From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay5-d.mail.gandi.net ([217.70.183.197]:47649 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752672AbeENJGv (ORCPT ); Mon, 14 May 2018 05:06:51 -0400 Date: Mon, 14 May 2018 11:06:46 +0200 From: jacopo mondi Subject: Re: [PATCH v5 12/14] media: ov772x: avoid accessing registers under power saving mode Message-ID: <20180514090646.GD5956@w540> References: <1525616369-8843-1-git-send-email-akinobu.mita@gmail.com> <1525616369-8843-13-git-send-email-akinobu.mita@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="N1GIdlSm9i+YlY4t" Content-Disposition: inline In-Reply-To: <1525616369-8843-13-git-send-email-akinobu.mita@gmail.com> Sender: devicetree-owner@vger.kernel.org To: Akinobu Mita Cc: linux-media@vger.kernel.org, devicetree@vger.kernel.org, Jacopo Mondi , Laurent Pinchart , Hans Verkuil , Sakari Ailus , Mauro Carvalho Chehab List-ID: --N1GIdlSm9i+YlY4t Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Hi Akinobu, a small nit below On Sun, May 06, 2018 at 11:19:27PM +0900, Akinobu Mita wrote: > 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 > --- > * v5 > - 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 9292a18..262a7e5 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; Isn't this unrelated? Apart from that, Reviewed-by: Jacopo Mondi Thanks j > 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 > --N1GIdlSm9i+YlY4t Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJa+VGmAAoJEHI0Bo8WoVY8oJEQAKcboDX1rRBSkzZOuud7gHlC BodHQSJRTAVVSMPm1sjHXfvSOMnr+yepZ38ToXtvZg8Klqtullt574N7LAvH6Moh 4V42f8z33oJaAiyXTunb3ciw9a4PvSDNi/cWBKCswEx5nmAgYVuEd+0Q9tK9Bbw/ pLga4Er9Ydy0Y9dSMhfp/AKKccHz56SXHMrWWZQBRSVh4PFAX8sD5Vh9fXJjHTrL T7sBxmzaadRRjmeGbIR+SeMrD8O+UW76vXSLjHi2DtHPM5u3rBFIPnH4mLMO/PxB DV4Dyz1kGcMT13z5Rvs0qfiznv6ssWY7rIKCm95P/MeTH1DXp/P+sYvEnLk7tZ9J bYWUgLasslambCdbw4ZGQ+Omk6FDMdP1KQnPgVVMNhO4HZFaTfw0mvIxD0Jollcb GtfG1Q28gWthcsWIgmNXNqV2xOTCt3cBi4y2cOQ0weL68334xlbuKSWfpcquFTbw FyqNPCKqUlHp5ZW6WKac3tO7ZJlJppbkxSLq8wQxunsdfvBuv8jZuy1xk66AuRmJ PgHtuz5y7LOD+ztNhwMKajzRZzHlyTxFqDZyrss3SaAoUlQA9qOVKYMI0EegUhXn oItLCI2Um51g/l2AKoEGqao2eXPQALwZtG5T95Dd6yO+yPUJKymaugGH277pa4hp mfRyHqA2goaY/sK+DrQc =zzUZ -----END PGP SIGNATURE----- --N1GIdlSm9i+YlY4t--