linux-kernel - Re: [PATCH 07/10] watchdog: xilinx: Fix OF binding

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Date:	Mon, 03 Feb 2014 09:01:16 +0100
From:	Michal Simek <monstr@...str.eu>
To:	monstr@...str.eu
CC:	Rob Herring <robherring2@...il.com>,
	Michal Simek <michal.simek@...inx.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Wim Van Sebroeck <wim@...ana.be>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	linux-watchdog@...r.kernel.org,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 07/10] watchdog: xilinx: Fix OF binding

On 02/03/2014 08:59 AM, Michal Simek wrote:
> On 01/31/2014 06:33 PM, Rob Herring wrote:
>> On Fri, Jan 31, 2014 at 8:18 AM, Michal Simek <michal.simek@...inx.com> wrote:
>>> Use of_property_read_u32 functions to clean OF probing.
>>
>> The subject is a bit misleading as this doesn't really fix anything.
> 
> fair enough. Will change it.
> 
>>
>>>
>>> Signed-off-by: Michal Simek <michal.simek@...inx.com>
>>> ---
>>>
>>>  drivers/watchdog/of_xilinx_wdt.c | 25 ++++++++++---------------
>>>  1 file changed, 10 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
>>> index c229cc4..475440a6 100644
>>> --- a/drivers/watchdog/of_xilinx_wdt.c
>>> +++ b/drivers/watchdog/of_xilinx_wdt.c
>>> @@ -147,8 +147,7 @@ static u32 xwdt_selftest(struct xwdt_device *xdev)
>>>  static int xwdt_probe(struct platform_device *pdev)
>>>  {
>>>         int rc;
>>> -       u32 *tmptr;
>>> -       u32 *pfreq;
>>> +       u32 pfreq, enable_once;
>>>         struct resource *res;
>>>         struct xwdt_device *xdev;
>>>         bool no_timeout = false;
>>> @@ -168,28 +167,24 @@ static int xwdt_probe(struct platform_device *pdev)
>>>         if (IS_ERR(xdev->base))
>>>                 return PTR_ERR(xdev->base);
>>>
>>> -       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;
>>
>> You can kill this...
>>
>>>         }
>>>
>>> -       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;
>>
>> and this...
>>
>>> -       } 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 && enable_once) {
>>>                 dev_warn(&pdev->dev,
>>>                          "Parameter \"xlnx,wdt-enable-once\" not found\n");
>>>                 watchdog_set_nowayout(xilinx_wdt_wdd, true);
>>> @@ -201,7 +196,7 @@ static int xwdt_probe(struct platform_device *pdev)
>>>   */
>>>         if (!no_timeout)
>>
>> and use "if (pfreq && xdev->wdt_interval)" if you initialize pfreq to 0.
> 
> 
> I just wanted to to change functions not logic in the driver.
> But it can be changed too.
> 
>>>                 xilinx_wdt_wdd->timeout = 2 * ((1 << xdev->wdt_interval) /
>>> -                                         *pfreq);
>>> +                                         pfreq);
>>
>> Is the wdog really usable if the timeout properties are missing? Seems
>> like you should fail to probe rather than warn.
> 
> There are 2 things.
> 1. timeout - you don't need pfreq and wdt_interval to use this driver
> but for that there should be module parameter timeout there.
> It should be added.
> 
> 2. about warn - based on 1 I don't think driver should failed
> but I am looking at logic above which I have added there but should be different.
> 
> u32 enable_once = 0;
> if (!rc)
> 	dev_warn
> 

if (rc) here sorry.

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform



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