edac: only create sdram_scrub_rate where supported

Currently, sdram_scrub_rate sysfs node is created even if the device
doesn't support get/set the scub rate. Change the logic to only
create this device node when the operation is supported.

Reported-by: Felipe Balbi <balbi@ti.com>
Acked-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 19 insertions, 10 deletions

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 0ca1ca71157f..963a91edb259 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -7,7 +7,7 @@
  *
  * Written Doug Thompson <norsk5@xmission.com> www.softwarebitmaker.com
  *
- * (c) 2012 - Mauro Carvalho Chehab <mchehab@redhat.com>
+ * (c) 2012-2013 - Mauro Carvalho Chehab <mchehab@redhat.com>
  *      The entire API were re-written, and ported to use struct device
  *
  */
@@ -677,9 +677,6 @@ static ssize_t mci_sdram_scrub_rate_store(struct device *dev,
         unsigned long bandwidth = 0;
         int new_bw = 0;
 
-        if (!mci->set_sdram_scrub_rate)
-                return -ENODEV;
-
         if (strict_strtoul(data, 10, &bandwidth) < 0)
                 return -EINVAL;
 
@@ -703,9 +700,6 @@ static ssize_t mci_sdram_scrub_rate_show(struct device *dev,
         struct mem_ctl_info *mci = to_mci(dev);
         int bandwidth = 0;
 
-        if (!mci->get_sdram_scrub_rate)
-                return -ENODEV;
-
         bandwidth = mci->get_sdram_scrub_rate(mci);
         if (bandwidth < 0) {
                 edac_printk(KERN_DEBUG, EDAC_MC, "Error reading scrub rate\n");
@@ -866,8 +860,7 @@ DEVICE_ATTR(ce_count, S_IRUGO, mci_ce_count_show, NULL);
 DEVICE_ATTR(max_location, S_IRUGO, mci_max_location_show, NULL);
 
 /* memory scrubber attribute file */
-DEVICE_ATTR(sdram_scrub_rate, S_IRUGO | S_IWUSR, mci_sdram_scrub_rate_show,
-        mci_sdram_scrub_rate_store);
+DEVICE_ATTR(sdram_scrub_rate, 0, NULL, NULL);
 
 static struct attribute *mci_attrs[] = {
         &dev_attr_reset_counters.attr,
@@ -878,7 +871,6 @@ static struct attribute *mci_attrs[] = {
         &dev_attr_ce_noinfo_count.attr,
         &dev_attr_ue_count.attr,
         &dev_attr_ce_count.attr,
-        &dev_attr_sdram_scrub_rate.attr,
         &dev_attr_max_location.attr,
         NULL
 };
@@ -1012,6 +1004,22 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci)
                 return err;
         }
 
+        if (mci->set_sdram_scrub_rate || mci->get_sdram_scrub_rate) {
+                if (mci->get_sdram_scrub_rate) {
+                        dev_attr_sdram_scrub_rate.attr.mode |= S_IRUGO;
+                        dev_attr_sdram_scrub_rate.show = &mci_sdram_scrub_rate_show;
+                }
+                if (mci->set_sdram_scrub_rate) {
+                        dev_attr_sdram_scrub_rate.attr.mode |= S_IWUSR;
+                        dev_attr_sdram_scrub_rate.store = &mci_sdram_scrub_rate_store;
+                }
+                err = device_create_file(&mci->dev,
+                                         &dev_attr_sdram_scrub_rate);
+                if (err) {
+                        edac_dbg(1, "failure: create sdram_scrub_rate\n");
+                        goto fail2;
+                }
+        }
         /*
          * Create the dimm/rank devices
          */
@@ -1056,6 +1064,7 @@ fail:
                         continue;
                 device_unregister(&dimm->dev);
         }
+fail2:
         device_unregister(&mci->dev);
         bus_unregister(&mci->bus);
         kfree(mci->bus.name);