From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f68.google.com ([74.125.83.68]:39550 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754033AbeD2ROI (ORCPT ); Sun, 29 Apr 2018 13:14:08 -0400 From: Akinobu Mita Subject: [PATCH v4 12/14] media: ov772x: avoid accessing registers under power saving mode Date: Mon, 30 Apr 2018 02:13:11 +0900 Message-Id: <1525021993-17789-13-git-send-email-akinobu.mita@gmail.com> In-Reply-To: <1525021993-17789-1-git-send-email-akinobu.mita@gmail.com> References: <1525021993-17789-1-git-send-email-akinobu.mita@gmail.com> Sender: devicetree-owner@vger.kernel.org To: linux-media@vger.kernel.org, devicetree@vger.kernel.org Cc: Akinobu Mita , Jacopo Mondi , Laurent Pinchart , Hans Verkuil , Sakari Ailus , Mauro Carvalho Chehab List-ID: The set_fmt() in subdev pad ops, the s_ctrl() for subdev control handler, and the s_frame_interval() in subdev video ops could be called when the device is under power saving mode. These callbacks for ov772x driver cause updating H/W registers that will fail under power saving mode. This avoids it by not apply any changes to H/W if the device is not powered up. Instead the changes will be restored right after power-up. Cc: Jacopo Mondi Cc: Laurent Pinchart Cc: Hans Verkuil Cc: Sakari Ailus Cc: Mauro Carvalho Chehab Signed-off-by: Akinobu Mita --- * v4 - No changes drivers/media/i2c/ov772x.c | 79 +++++++++++++++++++++++++++++++++++++--------- 1 file changed, 64 insertions(+), 15 deletions(-) diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c index 3e6ca98..bd37169 100644 --- a/drivers/media/i2c/ov772x.c +++ b/drivers/media/i2c/ov772x.c @@ -741,19 +741,30 @@ static int ov772x_s_frame_interval(struct v4l2_subdev *sd, struct ov772x_priv *priv = to_ov772x(sd); struct v4l2_fract *tpf = &ival->interval; unsigned int fps; - int ret; + int ret = 0; fps = ov772x_select_fps(priv, tpf); - ret = ov772x_set_frame_rate(priv, fps, priv->cfmt, priv->win); - if (ret) - return ret; + mutex_lock(&priv->lock); + /* + * If the device is not powered up by the host driver do + * not apply any changes to H/W at this time. Instead + * the frame rate will be restored right after power-up. + */ + if (priv->power_count > 0) { + ret = ov772x_set_frame_rate(priv, fps, priv->cfmt, priv->win); + if (ret) + goto error; + } tpf->numerator = 1; tpf->denominator = fps; priv->fps = fps; - return 0; +error: + mutex_unlock(&priv->lock); + + return ret; } static int ov772x_s_ctrl(struct v4l2_ctrl *ctrl) @@ -765,6 +776,16 @@ static int ov772x_s_ctrl(struct v4l2_ctrl *ctrl) int ret = 0; u8 val; + /* 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 right after power-up. + */ + if (priv->power_count == 0) + return 0; + switch (ctrl->id) { case V4L2_CID_VFLIP: val = ctrl->val ? VFLIP_IMG : 0x00; @@ -885,6 +906,10 @@ static int ov772x_power_off(struct ov772x_priv *priv) return 0; } +static int ov772x_set_params(struct ov772x_priv *priv, + const struct ov772x_color_format *cfmt, + const struct ov772x_win_size *win); + static int ov772x_s_power(struct v4l2_subdev *sd, int on) { struct ov772x_priv *priv = to_ov772x(sd); @@ -895,8 +920,20 @@ static int ov772x_s_power(struct v4l2_subdev *sd, int on) /* If the power count is modified from 0 to != 0 or from != 0 to 0, * update the power state. */ - if (priv->power_count == !on) - ret = on ? ov772x_power_on(priv) : ov772x_power_off(priv); + if (priv->power_count == !on) { + if (on) { + ret = ov772x_power_on(priv); + /* + * Restore the format, the frame rate, and + * the controls + */ + if (!ret) + ret = ov772x_set_params(priv, priv->cfmt, + priv->win); + } else { + ret = ov772x_power_off(priv); + } + } if (!ret) { /* Update the power count. */ @@ -1163,7 +1200,7 @@ static int ov772x_set_fmt(struct v4l2_subdev *sd, struct v4l2_mbus_framefmt *mf = &format->format; const struct ov772x_color_format *cfmt; const struct ov772x_win_size *win; - int ret; + int ret = 0; if (format->pad) return -EINVAL; @@ -1184,14 +1221,24 @@ static int ov772x_set_fmt(struct v4l2_subdev *sd, return 0; } - ret = ov772x_set_params(priv, cfmt, win); - if (ret < 0) - return ret; - + mutex_lock(&priv->lock); + /* + * If the device is not powered up by the host driver do + * not apply any changes to H/W at this time. Instead + * the format will be restored right after power-up. + */ + if (priv->power_count > 0) { + ret = ov772x_set_params(priv, cfmt, win); + if (ret < 0) + goto error; + } priv->win = win; priv->cfmt = cfmt; - return 0; +error: + mutex_unlock(&priv->lock); + + return ret; } static int ov772x_video_probe(struct ov772x_priv *priv) @@ -1201,7 +1248,7 @@ static int ov772x_video_probe(struct ov772x_priv *priv) const char *devname; int ret; - ret = ov772x_s_power(&priv->subdev, 1); + ret = ov772x_power_on(priv); if (ret < 0) return ret; @@ -1241,7 +1288,7 @@ static int ov772x_video_probe(struct ov772x_priv *priv) ret = v4l2_ctrl_handler_setup(&priv->hdl); done: - ov772x_s_power(&priv->subdev, 0); + ov772x_power_off(priv); return ret; } @@ -1340,6 +1387,8 @@ static int ov772x_probe(struct i2c_client *client, v4l2_i2c_subdev_init(&priv->subdev, client, &ov772x_subdev_ops); v4l2_ctrl_handler_init(&priv->hdl, 3); + /* Use our mutex for the controls */ + priv->hdl.lock = &priv->lock; priv->vflip_ctrl = v4l2_ctrl_new_std(&priv->hdl, &ov772x_ctrl_ops, V4L2_CID_VFLIP, 0, 1, 1, 0); priv->hflip_ctrl = v4l2_ctrl_new_std(&priv->hdl, &ov772x_ctrl_ops, -- 2.7.4