Re: [PATCH 1/3 v2] mfd: Add LPC driver for Intel ICH chipsets
From: Aaron Sierra
Date: Tue Feb 07 2012 - 16:01:06 EST
> > +static int __devinit lpc_ich_probe(struct pci_dev *dev,
> > + const struct pci_device_id *id)
> > +{
> > + u32 base_addr_cfg;
> > + u32 base_addr;
> > + u8 reg_save;
> > + int ret;
> > + int cells = 0;
> > + int acpi_conflict = 0;
> > +
> You can use bool for acpi_conflict (and cells, but I don't think that
> is needed anyway).
I agree that bool is a better type choice. See my comment at the end
regarding my reason for using cells.
> > +pm_done:
> > + /* Setup GPIO base register */
> > + pci_read_config_dword(dev, GPIOBASE, &base_addr_cfg);
> > + base_addr = base_addr_cfg & 0x0000ff80;
> > + if (!base_addr) {
> > + dev_err(&dev->dev, "I/O space for GPIO
> > uninitialized\n");
> > + /* GPIO in power-management space may still be
> > available */
> > + goto gpio_reg;
> > + }
> > +
> > + gpio_ich_res[ICH_RES_GPIO].start = base_addr;
> > + gpio_ich_res[ICH_RES_GPIO].end = base_addr +
> > GPIOBASE_IO_SIZE - 1;
> > + ret =
> > acpi_check_resource_conflict(&gpio_ich_res[ICH_RES_GPIO]);
> > + if (ret) {
> > + /* this isn't necessarily fatal for the GPIO */
> > + gpio_ich_res[ICH_RES_GPIO].start = 0;
> > + gpio_ich_res[ICH_RES_GPIO].end = 0;
> > + acpi_conflict++;
>
> acpi_conflict = true;
>
> After all, it does not really matter how many conflicts were
> detected.
I agree.
> > +gpio_reg:
> > + lpc_ich_finalize_cell(&lpc_ich_cells[LPC_GPIO], id);
> > + ret = mfd_add_devices(&dev->dev, 0,
> > &lpc_ich_cells[LPC_GPIO],
> > + 1, NULL, 0);
> > + if (!ret)
> > + cells++;
> > +
> So if there is an error, ret < 0, correct ?
>
> > + if (acpi_conflict)
> > + dev_info(&dev->dev, "ACPI resource conflicts found;
> > "
> > + "consider using
> > acpi_enforce_resources=lax?\n");
> > +
> > + if (cells)
> > + return 0;
> > + else
> > + return -ENODEV;
>
> If the above is true, you can just return ret, and you don't need the
> cells variable. Or, even better, move the acpi warning above the call
> to mfd_add_devices().
The cells variable isn't strictly necessary when we're only dealing
with one cell registration, as we have if only looking at the lpc_ich
and gpio-ich patches. The iTCO_wdt patch adds a second call to
mfd_add_devices, so when we return we're interested if either of the
calls succeeded. This was intended to be a forward thinking
implementation, but I have no qualms about simplifying it in the
initial lpc_ich patch.
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