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Message-ID: <20140901113805.GO7374@lee--X1>
Date: Mon, 1 Sep 2014 12:38:05 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, linux-kernel@...r.kernel.org,
Samuel Ortiz <sameo@...ux.intel.com>,
Chang Rebecca Swee Fun <rebecca.swee.fun.chang@...el.com>
Subject: Re: [PATCH v1 1/5] mfd: lpc_sch: reduce duplicate code
On Mon, 01 Sep 2014, Andy Shevchenko wrote:
> On Mon, 2014-09-01 at 10:13 +0100, Lee Jones wrote:
> > On Fri, 22 Aug 2014, Andy Shevchenko wrote:
> >
> > > This patch refactors the driver to use helper functions instead of
> > > copy'n'pasted pieces of code.
> > >
> > > Tested-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@...el.com>
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > > ---
> > > drivers/mfd/lpc_sch.c | 146 ++++++++++++++++++++++----------------------------
> > > 1 file changed, 64 insertions(+), 82 deletions(-)
> > >
> > > diff --git a/drivers/mfd/lpc_sch.c b/drivers/mfd/lpc_sch.c
> > > index 4ee7550..0f01ef0 100644
> > > --- a/drivers/mfd/lpc_sch.c
> > > +++ b/drivers/mfd/lpc_sch.c
> > > @@ -40,41 +40,6 @@
> >
> > [...]
>
> Thanks for review, my answers below.
>
> >
> > > -static int lpc_sch_probe(struct pci_dev *dev,
> > > - const struct pci_device_id *id)
> > > +static int lpc_sch_get_io(struct pci_dev *pdev, int where, const char *name,
> > > + struct resource *res, int size)
> > > {
> > > unsigned int base_addr_cfg;
> > > unsigned short base_addr;
> > > - int i, cells = 0;
> > > - int ret;
> > >
> > > - pci_read_config_dword(dev, SMBASE, &base_addr_cfg);
> > > + pci_read_config_dword(pdev, where, &base_addr_cfg);
> > > base_addr = 0;
> > > if (!(base_addr_cfg & (1 << 31)))
> > > - dev_warn(&dev->dev, "Decode of the SMBus I/O range disabled\n");
> > > + dev_warn(&pdev->dev, "Decode of the %s I/O range disabled\n",
> > > + name);
> > > else
> > > base_addr = (unsigned short)base_addr_cfg;
> > >
> > > if (base_addr == 0) {
> > > - dev_warn(&dev->dev, "I/O space for SMBus uninitialized\n");
> > > - } else {
> > > - lpc_sch_cells[cells++] = isch_smbus_cell;
> > > - smbus_sch_resource.start = base_addr;
> > > - smbus_sch_resource.end = base_addr + SMBUS_IO_SIZE - 1;
> > > + dev_warn(&pdev->dev, "I/O space for %s uninitialized\n", name);
> > > + return -ENODEV;
> >
> > If you're going to return an error, you need to use dev_err() above.
>
> Okay.
>
> > > }
> > >
> > > - pci_read_config_dword(dev, GPIOBASE, &base_addr_cfg);
> > > - base_addr = 0;
> > > - if (!(base_addr_cfg & (1 << 31)))
> > > - dev_warn(&dev->dev, "Decode of the GPIO I/O range disabled\n");
> > > + res->start = base_addr;
> > > + res->end = base_addr + size - 1;
> > > + res->flags = IORESOURCE_IO;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int lpc_sch_populate_cell(struct pci_dev *pdev, int where,
> > > + const char *name, int size, int id,
> > > + struct mfd_cell *cell)
> > > +{
> > > + struct resource *res;
> > > + int ret;
> > > +
> > > + res = devm_kzalloc(&pdev->dev, sizeof(*res), GFP_KERNEL);
> > > + if (!res)
> > > + return -ENOMEM;
> > > +
> > > + ret = lpc_sch_get_io(pdev, where, name, res, size);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + memset(cell, 0, sizeof(*cell));
> > > +
> > > + cell->name = name;
> > > + cell->resources = res;
> > > + cell->num_resources = 1;
> > > + cell->ignore_resource_conflicts = true;
> > > + cell->id = id;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int lpc_sch_probe(struct pci_dev *dev,
> > > + const struct pci_device_id *id)
> > > +{
> > > + struct mfd_cell lpc_sch_cells[3];
> > > + int size, cells = 0;
> > > + int ret;
> > > +
> > > + ret = lpc_sch_populate_cell(dev, SMBASE, "isch_smbus", SMBUS_IO_SIZE,
> > > + id->device, &lpc_sch_cells[cells]);
> > > + if (!ret)
> > > + cells++;
> >
> > You're masking errors here. You need to return on error.
>
> No, I don't. It's a local error, I just need to understand if the HW has
> or hasn't the IP part we're looking for.
Yes, you do. -ENOMEM is not a local error, it needs to be returned.
> I could, let's say, return true or false, if you prefer, with the above
> meaning.
I don't see this very often, which makes me wonder if it's the right
thing to do at all; however, if you're going to this then please
return a local state, instead of a Linux Error Code.
#define LCP_SKIP_RESOURCE /* Seems resonable? */
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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