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/*
* OMAP36xx-specific clkops
*
* Copyright (C) 2010 Texas Instruments, Inc.
* Copyright (C) 2010 Nokia Corporation
*
* Mike Turquette
* Vijaykumar GN
* Paul Walmsley
*
* Parts of this code are based on code written by
* Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu,
* Russell King
*
* 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.
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include "clock.h"
#include "clock36xx.h"
#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
/**
* omap36xx_pwrdn_clk_enable_with_hsdiv_restore - enable clocks suffering
* from HSDivider PWRDN problem Implements Errata ID: i556.
* @clk: DPLL output struct clk
*
* 3630 only: dpll3_m3_ck, dpll4_m2_ck, dpll4_m3_ck, dpll4_m4_ck,
* dpll4_m5_ck & dpll4_m6_ck dividers gets loaded with reset
* valueafter their respective PWRDN bits are set. Any dummy write
* (Any other value different from the Read value) to the
* corresponding CM_CLKSEL register will refresh the dividers.
*/
int omap36xx_pwrdn_clk_enable_with_hsdiv_restore(struct clk_hw *clk)
{
struct clk_divider *parent;
struct clk_hw *parent_hw;
u32 dummy_v, orig_v;
struct clk_hw_omap *omap_clk = to_clk_hw_omap(clk);
int ret;
/* Clear PWRDN bit of HSDIVIDER */
ret = omap2_dflt_clk_enable(clk);
parent_hw = __clk_get_hw(__clk_get_parent(clk->clk));
parent = to_clk_divider(parent_hw);
/* Restore the dividers */
if (!ret) {
orig_v = omap2_clk_readl(omap_clk, parent->reg);
dummy_v = orig_v;
/* Write any other value different from the Read value */
dummy_v ^= (1 << parent->shift);
omap2_clk_writel(dummy_v, omap_clk, parent->reg);
/* Write the original divider */
omap2_clk_writel(orig_v, omap_clk, parent->reg);
}
return ret;
}
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