| Message ID | 1452231864-11171-3-git-send-email-peter.chen@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Friday 08 January 2016 13:44:24 Peter Chen wrote: > + u32 duration_us = 0; > + of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us); > + if (duration_us > 0) { > + usleep_range(duration_us, duration_us + 10); > + dev_info(&hdev->dev, "The delay is %d us\n", duration_us); > + } > + I think especially for an example, it would be better to use error checking and not initialize the variable: u32 duration_us; int ret; ... ret = of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us); if (!ret && duration_us > 0) { ... } The effect is the same as the other one. Arnd
On Fri, Jan 08, 2016 at 09:26:10AM +0100, Arnd Bergmann wrote: > On Friday 08 January 2016 13:44:24 Peter Chen wrote: > > + u32 duration_us = 0; > > > + of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us); > > + if (duration_us > 0) { > > + usleep_range(duration_us, duration_us + 10); > > + dev_info(&hdev->dev, "The delay is %d us\n", duration_us); > > + } > > + > > I think especially for an example, it would be better to use error checking and > not initialize the variable: > > u32 duration_us; > int ret; > ... > ret = of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us); > if (!ret && duration_us > 0) { > ... > } > > The effect is the same as the other one. > Thanks, will change.
diff --git a/arch/arm/boot/dts/imx6sx-sdb.dtsi b/arch/arm/boot/dts/imx6sx-sdb.dtsi index 94ac400..fe0fd95 100644 --- a/arch/arm/boot/dts/imx6sx-sdb.dtsi +++ b/arch/arm/boot/dts/imx6sx-sdb.dtsi @@ -275,6 +275,15 @@ vbus-supply = <®_usb_otg2_vbus>; dr_mode = "host"; status = "okay"; + + #address-cells = <1>; + #size-cells = <0>; + hub: genesys@01 { + compatible = "05e3,0608"; + reg = <0x01>; + delay-duration-us = <50>; + }; + }; &usdhc2 { diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 4c77001..1babfd4 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -27,6 +27,7 @@ #include <linux/random.h> #include <linux/pm_qos.h> #include <linux/of_platform.h> +#include <linux/of.h> #include <asm/uaccess.h> #include <asm/byteorder.h> @@ -1748,6 +1749,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) struct usb_device *hdev; struct usb_hub *hub; int ret; + u32 duration_us = 0; desc = intf->cur_altsetting; hdev = interface_to_usbdev(intf); @@ -1873,6 +1875,12 @@ descriptor_error: return ret; } + of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us); + if (duration_us > 0) { + usleep_range(duration_us, duration_us + 10); + dev_info(&hdev->dev, "The delay is %d us\n", duration_us); + } + if (hub_configure(hub, endpoint) >= 0) return 0;
In this example, we take HUB driver as an example to show how to get properties in USB device driver if this device has device node. Signed-off-by: Peter Chen <peter.chen@freescale.com> --- arch/arm/boot/dts/imx6sx-sdb.dtsi | 9 +++++++++ drivers/usb/core/hub.c | 8 ++++++++ 2 files changed, 17 insertions(+)