[linux,dev-4.10,v2] drivers/hwmon/occ: Add sysfs_notify on error

From: "Edward A. James" <eajames@us.ibm.com>

For userspace polling, we need to notify sysfs that the state of our
error entry has changed.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
---
 drivers/hwmon/occ/common.c | 44 +++++++++++++++++++++++++++++++-------------
 drivers/hwmon/occ/common.h |  4 +++-
 drivers/hwmon/occ/p8_i2c.c | 28 ++++++++++++++--------------
 drivers/hwmon/occ/p9_sbe.c | 34 ++++++++++++++++------------------
 4 files changed, 64 insertions(+), 46 deletions(-)

Tested-by: Lei YU <mine260309@gmail.com>

Without this patch, the occ hwmon sensor readings are all empty on P8.
With this patch the issue is fixed and all the readings are OK.

Note: I replied to the [v3] mail but it's found archived.
So reply here again, but I meant to acknowledge the [v3] version.


On Thu, Jul 6, 2017 at 6:47 AM, Eddie James <eajames@linux.vnet.ibm.com> wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
>
> For userspace polling, we need to notify sysfs that the state of our
> error entry has changed.
>
> Signed-off-by: Edward A. James <eajames@us.ibm.com>
> ---
>  drivers/hwmon/occ/common.c | 44 +++++++++++++++++++++++++++++++-------------
>  drivers/hwmon/occ/common.h |  4 +++-
>  drivers/hwmon/occ/p8_i2c.c | 28 ++++++++++++++--------------
>  drivers/hwmon/occ/p9_sbe.c | 34 ++++++++++++++++------------------
>  4 files changed, 64 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
> index 4e3e411..a676f20 100644
> --- a/drivers/hwmon/occ/common.c
> +++ b/drivers/hwmon/occ/common.c
> @@ -163,9 +163,22 @@ void occ_parse_poll_response(struct occ *occ)
>         }
>  }
>
> +void occ_set_error(struct occ *occ, int error)
> +{
> +       occ->error_count++;
> +       if (occ->error_count > OCC_ERROR_COUNT_THRESHOLD)
> +               occ->error = error;
> +}
> +
> +void occ_reset_error(struct occ *occ)
> +{
> +       occ->error_count = 0;
> +       occ->error = 0;
> +}
> +
>  int occ_poll(struct occ *occ)
>  {
> -       int rc;
> +       int rc, error = occ->error;
>         struct occ_poll_response_header *header;
>         u16 checksum = occ->poll_cmd_data + 1;
>         u8 cmd[8];
> @@ -181,7 +194,7 @@ int occ_poll(struct occ *occ)
>
>         rc = occ->send_cmd(occ, cmd);
>         if (rc)
> -               return rc;
> +               goto done;
>
>         header = (struct occ_poll_response_header *)occ->resp.data;
>
> @@ -197,19 +210,21 @@ int occ_poll(struct occ *occ)
>
>         if (header->status & OCC_STAT_MASTER) {
>                 if (hweight8(header->occs_present) !=
> -                   atomic_read(&occ_num_occs)) {
> -                       occ->error = -EXDEV;
> -                       occ->bad_present_count++;
> -               } else
> -                       occ->bad_present_count = 0;
> +                   atomic_read(&occ_num_occs))
> +                       occ->error = -ENXIO;
>         }
>
> +done:
> +       /* notify userspace if we change error state and have an error */
> +       if (occ->error != error && occ->error && occ->error_attr_name)
> +               sysfs_notify(&occ->bus_dev->kobj, NULL, occ->error_attr_name);
> +
>         return rc;
>  }
>
>  int occ_set_user_power_cap(struct occ *occ, u16 user_power_cap)
>  {
> -       int rc;
> +       int rc, error = occ->error;
>         u8 cmd[8];
>         u16 checksum = 0x24;
>         __be16 user_power_cap_be;
> @@ -239,6 +254,10 @@ int occ_set_user_power_cap(struct occ *occ, u16 user_power_cap)
>         rc = occ->send_cmd(occ, cmd);
>         mutex_unlock(&occ->lock);
>
> +       /* notify userspace if we change error state and have an error*/
> +       if (occ->error != error && occ->error && occ->error_attr_name)
> +               sysfs_notify(&occ->bus_dev->kobj, NULL, occ->error_attr_name);
> +
>         return rc;
>  }
>
> @@ -260,14 +279,12 @@ int occ_update_response(struct occ *occ)
>  static ssize_t occ_show_error(struct device *dev,
>                               struct device_attribute *attr, char *buf)
>  {
> -       int error = 0;
>         struct occ *occ = dev_get_drvdata(dev);
>
> -       if (occ->error_count > OCC_ERROR_COUNT_THRESHOLD || occ->last_safe ||
> -           occ->bad_present_count > OCC_ERROR_COUNT_THRESHOLD)
> -               error = occ->error;
> +       if (occ->error)
> +               return snprintf(buf, PAGE_SIZE - 1, "%d\n", occ->error);
>
> -       return snprintf(buf, PAGE_SIZE - 1, "%d\n", error);
> +       return 0;
>  }
>
>  static ssize_t occ_show_status(struct device *dev,
> @@ -1152,6 +1169,7 @@ int occ_create_status_attrs(struct occ *occ)
>                 (struct sensor_device_attribute)SENSOR_ATTR(occ_error, 0444,
>                                                             occ_show_error,
>                                                             NULL, 0);
> +       occ->error_attr_name = occ->status_attrs[7].dev_attr.attr.name;
>
>         for (i = 0; i < OCC_NUM_STATUS_ATTRS; ++i) {
>                 rc = device_create_file(dev, &occ->status_attrs[i].dev_attr);
> diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h
