drivers/clk/imx/clk-composite-8m.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2018 NXP
   4  */
   5
   6 #include <linux/clk-provider.h>
   7 #include <linux/errno.h>
   8 #include <linux/export.h>
   9 #include <linux/io.h>
  10 #include <linux/slab.h>
  11
  12 #include "clk.h"
  13
  14 #define PCG_PREDIV_SHIFT        16
  15 #define PCG_PREDIV_WIDTH        3
  16 #define PCG_PREDIV_MAX          8
  17
  18 #define PCG_DIV_SHIFT           0
  19 #define PCG_CORE_DIV_WIDTH      3
  20 #define PCG_DIV_WIDTH           6
  21 #define PCG_DIV_MAX             64
  22
  23 #define PCG_PCS_SHIFT           24
  24 #define PCG_PCS_MASK            0x7
  25
  26 #define PCG_CGC_SHIFT           28
  27
  28 static unsigned long imx8m_clk_composite_divider_recalc_rate(struct clk_hw *hw,
  29                                                 unsigned long parent_rate)
  30 {
  31         struct clk_divider *divider = to_clk_divider(hw);
  32         unsigned long prediv_rate;
  33         unsigned int prediv_value;
  34         unsigned int div_value;
  35
  36         prediv_value = readl(divider->reg) >> divider->shift;
  37         prediv_value &= clk_div_mask(divider->width);
  38
  39         prediv_rate = divider_recalc_rate(hw, parent_rate, prediv_value,
  40                                                 NULL, divider->flags,
  41                                                 divider->width);
  42
  43         div_value = readl(divider->reg) >> PCG_DIV_SHIFT;
  44         div_value &= clk_div_mask(PCG_DIV_WIDTH);
  45
  46         return divider_recalc_rate(hw, prediv_rate, div_value, NULL,
  47                                    divider->flags, PCG_DIV_WIDTH);
  48 }
  49
  50 static int imx8m_clk_composite_compute_dividers(unsigned long rate,
  51                                                 unsigned long parent_rate,
  52                                                 int *prediv, int *postdiv)
  53 {
  54         int div1, div2;
  55         int error = INT_MAX;
  56         int ret = -EINVAL;
  57
  58         *prediv = 1;
  59         *postdiv = 1;
  60
  61         for (div1 = 1; div1 <= PCG_PREDIV_MAX; div1++) {
  62                 for (div2 = 1; div2 <= PCG_DIV_MAX; div2++) {
  63                         int new_error = ((parent_rate / div1) / div2) - rate;
  64
  65                         if (abs(new_error) < abs(error)) {
  66                                 *prediv = div1;
  67                                 *postdiv = div2;
  68                                 error = new_error;
  69                                 ret = 0;
  70                         }
  71                 }
  72         }
  73         return ret;
  74 }
  75
  76 static long imx8m_clk_composite_divider_round_rate(struct clk_hw *hw,
  77                                                 unsigned long rate,
  78                                                 unsigned long *prate)
  79 {
  80         int prediv_value;
  81         int div_value;
  82
  83         imx8m_clk_composite_compute_dividers(rate, *prate,
  84                                                 &prediv_value, &div_value);
  85         rate = DIV_ROUND_UP(*prate, prediv_value);
  86
  87         return DIV_ROUND_UP(rate, div_value);
  88
  89 }
  90
  91 static int imx8m_clk_composite_divider_set_rate(struct clk_hw *hw,
  92                                         unsigned long rate,
  93                                         unsigned long parent_rate)
  94 {
  95         struct clk_divider *divider = to_clk_divider(hw);
  96         unsigned long flags;
  97         int prediv_value;
  98         int div_value;
  99         int ret;
 100         u32 val;
 101
 102         ret = imx8m_clk_composite_compute_dividers(rate, parent_rate,
 103                                                 &prediv_value, &div_value);
 104         if (ret)
 105                 return -EINVAL;
 106
 107         spin_lock_irqsave(divider->lock, flags);
 108
 109         val = readl(divider->reg);
 110         val &= ~((clk_div_mask(divider->width) << divider->shift) |
 111                         (clk_div_mask(PCG_DIV_WIDTH) << PCG_DIV_SHIFT));
 112
 113         val |= (u32)(prediv_value  - 1) << divider->shift;
 114         val |= (u32)(div_value - 1) << PCG_DIV_SHIFT;
 115         writel(val, divider->reg);
 116
 117         spin_unlock_irqrestore(divider->lock, flags);
 118
 119         return ret;
 120 }
 121
 122 static const struct clk_ops imx8m_clk_composite_divider_ops = {
 123         .recalc_rate = imx8m_clk_composite_divider_recalc_rate,
 124         .round_rate = imx8m_clk_composite_divider_round_rate,
 125         .set_rate = imx8m_clk_composite_divider_set_rate,
 126 };
 127
 128 static u8 imx8m_clk_composite_mux_get_parent(struct clk_hw *hw)
 129 {
 130         return clk_mux_ops.get_parent(hw);
 131 }
 132
 133 static int imx8m_clk_composite_mux_set_parent(struct clk_hw *hw, u8 index)
 134 {
 135         struct clk_mux *mux = to_clk_mux(hw);
 136         u32 val = clk_mux_index_to_val(mux->table, mux->flags, index);
 137         unsigned long flags = 0;
 138         u32 reg;
 139
 140         if (mux->lock)
 141                 spin_lock_irqsave(mux->lock, flags);
 142
 143         reg = readl(mux->reg);
 144         reg &= ~(mux->mask << mux->shift);
 145         val = val << mux->shift;
 146         reg |= val;
 147         /*
 148          * write twice to make sure non-target interface
 149          * SEL_A/B point the same clk input.
