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Message-ID: <20150429183059.GA9169@x1>
Date: Wed, 29 Apr 2015 19:30:59 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Andrew Bresticker <abrestic@...omium.org>
Cc: Thierry Reding <thierry.reding@...il.com>,
Stephen Warren <swarren@...dotorg.org>,
Alexandre Courbot <gnurou@...il.com>,
"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Samuel Ortiz <sameo@...ux.intel.com>
Subject: Re: [PATCH V7 5/9] mfd: Add driver for NVIDIA Tegra XUSB
On Wed, 29 Apr 2015, Andrew Bresticker wrote:
> Lee,
>
> On Wed, Apr 29, 2015 at 2:23 AM, Lee Jones <lee.jones@...aro.org> wrote:
> > On Mon, 27 Apr 2015, Andrew Bresticker wrote:
> >
> >> Add an MFD driver for the XUSB host complex found on NVIDIA Tegra124
> >> and later SoCs.
> >>
> >> Signed-off-by: Andrew Bresticker <abrestic@...omium.org>
> >> Cc: Samuel Ortiz <sameo@...ux.intel.com>
> >> Cc: Lee Jones <lee.jones@...aro.org>
>
> >> --- /dev/null
> >> +++ b/drivers/mfd/tegra-xusb.c
>
> >> +struct tegra_xusb_soc_data {
> >> + struct mfd_cell *devs;
> >> + unsigned int num_devs;
> >> +};
> >> +
> >> +static struct resource tegra_xhci_resources[] = {
> >> + {
> >> + .name = "host",
> >> + .flags = IORESOURCE_IRQ,
> >> + },
> >> + {
> >> + .name = "xhci",
> >> + .flags = IORESOURCE_MEM,
> >> + },
> >> + {
> >> + .name = "ipfs",
> >> + .flags = IORESOURCE_MEM,
> >> + },
> >> +};
> >> +
> >> +static struct resource tegra_xusb_mbox_resources[] = {
> >> + {
> >> + .name = "smi",
> >> + .flags = IORESOURCE_IRQ,
> >> + },
> >> +};
> >
> > DEFINE_RES_IRQ_NAMED()
> >
> >> +static struct mfd_cell tegra124_xusb_devs[] = {
> >> + {
> >> + .name = "tegra-xhci",
> >> + .of_compatible = "nvidia,tegra124-xhci",
> >> + },
> >> + {
> >> + .name = "tegra-xusb-mbox",
> >> + .of_compatible = "nvidia,tegra124-xusb-mbox",
> >> + },
> >> +};
> >> +
> >> +static const struct tegra_xusb_soc_data tegra124_xusb_data = {
> >> + .devs = tegra124_xusb_devs,
> >> + .num_devs = ARRAY_SIZE(tegra124_xusb_devs),
> >> +};
> >> +
> >> +static const struct of_device_id tegra_xusb_of_match[] = {
> >> + { .compatible = "nvidia,tegra124-xusb", .data = &tegra124_xusb_data },
> >
> > Yuk! Why are you mixing platform data and DT in this way?
> >
> > Why can't you just stick all of this in DT?
>
> I assume you mean the resources? The compatible strings will at least
> need to be SoC-specific since they will change from SoC to SoC.
