LXR linux/drivers/clk/imx/clk-pfd.c

   1/*
   2 * Copyright 2012 Freescale Semiconductor, Inc.
   3 * Copyright 2012 Linaro Ltd.
   4 *
   5 * The code contained herein is licensed under the GNU General Public
   6 * License. You may obtain a copy of the GNU General Public License
   7 * Version 2 or later at the following locations:
   8 *
   9 * http://www.opensource.org/licenses/gpl-license.html
  10 * http://www.gnu.org/copyleft/gpl.html
  11 */
  12
  13#include <linux/clk-provider.h>
  14#include <linux/io.h>
  15#include <linux/slab.h>
  16#include <linux/err.h>
  17#include "clk.h"
  18
  19/**
  20 * struct clk_pfd - IMX PFD clock
  21 * @clk_hw:     clock source
  22 * @reg:        PFD register address
  23 * @idx:        the index of PFD encoded in the register
  24 *
  25 * PFD clock found on i.MX6 series.  Each register for PFD has 4 clk_pfd
  26 * data encoded, and member idx is used to specify the one.  And each
  27 * register has SET, CLR and TOG registers at offset 0x4 0x8 and 0xc.
  28 */
  29struct clk_pfd {
  30        struct clk_hw   hw;
  31        void __iomem    *reg;
  32        u8              idx;
  33};
  34
  35#define to_clk_pfd(_hw) container_of(_hw, struct clk_pfd, hw)
  36
  37#define SET     0x4
  38#define CLR     0x8
  39#define OTG     0xc
  40
  41static int clk_pfd_enable(struct clk_hw *hw)
  42{
  43        struct clk_pfd *pfd = to_clk_pfd(hw);
  44
  45        writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + CLR);
  46
  47        return 0;
  48}
  49
  50static void clk_pfd_disable(struct clk_hw *hw)
  51{
  52        struct clk_pfd *pfd = to_clk_pfd(hw);
  53
  54        writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + SET);
  55}
  56
  57static unsigned long clk_pfd_recalc_rate(struct clk_hw *hw,
  58                                         unsigned long parent_rate)
  59{
  60        struct clk_pfd *pfd = to_clk_pfd(hw);
  61        u64 tmp = parent_rate;
  62        u8 frac = (readl_relaxed(pfd->reg) >> (pfd->idx * 8)) & 0x3f;
  63
  64        tmp *= 18;
  65        do_div(tmp, frac);
  66
  67        return tmp;
  68}
  69
  70static long clk_pfd_round_rate(struct clk_hw *hw, unsigned long rate,
  71                               unsigned long *prate)
  72{
  73        u64 tmp = *prate;
  74        u8 frac;
  75
  76        tmp = tmp * 18 + rate / 2;
  77        do_div(tmp, rate);
  78        frac = tmp;
  79        if (frac < 12)
  80                frac = 12;
  81        else if (frac > 35)
  82                frac = 35;
  83        tmp = *prate;
  84        tmp *= 18;
  85        do_div(tmp, frac);
  86
  87        return tmp;
  88}
  89
  90static int clk_pfd_set_rate(struct clk_hw *hw, unsigned long rate,
  91                unsigned long parent_rate)
  92{
  93        struct clk_pfd *pfd = to_clk_pfd(hw);
  94        u64 tmp = parent_rate;
  95        u8 frac;
  96
  97        tmp = tmp * 18 + rate / 2;
  98        do_div(tmp, rate);
  99        frac = tmp;
 100        if (frac < 12)
 101                frac = 12;
 102        else if (frac > 35)
 103                frac = 35;
 104
 105        writel_relaxed(0x3f << (pfd->idx * 8), pfd->reg + CLR);
 106        writel_relaxed(frac << (pfd->idx * 8), pfd->reg + SET);
 107
 108        return 0;
 109}
 110
 111static int clk_pfd_is_enabled(struct clk_hw *hw)
 112{
 113        struct clk_pfd *pfd = to_clk_pfd(hw);
 114
 115        if (readl_relaxed(pfd->reg) & (1 << ((pfd->idx + 1) * 8 - 1)))
 116                return 0;
 117
 118        return 1;
 119}
 120
 121static const struct clk_ops clk_pfd_ops = {
 122        .enable         = clk_pfd_enable,
 123        .disable        = clk_pfd_disable,
 124        .recalc_rate    = clk_pfd_recalc_rate,
 125        .round_rate     = clk_pfd_round_rate,
 126        .set_rate       = clk_pfd_set_rate,
 127        .is_enabled     = clk_pfd_is_enabled,
 128};
 129
 130struct clk *imx_clk_pfd(const char *name, const char *parent_name,
 131                        void __iomem *reg, u8 idx)
 132{
 133        struct clk_pfd *pfd;
 134        struct clk *clk;
 135        struct clk_init_data init;
 136
 137        pfd = kzalloc(sizeof(*pfd), GFP_KERNEL);
 138        if (!pfd)
 139                return ERR_PTR(-ENOMEM);
 140
 141        pfd->reg = reg;
 142        pfd->idx = idx;
 143
 144        init.name = name;
 145        init.ops = &clk_pfd_ops;
 146        init.flags = 0;
 147        init.parent_names = &parent_name;
 148        init.num_parents = 1;
 149
 150        pfd->hw.init = &init;
 151
 152        clk = clk_register(NULL, &pfd->hw);
 153        if (IS_ERR(clk))
 154                kfree(pfd);
 155
 156        return clk;
 157}
 158