drivers/clk/x86/clk-pmc-atom.c

   1 /*
   2  * Intel Atom platform clocks driver for BayTrail and CherryTrail SoCs
   3  *
   4  * Copyright (C) 2016, Intel Corporation
   5  * Author: Irina Tirdea <irina.tirdea@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  */
  16
  17 #include <linux/clk-provider.h>
  18 #include <linux/clkdev.h>
  19 #include <linux/err.h>
  20 #include <linux/platform_data/x86/clk-pmc-atom.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23
  24 #define PLT_CLK_NAME_BASE       "pmc_plt_clk"
  25
  26 #define PMC_CLK_CTL_OFFSET              0x60
  27 #define PMC_CLK_CTL_SIZE                4
  28 #define PMC_CLK_NUM                     6
  29 #define PMC_CLK_CTL_GATED_ON_D3         0x0
  30 #define PMC_CLK_CTL_FORCE_ON            0x1
  31 #define PMC_CLK_CTL_FORCE_OFF           0x2
  32 #define PMC_CLK_CTL_RESERVED            0x3
  33 #define PMC_MASK_CLK_CTL                GENMASK(1, 0)
  34 #define PMC_MASK_CLK_FREQ               BIT(2)
  35 #define PMC_CLK_FREQ_XTAL               (0 << 2)        /* 25 MHz */
  36 #define PMC_CLK_FREQ_PLL                (1 << 2)        /* 19.2 MHz */
  37
  38 struct clk_plt_fixed {
  39         struct clk_hw *clk;
  40         struct clk_lookup *lookup;
  41 };
  42
  43 struct clk_plt {
  44         struct clk_hw hw;
  45         void __iomem *reg;
  46         struct clk_lookup *lookup;
  47         /* protect access to PMC registers */
  48         spinlock_t lock;
  49 };
  50
  51 #define to_clk_plt(_hw) container_of(_hw, struct clk_plt, hw)
  52
  53 struct clk_plt_data {
  54         struct clk_plt_fixed **parents;
  55         u8 nparents;
  56         struct clk_plt *clks[PMC_CLK_NUM];
  57 };
  58
  59 /* Return an index in parent table */
  60 static inline int plt_reg_to_parent(int reg)
  61 {
  62         switch (reg & PMC_MASK_CLK_FREQ) {
  63         default:
  64         case PMC_CLK_FREQ_XTAL:
  65                 return 0;
  66         case PMC_CLK_FREQ_PLL:
  67                 return 1;
  68         }
  69 }
  70
  71 /* Return clk index of parent */
  72 static inline int plt_parent_to_reg(int index)
  73 {
  74         switch (index) {
  75         default:
  76         case 0:
  77                 return PMC_CLK_FREQ_XTAL;
  78         case 1:
  79                 return PMC_CLK_FREQ_PLL;
  80         }
  81 }
  82
  83 /* Abstract status in simpler enabled/disabled value */
  84 static inline int plt_reg_to_enabled(int reg)
  85 {
  86         switch (reg & PMC_MASK_CLK_CTL) {
  87         case PMC_CLK_CTL_GATED_ON_D3:
  88         case PMC_CLK_CTL_FORCE_ON:
  89                 return 1;       /* enabled */
  90         case PMC_CLK_CTL_FORCE_OFF:
  91         case PMC_CLK_CTL_RESERVED:
  92         default:
  93                 return 0;       /* disabled */
  94         }
  95 }
  96
  97 static void plt_clk_reg_update(struct clk_plt *clk, u32 mask, u32 val)
  98 {
  99         u32 tmp;
 100         unsigned long flags;
 101
 102         spin_lock_irqsave(&clk->lock, flags);
 103
 104         tmp = readl(clk->reg);
 105         tmp = (tmp & ~mask) | (val & mask);
 106         writel(tmp, clk->reg);
 107
 108         spin_unlock_irqrestore(&clk->lock, flags);
 109 }
 110
 111 static int plt_clk_set_parent(struct clk_hw *hw, u8 index)
 112 {
 113         struct clk_plt *clk = to_clk_plt(hw);
 114
 115         plt_clk_reg_update(clk, PMC_MASK_CLK_FREQ, plt_parent_to_reg(index));
 116
 117         return 0;
 118 }
 119
 120 static u8 plt_clk_get_parent(struct clk_hw *hw)
 121 {
 122         struct clk_plt *clk = to_clk_plt(hw);
 123         u32 value;
 124
 125         value = readl(clk->reg);
 126
 127         return plt_reg_to_parent(value);
 128 }
 129
 130 static int plt_clk_enable(struct clk_hw *hw)
 131 {
 132         struct clk_plt *clk = to_clk_plt(hw);
 133
 134         plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_ON);
 135
 136         return 0;
 137 }
 138
 139 static void plt_clk_disable(struct clk_hw *hw)
 140 {
 141         struct clk_plt *clk = to_clk_plt(hw);
 142