>
> >> + {},
> >> +};
> >> +
> >> +MODULE_DEVICE_TABLE(of, tegra_xusb_of_match);
> >> +static struct regmap_config tegra_fpci_regmap_config = {
> >> + .reg_bits = 32,
> >> + .val_bits = 32,
> >> + .reg_stride = 4,
> >> +};
> >> +
> >> +static int tegra_xusb_probe(struct platform_device *pdev)
> >> +{
> >> + const struct tegra_xusb_soc_data *soc;
> >> + const struct of_device_id *match;
> >> + struct tegra_xusb *xusb;
> >> + struct resource *res;
> >> + void __iomem *fpci_base;
> >> + int irq, ret;
> >> +
> >> + xusb = devm_kzalloc(&pdev->dev, sizeof(*xusb), GFP_KERNEL);
> >> + if (!xusb)
> >> + return -ENOMEM;
> >> + platform_set_drvdata(pdev, xusb);
> >> +
> >> + match = of_match_node(tegra_xusb_of_match, pdev->dev.of_node);
> >> + soc = match->data;
> >> +
> >> + irq = platform_get_irq_byname(pdev, "host");
> >> + if (irq < 0)
> >> + return irq;
> >> + tegra_xhci_resources[0].start = irq;
> >> + tegra_xhci_resources[0].end = irq;
> >> +
> >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
> >> + if (!res)
> >> + return -ENODEV;
> >> + tegra_xhci_resources[1].start = res->start;
> >> + tegra_xhci_resources[1].end = res->end;
> >> +
> >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ipfs");
> >> + if (!res)
> >> + return -ENODEV;
> >> + tegra_xhci_resources[2].start = res->start;
> >> + tegra_xhci_resources[2].end = res->end;
> >> +
> >> + soc->devs[0].resources = tegra_xhci_resources;
> >> + soc->devs[0].num_resources = ARRAY_SIZE(tegra_xhci_resources);
> >> +
> >> + irq = platform_get_irq_byname(pdev, "smi");
> >> + if (irq < 0)
> >> + return irq;
> >> + tegra_xusb_mbox_resources[0].start = irq;
> >> + tegra_xusb_mbox_resources[0].end = irq;
> >> +
> >> + soc->devs[1].resources = tegra_xusb_mbox_resources;
> >> + soc->devs[1].num_resources = ARRAY_SIZE(tegra_xusb_mbox_resources);
> >> +
> >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "fpci");
> >> + fpci_base = devm_ioremap_resource(&pdev->dev, res);
> >> + if (IS_ERR(fpci_base))
> >> + return PTR_ERR(fpci_base);
> >
> > This stuff is not good.
> >
> > Either let MFD handle it with mfd_cells or stick all of this stuff in
> > DT and parse it from the child devices.
>
> I'm not sure what exactly you mean by "let MFD handle it with
> mfd_cells" here - is that not what I'm doing now? Anyway I think that
> leaves two ways of representing this in DT.
>
> Either have the MFD take a single IOMEM resource and divide it up
> statically within the driver:
>
> usb@0,70090000 {
> compatible = "nvidia,tegra124-xusb";
> reg = <0x0 0x70090000 0x0 0xa000>;
>
> usb-host {
> compatible = "nvidia,tegra124-xhci";
> interrupts = <...>;
> ...
> }:
>
> mailbox {
> compatible = "nvidia,tegra124-xusb-mbox";
> interrupts = <...>;
> ...
> };
> };
>
> ... or have the MFD take only the shared FPCI resource and have the
> sub-devices parse the rest from DT:
>
> usb@0,70098000 {
> compatible = "nvidia,tegra124-xusb";
> reg = <0x0 0x70098000 0x0 0x1000>;
> ranges;
>
> usb-host@0,70090000 {
> compatible = "nvidia,tegra124-xhci";
> reg = <0x0 0x70090000 0x0 0x8000>,
> <0x0 0x70099000 0x0 0x1000>;
> interrupts = <...>;
> ...
> }:
>
> mailbox {
> compatible = "nvidia,tegra124-xusb-mbox";
> interrupts = <...>;
> ...
> };
> };
>
> I don't have a strong preference here, but I think the former more
> accurately represents the resource hierarchy. Since Thierry requested
> the use of an MFD, I'd like him to weigh in on this - Thierry?
The latter is what I had in mind.
> >> + tegra_fpci_regmap_config.max_register = res->end - res->start - 3;
> >> + xusb->fpci_regs = devm_regmap_init_mmio(&pdev->dev, fpci_base,
> >> + &tegra_fpci_regmap_config);
> >> + if (IS_ERR(xusb->fpci_regs)) {
> >> + ret = PTR_ERR(xusb->fpci_regs);
> >> + dev_err(&pdev->dev, "Failed to init regmap: %d\n", ret);
> >> + return ret;
> >> + }
> >> +
> >> + ret = mfd_add_devices(&pdev->dev, -1, soc->devs, soc->num_devs,
> >> + NULL, 0, NULL);
> >> + if (ret) {
> >> + dev_err(&pdev->dev, "Failed to add MFD devices: %d\n", ret);
> >> + return ret;
> >> + }
> >> +
> >> + return 0;
> >> +}
>
> >> --- /dev/null
> >> +++ b/include/soc/tegra/xusb.h
>
> >> +struct tegra_xusb {
> >> + struct regmap *fpci_regs;
> >
> > Are you going to add to this?
>
> No, I don't have any plans to add to this struct.
Then you don't require a struct. :)
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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