drivers/clk/mediatek/clk-mux.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2018 MediaTek Inc.
   4  * Author: Owen Chen <owen.chen@mediatek.com>
   5  */
   6
   7 #include <linux/clk.h>
   8 #include <linux/clk-provider.h>
   9 #include <linux/compiler_types.h>
  10 #include <linux/container_of.h>
  11 #include <linux/err.h>
  12 #include <linux/mfd/syscon.h>
  13 #include <linux/module.h>
  14 #include <linux/regmap.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/slab.h>
  17
  18 #include "clk-mux.h"
  19
  20 struct mtk_clk_mux {
  21         struct clk_hw hw;
  22         struct regmap *regmap;
  23         const struct mtk_mux *data;
  24         spinlock_t *lock;
  25         bool reparent;
  26 };
  27
  28 static inline struct mtk_clk_mux *to_mtk_clk_mux(struct clk_hw *hw)
  29 {
  30         return container_of(hw, struct mtk_clk_mux, hw);
  31 }
  32
  33 static int mtk_clk_mux_enable_setclr(struct clk_hw *hw)
  34 {
  35         struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
  36         unsigned long flags = 0;
  37
  38         if (mux->lock)
  39                 spin_lock_irqsave(mux->lock, flags);
  40         else
  41                 __acquire(mux->lock);
  42
  43         regmap_write(mux->regmap, mux->data->clr_ofs,
  44                      BIT(mux->data->gate_shift));
  45
  46         /*
  47          * If the parent has been changed when the clock was disabled, it will
  48          * not be effective yet. Set the update bit to ensure the mux gets
  49          * updated.
  50          */
  51         if (mux->reparent && mux->data->upd_shift >= 0) {
  52                 regmap_write(mux->regmap, mux->data->upd_ofs,
  53                              BIT(mux->data->upd_shift));
  54                 mux->reparent = false;
  55         }
  56
  57         if (mux->lock)
  58                 spin_unlock_irqrestore(mux->lock, flags);
  59         else
  60                 __release(mux->lock);
  61
  62         return 0;
  63 }
  64
  65 static void mtk_clk_mux_disable_setclr(struct clk_hw *hw)
  66 {
  67         struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
  68
  69         regmap_write(mux->regmap, mux->data->set_ofs,
  70                         BIT(mux->data->gate_shift));
  71 }
  72
  73 static int mtk_clk_mux_is_enabled(struct clk_hw *hw)
  74 {
  75         struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
  76         u32 val;
  77
  78         regmap_read(mux->regmap, mux->data->mux_ofs, &val);
  79
  80         return (val & BIT(mux->data->gate_shift)) == 0;
  81 }
  82
  83 static u8 mtk_clk_mux_get_parent(struct clk_hw *hw)
  84 {
  85         struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
  86         u32 mask = GENMASK(mux->data->mux_width - 1, 0);
  87         u32 val;
  88
  89         regmap_read(mux->regmap, mux->data->mux_ofs, &val);
  90         val = (val >> mux->data->mux_shift) & mask;
  91
  92         return val;
  93 }
  94
  95 static int mtk_clk_mux_set_parent_setclr_lock(struct clk_hw *hw, u8 index)
  96 {
  97         struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
  98         u32 mask = GENMASK(mux->data->mux_width - 1, 0);
  99         u32 val, orig;
 100         unsigned long flags = 0;
 101
 102         if (mux->lock)
 103                 spin_lock_irqsave(mux->lock, flags);
 104         else
 105                 __acquire(mux->lock);
 106
 107         regmap_read(mux->regmap, mux->data->mux_ofs, &orig);
 108         val = (orig & ~(mask << mux->data->mux_shift))
 109                         | (index << mux->data->mux_shift);
 110
 111         if (val != orig) {
 112                 regmap_write(mux->regmap, mux->data->clr_ofs,
 113                                 mask << mux->data->mux_shift);
 114                 regmap_write(mux->regmap, mux->data->set_ofs,
 115                                 index << mux->data->mux_shift);
 116
 117                 if (mux->data->upd_shift >= 0) {
 118                         regmap_write(mux->regmap, mux->data->upd_ofs,
 119                                         BIT(mux->data->upd_shift));
 120                         mux->reparent = true;
 121                 }
 122         }
 123
 124         if (mux->lock)
 125                 spin_unlock_irqrestore(mux->lock, flags);
 126         else
 127                 __release(mux->lock);
 128
 129         return 0;
 130 }
 131
 132 const struct clk_ops mtk_mux_clr_set_upd_ops = {
 133         .get_parent = mtk_clk_mux_get_parent,
 134         .set_parent = mtk_clk_mux_set_parent_setclr_lock,
 135 };
 136 EXPORT_SYMBOL_GPL(mtk_mux_clr_set_upd_ops);
 137
 138 const struct clk_ops mtk_mux_gate_clr_set_upd_ops  = {
 139         .enable = mtk_clk_mux_enable_setclr,
 140         .disable = mtk_clk_mux_disable_setclr,
 141         .is_enabled = mtk_clk_mux_is_enabled,
 142         .get_parent = mtk_clk_mux_get_parent,
 143         .set_parent = mtk_clk_mux_set_parent_setclr_lock,
 144 };
 145 EXPORT_SYMBOL_GPL(mtk_mux_gate_clr_set_upd_ops);
 146
 147 static struct clk_hw *mtk_clk_register_mux(const struct mtk_mux *mux,
 148                                  struct regmap *regmap,
