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Message-ID: <CACxGe6uDVdemjbjY_i-_M_-VT8HuLdtXP-R9V8kB+pSSin4dEw@mail.gmail.com>
Date: Wed, 20 Jul 2011 14:02:11 -0600
From: Grant Likely <grant.likely@...retlab.ca>
To: achew@...dia.com
Cc: olof@...om.net, swarren@...dia.com, dwillemsen@...dia.com,
rklein@...dia.com, mogantyv@...dia.com,
devicetree-discuss@...ts.ozlabs.org, linux-tegra@...r.kernel.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3 v2] usb: tegra20-ehci: Add devicetree support.
On Wed, Jul 20, 2011 at 1:38 PM, <achew@...dia.com> wrote:
> From: Andrew Chew <achew@...dia.com>
>
> Add code to try to get platform data information (register base, irq,
> modes, various tuning parameters) from device tree, if not present in board
> files.
>
> Signed-off-by: Andrew Chew <achew@...dia.com>
> ---
> .../devicetree/bindings/usb/tegra20-ehci.txt | 28 +++
> drivers/usb/host/ehci-tegra.c | 221 ++++++++++++++++++++
> 2 files changed, 249 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/usb/tegra20-ehci.txt
>
> diff --git a/Documentation/devicetree/bindings/usb/tegra20-ehci.txt b/Documentation/devicetree/bindings/usb/tegra20-ehci.txt
> new file mode 100644
> index 0000000..5a73a96
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/tegra20-ehci.txt
> @@ -0,0 +1,28 @@
> +NVIDIA Tegra20 SOC USB controllers
> +
> +The device node for a USB controller that is part of a Tegra20
> +SOC is as described in the document "Open Firmware Recommended
> +Practice: Universal Serial Bus" with the following modifications
> +and additions:
> +
> +Required properties:
> + - compatible: Should be "nvidia,tegra20-ehci".
> + - mode: Should be one of "device", "host", or "otg".
> + - power_down_on_bus_suspend: For host mode only, should be <1> if you
> + want the USB phy to power down when the host is suspended. Else, it
> + should be <0>.
We use '-' in property names, not '_'
Boolean values like this should be based on whether or not the
property is present. ie. default to not powering down the phy unless
an empty "power-down-on-suspend" property is present.
> + - type: Should be one of "utmi" or "ulpi".
phy-type perhaps?
> +
> +Required properties for type = "utmi". These values are derived from
> +characterization by system engineering.
> + - hssync_start_delay
> + - idle_wait_delay
> + - elastic_limit
> + - term_range_adj
> + - xcvr_setup
> + - xcvr_lsfslew
> + - xcvr_lsrslew
All of these custom properties should be prefixed with "nvidia," to
avoid namespace collisions.
> +
> +Required properties for type = "ulpi":
> + - reset_gpio: The GPIO used to drive reset
> + - clk
> diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
> index 02b2bfd..89144d5 100644
> --- a/drivers/usb/host/ehci-tegra.c
> +++ b/drivers/usb/host/ehci-tegra.c
> @@ -21,10 +21,20 @@
> #include <linux/platform_data/tegra_usb.h>
> #include <linux/irq.h>
> #include <linux/usb/otg.h>
> +
> +#if defined(CONFIG_OF)
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#endif
> +
linux/of* headers are always safe to include. Don't separate them
from the rest of the #includes.
> #include <mach/usb_phy.h>
>
> #define TEGRA_USB_DMA_ALIGN 32
>
> +static u64 tegra_ehci_dmamask = DMA_BIT_MASK(TEGRA_USB_DMA_ALIGN);
> +
> struct tegra_ehci_hcd {
> struct ehci_hcd *ehci;
> struct tegra_usb_phy *phy;
> @@ -574,9 +584,181 @@ static const struct hc_driver tegra_ehci_hc_driver = {
> .port_handed_over = ehci_port_handed_over,
> };
>
> +#if defined(CONFIG_OF)
> +static int tegra_ehci_parse_dt_node_utmi(struct device_node *dn,
> + struct platform_device *pdev,
> + struct tegra_ehci_platform_data *pdata)
> +{
> + struct device *dev = &pdev->dev;
> + struct tegra_utmip_config *phy_config;
> + int retval;
> +
> + phy_config = devm_kzalloc(dev, sizeof(struct tegra_utmip_config),
> + GFP_KERNEL);
> + if (!phy_config)
> + return -ENOMEM;
> +
> + retval = of_property_read_u32(dn, "hssync_start_delay",
> + (u32 *)&phy_config->hssync_start_delay);
Gah! Don't cast pointers that way. It will break badly if the sizes
don't match. The variable *must* be a u32.
