USB: full autosuspend and power management support for usbsevseg

This patch adds to the usbsevseg driver:

- suspend/resume support
- reset_resume support
- autosuspend using the display's power state to determine idleness

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Harrison Metzger <harrisonmetz@gmail.com>

1 files changed, 63 insertions, 6 deletions

diff --git a/drivers/usb/misc/usbsevseg.c b/drivers/usb/misc/usbsevseg.c
index 28a6a3a09538..3db255537e79 100644
--- a/drivers/usb/misc/usbsevseg.c
+++ b/drivers/usb/misc/usbsevseg.c
@@ -38,6 +38,7 @@ static char *display_textmodes[] = {"raw", "hex", "ascii", NULL};
 
 struct usb_sevsegdev {
         struct usb_device *udev;
+        struct usb_interface *intf;
 
         u8 powered;
         u8 mode_msb;
@@ -46,6 +47,8 @@ struct usb_sevsegdev {
         u8 textmode;
         u8 text[MAXLEN];
         u16 textlength;
+
+        u8 shadow_power; /* for PM */
 };
 
 /* sysfs_streq can't replace this completely
@@ -65,6 +68,12 @@ static void update_display_powered(struct usb_sevsegdev *mydev)
 {
         int rc;
 
+        if (!mydev->shadow_power && mydev->powered) {
+                rc = usb_autopm_get_interface(mydev->intf);
+                if (rc < 0)
+                        return;
+        }
+
         rc = usb_control_msg(mydev->udev,
                         usb_sndctrlpipe(mydev->udev, 0),
                         0x12,
@@ -76,12 +85,18 @@ static void update_display_powered(struct usb_sevsegdev *mydev)
                         2000);
         if (rc < 0)
                 dev_dbg(&mydev->udev->dev, "power retval = %d\n", rc);
+
+        if (mydev->shadow_power && !mydev->powered)
+                usb_autopm_put_interface(mydev->intf);
 }
 
 static void update_display_mode(struct usb_sevsegdev *mydev)
 {
         int rc;
 
+        if(mydev->shadow_power != 1)
+                return;
+
         rc = usb_control_msg(mydev->udev,
                         usb_sndctrlpipe(mydev->udev, 0),
                         0x12,
@@ -96,14 +111,17 @@ static void update_display_mode(struct usb_sevsegdev *mydev)
                 dev_dbg(&mydev->udev->dev, "mode retval = %d\n", rc);
 }
 
-static void update_display_visual(struct usb_sevsegdev *mydev)
+static void update_display_visual(struct usb_sevsegdev *mydev, gfp_t mf)
 {
         int rc;
         int i;
         unsigned char *buffer;
         u8 decimals = 0;
 
-        buffer = kzalloc(MAXLEN, GFP_KERNEL);
+        if(mydev->shadow_power != 1)
+                return;
+
+        buffer = kzalloc(MAXLEN, mf);
         if (!buffer) {
                 dev_err(&mydev->udev->dev, "out of memory\n");
                 return;
@@ -163,7 +181,7 @@ static ssize_t set_attr_##name(struct device *dev, 		\
         struct usb_sevsegdev *mydev = usb_get_intfdata(intf);   \
                                                                 \
         mydev->name = simple_strtoul(buf, NULL, 10);            \
-        update_fcn(mydev); \
+        update_fcn(mydev);                                      \
                                                                 \
         return count;                                           \
 }                                                               \
@@ -194,7 +212,7 @@ static ssize_t set_attr_text(struct device *dev,
         if (end > 0)
                 memcpy(mydev->text, buf, end);
 
-        update_display_visual(mydev);
+        update_display_visual(mydev, GFP_KERNEL);
         return count;
 }
 
@@ -242,7 +260,7 @@ static ssize_t set_attr_decimals(struct device *dev,
                 if (buf[i] == '1')
                         mydev->decimals[end-1-i] = 1;
 
-        update_display_visual(mydev);
+        update_display_visual(mydev, GFP_KERNEL);
 
         return count;
 }
@@ -286,7 +304,7 @@ static ssize_t set_attr_textmode(struct device *dev,
         for (i = 0; display_textmodes[i]; i++) {
                 if (sysfs_streq(display_textmodes[i], buf)) {
                         mydev->textmode = i;
-                        update_display_visual(mydev);
+                        update_display_visual(mydev, GFP_KERNEL);
                         return count;
                 }
         }
@@ -330,6 +348,7 @@ static int sevseg_probe(struct usb_interface *interface,
         }
 
         mydev->udev = usb_get_dev(udev);
+        mydev->intf = interface;
         usb_set_intfdata(interface, mydev);
 
         /*set defaults */
@@ -364,11 +383,49 @@ static void sevseg_disconnect(struct usb_interface *interface)
         dev_info(&interface->dev, "USB 7 Segment now disconnected\n");
 }
 
+static int sevseg_suspend(struct usb_interface *intf, pm_message_t message)
+{
+        struct usb_sevsegdev *mydev;
+
+        mydev = usb_get_intfdata(intf);
+        mydev->shadow_power = 0;
+
+        return 0;
+}
+
+static int sevseg_resume(struct usb_interface *intf)
+{
+        struct usb_sevsegdev *mydev;
+
+        mydev = usb_get_intfdata(intf);
+        mydev->shadow_power = 1;
+        update_display_mode(mydev);
+        update_display_visual(mydev, GFP_NOIO);
+
+        return 0;
+}
+
+static int sevseg_reset_resume(struct usb_interface *intf)
+{
+        struct usb_sevsegdev *mydev;
+
+        mydev = usb_get_intfdata(intf);
+        mydev->shadow_power = 1;
+        update_display_mode(mydev);
+        update_display_visual(mydev, GFP_NOIO);
+
+        return 0;
+}
+
 static struct usb_driver sevseg_driver = {
         .name =         "usbsevseg",
         .probe =        sevseg_probe,
         .disconnect =   sevseg_disconnect,
+        .suspend =      sevseg_suspend,
+        .resume =       sevseg_resume,
+        .reset_resume = sevseg_reset_resume,
         .id_table =     id_table,
+        .supports_autosuspend = 1,
 };
 
 static int __init usb_sevseg_init(void)