linux-kernel - [PATCH v2 2/3] media: mt9m111: fix device power usage

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Date:   Fri, 16 Sep 2022 15:57:12 +0200
From:   Marco Felsch <m.felsch@...gutronix.de>
To:     mchehab@...nel.org, sakari.ailus@...ux.intel.com,
        laurent.pinchart+renesas@...asonboard.com, akinobu.mita@...il.com,
        jacopo+renesas@...ndi.org
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/3] media: mt9m111: fix device power usage

Currently the driver turn off the power after probe and toggle it during
.stream by using the .s_power callback. This is problematic since other
callbacks like .set_fmt accessing the hardware as well which will fail.
So in the end the default format is the only supported format.

Remove the hardware register access from the callbacks and instead sync
the state once right before the stream gets enabled to fix this for
.set_fmt() and .set_selection(). For the debug register access we need
to turn the device on/off before accessing the registers to fix this and
finally for the ctrls access we need the device to be powered to fix
this.

Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
---
Changelog:

v2:
- squash patch 2 and 3
---
 drivers/media/i2c/mt9m111.c | 40 ++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/drivers/media/i2c/mt9m111.c b/drivers/media/i2c/mt9m111.c
index 52be1c310455..8de93ab99cbc 100644
--- a/drivers/media/i2c/mt9m111.c
+++ b/drivers/media/i2c/mt9m111.c
@@ -455,7 +455,7 @@ static int mt9m111_set_selection(struct v4l2_subdev *sd,
 	struct mt9m111 *mt9m111 = to_mt9m111(client);
 	struct v4l2_rect rect = sel->r;
 	int width, height;
-	int ret, align = 0;
+	int align = 0;
 
 	if (sel->which != V4L2_SUBDEV_FORMAT_ACTIVE ||
 	    sel->target != V4L2_SEL_TGT_CROP)
@@ -481,14 +481,11 @@ static int mt9m111_set_selection(struct v4l2_subdev *sd,
 	width = min(mt9m111->width, rect.width);
 	height = min(mt9m111->height, rect.height);
 
-	ret = mt9m111_setup_geometry(mt9m111, &rect, width, height, mt9m111->fmt->code);
-	if (!ret) {
-		mt9m111->rect = rect;
-		mt9m111->width = width;
-		mt9m111->height = height;
-	}
+	mt9m111->rect = rect;
+	mt9m111->width = width;
+	mt9m111->height = height;
 
-	return ret;
+	return 0;
 }
 
 static int mt9m111_get_selection(struct v4l2_subdev *sd,
@@ -632,7 +629,6 @@ static int mt9m111_set_fmt(struct v4l2_subdev *sd,
 	const struct mt9m111_datafmt *fmt;
 	struct v4l2_rect *rect = &mt9m111->rect;
 	bool bayer;
-	int ret;
 
 	if (mt9m111->is_streaming)
 		return -EBUSY;
@@ -681,16 +677,11 @@ static int mt9m111_set_fmt(struct v4l2_subdev *sd,
 		return 0;
 	}
 
-	ret = mt9m111_setup_geometry(mt9m111, rect, mf->width, mf->height, mf->code);
-	if (!ret)
-		ret = mt9m111_set_pixfmt(mt9m111, mf->code);
-	if (!ret) {
-		mt9m111->width	= mf->width;
-		mt9m111->height	= mf->height;
-		mt9m111->fmt	= fmt;
-	}
+	mt9m111->width	= mf->width;
+	mt9m111->height	= mf->height;
+	mt9m111->fmt	= fmt;
 
-	return ret;
+	return 0;
 }
 
 static const struct mt9m111_mode_info *
@@ -748,6 +739,8 @@ mt9m111_find_mode(struct mt9m111 *mt9m111, unsigned int req_fps,
 	return mode;
 }
 
+static int mt9m111_s_power(struct v4l2_subdev *sd, int on);
+
 #ifdef CONFIG_VIDEO_ADV_DEBUG
 static int mt9m111_g_register(struct v4l2_subdev *sd,
 			      struct v4l2_dbg_register *reg)
@@ -758,10 +751,14 @@ static int mt9m111_g_register(struct v4l2_subdev *sd,
 	if (reg->reg > 0x2ff)
 		return -EINVAL;
 
+	mt9m111_s_power(sd, 1);
+
 	val = mt9m111_reg_read(client, reg->reg);
 	reg->size = 2;
 	reg->val = (u64)val;
 
+	mt9m111_s_power(sd, 0);
+
 	if (reg->val > 0xffff)
 		return -EIO;
 
@@ -776,9 +773,13 @@ static int mt9m111_s_register(struct v4l2_subdev *sd,
 	if (reg->reg > 0x2ff)
 		return -EINVAL;
 
+	mt9m111_s_power(sd, 1);
+
 	if (mt9m111_reg_write(client, reg->reg, reg->val) < 0)
 		return -EIO;
 
+	mt9m111_s_power(sd, 0);
+
 	return 0;
 }
 #endif
@@ -891,6 +892,9 @@ static int mt9m111_s_ctrl(struct v4l2_ctrl *ctrl)
 	struct mt9m111 *mt9m111 = container_of(ctrl->handler,
 					       struct mt9m111, hdl);
 
+	if (!mt9m111->is_streaming)
+		return 0;
+
 	switch (ctrl->id) {
 	case V4L2_CID_VFLIP:
 		return mt9m111_set_flip(mt9m111, ctrl->val,
-- 
2.30.2