> + if (retval) {
> + dev_err(dev, "Missing dt property \"hssync_start_delay\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_u32(dn, "elastic_limit",
> + (u32 *)&phy_config->elastic_limit);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"elastic_limit\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_u32(dn, "idle_wait_delay",
> + (u32 *)&phy_config->idle_wait_delay);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"idle_wait_delay\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_u32(dn, "term_range_adj",
> + (u32 *)&phy_config->term_range_adj);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"term_range_adj\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_u32(dn, "xcvr_setup",
> + (u32 *)&phy_config->xcvr_setup);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"xcvr_setup\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_u32(dn, "xcvr_lsfslew",
> + (u32 *)&phy_config->xcvr_lsfslew);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"xcvr_lsfslew\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_u32(dn, "xcvr_lsrslew",
> + (u32 *)&phy_config->xcvr_lsrslew);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"xcvr_lsrslew\"\n");
> + return retval;
> + }
Can the driver use sane defaults for any of these values? This patch
will be a lot smaller if there isn't the need to check all the return
values each time.
> +
> + pdata->phy_config = phy_config;
> +
> + return 0;
> +}
> +
> +static int tegra_ehci_parse_dt_node_ulpi(struct device_node *dn,
> + struct platform_device *pdev,
> + struct tegra_ehci_platform_data *pdata)
> +{
> + struct device *dev = &pdev->dev;
> + struct tegra_ulpi_config *phy_config;
> + int retval;
> +
> + phy_config = devm_kzalloc(dev, sizeof(struct tegra_ulpi_config),
> + GFP_KERNEL);
> + if (!phy_config)
> + return -ENOMEM;
> +
> + retval = of_property_read_u32(dn, "reset_gpio",
> + &phy_config->reset_gpio);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"reset_gpio\"\n");
> + return retval;
> + }
> +
> + retval = of_property_read_string(dn, "clk",
> + (char **)&phy_config->clk);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"clk\"\n");
> + return retval;
> + }
> +
> + pdata->phy_config = phy_config;
> +
> + return 0;
> +}
> +
> +static struct tegra_ehci_platform_data *
> +tegra_ehci_parse_dt_node(struct device_node *dn,
> + struct platform_device *pdev)
Nit: to be friendly for grepping, function name should remain on same
line as return value and annotation. Keep line breaks in the
parameter list.
> +{
> + struct device *dev = &pdev->dev;
> + struct tegra_ehci_platform_data *pdata;
> + char *mode;
> + char *type;
> + int retval;
> +
> + pdata = devm_kzalloc(dev, sizeof(struct tegra_ehci_platform_data),
> + GFP_KERNEL);
> + if (!pdata)
> + return NULL;
> +
> + retval = of_property_read_string(dn, "mode", &mode);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"mode\"\n");
> + goto fail;
> + }
> +
> + if (strcmp(mode, "device") == 0)
> + pdata->operating_mode = TEGRA_USB_DEVICE;
> + else if (strcmp(mode, "host") == 0)
> + pdata->operating_mode = TEGRA_USB_HOST;
> + else if (strcmp(mode, "otg") == 0)
> + pdata->operating_mode = TEGRA_USB_OTG;
> + else {
> + dev_err(dev, "Invalid dt property \"mode\" value %s\n", mode);
> + goto fail;
> + }
> +
> + retval = of_property_read_u32(dn, "power_down_on_bus_suspend",
> + &pdata->power_down_on_bus_suspend);
> + if (retval) {
> + dev_err(dev, "Missing dt property "
> + "\"power_down_on_bus_suspend\"\n");
> + goto fail;
> + }
> +
> + retval = of_property_read_string(dn, "type", &type);
> + if (retval) {
> + dev_err(dev, "Missing dt property \"type\"\n");
> + goto fail;
> + }
> +
> + if (strcmp(type, "utmi") == 0) {
> + retval = tegra_ehci_parse_dt_node_utmi(dn, pdev, pdata);
> + if (retval)
> + goto fail;
> + } else if (strcmp(type, "ulpi") == 0) {
> + retval = tegra_ehci_parse_dt_node_ulpi(dn, pdev, pdata);
> + if (retval)
> + goto fail;
> + } else {
> + dev_err(dev, "Invalid dt property \"type\" value %s\n", type);
> + goto fail;
> + }
> +
> + return pdata;
> +
> +fail:
> + devm_kfree(dev, pdata);
> +
> + return NULL;
> +}
> +#endif
> +
> static int tegra_ehci_probe(struct platform_device *pdev)
> {
> struct resource *res;
> +#if defined(CONFIG_OF)
> + struct device_node *dn = pdev->dev.of_node;
> + struct resource of_res;
> +#endif
> struct usb_hcd *hcd;
> struct tegra_ehci_hcd *tegra;
> struct tegra_ehci_platform_data *pdata;
> @@ -584,7 +766,20 @@ static int tegra_ehci_probe(struct platform_device *pdev)
> int irq;
> int instance = pdev->id;
>
> + /*
> + * See if there's any platform data passed via board files.
