clk: vexpress: Add separate SP810 driver
Factor out the SP810 clocking code into a separate driver, selecting better (faster) parent at clk_prepare() time. This is to avoid problems with clocking infrastructure initialisation order, in particular to avoid dependency of fixed clock being initialized before SP810. It also makes vexpress platform OF-based clock initialisation code unnecessary. Signed-off-by: Pawel Moll <pawel.moll@arm.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Mike Turquette <mturquette@linaro.org> [mturquette@linaro.org: add .unprepare, FIXME comment, cleaned up code]
This commit is contained in:
Pawel Moll
Mike Turquette
Родитель
476ba5ffa4
Коммит
6e973d2c43
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@ -21,6 +21,8 @@
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#include <linux/regulator/fixed.h>
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#include <linux/regulator/machine.h>
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#include <linux/vexpress.h>
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#include <linux/clk-provider.h>
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#include <linux/clkdev.h>
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#include <asm/arch_timer.h>
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#include <asm/mach-types.h>
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@ -433,7 +435,7 @@ static void __init v2m_dt_timer_init(void)
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{
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struct device_node *node = NULL;
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vexpress_clk_of_init();
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of_clk_init(NULL);
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do {
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node = of_find_compatible_node(node, NULL, "arm,sp804");
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@ -441,6 +443,10 @@ static void __init v2m_dt_timer_init(void)
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if (node) {
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pr_info("Using SP804 '%s' as a clock & events source\n",
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node->full_name);
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WARN_ON(clk_register_clkdev(of_clk_get_by_name(node,
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"timclken1"), "v2m-timer0", "sp804"));
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WARN_ON(clk_register_clkdev(of_clk_get_by_name(node,
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"timclken2"), "v2m-timer1", "sp804"));
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v2m_sp804_init(of_iomap(node, 0),
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irq_of_parse_and_map(node, 0));
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}
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@ -3,5 +3,5 @@ obj-$(CONFIG_ICST) += clk-icst.o
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obj-$(CONFIG_ARCH_INTEGRATOR) += clk-integrator.o
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obj-$(CONFIG_INTEGRATOR_IMPD1) += clk-impd1.o
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obj-$(CONFIG_ARCH_REALVIEW) += clk-realview.o
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obj-$(CONFIG_ARCH_VEXPRESS) += clk-vexpress.o
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obj-$(CONFIG_ARCH_VEXPRESS) += clk-vexpress.o clk-sp810.o
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obj-$(CONFIG_VEXPRESS_CONFIG) += clk-vexpress-osc.o
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@ -0,0 +1,188 @@
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Copyright (C) 2013 ARM Limited
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*/
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#include <linux/amba/sp810.h>
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#include <linux/clkdev.h>
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#include <linux/clk-provider.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#define to_clk_sp810_timerclken(_hw) \
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container_of(_hw, struct clk_sp810_timerclken, hw)
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struct clk_sp810;
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struct clk_sp810_timerclken {
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struct clk_hw hw;
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struct clk *clk;
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struct clk_sp810 *sp810;
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int channel;
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};
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struct clk_sp810 {
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struct device_node *node;
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int refclk_index, timclk_index;
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void __iomem *base;
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spinlock_t lock;
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struct clk_sp810_timerclken timerclken[4];
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struct clk *refclk;
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struct clk *timclk;
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};
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static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
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{
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struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
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u32 val = readl(timerclken->sp810->base + SCCTRL);
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return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
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}
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static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
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{
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struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
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struct clk_sp810 *sp810 = timerclken->sp810;
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u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
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unsigned long flags = 0;
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if (WARN_ON(index > 1))
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return -EINVAL;
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spin_lock_irqsave(&sp810->lock, flags);
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val = readl(sp810->base + SCCTRL);
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val &= ~(1 << shift);
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val |= index << shift;
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writel(val, sp810->base + SCCTRL);
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spin_unlock_irqrestore(&sp810->lock, flags);
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return 0;
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}
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/*
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* FIXME - setting the parent every time .prepare is invoked is inefficient.
