From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:39617 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754289AbeDVP46 (ORCPT ); Sun, 22 Apr 2018 11:56:58 -0400 From: Akinobu Mita Subject: [PATCH v3 07/11] media: ov772x: handle nested s_power() calls Date: Mon, 23 Apr 2018 00:56:13 +0900 Message-Id: <1524412577-14419-8-git-send-email-akinobu.mita@gmail.com> In-Reply-To: <1524412577-14419-1-git-send-email-akinobu.mita@gmail.com> References: <1524412577-14419-1-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: Depending on the v4l2 driver, calling s_power() could be nested. So the actual transitions between power saving mode and normal operation mode should only happen at the first power on and the last power off. This adds an s_power() nesting counter and updates the power state if the counter is modified from 0 to != 0 or from != 0 to 0. Cc: Jacopo Mondi Cc: Laurent Pinchart Cc: Hans Verkuil Cc: Sakari Ailus Cc: Mauro Carvalho Chehab Signed-off-by: Akinobu Mita --- * v3 - Rename mutex name from power_lock to lock - Add warning for duplicated s_power call drivers/media/i2c/ov772x.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c index 95c1c95d..8c0b850 100644 --- a/drivers/media/i2c/ov772x.c +++ b/drivers/media/i2c/ov772x.c @@ -424,6 +424,9 @@ struct ov772x_priv { /* band_filter = COM8[5] ? 256 - BDBASE : 0 */ unsigned short band_filter; unsigned int fps; + /* lock to protect power_count */ + struct mutex lock; + int power_count; #ifdef CONFIG_MEDIA_CONTROLLER struct media_pad pad; #endif @@ -871,9 +874,26 @@ static int ov772x_power_off(struct ov772x_priv *priv) static int ov772x_s_power(struct v4l2_subdev *sd, int on) { struct ov772x_priv *priv = to_ov772x(sd); + int ret = 0; + + 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) + ret = on ? ov772x_power_on(priv) : ov772x_power_off(priv); + + if (!ret) { + /* Update the power count. */ + priv->power_count += on ? 1 : -1; + WARN(priv->power_count < 0, "Unbalanced power count\n"); + WARN(priv->power_count > 1, "Duplicated s_power call\n"); + } + + mutex_unlock(&priv->lock); - return on ? ov772x_power_on(priv) : - ov772x_power_off(priv); + return ret; } static const struct ov772x_win_size *ov772x_select_win(u32 width, u32 height) @@ -1303,6 +1323,7 @@ static int ov772x_probe(struct i2c_client *client, return -ENOMEM; priv->info = client->dev.platform_data; + mutex_init(&priv->lock); v4l2_i2c_subdev_init(&priv->subdev, client, &ov772x_subdev_ops); v4l2_ctrl_handler_init(&priv->hdl, 3); @@ -1313,8 +1334,10 @@ static int ov772x_probe(struct i2c_client *client, v4l2_ctrl_new_std(&priv->hdl, &ov772x_ctrl_ops, V4L2_CID_BAND_STOP_FILTER, 0, 256, 1, 0); priv->subdev.ctrl_handler = &priv->hdl; - if (priv->hdl.error) - return priv->hdl.error; + if (priv->hdl.error) { + ret = priv->hdl.error; + goto error_mutex_destroy; + } priv->clk = clk_get(&client->dev, "xclk"); if (IS_ERR(priv->clk)) { @@ -1362,6 +1385,8 @@ static int ov772x_probe(struct i2c_client *client, clk_put(priv->clk); error_ctrl_free: v4l2_ctrl_handler_free(&priv->hdl); +error_mutex_destroy: + mutex_destroy(&priv->lock); return ret; } @@ -1376,6 +1401,7 @@ static int ov772x_remove(struct i2c_client *client) gpiod_put(priv->pwdn_gpio); v4l2_async_unregister_subdev(&priv->subdev); v4l2_ctrl_handler_free(&priv->hdl); + mutex_destroy(&priv->lock); return 0; } -- 2.7.4