Messages in this thread | | | Date | Sat, 22 Feb 2014 15:18:16 -0800 | From | Guenter Roeck <> | Subject | Re: [PATCH v3 07/11] watchdog: xilinx: Use of_property_read_u32 |
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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.simek@xilinx.com> >>>> Reviewed-by: Guenter Roeck<linux@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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