Re: [PATCH v1 1/5] mfd: lpc_sch: reduce duplicate code

Lee Jones
2014-09-01T13:46:18Z

On Mon, 01 Sep 2014, Andy Shevchenko wrote:

> On Mon, 2014-09-01 at 12:38 +0100, Lee Jones wrote:
> > 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@intel.com>
> > > > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.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.
>
> Okay, what about 1 — IP is present and we have no error, 0 — no ip, no
> error, -err — error that should be returned, would it work for you?

I would suggest -E<error_message> for messages to be passed back, 0
for 'everything found and correct' and >0 (#defined of course) for any
local messages you wish to pass 'IP not found', etc.

> > #define LCP_SKIP_RESOURCE /* Seems resonable? */
>
>
>

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
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