media: ov2640: make s_ctrl() work in power-down mode

The s_ctrl() operation can be called when the device is placed into
power down mode.  Then, applying controls to H/W should be postponed at
this time.  Instead the controls will be restored when the streaming is
started.

Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/drivers/media/i2c/ov2640.c b/drivers/media/i2c/ov2640.c
index 68a356d718af7b33ba982a51a199fd5b336d46d3..beb722065152e57fabec16cfbe9d8c790843cdf1 100644 (file)
--- a/drivers/media/i2c/ov2640.c
+++ b/drivers/media/i2c/ov2640.c
@@ -308,8 +308,9 @@ struct ov2640_priv {
        struct gpio_desc *resetb_gpio;
        struct gpio_desc *pwdn_gpio;
 
-       struct mutex lock; /* lock to protect streaming */
+       struct mutex lock; /* lock to protect streaming and power_count */
        bool streaming;
+       int power_count;
 };
 
 /*
@@ -712,9 +713,20 @@ static int ov2640_s_ctrl(struct v4l2_ctrl *ctrl)
        struct v4l2_subdev *sd =
                &container_of(ctrl->handler, struct ov2640_priv, hdl)->subdev;
        struct i2c_client  *client = v4l2_get_subdevdata(sd);
+       struct ov2640_priv *priv = to_ov2640(client);
        u8 val;
        int ret;
 
+       /* v4l2_ctrl_lock() locks our own mutex */
+
+       /*
+        * If the device is not powered up by the host driver, do not apply any
+        * controls to H/W at this time. Instead the controls will be restored
+        * when the streaming is started.
+        */
+       if (!priv->power_count)
+               return 0;
+
        ret = i2c_smbus_write_byte_data(client, BANK_SEL, BANK_SEL_SENS);
        if (ret < 0)
                return ret;
@@ -766,12 +778,9 @@ static int ov2640_s_register(struct v4l2_subdev *sd,
 }
 #endif
 
-static int ov2640_s_power(struct v4l2_subdev *sd, int on)
+static void ov2640_set_power(struct ov2640_priv *priv, int on)
 {
 #ifdef CONFIG_GPIOLIB
-       struct i2c_client *client = v4l2_get_subdevdata(sd);
-       struct ov2640_priv *priv = to_ov2640(client);
-
        if (priv->pwdn_gpio)
                gpiod_direction_output(priv->pwdn_gpio, !on);
        if (on && priv->resetb_gpio) {
@@ -781,6 +790,25 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int on)
                gpiod_set_value(priv->resetb_gpio, 0);
        }
 #endif
+}
+
+static int ov2640_s_power(struct v4l2_subdev *sd, int on)
+{
+       struct i2c_client *client = v4l2_get_subdevdata(sd);
+       struct ov2640_priv *priv = to_ov2640(client);
+
+       mutex_lock(&priv->lock);
+
+       /*
+        * If the power count is modified from 0 to != 0 or from != 0 to 0,
+        * update the power state.
+        */
+       if (priv->power_count == !on)
+               ov2640_set_power(priv, on);
+       priv->power_count += on ? 1 : -1;
+       WARN_ON(priv->power_count < 0);
+       mutex_unlock(&priv->lock);
+
        return 0;
 }
 
@@ -1005,6 +1033,8 @@ static int ov2640_s_stream(struct v4l2_subdev *sd, int on)
                if (on) {
                        ret = ov2640_set_params(client, priv->win,
                                                priv->cfmt_code);
+                       if (!ret)
+                               ret = __v4l2_ctrl_handler_setup(&priv->hdl);
                }
        }
        if (!ret)
@@ -1049,8 +1079,6 @@ static int ov2640_video_probe(struct i2c_client *client)
                 "%s Product ID %0x:%0x Manufacturer ID %x:%x\n",
                 devname, pid, ver, midh, midl);
 
-       ret = v4l2_ctrl_handler_setup(&priv->hdl);
-
 done:
        ov2640_s_power(&priv->subdev, 0);
        return ret;
@@ -1158,6 +1186,7 @@ static int ov2640_probe(struct i2c_client *client,
        priv->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
        mutex_init(&priv->lock);
        v4l2_ctrl_handler_init(&priv->hdl, 2);
+       priv->hdl.lock = &priv->lock;
        v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,
                        V4L2_CID_VFLIP, 0, 1, 1, 0);
        v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,