linux-kernel - Re: [PATCH v2 3/4] gpio-langwell: use managed functions pcim_* and devm

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Date:	Wed, 22 May 2013 11:50:00 +0300
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Andy Shevchenko <andy.shevchenko@...il.com>
Cc:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	David Cohen <david.a.cohen@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] gpio-langwell: use managed functions pcim_* and
 devm_*

On Wed, May 22, 2013 at 11:36:15AM +0300, Andy Shevchenko wrote:
> On Wed, May 22, 2013 at 11:05 AM, Mika Westerberg
> <mika.westerberg@...ux.intel.com> wrote:
> > On Wed, May 22, 2013 at 10:47:38AM +0300, Andy Shevchenko wrote:
> >> This makes the error handling much more simpler than open-coding everything and
> >> in addition makes the probe function smaller an tidier.
> >>
> >> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> >
> > In general this change looks good. Getting rid of 61 lines is certainly an
> > improvement!
> >
> > David, are you able to check that this still works on your hardware? (I'm
> > pretty sure that Andy has tested this already on Medfield)
> 
> I also wonder if it still okay on other platforms where this IP block
> is embedded.
> 
> > I have few minor comments, though. See below.
> 
> Thank you for the review. See my answers below.
> 
> >> ---
> >>  drivers/gpio/gpio-langwell.c | 82 ++++++++++++--------------------------------
> >>  1 file changed, 21 insertions(+), 61 deletions(-)
> >>
> >> diff --git a/drivers/gpio/gpio-langwell.c b/drivers/gpio/gpio-langwell.c
> >> index 8203084..8672282 100644
> >> --- a/drivers/gpio/gpio-langwell.c
> >> +++ b/drivers/gpio/gpio-langwell.c
> >> @@ -320,56 +320,35 @@ static const struct dev_pm_ops lnw_gpio_pm_ops = {
> >>  static int lnw_gpio_probe(struct pci_dev *pdev,
> >>                         const struct pci_device_id *id)
> >>  {
> >> -     void __iomem *base;
> >> -     resource_size_t start, len;
> >>       struct lnw_gpio *lnw;
> >>       u32 gpio_base;
> >>       u32 irq_base;
> >>       int retval;
> >>       int ngpio = id->driver_data;
> >>
> >> -     retval = pci_enable_device(pdev);
> >> +     retval = pcim_enable_device(pdev);
> >>       if (retval)
> >>               return retval;
> >>
> >> -     retval = pci_request_regions(pdev, "langwell_gpio");
> >> +     retval = pcim_iomap_regions(pdev, 1 << 0 | 1 << 1, pci_name(pdev));
> >
> > I wonder if "langwell_gpio" is still a better name compared to
> > pci_name(pdev)?
> 
> This is used as an internal name for certain resource.
> 
> It could be seen in case of using printk("%pR") for example. But even
> in that case I prefer to see the actual device as well to which
> the resource belongs to.
> 
> My general opinion is better to use pci_name(pdev) in the pci drivers instead
> of hardcoded pseudo-unique strings.

Fair enough :)

> >>       if (retval) {
> >> -             dev_err(&pdev->dev, "error requesting resources\n");
> >> -             goto err_pci_req_region;
> >> -     }
> >> -     /* get the gpio_base from bar1 */
> >> -     start = pci_resource_start(pdev, 1);
> >> -     len = pci_resource_len(pdev, 1);
> >> -     base = ioremap_nocache(start, len);
> >> -     if (!base) {
> >> -             dev_err(&pdev->dev, "error mapping bar1\n");
> >> -             retval = -EFAULT;
> >> -             goto err_ioremap;
> >> +             dev_err(&pdev->dev, "I/O memory mapping error\n");
> >> +             return retval;
> >>       }
> >>
> >> -     irq_base = readl(base);
> >> -     gpio_base = readl(sizeof(u32) + base);
> >> +     irq_base = readl(pcim_iomap_table(pdev)[1]);
> >> +     gpio_base = readl(sizeof(u32) + pcim_iomap_table(pdev)[1]);
> >
> > Using pcim_iomap_table(pdev)[] is a bit confusing, at least for me. Can you
> > add a variable where you store that pointer and use that instead?
> 
> [Hmm... It returns pointer to an array of pointers.
> Okay,  I will relive base variable for this as we discussed privately.

Cool, thanks!
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