 143         plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_OFF);
 144 }
 145
 146 static int plt_clk_is_enabled(struct clk_hw *hw)
 147 {
 148         struct clk_plt *clk = to_clk_plt(hw);
 149         u32 value;
 150
 151         value = readl(clk->reg);
 152
 153         return plt_reg_to_enabled(value);
 154 }
 155
 156 static const struct clk_ops plt_clk_ops = {
 157         .enable = plt_clk_enable,
 158         .disable = plt_clk_disable,
 159         .is_enabled = plt_clk_is_enabled,
 160         .get_parent = plt_clk_get_parent,
 161         .set_parent = plt_clk_set_parent,
 162         .determine_rate = __clk_mux_determine_rate,
 163 };
 164
 165 static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
 166                                         void __iomem *base,
 167                                         const char **parent_names,
 168                                         int num_parents)
 169 {
 170         struct clk_plt *pclk;
 171         struct clk_init_data init;
 172         int ret;
 173
 174         pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
 175         if (!pclk)
 176                 return ERR_PTR(-ENOMEM);
 177
 178         init.name =  kasprintf(GFP_KERNEL, "%s_%d", PLT_CLK_NAME_BASE, id);
 179         init.ops = &plt_clk_ops;
 180         init.flags = 0;
 181         init.parent_names = parent_names;
 182         init.num_parents = num_parents;
 183
 184         pclk->hw.init = &init;
 185         pclk->reg = base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
 186         spin_lock_init(&pclk->lock);
 187
 188         ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
 189         if (ret) {
 190                 pclk = ERR_PTR(ret);
 191                 goto err_free_init;
 192         }
 193
 194         pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
 195         if (!pclk->lookup) {
 196                 pclk = ERR_PTR(-ENOMEM);
 197                 goto err_free_init;
 198         }
 199
 200 err_free_init:
 201         kfree(init.name);
 202         return pclk;
 203 }
 204
 205 static void plt_clk_unregister(struct clk_plt *pclk)
 206 {
 207         clkdev_drop(pclk->lookup);
 208 }
 209
 210 static struct clk_plt_fixed *plt_clk_register_fixed_rate(struct platform_device *pdev,
 211                                                  const char *name,
 212                                                  const char *parent_name,
 213                                                  unsigned long fixed_rate)
 214 {
 215         struct clk_plt_fixed *pclk;
 216
 217         pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
 218         if (!pclk)
 219                 return ERR_PTR(-ENOMEM);
 220
 221         pclk->clk = clk_hw_register_fixed_rate(&pdev->dev, name, parent_name,
 222                                                0, fixed_rate);
 223         if (IS_ERR(pclk->clk))
 224                 return ERR_CAST(pclk->clk);
 225
 226         pclk->lookup = clkdev_hw_create(pclk->clk, name, NULL);
 227         if (!pclk->lookup) {
 228                 clk_hw_unregister_fixed_rate(pclk->clk);
 229                 return ERR_PTR(-ENOMEM);
 230         }
 231
 232         return pclk;
 233 }
 234
 235 static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk)
 236 {
 237         clkdev_drop(pclk->lookup);
 238         clk_hw_unregister_fixed_rate(pclk->clk);
 239 }
 240
 241 static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
 242                                                unsigned int i)
 243 {
 244         while (i--)
 245                 plt_clk_unregister_fixed_rate(data->parents[i]);
 246 }
 247
 248 static void plt_clk_free_parent_names_loop(const char **parent_names,
 249                                            unsigned int i)
 250 {
 251         while (i--)
 252                 kfree_const(parent_names[i]);
 253         kfree(parent_names);
 254 }
 255
 256 static void plt_clk_unregister_loop(struct clk_plt_data *data,
 257                                     unsigned int i)
 258 {
 259         while (i--)
