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clock3517.c

/*
 * OMAP3517/3505-specific clock framework functions
 *
 * Copyright (C) 2010 Texas Instruments, Inc.
 * Copyright (C) 2010 Nokia Corporation
 *
 * Ranjith Lohithakshan
 * 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/io.h>

#include <plat/clock.h>

#include "clock.h"
#include "clock3517.h"
#include "cm2xxx_3xxx.h"
#include "cm-regbits-34xx.h"

/*
 * In AM35xx IPSS, the {ICK,FCK} enable bits for modules are exported
 * in the same register at a bit offset of 0x8. The EN_ACK for ICK is
 * at an offset of 4 from ICK enable bit.
 */
#define AM35XX_IPSS_ICK_MASK              0xF
#define AM35XX_IPSS_ICK_EN_ACK_OFFSET           0x4
#define AM35XX_IPSS_ICK_FCK_OFFSET        0x8
#define AM35XX_IPSS_CLK_IDLEST_VAL        0

/**
 * am35xx_clk_find_idlest - return clock ACK info for AM35XX IPSS
 * @clk: struct clk * being enabled
 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
 * @idlest_val: pointer to a u8 to store the CM_IDLEST indicator
 *
 * The interface clocks on AM35xx IPSS reflects the clock idle status
 * in the enable register itsel at a bit offset of 4 from the enable
 * bit. A value of 1 indicates that clock is enabled.
 */
static void am35xx_clk_find_idlest(struct clk *clk,
                                  void __iomem **idlest_reg,
                                  u8 *idlest_bit,
                                  u8 *idlest_val)
{
      *idlest_reg = (__force void __iomem *)(clk->enable_reg);
      *idlest_bit = clk->enable_bit + AM35XX_IPSS_ICK_EN_ACK_OFFSET;
      *idlest_val = AM35XX_IPSS_CLK_IDLEST_VAL;
}

/**
 * am35xx_clk_find_companion - find companion clock to @clk
 * @clk: struct clk * to find the companion clock of
 * @other_reg: void __iomem ** to return the companion clock CM_*CLKEN va in
 * @other_bit: u8 ** to return the companion clock bit shift in
 *
 * Some clocks don't have companion clocks.  For example, modules with
 * only an interface clock (such as HECC) don't have a companion
 * clock.  Right now, this code relies on the hardware exporting a bit
 * in the correct companion register that indicates that the
 * nonexistent 'companion clock' is active.  Future patches will
 * associate this type of code with per-module data structures to
 * avoid this issue, and remove the casts.  No return value.
 */
static void am35xx_clk_find_companion(struct clk *clk, void __iomem **other_reg,
                                  u8 *other_bit)
{
      *other_reg = (__force void __iomem *)(clk->enable_reg);
      if (clk->enable_bit & AM35XX_IPSS_ICK_MASK)
            *other_bit = clk->enable_bit + AM35XX_IPSS_ICK_FCK_OFFSET;
      else
            *other_bit = clk->enable_bit - AM35XX_IPSS_ICK_FCK_OFFSET;
}

const struct clkops clkops_am35xx_ipss_module_wait = {
      .enable           = omap2_dflt_clk_enable,
      .disable    = omap2_dflt_clk_disable,
      .find_idlest      = am35xx_clk_find_idlest,
      .find_companion   = am35xx_clk_find_companion,
};

/**
 * am35xx_clk_ipss_find_idlest - return CM_IDLEST info for IPSS
 * @clk: struct clk * being enabled
 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
 * @idlest_val: pointer to a u8 to store the CM_IDLEST indicator
 *
 * The IPSS target CM_IDLEST bit is at a different shift from the
 * CM_{I,F}CLKEN bit.  Pass back the correct info via @idlest_reg
 * and @idlest_bit.  No return value.
 */
static void am35xx_clk_ipss_find_idlest(struct clk *clk,
                                  void __iomem **idlest_reg,
                                  u8 *idlest_bit,
                                  u8 *idlest_val)
{
      u32 r;

      r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
      *idlest_reg = (__force void __iomem *)r;
      *idlest_bit = AM35XX_ST_IPSS_SHIFT;
      *idlest_val = OMAP34XX_CM_IDLEST_VAL;
}

const struct clkops clkops_am35xx_ipss_wait = {
      .enable           = omap2_dflt_clk_enable,
      .disable    = omap2_dflt_clk_disable,
      .find_idlest      = am35xx_clk_ipss_find_idlest,
      .find_companion   = omap2_clk_dflt_find_companion,
};



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