From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- arch/arm/mach-mxs/clock.c | 198 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 198 insertions(+) create mode 100644 arch/arm/mach-mxs/clock.c (limited to 'arch/arm/mach-mxs/clock.c') diff --git a/arch/arm/mach-mxs/clock.c b/arch/arm/mach-mxs/clock.c new file mode 100644 index 00000000..a7093c88 --- /dev/null +++ b/arch/arm/mach-mxs/clock.c @@ -0,0 +1,198 @@ +/* + * Based on arch/arm/plat-omap/clock.c + * + * Copyright (C) 2004 - 2005 Nokia corporation + * Written by Tuukka Tikkanen + * Modified for omap shared clock framework by Tony Lindgren + * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2008 Juergen Beisert, kernel@pengutronix.de + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + * MA 02110-1301, USA. + */ + +/* #define DEBUG */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +static LIST_HEAD(clocks); +static DEFINE_MUTEX(clocks_mutex); + +/*------------------------------------------------------------------------- + * Standard clock functions defined in include/linux/clk.h + *-------------------------------------------------------------------------*/ + +static void __clk_disable(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return; + WARN_ON(!clk->usecount); + + if (!(--clk->usecount)) { + if (clk->disable) + clk->disable(clk); + __clk_disable(clk->parent); + } +} + +static int __clk_enable(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + if (clk->usecount++ == 0) { + __clk_enable(clk->parent); + + if (clk->enable) + clk->enable(clk); + } + return 0; +} + +/* This function increments the reference count on the clock and enables the + * clock if not already enabled. The parent clock tree is recursively enabled + */ +int clk_enable(struct clk *clk) +{ + int ret = 0; + + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + mutex_lock(&clocks_mutex); + ret = __clk_enable(clk); + mutex_unlock(&clocks_mutex); + + return ret; +} +EXPORT_SYMBOL(clk_enable); + +/* This function decrements the reference count on the clock and disables + * the clock when reference count is 0. The parent clock tree is + * recursively disabled + */ +void clk_disable(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return; + + mutex_lock(&clocks_mutex); + __clk_disable(clk); + mutex_unlock(&clocks_mutex); +} +EXPORT_SYMBOL(clk_disable); + +/* Retrieve the *current* clock rate. If the clock itself + * does not provide a special calculation routine, ask + * its parent and so on, until one is able to return + * a valid clock rate + */ +unsigned long clk_get_rate(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return 0UL; + + if (clk->get_rate) + return clk->get_rate(clk); + + return clk_get_rate(clk->parent); +} +EXPORT_SYMBOL(clk_get_rate); + +/* Round the requested clock rate to the nearest supported + * rate that is less than or equal to the requested rate. + * This is dependent on the clock's current parent. + */ +long clk_round_rate(struct clk *clk, unsigned long rate) +{ + if (clk == NULL || IS_ERR(clk) || !clk->round_rate) + return 0; + + return clk->round_rate(clk, rate); +} +EXPORT_SYMBOL(clk_round_rate); + +/* Set the clock to the requested clock rate. The rate must + * match a supported rate exactly based on what clk_round_rate returns + */ +int clk_set_rate(struct clk *clk, unsigned long rate) +{ + int ret = -EINVAL; + + if (clk == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0) + return ret; + + mutex_lock(&clocks_mutex); + ret = clk->set_rate(clk, rate); + mutex_unlock(&clocks_mutex); + + return ret; +} +EXPORT_SYMBOL(clk_set_rate); + +/* Set the clock's parent to another clock source */ +int clk_set_parent(struct clk *clk, struct clk *parent) +{ + int ret = -EINVAL; + struct clk *old; + + if (clk == NULL || IS_ERR(clk) || parent == NULL || + IS_ERR(parent) || clk->set_parent == NULL) + return ret; + + if (clk->usecount) + clk_enable(parent); + + mutex_lock(&clocks_mutex); + ret = clk->set_parent(clk, parent); + if (ret == 0) { + old = clk->parent; + clk->parent = parent; + } else { + old = parent; + } + mutex_unlock(&clocks_mutex); + + if (clk->usecount) + clk_disable(old); + + return ret; +} +EXPORT_SYMBOL(clk_set_parent); + +/* Retrieve the clock's parent clock source */ +struct clk *clk_get_parent(struct clk *clk) +{ + struct clk *ret = NULL; + + if (clk == NULL || IS_ERR(clk)) + return ret; + + return clk->parent; +} +EXPORT_SYMBOL(clk_get_parent); -- cgit v1.2.3