[media] via-camera: Add suspend/resume support

Add suspend/resume support to the via-camera driver, so that the video
continues streaming over a suspend-resume cycle.

Originally implemented by Jon Corbet.

[mchehab@redhat.com: fix a small CodingStyle issue]
Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/media/video/via-camera.c b/drivers/media/video/via-camera.c
index 2f973cd56408..3f0146fcf752 100644
--- a/drivers/media/video/via-camera.c
+++ b/drivers/media/video/via-camera.c
@@ -1246,6 +1246,62 @@ static const struct v4l2_ioctl_ops viacam_ioctl_ops = {
 /*
  * Power management.
  */
+#ifdef CONFIG_PM
+
+static int viacam_suspend(void *priv)
+{
+        struct via_camera *cam = priv;
+        enum viacam_opstate state = cam->opstate;
+
+        if (cam->opstate != S_IDLE) {
+                viacam_stop_engine(cam);
+                cam->opstate = state; /* So resume restarts */
+        }
+
+        return 0;
+}
+
+static int viacam_resume(void *priv)
+{
+        struct via_camera *cam = priv;
+        int ret = 0;
+
+        /*
+         * Get back to a reasonable operating state.
+         */
+        via_write_reg_mask(VIASR, 0x78, 0, 0x80);
+        via_write_reg_mask(VIASR, 0x1e, 0xc0, 0xc0);
+        viacam_int_disable(cam);
+        set_bit(CF_CONFIG_NEEDED, &cam->flags);
+        /*
+         * Make sure the sensor's power state is correct
+         */
+        if (cam->users > 0)
+                via_sensor_power_up(cam);
+        else
+                via_sensor_power_down(cam);
+        /*
+         * If it was operating, try to restart it.
+         */
+        if (cam->opstate != S_IDLE) {
+                mutex_lock(&cam->lock);
+                ret = viacam_configure_sensor(cam);
+                if (!ret)
+                        ret = viacam_config_controller(cam);
+                mutex_unlock(&cam->lock);
+                if (!ret)
+                        viacam_start_engine(cam);
+        }
+
+        return ret;
+}
+
+static struct viafb_pm_hooks viacam_pm_hooks = {
+        .suspend = viacam_suspend,
+        .resume = viacam_resume
+};
+
+#endif /* CONFIG_PM */
 
 /*
  * Setup stuff.
@@ -1369,6 +1425,14 @@ static __devinit int viacam_probe(struct platform_device *pdev)
                 goto out_irq;
         video_set_drvdata(&cam->vdev, cam);
 
+#ifdef CONFIG_PM
+        /*
+         * Hook into PM events
+         */
+        viacam_pm_hooks.private = cam;
+        viafb_pm_register(&viacam_pm_hooks);
+#endif
+
         /* Power the sensor down until somebody opens the device */
         via_sensor_power_down(cam);
         return 0;