drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c

   1 /*
   2  * Xilinx 'Clocking Wizard' driver
   3  *
   4  *  Copyright (C) 2013 - 2014 Xilinx
   5  *
   6  *  Sören Brinkmann <soren.brinkmann@xilinx.com>
   7  *
   8  * This program is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License v2 as published by
  10  * the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/platform_device.h>
  22 #include <linux/clk.h>
  23 #include <linux/clk-provider.h>
  24 #include <linux/slab.h>
  25 #include <linux/io.h>
  26 #include <linux/of.h>
  27 #include <linux/module.h>
  28 #include <linux/err.h>
  29
  30 #define WZRD_NUM_OUTPUTS        7
  31 #define WZRD_ACLK_MAX_FREQ      250000000UL
  32
  33 #define WZRD_CLK_CFG_REG(n)     (0x200 + 4 * (n))
  34
  35 #define WZRD_CLKOUT0_FRAC_EN    BIT(18)
  36 #define WZRD_CLKFBOUT_FRAC_EN   BIT(26)
  37
  38 #define WZRD_CLKFBOUT_MULT_SHIFT        8
  39 #define WZRD_CLKFBOUT_MULT_MASK         (0xff << WZRD_CLKFBOUT_MULT_SHIFT)
  40 #define WZRD_DIVCLK_DIVIDE_SHIFT        0
  41 #define WZRD_DIVCLK_DIVIDE_MASK         (0xff << WZRD_DIVCLK_DIVIDE_SHIFT)
  42 #define WZRD_CLKOUT_DIVIDE_SHIFT        0
  43 #define WZRD_CLKOUT_DIVIDE_MASK         (0xff << WZRD_DIVCLK_DIVIDE_SHIFT)
  44
  45 enum clk_wzrd_int_clks {
  46         wzrd_clk_mul,
  47         wzrd_clk_mul_div,
  48         wzrd_clk_int_max
  49 };
  50
  51 /**
  52  * struct clk_wzrd:
  53  * @clk_data:           Clock data
  54  * @nb:                 Notifier block
  55  * @base:               Memory base
  56  * @clk_in1:            Handle to input clock 'clk_in1'
  57  * @axi_clk:            Handle to input clock 's_axi_aclk'
  58  * @clks_internal:      Internal clocks
  59  * @clkout:             Output clocks
  60  * @speed_grade:        Speed grade of the device
  61  * @suspended:          Flag indicating power state of the device
  62  */
  63 struct clk_wzrd {
  64         struct clk_onecell_data clk_data;
  65         struct notifier_block nb;
  66         void __iomem *base;
  67         struct clk *clk_in1;
  68         struct clk *axi_clk;
  69         struct clk *clks_internal[wzrd_clk_int_max];
  70         struct clk *clkout[WZRD_NUM_OUTPUTS];
  71         int speed_grade;
  72         bool suspended;
  73 };
  74
  75 #define to_clk_wzrd(_nb) container_of(_nb, struct clk_wzrd, nb)
  76
  77 /* maximum frequencies for input/output clocks per speed grade */
  78 static const unsigned long clk_wzrd_max_freq[] = {
  79         800000000UL,
  80         933000000UL,
  81         1066000000UL
  82 };
  83
  84 static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long event,
  85                                  void *data)
  86 {
  87         unsigned long max;
  88         struct clk_notifier_data *ndata = data;
  89         struct clk_wzrd *clk_wzrd = to_clk_wzrd(nb);
  90
  91         if (clk_wzrd->suspended)
  92                 return NOTIFY_OK;
  93
  94         if (ndata->clk == clk_wzrd->clk_in1)
  95                 max = clk_wzrd_max_freq[clk_wzrd->speed_grade - 1];
  96         else if (ndata->clk == clk_wzrd->axi_clk)
  97                 max = WZRD_ACLK_MAX_FREQ;
  98         else
  99                 return NOTIFY_DONE;     /* should never happen */
 100
 101         switch (event) {
 102         case PRE_RATE_CHANGE:
 103                 if (ndata->new_rate > max)
 104                         return NOTIFY_BAD;
 105                 return NOTIFY_OK;
 106         case POST_RATE_CHANGE:
 107         case ABORT_RATE_CHANGE:
 108         default:
 109                 return NOTIFY_DONE;
 110         }
 111 }
 112
 113 static int __maybe_unused clk_wzrd_suspend(struct device *dev)
 114 {
 115         struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
 116
 117         clk_disable_unprepare(clk_wzrd->axi_clk);
 118         clk_wzrd->suspended = true;
 119
 120         return 0;
 121 }
 122
 123 static int __maybe_unused clk_wzrd_resume(struct device *dev)
 124 {
 125         int ret;
 126         struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
 127
 128         ret = clk_prepare_enable(clk_wzrd->axi_clk);
 129         if (ret) {
 130                 dev_err(dev, "unable to enable s_axi_aclk\n");
 131                 return ret;
 132         }
 133
 134         clk_wzrd->suspended = false;
 135
 136         return 0;
 137 }
 138
 139 static SIMPLE_DEV_PM_OPS(clk_wzrd_dev_pm_ops, clk_wzrd_suspend,
 140                          clk_wzrd_resume);
