
> > +	*val = ret & BIT(nr) ? 1 : 0;

We should switch this to the non-branchy solution.

> +
> > +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_ops_mfr_status_bit,
> > +			ucd9000_debugfs_get_mfr_status_bit, NULL, "%1lld\n");
> +
> +static int ucd9000_debugfs_get_mfr_status_word(void *data, u64 *val)
> +{
> > +	struct ucd9000_debugfs_entry *entry = data;
> > +	struct i2c_client *client = entry->client;
> > +	u32 buffer;
> > +	int ret;
> +
> > +	ret = ucd9000_get_mfr_status(client, &buffer);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev,
> > +			"Failed to read mfr status. rc:%d\n", ret);
> > +		return ret;
> > +	}
> +
> > +	*val = ret;
> +
> > +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_ops_mfr_status_word,
> > +			ucd9000_debugfs_get_mfr_status_word, NULL, "%08llx\n");
> +
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> > +				struct ucd9000_data *data)
> +{
> > +	struct ucd9000_debugfs_entry *entries;
> > +	char name[UCD9000_NAME_SIZE];
> > +	int i;
> +
> > +	ucd9000_debugfs_dir = debugfs_create_dir("ucd9000", NULL);
> > +	if (IS_ERR(ucd9000_debugfs_dir)) {
> > +		ucd9000_debugfs_dir = NULL;
> > +		dev_warn(&client->dev, "Failed to create debugfs dir\n");
> > +		return 0;
> > +	}
> +
> > +	entries = devm_kzalloc(&client->dev, sizeof(*entries) *
> > +				(UCD90160_GPI_COUNT + 1) * 10,
> > +				GFP_KERNEL);
> > +	if (!entries)
> > +		return -ENOMEM;
> +
> > +	for (i = 0; i < UCD90160_GPI_COUNT; i++) {
> > +		entries[i].client = client;
> > +		entries[i].index = UCD90160_GPI_FAULT_BASE + i;
> > +		scnprintf(name, UCD9000_NAME_SIZE, "gpi%d_alarm", i+1);
> > +		debugfs_create_file(name, 0444, ucd9000_debugfs_dir,
> > +				&entries[i],
> > +				&ucd9000_debugfs_ops_mfr_status_bit);
> > +	}
> > +	entries[i].client = client;
> > +	scnprintf(name, UCD9000_NAME_SIZE, "mfr_status");
> > +	debugfs_create_file(name, 0444, ucd9000_debugfs_dir, &entries[i],
> > +				&ucd9000_debugfs_ops_mfr_status_word);

Given the static ucd9000_debugfs_dir, how does this work if there are multiple
devices? It's a naive question - I haven't looked into it at all, but I'm
curious.

Cheers,

Andrew

> +
> > +	return 0;
> +}
> +#else
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> > +				struct ucd9000_data *data)
> +{
> > +	return 0;
> +}
> +#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
> +
>  static ssize_t ucd9000_clear_logged_faults(struct device *dev,
> >  				struct device_attribute *attr, const char *buf,
> >  				size_t count)
> @@ -345,12 +460,19 @@ static int ucd9000_probe(struct i2c_client *client,
> >  	if (ret < 0)
> >  		return ret;
>  
> > +	if (mid->driver_data == ucd90160) {
> > +		ret = ucd9000_init_debugfs(client, data);
> > +		if (ret < 0)
> > +			dev_warn(&client->dev, "Failed to register debugfs\n");
> > +	}
> +
> >  	return  pmbus_do_probe(client, mid, info);
>  }
>  
>  static int ucd9000_remove(struct i2c_client *client)
>  {
> >  	sysfs_remove_group(&client->dev.kobj, &ucd9000_attr_group);
> > +	debugfs_remove_recursive(ucd9000_debugfs_dir);
> >  	return pmbus_do_remove(client);
>  }
>  
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