HID: i2c-hid: Fix suspend/resume when already runtime suspended

On ACPI-based systems ACPI power domain code runtime resumes device before
calling suspend method, which ensures that i2c-hid suspend code starts with
device not in low-power state and with interrupts enabled.

On other systems, especially if device is not a part of any power domain,
we may end up calling driver's system-level suspend routine while the
device is runtime-suspended (with controller in presumably low power state
and interrupts disabled). This will result in interrupts being essentially
disabled twice, and we will only re-enable them after both system resume
and runtime resume methods complete. Unfortunately i2c_hid_resume() calls
i2c_hid_hwreset() and that only works properly if interrupts are enabled.

Also if device is runtime-suspended driver's suspend code may fail if it
tries to issue I/O requests.

Let's fix it by runtime-resuming the device if we need to run HID driver's
suspend code and also disabling interrupts only if device is not already
runtime-suspended. Also on resume we mark the device as running at full
power (since that is what resetting will do to it).

Reviewed-by: Benson Leung <bleung@chromium.org>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index a2c6c98..5b10a5d 100644 (file)
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -1108,13 +1108,30 @@ static int i2c_hid_suspend(struct device *dev)
        struct i2c_client *client = to_i2c_client(dev);
        struct i2c_hid *ihid = i2c_get_clientdata(client);
        struct hid_device *hid = ihid->hid;
-       int ret = 0;
+       int ret;
        int wake_status;
 
-       if (hid->driver && hid->driver->suspend)
+       if (hid->driver && hid->driver->suspend) {
+               /*
+                * Wake up the device so that IO issues in
+                * HID driver's suspend code can succeed.
+                */
+               ret = pm_runtime_resume(dev);
+               if (ret < 0)
+                       return ret;
+
                ret = hid->driver->suspend(hid, PMSG_SUSPEND);
+               if (ret < 0)
+                       return ret;
+       }
+
+       if (!pm_runtime_suspended(dev)) {
+               /* Save some power */
+               i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
+
+               disable_irq(ihid->irq);
+       }
 
-       disable_irq(ihid->irq);
        if (device_may_wakeup(&client->dev)) {
                wake_status = enable_irq_wake(ihid->irq);
                if (!wake_status)
@@ -1124,10 +1141,7 @@ static int i2c_hid_suspend(struct device *dev)
                                wake_status);
        }
 
-       /* Save some power */
-       i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
-
-       return ret;
+       return 0;
 }
 
 static int i2c_hid_resume(struct device *dev)
@@ -1138,11 +1152,6 @@ static int i2c_hid_resume(struct device *dev)
        struct hid_device *hid = ihid->hid;
        int wake_status;
 
-       enable_irq(ihid->irq);
-       ret = i2c_hid_hwreset(client);
-       if (ret)
-               return ret;
-
        if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
                wake_status = disable_irq_wake(ihid->irq);
                if (!wake_status)
@@ -1152,6 +1161,16 @@ static int i2c_hid_resume(struct device *dev)
                                wake_status);
        }
 
+       /* We'll resume to full power */
+       pm_runtime_disable(dev);
+       pm_runtime_set_active(dev);
+       pm_runtime_enable(dev);
+
+       enable_irq(ihid->irq);
+       ret = i2c_hid_hwreset(client);
+       if (ret)
+               return ret;
+
        if (hid->driver && hid->driver->reset_resume) {
                ret = hid->driver->reset_resume(hid);
                return ret;