Re: [PATCH v1 4/5] mfd: lpc_sch: Add support for Intel Quark X1000

Lee Jones
2014-09-01T11:32:06Z

On Mon, 01 Sep 2014, Andy Shevchenko wrote:

> On Mon, 2014-09-01 at 10:22 +0100, Lee Jones wrote:
> > On Fri, 22 Aug 2014, Andy Shevchenko wrote:
> >
> > > Intel Quark X1000 SoC supports IRQ based GPIO. This patch will
> > > enable MFD support for Quark X1000 and provide IRQ resources
> > > to Quark X1000 GPIO device driver.
> > >
> > > Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
> > > Tested-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>
> See my answers below.
>
> > > ---
> > > drivers/mfd/lpc_sch.c | 41 +++++++++++++++++++++++++++++++++++------
> > > 1 file changed, 35 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/mfd/lpc_sch.c b/drivers/mfd/lpc_sch.c
> > > index c4eb359..6145a4c 100644
> > > --- a/drivers/mfd/lpc_sch.c
> > > +++ b/drivers/mfd/lpc_sch.c
> > > @@ -37,6 +37,9 @@
> > > #define GPIO_IO_SIZE 64
> > > #define GPIO_IO_SIZE_CENTERTON 128
> > >
> > > +/* Intel Quark X1000 GPIO IRQ Number */
> > > +#define GPIO_IRQ_QUARK_X1000 9
> > > +
> > > #define WDTBASE 0x84
> > > #define WDT_IO_SIZE 64
> > >
> > > @@ -44,28 +47,37 @@ enum sch_chipsets {
> > > LPC_SCH = 0, /* Intel Poulsbo SCH */
> > > LPC_ITC, /* Intel Tunnel Creek */
> > > LPC_CENTERTON, /* Intel Centerton */
> > > + LPC_QUARK_X1000, /* Intel Quark X1000 */
> > > };
> > >
> > > struct lpc_sch_info {
> > > unsigned int io_size_smbus;
> > > unsigned int io_size_gpio;
> > > unsigned int io_size_wdt;
> > > + int irq_gpio;
> > > };
> > >
> > > static struct lpc_sch_info sch_chipset_info[] = {
> > > [LPC_SCH] = {
> > > .io_size_smbus = SMBUS_IO_SIZE,
> > > .io_size_gpio = GPIO_IO_SIZE,
> > > + .irq_gpio = -1,
> > > },
> > > [LPC_ITC] = {
> > > .io_size_smbus = SMBUS_IO_SIZE,
> > > .io_size_gpio = GPIO_IO_SIZE,
> > > .io_size_wdt = WDT_IO_SIZE,
> > > + .irq_gpio = -1,
> > > },
> > > [LPC_CENTERTON] = {
> > > .io_size_smbus = SMBUS_IO_SIZE,
> > > .io_size_gpio = GPIO_IO_SIZE_CENTERTON,
> > > .io_size_wdt = WDT_IO_SIZE,
> > > + .irq_gpio = -1,
> > > + },
> > > + [LPC_QUARK_X1000] = {
> > > + .io_size_gpio = GPIO_IO_SIZE,
> > > + .irq_gpio = GPIO_IRQ_QUARK_X1000,
> > > },
> > > };
> > >
> > > @@ -73,6 +85,7 @@ static const struct pci_device_id lpc_sch_ids[] = {
> > > { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_SCH_LPC), LPC_SCH },
> > > { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ITC_LPC), LPC_ITC },
> > > { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_CENTERTON_ILB), LPC_CENTERTON },
> > > + { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_QUARK_X1000_ILB), LPC_QUARK_X1000 },
> > > { 0, }
> > > };
> > > MODULE_DEVICE_TABLE(pci, lpc_sch_ids);
> > > @@ -106,14 +119,26 @@ static int lpc_sch_get_io(struct pci_dev *pdev, int where, const char *name,
> > > return 0;
> > > }
> > >
> > > +static int lpc_sch_get_irq(struct resource *res, int irq)
> > > +{
> > > + if (irq < 0)
> > > + return -EINVAL;
> > > +
> > > + res->start = irq;
> > > + res->end = irq;
> > > + res->flags = IORESOURCE_IRQ;
> > > +
> > > + return 0;
> > > +}
> >
> > Why does this need to be a separate function?
> >
> > I fear that the code will become unnecessarily fragmented, just for the
> > sake of it.
>
> I could do this as a condition branch.

You could, but you don't.

> > > static int lpc_sch_populate_cell(struct pci_dev *pdev, int where,
> > > - const char *name, int size, int id,
> > > - struct mfd_cell *cell)
> > > + const char *name, int size, int irq,
> > > + int id, struct mfd_cell *cell)
> > > {
> > > struct resource *res;
> > > int ret;
> > >
> > > - res = devm_kzalloc(&pdev->dev, sizeof(*res), GFP_KERNEL);
> > > + res = devm_kcalloc(&pdev->dev, 2, sizeof(*res), GFP_KERNEL);
> > > if (!res)
> > > return -ENOMEM;
> > >
> > > @@ -129,6 +154,10 @@ static int lpc_sch_populate_cell(struct pci_dev *pdev, int where,
> > > cell->ignore_resource_conflicts = true;
> > > cell->id = id;
> > >
> > > + ret = lpc_sch_get_irq(++res, irq);
> > > + if (!ret)
> > > + cell->num_resources++;
> >
> > Once again, you're masking errors. If it's not an error, don't return
> > one. If it is, filter it back and fail the bind.
>
> I have to know if there is such resource or not. Taking into account you
> prefer to see lpc_sch_get_irq embedded in here I just can do as a
> condition branch and there will be no more question I hope.

This is true.

> > > return 0;
> > > }
> > >
> > > @@ -141,19 +170,19 @@ static int lpc_sch_probe(struct pci_dev *dev,
> > > int ret;
> > >
> > > ret = lpc_sch_populate_cell(dev, SMBASE, "isch_smbus",
> > > - info->io_size_smbus,
> > > + info->io_size_smbus, -1,
> > > id->device, &lpc_sch_cells[cells]);
> > > if (!ret)
> > > cells++;
> > >
> > > ret = lpc_sch_populate_cell(dev, GPIOBASE, "sch_gpio",
> > > - info->io_size_gpio,
> > > + info->io_size_gpio, info->irq_gpio,
> > > id->device, &lpc_sch_cells[cells]);
> > > if (!ret)
> > > cells++;
> > >
> > > ret = lpc_sch_populate_cell(dev, WDTBASE, "ie6xx_wdt",
> > > - info->io_size_wdt,
> > > + info->io_size_wdt, -1,
> > > id->device, &lpc_sch_cells[cells]);
> > > if (!ret)
> > > cells++;
>
>

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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