usb: gadget: consider link speed for bMaxPower

The USB 2.0 specification says that bMaxPower is the maximum power
consumption expressed in 2 mA units and the USB 3.0 specification says
that it is expressed in 8 mA units.

This patch renames bMaxPower to MaxPower and the various /2 and *2 are
removed. Before reporting the config descriptor, the proper value is
computer based on the speed, all in-tree users are updated. MaxPower is
also increased to u16 so we can store the nokia gadget value which is
larger than the max value allowed for u8.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

5 files changed, 30 insertions, 10 deletions

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 2a6bfe759c29..71475b6d8568 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -320,6 +320,25 @@ int usb_interface_id(struct usb_configuration *config,
 }
 EXPORT_SYMBOL_GPL(usb_interface_id);
 
+static u8 encode_bMaxPower(enum usb_device_speed speed,
+                struct usb_configuration *c)
+{
+        unsigned val;
+
+        if (c->MaxPower)
+                val = c->MaxPower;
+        else
+                val = CONFIG_USB_GADGET_VBUS_DRAW;
+        if (!val)
+                return 0;
+        switch (speed) {
+        case USB_SPEED_SUPER:
+                return DIV_ROUND_UP(val, 8);
+        default:
+                return DIV_ROUND_UP(val, 2);
+        };
+}
+
 static int config_buf(struct usb_configuration *config,
                 enum usb_device_speed speed, void *buf, u8 type)
 {
@@ -339,7 +358,7 @@ static int config_buf(struct usb_configuration *config,
         c->bConfigurationValue = config->bConfigurationValue;
         c->iConfiguration = config->iConfiguration;
         c->bmAttributes = USB_CONFIG_ATT_ONE | config->bmAttributes;
-        c->bMaxPower = config->bMaxPower ? : (CONFIG_USB_GADGET_VBUS_DRAW / 2);
+        c->bMaxPower = encode_bMaxPower(speed, config);
 
         /* There may be e.g. OTG descriptors */
         if (config->descriptors) {
@@ -656,7 +675,7 @@ static int set_config(struct usb_composite_dev *cdev,
         }
 
         /* when we return, be sure our power usage is valid */
-        power = c->bMaxPower ? (2 * c->bMaxPower) : CONFIG_USB_GADGET_VBUS_DRAW;
+        power = c->MaxPower ? c->MaxPower : CONFIG_USB_GADGET_VBUS_DRAW;
 done:
         usb_gadget_vbus_draw(gadget, power);
         if (result >= 0 && cdev->delayed_status)
@@ -1518,10 +1537,10 @@ composite_resume(struct usb_gadget *gadget)
                                 f->resume(f);
                 }
 
-                maxpower = cdev->config->bMaxPower;
+                maxpower = cdev->config->MaxPower;
 
                 usb_gadget_vbus_draw(gadget, maxpower ?
-                        (2 * maxpower) : CONFIG_USB_GADGET_VBUS_DRAW);
+                        maxpower : CONFIG_USB_GADGET_VBUS_DRAW);
         }
 
         cdev->suspended = 0;
diff --git a/drivers/usb/gadget/gmidi.c b/drivers/usb/gadget/gmidi.c
index 881aab86ae99..e879e2c9f461 100644
--- a/drivers/usb/gadget/gmidi.c
+++ b/drivers/usb/gadget/gmidi.c
@@ -125,7 +125,7 @@ static struct usb_configuration midi_config = {
         .bConfigurationValue = 1,
         /* .iConfiguration = DYNAMIC */
         .bmAttributes   = USB_CONFIG_ATT_ONE,
-        .bMaxPower      = CONFIG_USB_GADGET_VBUS_DRAW / 2,
+        .MaxPower       = CONFIG_USB_GADGET_VBUS_DRAW,
 };
 
 static int __init midi_bind_config(struct usb_configuration *c)
diff --git a/drivers/usb/gadget/nokia.c b/drivers/usb/gadget/nokia.c
index 661600abace8..1475d663b527 100644
--- a/drivers/usb/gadget/nokia.c
+++ b/drivers/usb/gadget/nokia.c
@@ -133,7 +133,7 @@ static struct usb_configuration nokia_config_500ma_driver = {
         .bConfigurationValue = 1,
         /* .iConfiguration = DYNAMIC */
         .bmAttributes   = USB_CONFIG_ATT_ONE,
-        .bMaxPower      = 250, /* 500mA */
+        .MaxPower       = 500,
 };
 
 static struct usb_configuration nokia_config_100ma_driver = {
@@ -141,7 +141,7 @@ static struct usb_configuration nokia_config_100ma_driver = {
         .bConfigurationValue = 2,
         /* .iConfiguration = DYNAMIC */
         .bmAttributes   = USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
-        .bMaxPower      = 50, /* 100 mA */
+        .MaxPower       = 100,
 };
 
 static int __init nokia_bind(struct usb_composite_dev *cdev)
diff --git a/drivers/usb/gadget/webcam.c b/drivers/usb/gadget/webcam.c
index 69cf5c2cd335..8cef1e658c29 100644
--- a/drivers/usb/gadget/webcam.c
+++ b/drivers/usb/gadget/webcam.c
@@ -336,7 +336,7 @@ static struct usb_configuration webcam_config_driver = {
         .bConfigurationValue    = 1,
         .iConfiguration         = 0, /* dynamic */
         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
-        .bMaxPower              = CONFIG_USB_GADGET_VBUS_DRAW / 2,
+        .MaxPower               = CONFIG_USB_GADGET_VBUS_DRAW,
 };
 
 static int /* __init_or_exit */
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index b09c37e04a91..dc512c9432d7 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -184,7 +184,8 @@ int config_ep_by_speed(struct usb_gadget *g, struct usb_function *f,
  * @bConfigurationValue: Copied into configuration descriptor.
  * @iConfiguration: Copied into configuration descriptor.
  * @bmAttributes: Copied into configuration descriptor.
- * @bMaxPower: Copied into configuration descriptor.
+ * @MaxPower: Power consumtion in mA. Used to compute bMaxPower in the
+ *      configuration descriptor after considering the bus speed.
  * @cdev: assigned by @usb_add_config() before calling @bind(); this is
  *      the device associated with this configuration.
  *
@@ -230,7 +231,7 @@ struct usb_configuration {
         u8                      bConfigurationValue;
         u8                      iConfiguration;
         u8                      bmAttributes;
-        u8                      bMaxPower;
+        u16                     MaxPower;
 
         struct usb_composite_dev        *cdev;