Re: [PATCH v5 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

Guenter Roeck
2018-03-16T13:46:42Z

On 03/15/2018 03:21 PM, Eddie James wrote:
> From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
>
> Expose the gpiN_fault fields of mfr_status as individual debugfs
> attributes. This provides a way for users to be easily notified of gpi
> faults. Also provide the whole mfr_status register in debugfs.
>
> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
> ---
> drivers/hwmon/pmbus/ucd9000.c | 137 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 136 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index a34ffc4..c1a1560 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/of_device.h>
> @@ -36,6 +37,7 @@
> #define UCD9000_NUM_PAGES 0xd6
> #define UCD9000_FAN_CONFIG_INDEX 0xe7
> #define UCD9000_FAN_CONFIG 0xe8
> +#define UCD9000_MFR_STATUS 0xf3
> #define UCD9000_GPIO_SELECT 0xfa
> #define UCD9000_GPIO_CONFIG 0xfb
> #define UCD9000_DEVICE_ID 0xfd
> @@ -63,13 +65,22 @@
> #define UCD901XX_NUM_GPIOS 26
> #define UCD90910_NUM_GPIOS 26
>
> +#define UCD9000_DEBUGFS_NAME_LEN 24
> +#define UCD9000_GPI_COUNT 8
> +
> 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;
> };
> #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;
> @@ -306,6 +317,121 @@ static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
> val);
> }
>
> +#ifdef CONFIG_DEBUG_FS
> +static int ucd9000_get_mfr_status(struct i2c_client *client, u8 *buffer)
> +{
> + int ret = pmbus_set_page(client, 0);
> +
> + if (ret < 0)
> + return ret;
> +
> + return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS, buffer);
> +}
> +
> +static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
> +{
> + struct ucd9000_debugfs_entry *entry = data;
> + struct i2c_client *client = entry->client;
> + u8 buffer[I2C_SMBUS_BLOCK_MAX];
> + int ret;
> +
> + ret = ucd9000_get_mfr_status(client, buffer);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * Attribute only created for devices with gpi fault bits at bits
> + * 16-23, which is the second byte of the response.
> + */
> + *val = !!(buffer[1] & BIT(entry->index));
> +
> + return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
> + ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");
> +
> +static ssize_t ucd9000_debugfs_read_mfr_status(struct file *file,
> + char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct i2c_client *client = file->private_data;
> + u8 buffer[I2C_SMBUS_BLOCK_MAX] = { 0 };
> + char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2] = { 0 };

Is it still necessary to initialize these variables ?

> + char *res;
> + int rc;
> +
> + rc = ucd9000_get_mfr_status(client, buffer);
> + if (rc < 0)
> + return rc;
> +
> + res = bin2hex(str, buffer, rc);

Please add some limit here, such as
res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));

> + *res++ = '\n';
> +
> + return simple_read_from_buffer(buf, count, ppos, str, (res - str) + 1);
> +}
> +
> +static const struct file_operations ucd9000_debugfs_show_mfr_status_fops = {
> + .llseek = noop_llseek,
> + .read = ucd9000_debugfs_read_mfr_status,
> + .open = simple_open,
> +};
> +
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> + const struct i2c_device_id *mid,
> + struct ucd9000_data *data)
> +{
> + struct dentry *debugfs;
> + struct ucd9000_debugfs_entry *entries;
> + int i;
> + char name[UCD9000_DEBUGFS_NAME_LEN];
> +
> + debugfs = pmbus_get_debugfs_dir(client);
> + if (!debugfs)
> + return -ENOENT;
> +
> + data->debugfs = debugfs_create_dir(client->name, debugfs);
> + if (!data->debugfs)
> + return -ENOENT;
> +
> + /*
> + * Of the chips this driver supports, only the UCD9090, UCD90160,
> + * and UCD90910 report GPI faults in their MFR_STATUS register, so only
> + * create the GPI fault debugfs attributes for those chips.
> + */
> + if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
> + mid->driver_data == ucd90910) {
> + entries = devm_kzalloc(&client->dev,
> + sizeof(*entries) * UCD9000_GPI_COUNT,
> + GFP_KERNEL);
> + if (!entries)
> + return -ENOMEM;
> +
> + for (i = 0; i < UCD9000_GPI_COUNT; i++) {
> + entries[i].client = client;
> + entries[i].index = i;
> + scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
> + "gpi%d_alarm", i + 1);
> + debugfs_create_file(name, 0444, data->debugfs,
> + &entries[i],
> + &ucd9000_debugfs_mfr_status_bit);
> + }
> + }
> +
> + scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
> + debugfs_create_file(name, 0444, data->debugfs, client,
> + &ucd9000_debugfs_show_mfr_status_fops);
> +
> + return 0;
> +}
> +#else
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> + const struct i2c_device_id *mid,
> + struct ucd9000_data *data)
> +{
> + return 0;
> +}
> +#endif /* CONFIG_DEBUG_FS */
> +
> static void ucd9000_probe_gpio(struct i2c_client *client,
> const struct i2c_device_id *mid,
> struct ucd9000_data *data)
> @@ -464,7 +590,16 @@ static int ucd9000_probe(struct i2c_client *client,
>
> ucd9000_probe_gpio(client, mid, data);
>
> - return pmbus_do_probe(client, mid, info);
> + ret = pmbus_do_probe(client, mid, info);
> + if (ret)
> + return ret;
> +
> + ret = ucd9000_init_debugfs(client, mid, data);
> + if (ret)
> + dev_warn(&client->dev, "Failed to register debugfs: %d\n",
> + ret);
> +
> + return 0;
> }
>
> /* This is the driver that will be inserted */
>