hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

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>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 137 insertions, 1 deletions

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index ef2c5bfc9cf8..70cecb06f93c 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>
@@ -37,6 +38,7 @@ enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
 #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
@@ -64,15 +66,24 @@ enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
 #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;
 #ifdef CONFIG_GPIOLIB
         struct gpio_chip gpio;
 #endif
+        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;
@@ -359,6 +370,122 @@ static void ucd9000_probe_gpio(struct i2c_client *client,
 }
 #endif /* CONFIG_GPIOLIB */
 
+#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];
+        char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2];
+        char *res;
+        int rc;
+
+        rc = ucd9000_get_mfr_status(client, buffer);
+        if (rc < 0)
+                return rc;
+
+        res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));
+        *res++ = '\n';
+        *res = 0;
+
+        return simple_read_from_buffer(buf, count, ppos, str, res - str);
+}
+
+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 int ucd9000_probe(struct i2c_client *client,
                          const struct i2c_device_id *id)
 {
@@ -475,7 +602,16 @@ 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 */