Re: [RFC v5 07/15] usb: ehci: add vbus-gpio parameter

[Sergei Shtylyov]

On 02/18/2016 09:06 PM, Antony Pavlov wrote:

This patch retrieves and configures the vbus control gpio via
the device tree.

This patch is based on a ehci-s5p.c commit fd81d59c90d38661
("USB: ehci-s5p: Add vbus setup function to the s5p ehci glue layer").

Signed-off-by: Antony Pavlov <antonynpav...@gmail.com>
Cc: Alan Stern <st...@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-ker...@vger.kernel.org
---
  drivers/usb/host/ehci-platform.c | 22 ++++++++++++++++++++++
  1 file changed, 22 insertions(+)

diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
index bd7082f2..0d95ced 100644
--- a/drivers/usb/host/ehci-platform.c
+++ b/drivers/usb/host/ehci-platform.c
@@ -28,6 +28,7 @@
  #include <linux/io.h>
  #include <linux/module.h>
  #include <linux/of.h>
+#include <linux/of_gpio.h>
  #include <linux/phy/phy.h>
  #include <linux/platform_device.h>
  #include <linux/reset.h>
@@ -142,6 +143,25 @@ static struct usb_ehci_pdata ehci_platform_defaults = {
        .power_off =            ehci_platform_power_off,
  };

+static void setup_vbus_gpio(struct device *dev)
+{
+       int err;
+       int gpio;
+
+       if (!dev->of_node)
+               return;
+
+       gpio = of_get_named_gpio(dev->of_node, "vbus-gpio", 0);
+       if (!gpio_is_valid(gpio))
+               return;
+
+       err = devm_gpio_request_one(dev, gpio,
+                               GPIOF_OUT_INIT_HIGH | GPIOF_EXPORT_DIR_FIXED,
+                               "ehci_vbus_gpio");
+       if (err)
+               dev_err(dev, "can't request ehci vbus gpio %d", gpio);

I don't understand this.  If you get an error here, what's the point of
allowing the probe to continue?  Shouldn't you return an error code so
the probe will fail?

Please ignore the 'usb: ehci: add vbus-gpio parameter' patch!

In the new AR9331 patchseries I use chipidea USB driver (thanks to Marek for 
the suggestion)
in the AR9331 dtsi-file:

         usb: usb@1b000100 {
                 compatible = "chipidea,usb2";
                 reg = <0x1b000000 0x200>;

                 interrupt-parent = <&cpuintc>;
                 interrupts = <3>;
                 resets = <&rst 5>;

                 phy-names = "usb-phy";
                 phys = <&usb_phy>;

                 status = "disabled";
         };


so I use regulator in the TL-MR3020 board dts file:

         reg_usb_vbus: reg_usb_vbus {
                 compatible = "regulator-fixed";
                 regulator-name = "usb_vbus";
                 regulator-min-microvolt = <5000000>;

   Not 0?

                 regulator-max-microvolt = <5000000>;
                 gpio = <&gpio 8 GPIO_ACTIVE_HIGH>;

   Where's the switch if both voltages are equal?

                 enable-active-high;
         };

&usb {
         dr_mode = "host";
         vbus-supply = <&reg_usb_vbus>;
         status = "okay";
};

As a result there is no need in adding vbus-gpio parameter to ehci anymore!

[...]

MBR, Sergei

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