> + * If there isn't, then allocate one and fill it by parsing
> + * device tree node.
> + */
> pdata = pdev->dev.platform_data;
> +#if defined(CONFIG_OF)
> + if (!pdata) {
> + pdata = tegra_ehci_parse_dt_node(dn, pdev);
> +
> + pdev->dev.dma_mask = &tegra_ehci_dmamask;
> + pdev->dev.coherent_dma_mask = tegra_ehci_dmamask;
> + }
> +#endif
Drop the #if/#endif protection, and create an empty version of
tegra_ehci_parse_dt_node() when CONFIG_OF is not selected. It will
make the code cleaner.
> if (!pdata) {
> dev_err(&pdev->dev, "Platform data missing\n");
> return -EINVAL;
> @@ -625,7 +820,15 @@ static int tegra_ehci_probe(struct platform_device *pdev)
> clk_enable(tegra->emc_clk);
> clk_set_rate(tegra->emc_clk, 400000000);
>
> + /*
> + * If there isn't an IORESOURCE_MEM defined in the board file,
> + * then try to get that information from the device tree node.
> + */
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +#if defined(CONFIG_OF)
> + if (!res && (of_address_to_resource(dn, 0, &of_res) == 0))
> + res = &of_res;
> +#endif
Unnecessary. The register ranges are populated into the resource
table by default.
> if (!res) {
> dev_err(&pdev->dev, "Failed to get I/O memory\n");
> err = -ENXIO;
> @@ -658,7 +861,15 @@ static int tegra_ehci_probe(struct platform_device *pdev)
> tegra->power_down_on_bus_suspend = pdata->power_down_on_bus_suspend;
> tegra->ehci = hcd_to_ehci(hcd);
>
> + /*
> + * If there isn't an irq defined in the board file, then try to get
> + * that information from the device tree node.
> + */
> irq = platform_get_irq(pdev, 0);
> +#if defined(CONFIG_OF)
> + if (!irq)
> + irq = irq_of_parse_and_map(dn, 0);
> +#endif
Same here; unnecessary.
> if (!irq) {
> dev_err(&pdev->dev, "Failed to get IRQ\n");
> err = -ENODEV;
> @@ -773,6 +984,14 @@ static void tegra_ehci_hcd_shutdown(struct platform_device *pdev)
> hcd->driver->shutdown(hcd);
> }
>
> +static const struct of_device_id tegra_ehci_of_match[] = {
> + {
> + .compatible = "nvidia,tegra20-ehci",
> + },
The following form is more concise and preferred for match tables:
{ .compatible = "nvidia,tegra20-ehci", },
{},
> +};
> +MODULE_DEVICE_TABLE(of, tegra_ehci_of_match);
> +
> static struct platform_driver tegra_ehci_driver = {
> .probe = tegra_ehci_probe,
> .remove = tegra_ehci_remove,
> @@ -783,5 +1002,7 @@ static struct platform_driver tegra_ehci_driver = {
> .shutdown = tegra_ehci_hcd_shutdown,
> .driver = {
> .name = "tegra-ehci",
> + .owner = THIS_MODULE,
> + .of_match_table = tegra_ehci_of_match,
> }
> };
> --
> 1.7.6
>
> --
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>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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