On 02/22/2014 05:08 PM, Alejandro Cabrera wrote:
On 22/2/2014 10:46 AM, Wim Van Sebroeck wrote:
Hi All,

Hi Michal,

On Wed, Feb 12, 2014 at 02:41:21PM +0100, Michal Simek wrote:
Use of_property_read_u32 functions to clean probe function.

Signed-off-by: Michal Simek<michal.si...@xilinx.com>
Reviewed-by: Guenter Roeck<li...@roeck-us.net>
---

Changes in v3:
- Remove one if checking and use variable directly

Looks good.

Another comment/remark.

-    pfreq = (u32 *)of_get_property(pdev->dev.of_node,
-                    "clock-frequency", NULL);
-
-    if (pfreq == NULL) {
+    rc = of_property_read_u32(pdev->dev.of_node, "clock-frequency",&pfreq);
+    if (rc) {
          dev_warn(&pdev->dev,
               "The watchdog clock frequency cannot be obtained\n");
          no_timeout = true;
      }

-    tmptr = (u32 *)of_get_property(pdev->dev.of_node,
-                    "xlnx,wdt-interval", NULL);
-    if (tmptr == NULL) {
+    rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-interval",
+                &xdev->wdt_interval);
+    if (rc) {
          dev_warn(&pdev->dev,
               "Parameter \"xlnx,wdt-interval\" not found\n");
          no_timeout = true;
-    } else {
-        xdev->wdt_interval = *tmptr;
      }

-    tmptr = (u32 *)of_get_property(pdev->dev.of_node,
-                    "xlnx,wdt-enable-once", NULL);
-    if (tmptr == NULL) {
+    rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-enable-once",
+                &enable_once);
+    if (rc)
          dev_warn(&pdev->dev,
               "Parameter \"xlnx,wdt-enable-once\" not found\n");
-        watchdog_set_nowayout(xilinx_wdt_wdd, true);
-    }
All the above properties are optional. Is a warning really
warranted in this case ? I usually associate a warning with
something that is wrong, which is not the case here.

I would encourage you to drop those warnings, but that should be
a separate patch.
I agree with Guenter: these are not really warnings. Seperate patch is thus 
welcome.
Hi

I support Michal intention, I think it is a warning because device tree blob must have 
the "xlnx,wdt-enable-once" property specified in order to allow the system to 
be sure of the real value of this property. In addition to, this warning can be helpful 
to detect a wrong device tree specification.


The dt documentation states that the properties are optional.

Optional properties:
- clock-frequency       : Frequency of clock in Hz
- xlnx,wdt-enable-once  : 0 - Watchdog can be restarted
                          1 - Watchdog can be enabled just once
- xlnx,wdt-interval     : Watchdog timeout interval in 2^<val> clock cycles,
                          <val> is integer from 8 to 31.

This clearly conflicts with your statement. An optional property
is just that, optional. If it warrants a warning, it must
not be optional. If you claim that not providing the properties
would be "wrong", why are they defined as optional ?
What is your definition of "wrong" and "must have" ?
How do you expect anyone to know that omitting those
"optional" properties is by some definition "wrong" ?

Guenter


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