From patchwork Mon Apr 8 15:05:32 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guennadi Liakhovetski X-Patchwork-Id: 2408911 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id EFC72DFB78 for ; Mon, 8 Apr 2013 15:05:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964908Ab3DHPFu (ORCPT ); Mon, 8 Apr 2013 11:05:50 -0400 Received: from moutng.kundenserver.de ([212.227.126.187]:59879 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964852Ab3DHPFt (ORCPT ); Mon, 8 Apr 2013 11:05:49 -0400 Received: from axis700.grange (dslb-088-077-162-116.pools.arcor-ip.net [88.77.162.116]) by mrelayeu.kundenserver.de (node=mrbap1) with ESMTP (Nemesis) id 0MELbk-1UN1nK0q9w-00FeuB; Mon, 08 Apr 2013 17:05:42 +0200 Received: from 6a.grange (6a.grange [192.168.1.11]) by axis700.grange (Postfix) with ESMTPS id 905C940BB3; Mon, 8 Apr 2013 17:05:41 +0200 (CEST) Received: from lyakh by 6a.grange with local (Exim 4.72) (envelope-from ) id 1UPDdd-0004AA-8R; Mon, 08 Apr 2013 17:05:41 +0200 From: Guennadi Liakhovetski To: linux-media@vger.kernel.org Cc: Laurent Pinchart , Hans Verkuil , Sylwester Nawrocki , Sylwester Nawrocki , linux-sh@vger.kernel.org, Magnus Damm , Sakari Ailus , Prabhakar Lad , Guennadi Liakhovetski Subject: [PATCH v8 1/7] media: V4L2: add temporary clock helpers Date: Mon, 8 Apr 2013 17:05:32 +0200 Message-Id: <1365433538-15975-2-git-send-email-g.liakhovetski@gmx.de> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1365433538-15975-1-git-send-email-g.liakhovetski@gmx.de> References: <1365433538-15975-1-git-send-email-g.liakhovetski@gmx.de> X-Provags-ID: V02:K0:EWyowDtbSlR1dHXExmIrxYbQfUPOFcstSWrvbgb/lmo jOo8wRcZOv+L3PLm6B4Mp1qxjnoBIy0LPPkr6zF+ZnXm8N9L6Q pS5tCkrwiCEqAZcMy4zZ8wxk/dZinDlzPySdWy+AX16tb7FAt1 htxWD+6DlVV1qyasqCQESnhtTqTYF5UrY2LX0FYOcUQLy61rKe j0SCZbEx8w3HTGpKVmRI8zmQmQY2NiaFOlMJGKKhLe9v0xyWkS 6bMCBJ2dyLYg+p/s/kTZAf7dJRkw/UF0T/qkc142UTmDjM2FJV kU4cTIFU5DfQiSTWOMBl2NFS/6D7UbbjFl4RGlacGJG7kv9kY2 32lg1XPzi2w6zg0FIPfQaA4vwc1OvIEHR1YLv52rltlyFPoydF ayeOphEFIYdOQ== Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Typical video devices like camera sensors require an external clock source. Many such devices cannot even access their hardware registers without a running clock. These clock sources should be controlled by their consumers. This should be performed, using the generic clock framework. Unfortunately so far only very few systems have been ported to that framework. This patch adds a set of temporary helpers, mimicking the generic clock API, to V4L2. Platforms, adopting the clock API, should switch to using it. Eventually this temporary API should be removed. Signed-off-by: Guennadi Liakhovetski --- v8: Updated both (C) dates drivers/media/v4l2-core/Makefile | 2 +- drivers/media/v4l2-core/v4l2-clk.c | 177 ++++++++++++++++++++++++++++++++++++ include/media/v4l2-clk.h | 54 +++++++++++ 3 files changed, 232 insertions(+), 1 deletions(-) create mode 100644 drivers/media/v4l2-core/v4l2-clk.c create mode 100644 include/media/v4l2-clk.h diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile index aa50c46..628c630 100644 --- a/drivers/media/v4l2-core/Makefile +++ b/drivers/media/v4l2-core/Makefile @@ -5,7 +5,7 @@ tuner-objs := tuner-core.o videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \ - v4l2-event.o v4l2-ctrls.o v4l2-subdev.o + v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o ifeq ($(CONFIG_COMPAT),y) videodev-objs += v4l2-compat-ioctl32.o endif diff --git a/drivers/media/v4l2-core/v4l2-clk.c b/drivers/media/v4l2-core/v4l2-clk.c new file mode 100644 index 0000000..d7cc13e --- /dev/null +++ b/drivers/media/v4l2-core/v4l2-clk.c @@ -0,0 +1,177 @@ +/* + * V4L2 clock service + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +static DEFINE_MUTEX(clk_lock); +static LIST_HEAD(clk_list); + +static struct v4l2_clk *v4l2_clk_find(const char *dev_id, const char *id) +{ + struct v4l2_clk *clk; + + list_for_each_entry(clk, &clk_list, list) { + if (strcmp(dev_id, clk->dev_id)) + continue; + + if (!id || !clk->id || !strcmp(clk->id, id)) + return clk; + } + + return ERR_PTR(-ENODEV); +} + +struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id) +{ + struct v4l2_clk *clk; + + mutex_lock(&clk_lock); + clk = v4l2_clk_find(dev_name(dev), id); + + if (!IS_ERR(clk) && !try_module_get(clk->ops->owner)) + clk = ERR_PTR(-ENODEV); + mutex_unlock(&clk_lock); + + if (!IS_ERR(clk)) + atomic_inc(&clk->use_count); + + return clk; +} +EXPORT_SYMBOL(v4l2_clk_get); + +void v4l2_clk_put(struct v4l2_clk *clk) +{ + if (!IS_ERR(clk)) { + atomic_dec(&clk->use_count); + module_put(clk->ops->owner); + } +} +EXPORT_SYMBOL(v4l2_clk_put); + +int v4l2_clk_enable(struct v4l2_clk *clk) +{ + int ret; + mutex_lock(&clk->lock); + if (++clk->enable == 1 && clk->ops->enable) { + ret = clk->ops->enable(clk); + if (ret < 0) + clk->enable--; + } else { + ret = 0; + } + mutex_unlock(&clk->lock); + return ret; +} +EXPORT_SYMBOL(v4l2_clk_enable); + +void v4l2_clk_disable(struct v4l2_clk *clk) +{ + int enable; + + mutex_lock(&clk->lock); + enable = --clk->enable; + if (WARN(enable < 0, "Unbalanced %s() on %s:%s!\n", __func__, + clk->dev_id, clk->id)) + clk->enable++; + else if (!enable && clk->ops->disable) + clk->ops->disable(clk); + mutex_unlock(&clk->lock); +} +EXPORT_SYMBOL(v4l2_clk_disable); + +unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk) +{ + if (!clk->ops->get_rate) + return -ENOSYS; + + return clk->ops->get_rate(clk); +} +EXPORT_SYMBOL(v4l2_clk_get_rate); + +int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate) +{ + if (!clk->ops->set_rate) + return -ENOSYS; + + return clk->ops->set_rate(clk, rate); +} +EXPORT_SYMBOL(v4l2_clk_set_rate); + +struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops, + const char *dev_id, + const char *id, void *priv) +{ + struct v4l2_clk *clk; + int ret; + + if (!ops || !dev_id) + return ERR_PTR(-EINVAL); + + clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL); + if (!clk) + return ERR_PTR(-ENOMEM); + + clk->id = kstrdup(id, GFP_KERNEL); + clk->dev_id = kstrdup(dev_id, GFP_KERNEL); + if ((id && !clk->id) || !clk->dev_id) { + ret = -ENOMEM; + goto ealloc; + } + clk->ops = ops; + clk->priv = priv; + atomic_set(&clk->use_count, 0); + mutex_init(&clk->lock); + + mutex_lock(&clk_lock); + if (!IS_ERR(v4l2_clk_find(dev_id, id))) { + mutex_unlock(&clk_lock); + ret = -EEXIST; + goto eexist; + } + list_add_tail(&clk->list, &clk_list); + mutex_unlock(&clk_lock); + + return clk; + +eexist: +ealloc: + kfree(clk->id); + kfree(clk->dev_id); + kfree(clk); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(v4l2_clk_register); + +void v4l2_clk_unregister(struct v4l2_clk *clk) +{ + if (WARN(atomic_read(&clk->use_count), + "%s(): Refusing to unregister ref-counted %s:%s clock!\n", + __func__, clk->dev_id, clk->id)) + return; + + mutex_lock(&clk_lock); + list_del(&clk->list); + mutex_unlock(&clk_lock); + + kfree(clk->id); + kfree(clk->dev_id); + kfree(clk); +} +EXPORT_SYMBOL(v4l2_clk_unregister); diff --git a/include/media/v4l2-clk.h b/include/media/v4l2-clk.h new file mode 100644 index 0000000..89efbd7 --- /dev/null +++ b/include/media/v4l2-clk.h @@ -0,0 +1,54 @@ +/* + * V4L2 clock service + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * ATTENTION: This is a temporary API and it shall be replaced by the generic + * clock API, when the latter becomes widely available. + */ + +#ifndef MEDIA_V4L2_CLK_H +#define MEDIA_V4L2_CLK_H + +#include +#include +#include + +struct module; +struct device; + +struct v4l2_clk { + struct list_head list; + const struct v4l2_clk_ops *ops; + const char *dev_id; + const char *id; + int enable; + struct mutex lock; /* Protect the enable count */ + atomic_t use_count; + void *priv; +}; + +struct v4l2_clk_ops { + struct module *owner; + int (*enable)(struct v4l2_clk *clk); + void (*disable)(struct v4l2_clk *clk); + unsigned long (*get_rate)(struct v4l2_clk *clk); + int (*set_rate)(struct v4l2_clk *clk, unsigned long); +}; + +struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops, + const char *dev_name, + const char *name, void *priv); +void v4l2_clk_unregister(struct v4l2_clk *clk); +struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id); +void v4l2_clk_put(struct v4l2_clk *clk); +int v4l2_clk_enable(struct v4l2_clk *clk); +void v4l2_clk_disable(struct v4l2_clk *clk); +unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk); +int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate); + +#endif