 260                 plt_clk_unregister(data->clks[i]);
 261 }
 262
 263 static const char **plt_clk_register_parents(struct platform_device *pdev,
 264                                              struct clk_plt_data *data,
 265                                              const struct pmc_clk *clks)
 266 {
 267         const char **parent_names;
 268         unsigned int i;
 269         int err;
 270         int nparents = 0;
 271
 272         data->nparents = 0;
 273         while (clks[nparents].name)
 274                 nparents++;
 275
 276         data->parents = devm_kcalloc(&pdev->dev, nparents,
 277                                      sizeof(*data->parents), GFP_KERNEL);
 278         if (!data->parents)
 279                 return ERR_PTR(-ENOMEM);
 280
 281         parent_names = kcalloc(nparents, sizeof(*parent_names),
 282                                GFP_KERNEL);
 283         if (!parent_names)
 284                 return ERR_PTR(-ENOMEM);
 285
 286         for (i = 0; i < nparents; i++) {
 287                 data->parents[i] =
 288                         plt_clk_register_fixed_rate(pdev, clks[i].name,
 289                                                     clks[i].parent_name,
 290                                                     clks[i].freq);
 291                 if (IS_ERR(data->parents[i])) {
 292                         err = PTR_ERR(data->parents[i]);
 293                         goto err_unreg;
 294                 }
 295                 parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
 296         }
 297
 298         data->nparents = nparents;
 299         return parent_names;
 300
 301 err_unreg:
 302         plt_clk_unregister_fixed_rate_loop(data, i);
 303         plt_clk_free_parent_names_loop(parent_names, i);
 304         return ERR_PTR(err);
 305 }
 306
 307 static void plt_clk_unregister_parents(struct clk_plt_data *data)
 308 {
 309         plt_clk_unregister_fixed_rate_loop(data, data->nparents);
 310 }
 311
 312 static int plt_clk_probe(struct platform_device *pdev)
 313 {
 314         const struct pmc_clk_data *pmc_data;
 315         const char **parent_names;
 316         struct clk_plt_data *data;
 317         unsigned int i;
 318         int err;
 319
 320         pmc_data = dev_get_platdata(&pdev->dev);
 321         if (!pmc_data || !pmc_data->clks)
 322                 return -EINVAL;
 323
 324         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 325         if (!data)
 326                 return -ENOMEM;
 327
 328         parent_names = plt_clk_register_parents(pdev, data, pmc_data->clks);
 329         if (IS_ERR(parent_names))
 330                 return PTR_ERR(parent_names);
 331
 332         for (i = 0; i < PMC_CLK_NUM; i++) {
 333                 data->clks[i] = plt_clk_register(pdev, i, pmc_data->base,
 334                                                  parent_names, data->nparents);
 335                 if (IS_ERR(data->clks[i])) {
 336                         err = PTR_ERR(data->clks[i]);
 337                         goto err_unreg_clk_plt;
 338                 }
 339         }
 340
 341         plt_clk_free_parent_names_loop(parent_names, data->nparents);
 342
 343         platform_set_drvdata(pdev, data);
 344         return 0;
 345
 346 err_unreg_clk_plt:
 347         plt_clk_unregister_loop(data, i);
 348         plt_clk_unregister_parents(data);
 349         plt_clk_free_parent_names_loop(parent_names, data->nparents);
 350         return err;
 351 }
 352
 353 static int plt_clk_remove(struct platform_device *pdev)
 354 {
 355         struct clk_plt_data *data;
 356
 357         data = platform_get_drvdata(pdev);
 358
 359         plt_clk_unregister_loop(data, PMC_CLK_NUM);
 360         plt_clk_unregister_parents(data);
 361         return 0;
 362 }
 363
 364 static struct platform_driver plt_clk_driver = {
 365         .driver = {
 366                 .name = "clk-pmc-atom",
 367         },
 368         .probe = plt_clk_probe,
 369         .remove = plt_clk_remove,
 370 };
 371 builtin_platform_driver(plt_clk_driver);