 149                                  spinlock_t *lock)
 150 {
 151         struct mtk_clk_mux *clk_mux;
 152         struct clk_init_data init = {};
 153         int ret;
 154
 155         clk_mux = kzalloc(sizeof(*clk_mux), GFP_KERNEL);
 156         if (!clk_mux)
 157                 return ERR_PTR(-ENOMEM);
 158
 159         init.name = mux->name;
 160         init.flags = mux->flags | CLK_SET_RATE_PARENT;
 161         init.parent_names = mux->parent_names;
 162         init.num_parents = mux->num_parents;
 163         init.ops = mux->ops;
 164
 165         clk_mux->regmap = regmap;
 166         clk_mux->data = mux;
 167         clk_mux->lock = lock;
 168         clk_mux->hw.init = &init;
 169
 170         ret = clk_hw_register(NULL, &clk_mux->hw);
 171         if (ret) {
 172                 kfree(clk_mux);
 173                 return ERR_PTR(ret);
 174         }
 175
 176         return &clk_mux->hw;
 177 }
 178
 179 static void mtk_clk_unregister_mux(struct clk_hw *hw)
 180 {
 181         struct mtk_clk_mux *mux;
 182         if (!hw)
 183                 return;
 184
 185         mux = to_mtk_clk_mux(hw);
 186
 187         clk_hw_unregister(hw);
 188         kfree(mux);
 189 }
 190
 191 int mtk_clk_register_muxes(const struct mtk_mux *muxes,
 192                            int num, struct device_node *node,
 193                            spinlock_t *lock,
 194                            struct clk_hw_onecell_data *clk_data)
 195 {
 196         struct regmap *regmap;
 197         struct clk_hw *hw;
 198         int i;
 199
 200         regmap = device_node_to_regmap(node);
 201         if (IS_ERR(regmap)) {
 202                 pr_err("Cannot find regmap for %pOF: %pe\n", node, regmap);
 203                 return PTR_ERR(regmap);
 204         }
 205
 206         for (i = 0; i < num; i++) {
 207                 const struct mtk_mux *mux = &muxes[i];
 208
 209                 if (!IS_ERR_OR_NULL(clk_data->hws[mux->id])) {
 210                         pr_warn("%pOF: Trying to register duplicate clock ID: %d\n",
 211                                 node, mux->id);
 212                         continue;
 213                 }
 214
 215                 hw = mtk_clk_register_mux(mux, regmap, lock);
 216
 217                 if (IS_ERR(hw)) {
 218                         pr_err("Failed to register clk %s: %pe\n", mux->name,
 219                                hw);
 220                         goto err;
 221                 }
 222
 223                 clk_data->hws[mux->id] = hw;
 224         }
 225
 226         return 0;
 227
 228 err:
 229         while (--i >= 0) {
 230                 const struct mtk_mux *mux = &muxes[i];
 231
 232                 if (IS_ERR_OR_NULL(clk_data->hws[mux->id]))
 233                         continue;
 234
 235                 mtk_clk_unregister_mux(clk_data->hws[mux->id]);
 236                 clk_data->hws[mux->id] = ERR_PTR(-ENOENT);
 237         }
 238
 239         return PTR_ERR(hw);
 240 }
 241 EXPORT_SYMBOL_GPL(mtk_clk_register_muxes);
 242
 243 void mtk_clk_unregister_muxes(const struct mtk_mux *muxes, int num,
 244                               struct clk_hw_onecell_data *clk_data)
 245 {
 246         int i;
 247
 248         if (!clk_data)
 249                 return;
 250
 251         for (i = num; i > 0; i--) {
 252                 const struct mtk_mux *mux = &muxes[i - 1];
 253
 254                 if (IS_ERR_OR_NULL(clk_data->hws[mux->id]))
 255                         continue;
 256
 257                 mtk_clk_unregister_mux(clk_data->hws[mux->id]);
 258                 clk_data->hws[mux->id] = ERR_PTR(-ENOENT);
 259         }
 260 }
 261 EXPORT_SYMBOL_GPL(mtk_clk_unregister_muxes);
 262
 263 /*
 264  * This clock notifier is called when the frequency of the parent
 265  * PLL clock is to be changed. The idea is to switch the parent to a
 266  * stable clock, such as the main oscillator, while the PLL frequency
 267  * stabilizes.
 268  */
 269 static int mtk_clk_mux_notifier_cb(struct notifier_block *nb,
 270                                    unsigned long event, void *_data)
 271 {
 272         struct clk_notifier_data *data = _data;
 273         struct clk_hw *hw = __clk_get_hw(data->clk);
 274         struct mtk_mux_nb *mux_nb = to_mtk_mux_nb(nb);
 275         int ret = 0;
 276
 277         switch (event) {
 278         case PRE_RATE_CHANGE:
 279                 mux_nb->original_index = mux_nb->ops->get_parent(hw);
 280                 ret = mux_nb->ops->set_parent(hw, mux_nb->bypass_index);
 281                 break;
 282         case POST_RATE_CHANGE:
 283         case ABORT_RATE_CHANGE:
 284                 ret = mux_nb->ops->set_parent(hw, mux_nb->original_index);
 285                 break;
 286         }
 287
 288         return notifier_from_errno(ret);
 289 }
 290
 291 int devm_mtk_clk_mux_notifier_register(struct device *dev, struct clk *clk,
 292                                        struct mtk_mux_nb *mux_nb)
 293 {
 294         mux_nb->nb.notifier_call = mtk_clk_mux_notifier_cb;
 295
 296         return devm_clk_notifier_register(dev, clk, &mux_nb->nb);
 297 }
 298 EXPORT_SYMBOL_GPL(devm_mtk_clk_mux_notifier_register);
 299
 300 MODULE_LICENSE("GPL");