 150          */
 151         writel(reg, mux->reg);
 152         writel(reg, mux->reg);
 153
 154         if (mux->lock)
 155                 spin_unlock_irqrestore(mux->lock, flags);
 156
 157         return 0;
 158 }
 159
 160 static int
 161 imx8m_clk_composite_mux_determine_rate(struct clk_hw *hw,
 162                                        struct clk_rate_request *req)
 163 {
 164         return clk_mux_ops.determine_rate(hw, req);
 165 }
 166
 167
 168 static const struct clk_ops imx8m_clk_composite_mux_ops = {
 169         .get_parent = imx8m_clk_composite_mux_get_parent,
 170         .set_parent = imx8m_clk_composite_mux_set_parent,
 171         .determine_rate = imx8m_clk_composite_mux_determine_rate,
 172 };
 173
 174 struct clk_hw *imx8m_clk_hw_composite_flags(const char *name,
 175                                         const char * const *parent_names,
 176                                         int num_parents, void __iomem *reg,
 177                                         u32 composite_flags,
 178                                         unsigned long flags)
 179 {
 180         struct clk_hw *hw = ERR_PTR(-ENOMEM), *mux_hw;
 181         struct clk_hw *div_hw, *gate_hw;
 182         struct clk_divider *div = NULL;
 183         struct clk_gate *gate = NULL;
 184         struct clk_mux *mux = NULL;
 185         const struct clk_ops *divider_ops;
 186         const struct clk_ops *mux_ops;
 187
 188         mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 189         if (!mux)
 190                 goto fail;
 191
 192         mux_hw = &mux->hw;
 193         mux->reg = reg;
 194         mux->shift = PCG_PCS_SHIFT;
 195         mux->mask = PCG_PCS_MASK;
 196         mux->lock = &imx_ccm_lock;
 197
 198         div = kzalloc(sizeof(*div), GFP_KERNEL);
 199         if (!div)
 200                 goto fail;
 201
 202         div_hw = &div->hw;
 203         div->reg = reg;
 204         if (composite_flags & IMX_COMPOSITE_CORE) {
 205                 div->shift = PCG_DIV_SHIFT;
 206                 div->width = PCG_CORE_DIV_WIDTH;
 207                 divider_ops = &clk_divider_ops;
 208                 mux_ops = &imx8m_clk_composite_mux_ops;
 209         } else if (composite_flags & IMX_COMPOSITE_BUS) {
 210                 div->shift = PCG_PREDIV_SHIFT;
 211                 div->width = PCG_PREDIV_WIDTH;
 212                 divider_ops = &imx8m_clk_composite_divider_ops;
 213                 mux_ops = &imx8m_clk_composite_mux_ops;
 214         } else {
 215                 div->shift = PCG_PREDIV_SHIFT;
 216                 div->width = PCG_PREDIV_WIDTH;
 217                 divider_ops = &imx8m_clk_composite_divider_ops;
 218                 mux_ops = &clk_mux_ops;
 219                 flags |= CLK_SET_PARENT_GATE;
 220         }
 221
 222         div->lock = &imx_ccm_lock;
 223         div->flags = CLK_DIVIDER_ROUND_CLOSEST;
 224
 225         gate = kzalloc(sizeof(*gate), GFP_KERNEL);
 226         if (!gate)
 227                 goto fail;
 228
 229         gate_hw = &gate->hw;
 230         gate->reg = reg;
 231         gate->bit_idx = PCG_CGC_SHIFT;
 232         gate->lock = &imx_ccm_lock;
 233
 234         hw = clk_hw_register_composite(NULL, name, parent_names, num_parents,
 235                         mux_hw, mux_ops, div_hw,
 236                         divider_ops, gate_hw, &clk_gate_ops, flags);
 237         if (IS_ERR(hw))
 238                 goto fail;
 239
 240         return hw;
 241
 242 fail:
 243         kfree(gate);
 244         kfree(div);
 245         kfree(mux);
 246         return ERR_CAST(hw);
 247 }
 248 EXPORT_SYMBOL_GPL(imx8m_clk_hw_composite_flags);