From patchwork Mon Apr 8 11:07:05 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guennadi Liakhovetski X-Patchwork-Id: 2407851 Return-Path: X-Original-To: patchwork-linux-sh@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 67F8CDFB78 for ; Mon, 8 Apr 2013 11:07:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754977Ab3DHLHf (ORCPT ); Mon, 8 Apr 2013 07:07:35 -0400 Received: from moutng.kundenserver.de ([212.227.126.187]:64520 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762574Ab3DHLHd (ORCPT ); Mon, 8 Apr 2013 07:07:33 -0400 Received: from axis700.grange (dslb-088-077-162-116.pools.arcor-ip.net [88.77.162.116]) by mrelayeu.kundenserver.de (node=mrbap3) with ESMTP (Nemesis) id 0M1GfI-1Uitet2l0S-00tDqc; Mon, 08 Apr 2013 13:07:24 +0200 Received: from 6a.grange (6a.grange [192.168.1.11]) by axis700.grange (Postfix) with ESMTPS id D21F040BB4; Mon, 8 Apr 2013 13:07:22 +0200 (CEST) Received: from lyakh by 6a.grange with local (Exim 4.72) (envelope-from ) id 1UP9v0-0003rk-Ia; Mon, 08 Apr 2013 13:07:22 +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 v7 1/7] media: V4L2: add temporary clock helpers Date: Mon, 8 Apr 2013 13:07:05 +0200 Message-Id: <1365419231-14830-2-git-send-email-g.liakhovetski@gmx.de> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1365419231-14830-1-git-send-email-g.liakhovetski@gmx.de> References: <1365419231-14830-1-git-send-email-g.liakhovetski@gmx.de> X-Provags-ID: V02:K0:a/WJzb5X/D3li/4mwJ+69XZJzLICubYTIQkDOMjshzz 9EHgyky+T7oAHDgWEbqzQahrCaZ0FTmPT6zdVb523k7tw3m6OC JGKw5jGp1l7yyL/PksztuNzCS94PsxQ0w9QS0JNRKgtX0JvJZP r3M8tOCT7l27Akj1JytZCY23zxiXDl6Q2WZKhwXXiKUl7wwc+q AXrh709IytJsul7Ha8Ft6cuFqe/aYea9R3oCsTMscImJxMU/4e xn2Ico3nWdqN1Ajh9sdXLHuH3th0wVj3AjLs/7tmrJiwa7FH68 ir6VhdOxgaWllh3t+u4+Rx9cRozGfXuNXMgekbMNWU9ev5gK8p b73b90ivqD9+TM6IQ+PN2x5jfutdpVgOq6T+J38cx+x3Cfb5p9 jVi9WNFBO+ndw== Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@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 --- v7: (thanks to all reviewers) 1. Updated the (C) date ;-) 2. Removed the struct v4l2-clock subdevice member 3. Switched from using subdevice name to device name 4. Added the slab.h header 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, 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