 141
 142 static int clk_wzrd_probe(struct platform_device *pdev)
 143 {
 144         int i, ret;
 145         u32 reg;
 146         unsigned long rate;
 147         const char *clk_name;
 148         struct clk_wzrd *clk_wzrd;
 149         struct resource *mem;
 150         struct device_node *np = pdev->dev.of_node;
 151
 152         clk_wzrd = devm_kzalloc(&pdev->dev, sizeof(*clk_wzrd), GFP_KERNEL);
 153         if (!clk_wzrd)
 154                 return -ENOMEM;
 155         platform_set_drvdata(pdev, clk_wzrd);
 156
 157         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 158         clk_wzrd->base = devm_ioremap_resource(&pdev->dev, mem);
 159         if (IS_ERR(clk_wzrd->base))
 160                 return PTR_ERR(clk_wzrd->base);
 161
 162         ret = of_property_read_u32(np, "speed-grade", &clk_wzrd->speed_grade);
 163         if (!ret) {
 164                 if (clk_wzrd->speed_grade < 1 || clk_wzrd->speed_grade > 3) {
 165                         dev_warn(&pdev->dev, "invalid speed grade '%d'\n",
 166                                  clk_wzrd->speed_grade);
 167                         clk_wzrd->speed_grade = 0;
 168                 }
 169         }
 170
 171         clk_wzrd->clk_in1 = devm_clk_get(&pdev->dev, "clk_in1");
 172         if (IS_ERR(clk_wzrd->clk_in1)) {
 173                 if (clk_wzrd->clk_in1 != ERR_PTR(-EPROBE_DEFER))
 174                         dev_err(&pdev->dev, "clk_in1 not found\n");
 175                 return PTR_ERR(clk_wzrd->clk_in1);
 176         }
 177
 178         clk_wzrd->axi_clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
 179         if (IS_ERR(clk_wzrd->axi_clk)) {
 180                 if (clk_wzrd->axi_clk != ERR_PTR(-EPROBE_DEFER))
 181                         dev_err(&pdev->dev, "s_axi_aclk not found\n");
 182                 return PTR_ERR(clk_wzrd->axi_clk);
 183         }
 184         ret = clk_prepare_enable(clk_wzrd->axi_clk);
 185         if (ret) {
 186                 dev_err(&pdev->dev, "enabling s_axi_aclk failed\n");
 187                 return ret;
 188         }
 189         rate = clk_get_rate(clk_wzrd->axi_clk);
 190         if (rate > WZRD_ACLK_MAX_FREQ) {
 191                 dev_err(&pdev->dev, "s_axi_aclk frequency (%lu) too high\n",
 192                         rate);
 193                 ret = -EINVAL;
 194                 goto err_disable_clk;
 195         }
 196
 197         /* we don't support fractional div/mul yet */
 198         reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
 199                     WZRD_CLKFBOUT_FRAC_EN;
 200         reg |= readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2)) &
 201                      WZRD_CLKOUT0_FRAC_EN;
 202         if (reg)
 203                 dev_warn(&pdev->dev, "fractional div/mul not supported\n");
 204
 205         /* register multiplier */
 206         reg = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
 207                      WZRD_CLKFBOUT_MULT_MASK) >> WZRD_CLKFBOUT_MULT_SHIFT;
 208         clk_name = kasprintf(GFP_KERNEL, "%s_mul", dev_name(&pdev->dev));
 209         if (!clk_name) {
 210                 ret = -ENOMEM;
 211                 goto err_disable_clk;
 212         }
 213         clk_wzrd->clks_internal[wzrd_clk_mul] = clk_register_fixed_factor(
 214                         &pdev->dev, clk_name,
 215                         __clk_get_name(clk_wzrd->clk_in1),
 216                         0, reg, 1);
 217         kfree(clk_name);
 218         if (IS_ERR(clk_wzrd->clks_internal[wzrd_clk_mul])) {
 219                 dev_err(&pdev->dev, "unable to register fixed-factor clock\n");
 220                 ret = PTR_ERR(clk_wzrd->clks_internal[wzrd_clk_mul]);
 221                 goto err_disable_clk;
 222         }
 223
 224         /* register div */
 225         reg = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
 226                         WZRD_DIVCLK_DIVIDE_MASK) >> WZRD_DIVCLK_DIVIDE_SHIFT;
 227         clk_name = kasprintf(GFP_KERNEL, "%s_mul_div", dev_name(&pdev->dev));
 228         if (!clk_name) {
 229                 ret = -ENOMEM;
 230                 goto err_rm_int_clk;
 231         }
 232
 233         clk_wzrd->clks_internal[wzrd_clk_mul_div] = clk_register_fixed_factor(
 234                         &pdev->dev, clk_name,
 235                         __clk_get_name(clk_wzrd->clks_internal[wzrd_clk_mul]),
 236                         0, 1, reg);