> index a5f86c3..acb50bc 100644
> --- a/drivers/hwmon/occ/common.h
> +++ b/drivers/hwmon/occ/common.h
> @@ -103,7 +103,6 @@ struct occ {
>
>         int error;
>         unsigned int error_count;
> -       unsigned int bad_present_count;
>         unsigned long last_safe;
>         unsigned long last_update;
>         struct mutex lock;
> @@ -116,6 +115,7 @@ struct occ {
>         struct attribute_group group;
>         const struct attribute_group *groups[2];
>         struct sensor_device_attribute *status_attrs;
> +       const char *error_attr_name;
>
>         u8 poll_cmd_data;
>         int (*send_cmd)(struct occ *occ, u8 *cmd);
> @@ -143,6 +143,8 @@ struct occ {
>  extern atomic_t occ_num_occs;
>
>  void occ_parse_poll_response(struct occ *occ);
> +void occ_reset_error(struct occ *occ);
> +void occ_set_error(struct occ *occ, int error);
>  int occ_poll(struct occ *occ);
>  int occ_set_user_power_cap(struct occ *occ, u16 user_power_cap);
>  int occ_update_response(struct occ *occ);
> diff --git a/drivers/hwmon/occ/p8_i2c.c b/drivers/hwmon/occ/p8_i2c.c
> index 29233b4..a7b1d4c 100644
> --- a/drivers/hwmon/occ/p8_i2c.c
> +++ b/drivers/hwmon/occ/p8_i2c.c
> @@ -98,7 +98,7 @@ static int p8_i2c_occ_putscom_be(struct i2c_client *client, u32 address,
>
>  static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
>  {
> -       int i, rc;
> +       int i, rc, error;
>         unsigned long start;
>         u16 data_length;
>         struct p8_i2c_occ *p8_i2c_occ = to_p8_i2c_occ(occ);
> @@ -161,22 +161,18 @@ static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
>                 rc = -EFAULT;
>         }
>
> -       occ->error = resp->return_status;
> -
>         if (rc < 0) {
> -               occ->error_count++;
> -               dev_warn(&client->dev, "occ bad response:%d\n",
> -                        resp->return_status);
> -               return rc;
> +               error = resp->return_status;
> +               dev_warn(&client->dev, "occ bad response:%d\n", error);
> +               goto done;
>         }
>
>         data_length = get_unaligned_be16(&resp->data_length_be);
>         if (data_length > OCC_RESP_DATA_BYTES) {
> -               occ->error_count++;
> -               occ->error = -EDOM;
> +               rc = -EDOM;
>                 dev_warn(&client->dev, "occ bad data length:%d\n",
>                          data_length);
> -               return occ->error;
> +               goto assign;
>         }
>
>         for (i = 8; i < data_length + 7; i += 8) {
> @@ -185,13 +181,17 @@ static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
>                         goto err;
>         }
>
> -       occ->error_count = 0;
> -       return data_length + 7;
> +       occ_reset_error(occ);
> +       return 0;
>
>  err:
> -       occ->error_count++;
> -       occ->error = rc;
>         dev_err(&client->dev, "i2c scom op failed rc:%d\n", rc);
> +
> +assign:
> +       error = rc;
> +
> +done:
> +       occ_set_error(occ, error);
>         return rc;
>  }
>
> diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
> index c85f133..db30a2d 100644
> --- a/drivers/hwmon/occ/p9_sbe.c
> +++ b/drivers/hwmon/occ/p9_sbe.c
> @@ -25,7 +25,7 @@ struct p9_sbe_occ {
>
>  static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
>  {
> -       int rc;
> +       int rc, error;
>         unsigned long start;
>         struct occ_client *client;
>         struct occ_response *resp = &occ->resp;
> @@ -35,9 +35,10 @@ static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
>
>  retry:
>         client = occ_drv_open(p9_sbe_occ->sbe, 0);
> -       if (!client)
> -               /* don't increment occ error counter */
> -               return -ENODEV;
> +       if (!client) {
> +               rc = -ENODEV;
> +               goto assign;
> +       }
>
>         rc = occ_drv_write(client, (const char *)&cmd[1], 7);
>         if (rc < 0)
> @@ -62,7 +63,8 @@ static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
>                 }
>                 break;
>         case RESP_RETURN_SUCCESS:
> -               rc = 0;
> +               occ_reset_error(occ);
> +               return 0;
>                 break;
>         case RESP_RETURN_CMD_INVAL:
>         case RESP_RETURN_CMD_LEN:
> @@ -77,23 +79,19 @@ static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
>                 rc = -EFAULT;
>         }
>
> -       occ->error = resp->return_status;
> -
> -       if (rc < 0) {
> -               occ->error_count++;
> -               dev_warn(occ->bus_dev, "occ bad response:%d\n",
> -                        resp->return_status);
> -               return rc;
> -       }
> -
> -       occ->error_count = 0;
> -       return 0;
> +       error = resp->return_status;
> +       dev_warn(occ->bus_dev, "occ bad response:%d\n", error);
> +       goto done;
>
>  err:
> -       occ->error_count++;
> -       occ->error = rc;
>         occ_drv_release(client);
>         dev_err(occ->bus_dev, "occ bus op failed rc:%d\n", rc);
> +
> +assign:
> +       error = rc;
> +
> +done:
> +       occ_set_error(occ, error);
>         return rc;
>  }
>
> --
> 1.8.3.1
>