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 orig, 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         orig = readl(divider->reg);
 110         val = orig & ~((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
 116         if (val != orig)
 117                 writel(val, divider->reg);
 118
 119         spin_unlock_irqrestore(divider->lock, flags);
 120
 121         return ret;
 122 }
 123
 124 static int imx8m_divider_determine_rate(struct clk_hw *hw,
 125                                       struct clk_rate_request *req)
 126 {
 127         struct clk_divider *divider = to_clk_divider(hw);
 128         int prediv_value;
 129         int div_value;
 130
 131         /* if read only, just return current value */
 132         if (divider->flags & CLK_DIVIDER_READ_ONLY) {
 133                 u32 val;
 134
 135                 val = readl(divider->reg);
 136                 prediv_value = val >> divider->shift;
 137                 prediv_value &= clk_div_mask(divider->width);
 138                 prediv_value++;
 139
 140                 div_value = val >> PCG_DIV_SHIFT;
 141                 div_value &= clk_div_mask(PCG_DIV_WIDTH);
 142                 div_value++;
 143
 144                 return divider_ro_determine_rate(hw, req, divider->table,
 145                                                  PCG_PREDIV_WIDTH + PCG_DIV_WIDTH,
 146                                                  divider->flags, prediv_value * div_value);
 147         }
 148
 149         return divider_determine_rate(hw, req, divider->table,
 150                                       PCG_PREDIV_WIDTH + PCG_DIV_WIDTH,
 151                                       divider->flags);
 152 }
 153
 154 static const struct clk_ops imx8m_clk_composite_divider_ops = {
 155         .recalc_rate = imx8m_clk_composite_divider_recalc_rate,
 156         .round_rate = imx8m_clk_composite_divider_round_rate,
 157         .set_rate = imx8m_clk_composite_divider_set_rate,
 158         .determine_rate = imx8m_divider_determine_rate,
 159 };
 160
 161 static u8 imx8m_clk_composite_mux_get_parent(struct clk_hw *hw)
 162 {
 163         return clk_mux_ops.get_parent(hw);
 164 }
 165
 166 static int imx8m_clk_composite_mux_set_parent(struct clk_hw *hw, u8 index)
 167 {
 168         struct clk_mux *mux = to_clk_mux(hw);
 169         u32 val = clk_mux_index_to_val(mux->table, mux->flags, index);
 170         unsigned long flags = 0;
 171         u32 reg;
 172
 173         if (mux->lock)
 174                 spin_lock_irqsave(mux->lock, flags);
 175
 176         reg = readl(mux->reg);
 177         reg &= ~(mux->mask << mux->shift);
 178         val = val << mux->shift;
 179         reg |= val;
 180         /*
 181          * write twice to make sure non-target interface
 182          * SEL_A/B point the same clk input.
 183          */
 184         writel(reg, mux->reg);
 185         writel(reg, mux->reg);
 186
 187         if (mux->lock)
 188                 spin_unlock_irqrestore(mux->lock, flags);
 189
 190         return 0;
 191 }
 192
 193 static int
 194 imx8m_clk_composite_mux_determine_rate(struct clk_hw *hw,
 195                                        struct clk_rate_request *req)
 196 {
 197         return clk_mux_ops.determine_rate(hw, req);
 198 }
 199
 200
 201 static const struct clk_ops imx8m_clk_composite_mux_ops = {
 202         .get_parent = imx8m_clk_composite_mux_get_parent,
 203         .set_parent = imx8m_clk_composite_mux_set_parent,
 204         .determine_rate = imx8m_clk_composite_mux_determine_rate,
 205 };
 206
 207 struct clk_hw *__imx8m_clk_hw_composite(const char *name,
 208                                         const char * const *parent_names,
 209                                         int num_parents, void __iomem *reg,
 210                                         u32 composite_flags,
 211                                         unsigned long flags)
 212 {
 213         struct clk_hw *hw = ERR_PTR(-ENOMEM), *mux_hw;
 214         struct clk_hw *div_hw, *gate_hw = NULL;
 215         struct clk_divider *div;
 216         struct clk_gate *gate = NULL;
 217         struct clk_mux *mux;
 218         const struct clk_ops *divider_ops;
 219         const struct clk_ops *mux_ops;
 220
 221         mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 222         if (!mux)
 223                 return ERR_CAST(hw);
 224
 225         mux_hw = &mux->hw;
 226         mux->reg = reg;
 227         mux->shift = PCG_PCS_SHIFT;
 228         mux->mask = PCG_PCS_MASK;
 229         mux->lock = &imx_ccm_lock;
 230
 231         div = kzalloc(sizeof(*div), GFP_KERNEL);
 232         if (!div)
 233                 goto free_mux;
 234
 235         div_hw = &div->hw;
 236         div->reg = reg;
 237         if (composite_flags & IMX_COMPOSITE_CORE) {
 238                 div->shift = PCG_DIV_SHIFT;
 239                 div->width = PCG_CORE_DIV_WIDTH;
 240                 divider_ops = &clk_divider_ops;
 241                 mux_ops = &imx8m_clk_composite_mux_ops;
 242         } else if (composite_flags & IMX_COMPOSITE_BUS) {
 243                 div->shift = PCG_PREDIV_SHIFT;
 244                 div->width = PCG_PREDIV_WIDTH;
 245                 divider_ops = &imx8m_clk_composite_divider_ops;
 246                 mux_ops = &imx8m_clk_composite_mux_ops;
 247         } else {
 248                 div->shift = PCG_PREDIV_SHIFT;
 249                 div->width = PCG_PREDIV_WIDTH;
 250                 divider_ops = &imx8m_clk_composite_divider_ops;
 251                 mux_ops = &clk_mux_ops;
 252                 if (!(composite_flags & IMX_COMPOSITE_FW_MANAGED))
 253                         flags |= CLK_SET_PARENT_GATE;
 254         }
 255
 256         div->lock = &imx_ccm_lock;
 257         div->flags = CLK_DIVIDER_ROUND_CLOSEST;
 258
 259         /* skip registering the gate ops if M4 is enabled */
 260         if (!mcore_booted) {
 261                 gate = kzalloc(sizeof(*gate), GFP_KERNEL);
 262                 if (!gate)
 263                         goto free_div;
 264
 265                 gate_hw = &gate->hw;
 266                 gate->reg = reg;
 267                 gate->bit_idx = PCG_CGC_SHIFT;
 268                 gate->lock = &imx_ccm_lock;
 269         }
 270
 271         hw = clk_hw_register_composite(NULL, name, parent_names, num_parents,
 272                         mux_hw, mux_ops, div_hw,
 273                         divider_ops, gate_hw, &clk_gate_ops, flags);
 274         if (IS_ERR(hw))
 275                 goto free_gate;
 276
 277         return hw;
 278
 279 free_gate:
 280         kfree(gate);
 281 free_div:
 282         kfree(div);
 283 free_mux:
 284         kfree(mux);
 285         return ERR_CAST(hw);
 286 }
 287 EXPORT_SYMBOL_GPL(__imx8m_clk_hw_composite);