On 03/09/2018 11:19 AM, Eddie James wrote:
From: Christopher Bostic <cbos...@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 <cbos...@linux.vnet.ibm.com>
Signed-off-by: Andrew Jeffery <and...@aj.id.au>
Signed-off-by: Eddie James <eaja...@linux.vnet.ibm.com>
---
  drivers/hwmon/pmbus/ucd9000.c | 172 +++++++++++++++++++++++++++++++++++++++++-
  1 file changed, 171 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index e3a507f..297da0e 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;
@@ -328,6 +339,156 @@ static int ucd9000_gpio_direction_output(struct gpio_chip 
*gc,
                                          val);
  }
+#if IS_ENABLED(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;
+
+       /*
+        * 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.
+        */
+       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[4];
+       int ret;
+
+       /*
+        * This attribute is only created for devices that return 4 bytes for
+        * status_mfr, so it's safe to call with 4-byte buffer.
+        */
+       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;
+       }
+
+       /*
+        * 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 int ucd9000_debugfs_show_mfr_status_word2(void *data, u64 *val)
+{
+       struct i2c_client *client = data;
+       __be16 buffer;
+       int ret;
+
+       ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
+       if (ret < 0) {
+               dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
+                       ret);
+
+               return ret;
+       }
+
+       *val = be16_to_cpu(buffer);
+
+       return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word2,
+                        ucd9000_debugfs_show_mfr_status_word2, NULL,
+                        "%04llx\n");
+
+static int ucd9000_debugfs_show_mfr_status_word4(void *data, u64 *val)
+{
+       struct i2c_client *client = data;
+       __be32 buffer;
+       int ret;
+
+       ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
+       if (ret < 0) {
+               dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
+                       ret);
+
+               return ret;
+       }
+
+       *val = be32_to_cpu(buffer);
+
+       return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word4,
+                        ucd9000_debugfs_show_mfr_status_word4, NULL,
+                        "%08llx\n");
+
+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_mfr_status_word4);
+       } else if (mid->driver_data == ucd90120 ||
+                  mid->driver_data == ucd90124) {
+               scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
+               debugfs_create_file(name, 0444, data->debugfs, client,
+                                   &ucd9000_debugfs_mfr_status_word2);
+       }
+
+       return 0;
+}

Is all that complexity really worth it ? Why not just read the manufacturing
status as byte string into a buffer and use hexdump to pront it, no matter how
many bytes are actually returned ? This would also be less error prone, and
automatically support future chips.

Thanks,
Guenter

+#else
+static int ucd9000_init_debugfs(struct i2c_client *client,
+                               struct ucd9000_data *data)
+{
+       return 0;
+}
+#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
+
  static int ucd9000_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
  {
@@ -483,7 +644,16 @@ static int ucd9000_probe(struct i2c_client *client,
                return ret;
        }
- 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 */


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