 237         if (IS_ERR(clk_wzrd->clks_internal[wzrd_clk_mul_div])) {
 238                 dev_err(&pdev->dev, "unable to register divider clock\n");
 239                 ret = PTR_ERR(clk_wzrd->clks_internal[wzrd_clk_mul_div]);
 240                 goto err_rm_int_clk;
 241         }
 242
 243         /* register div per output */
 244         for (i = WZRD_NUM_OUTPUTS - 1; i >= 0 ; i--) {
 245                 const char *clkout_name;
 246
 247                 if (of_property_read_string_index(np, "clock-output-names", i,
 248                                                   &clkout_name)) {
 249                         dev_err(&pdev->dev,
 250                                 "clock output name not specified\n");
 251                         ret = -EINVAL;
 252                         goto err_rm_int_clks;
 253                 }
 254                 reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2) + i * 12);
 255                 reg &= WZRD_CLKOUT_DIVIDE_MASK;
 256                 reg >>= WZRD_CLKOUT_DIVIDE_SHIFT;
 257                 clk_wzrd->clkout[i] = clk_register_fixed_factor(&pdev->dev,
 258                                 clkout_name, clk_name, 0, 1, reg);
 259                 if (IS_ERR(clk_wzrd->clkout[i])) {
 260                         int j;
 261
 262                         for (j = i + 1; j < WZRD_NUM_OUTPUTS; j++)
 263                                 clk_unregister(clk_wzrd->clkout[j]);
 264                         dev_err(&pdev->dev,
 265                                 "unable to register divider clock\n");
 266                         ret = PTR_ERR(clk_wzrd->clkout[i]);
 267                         goto err_rm_int_clks;
 268                 }
 269         }
 270
 271         kfree(clk_name);
 272
 273         clk_wzrd->clk_data.clks = clk_wzrd->clkout;
 274         clk_wzrd->clk_data.clk_num = ARRAY_SIZE(clk_wzrd->clkout);
 275         of_clk_add_provider(np, of_clk_src_onecell_get, &clk_wzrd->clk_data);
 276
 277         if (clk_wzrd->speed_grade) {
 278                 clk_wzrd->nb.notifier_call = clk_wzrd_clk_notifier;
 279
 280                 ret = clk_notifier_register(clk_wzrd->clk_in1,
 281                                             &clk_wzrd->nb);
 282                 if (ret)
 283                         dev_warn(&pdev->dev,
 284                                  "unable to register clock notifier\n");
 285
 286                 ret = clk_notifier_register(clk_wzrd->axi_clk, &clk_wzrd->nb);
 287                 if (ret)
 288                         dev_warn(&pdev->dev,
 289                                  "unable to register clock notifier\n");
 290         }
 291
 292         return 0;
 293
 294 err_rm_int_clks:
 295         clk_unregister(clk_wzrd->clks_internal[1]);
 296 err_rm_int_clk:
 297         kfree(clk_name);
 298         clk_unregister(clk_wzrd->clks_internal[0]);
 299 err_disable_clk:
 300         clk_disable_unprepare(clk_wzrd->axi_clk);
 301
 302         return ret;
 303 }
 304
 305 static int clk_wzrd_remove(struct platform_device *pdev)
 306 {
 307         int i;
 308         struct clk_wzrd *clk_wzrd = platform_get_drvdata(pdev);
 309
 310         of_clk_del_provider(pdev->dev.of_node);
 311
 312         for (i = 0; i < WZRD_NUM_OUTPUTS; i++)
 313                 clk_unregister(clk_wzrd->clkout[i]);
 314         for (i = 0; i < wzrd_clk_int_max; i++)
 315                 clk_unregister(clk_wzrd->clks_internal[i]);
 316
 317         if (clk_wzrd->speed_grade) {
 318                 clk_notifier_unregister(clk_wzrd->axi_clk, &clk_wzrd->nb);
 319                 clk_notifier_unregister(clk_wzrd->clk_in1, &clk_wzrd->nb);
 320         }
 321
 322         clk_disable_unprepare(clk_wzrd->axi_clk);
 323
 324         return 0;
 325 }
 326
 327 static const struct of_device_id clk_wzrd_ids[] = {
 328         { .compatible = "xlnx,clocking-wizard" },
 329         { },
 330 };
 331 MODULE_DEVICE_TABLE(of, clk_wzrd_ids);
 332
 333 static struct platform_driver clk_wzrd_driver = {
 334         .driver = {
 335                 .name = "clk-wizard",
 336                 .of_match_table = clk_wzrd_ids,
 337                 .pm = &clk_wzrd_dev_pm_ops,
 338         },
 339         .probe = clk_wzrd_probe,
 340         .remove = clk_wzrd_remove,
 341 };
 342 module_platform_driver(clk_wzrd_driver);
 343
 344 MODULE_LICENSE("GPL");
 345 MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xilinx.com");
 346 MODULE_DESCRIPTION("Driver for the Xilinx Clocking Wizard IP core");