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* This is better handled by a dedicated clock tree configuration mechanism at
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* init-time. Revisit this later when such a mechanism exists
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*/
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static int clk_sp810_timerclken_prepare(struct clk_hw *hw)
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{
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struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
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struct clk_sp810 *sp810 = timerclken->sp810;
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struct clk *old_parent = __clk_get_parent(hw->clk);
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struct clk *new_parent;
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if (!sp810->refclk)
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sp810->refclk = of_clk_get(sp810->node, sp810->refclk_index);
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if (!sp810->timclk)
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sp810->timclk = of_clk_get(sp810->node, sp810->timclk_index);
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if (WARN_ON(IS_ERR(sp810->refclk) || IS_ERR(sp810->timclk)))
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return -ENOENT;
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/* Select fastest parent */
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if (clk_get_rate(sp810->refclk) > clk_get_rate(sp810->timclk))
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new_parent = sp810->refclk;
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else
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new_parent = sp810->timclk;
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/* Switch the parent if necessary */
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if (old_parent != new_parent) {
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clk_prepare(new_parent);
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clk_set_parent(hw->clk, new_parent);
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clk_unprepare(old_parent);
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}
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return 0;
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}
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static void clk_sp810_timerclken_unprepare(struct clk_hw *hw)
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{
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struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
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struct clk_sp810 *sp810 = timerclken->sp810;
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clk_put(sp810->timclk);
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clk_put(sp810->refclk);
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}
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static const struct clk_ops clk_sp810_timerclken_ops = {
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.prepare = clk_sp810_timerclken_prepare,
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.unprepare = clk_sp810_timerclken_unprepare,
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.get_parent = clk_sp810_timerclken_get_parent,
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.set_parent = clk_sp810_timerclken_set_parent,
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};
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struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
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void *data)
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{
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struct clk_sp810 *sp810 = data;
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if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
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ARRAY_SIZE(sp810->timerclken)))
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return NULL;
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return sp810->timerclken[clkspec->args[0]].clk;
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}
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void __init clk_sp810_of_setup(struct device_node *node)
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{
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struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
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const char *parent_names[2];
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char name[12];
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struct clk_init_data init;
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int i;
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if (!sp810) {
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pr_err("Failed to allocate memory for SP810!\n");
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return;
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}
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sp810->refclk_index = of_property_match_string(node, "clock-names",
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"refclk");
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parent_names[0] = of_clk_get_parent_name(node, sp810->refclk_index);
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sp810->timclk_index = of_property_match_string(node, "clock-names",
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"timclk");
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parent_names[1] = of_clk_get_parent_name(node, sp810->timclk_index);
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if (parent_names[0] <= 0 || parent_names[1] <= 0) {
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pr_warn("Failed to obtain parent clocks for SP810!\n");
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return;
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}
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sp810->node = node;
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sp810->base = of_iomap(node, 0);
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spin_lock_init(&sp810->lock);
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init.name = name;
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init.ops = &clk_sp810_timerclken_ops;
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init.flags = CLK_IS_BASIC;
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init.parent_names = parent_names;
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init.num_parents = ARRAY_SIZE(parent_names);
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for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
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snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
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sp810->timerclken[i].sp810 = sp810;
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sp810->timerclken[i].channel = i;
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sp810->timerclken[i].hw.init = &init;
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sp810->timerclken[i].clk = clk_register(NULL,
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&sp810->timerclken[i].hw);
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WARN_ON(IS_ERR(sp810->timerclken[i].clk));
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}
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of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
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}
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CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
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@ -15,8 +15,6 @@
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#include <linux/clkdev.h>
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#include <linux/clk-provider.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/vexpress.h>
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static struct clk *vexpress_sp810_timerclken[4];
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@ -86,50 +84,3 @@ void __init vexpress_clk_init(void __iomem *sp810_base)
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WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
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"v2m-timer1", "sp804"));
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}
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#if defined(CONFIG_OF)
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struct clk *vexpress_sp810_of_get(struct of_phandle_args *clkspec, void *data)
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{
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if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
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ARRAY_SIZE(vexpress_sp810_timerclken)))
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return NULL;
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return vexpress_sp810_timerclken[clkspec->args[0]];
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}
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void __init vexpress_clk_of_init(void)
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{
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struct device_node *node;
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struct clk *clk;
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struct clk *refclk, *timclk;
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of_clk_init(NULL);
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node = of_find_compatible_node(NULL, NULL, "arm,sp810");
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vexpress_sp810_init(of_iomap(node, 0));
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of_clk_add_provider(node, vexpress_sp810_of_get, NULL);
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/* Select "better" (faster) parent for SP804 timers */
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refclk = of_clk_get_by_name(node, "refclk");
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timclk = of_clk_get_by_name(node, "timclk");
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if (!WARN_ON(IS_ERR(refclk) || IS_ERR(timclk))) {
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int i = 0;
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if (clk_get_rate(refclk) > clk_get_rate(timclk))
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clk = refclk;
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else
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clk = timclk;
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for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
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WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i],
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clk));
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}
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WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
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"v2m-timer0", "sp804"));
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WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
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"v2m-timer1", "sp804"));
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}
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#endif
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