drivers/pwm/pwm-img.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Imagination Technologies Pulse Width Modulator driver
   4  *
   5  * Copyright (c) 2014-2015, Imagination Technologies
   6  *
   7  * Based on drivers/pwm/pwm-tegra.c, Copyright (c) 2010, NVIDIA Corporation
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/err.h>
  12 #include <linux/io.h>
  13 #include <linux/mfd/syscon.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_device.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pm_runtime.h>
  19 #include <linux/pwm.h>
  20 #include <linux/regmap.h>
  21 #include <linux/slab.h>
  22
  23 /* PWM registers */
  24 #define PWM_CTRL_CFG                            0x0000
  25 #define PWM_CTRL_CFG_NO_SUB_DIV                 0
  26 #define PWM_CTRL_CFG_SUB_DIV0                   1
  27 #define PWM_CTRL_CFG_SUB_DIV1                   2
  28 #define PWM_CTRL_CFG_SUB_DIV0_DIV1              3
  29 #define PWM_CTRL_CFG_DIV_SHIFT(ch)              ((ch) * 2 + 4)
  30 #define PWM_CTRL_CFG_DIV_MASK                   0x3
  31
  32 #define PWM_CH_CFG(ch)                          (0x4 + (ch) * 4)
  33 #define PWM_CH_CFG_TMBASE_SHIFT                 0
  34 #define PWM_CH_CFG_DUTY_SHIFT                   16
  35
  36 #define PERIP_PWM_PDM_CONTROL                   0x0140
  37 #define PERIP_PWM_PDM_CONTROL_CH_MASK           0x1
  38 #define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch)      ((ch) * 4)
  39
  40 #define IMG_PWM_PM_TIMEOUT                      1000 /* ms */
  41
  42 /*
  43  * PWM period is specified with a timebase register,
  44  * in number of step periods. The PWM duty cycle is also
  45  * specified in step periods, in the [0, $timebase] range.
  46  * In other words, the timebase imposes the duty cycle
  47  * resolution. Therefore, let's constraint the timebase to
  48  * a minimum value to allow a sane range of duty cycle values.
  49  * Imposing a minimum timebase, will impose a maximum PWM frequency.
  50  *
  51  * The value chosen is completely arbitrary.
  52  */
  53 #define MIN_TMBASE_STEPS                        16
  54
  55 #define IMG_PWM_NPWM                            4
  56
  57 struct img_pwm_soc_data {
  58         u32 max_timebase;
  59 };
  60
  61 struct img_pwm_chip {
  62         struct device   *dev;
  63         struct pwm_chip chip;
  64         struct clk      *pwm_clk;
  65         struct clk      *sys_clk;
  66         void __iomem    *base;
  67         struct regmap   *periph_regs;
  68         int             max_period_ns;
  69         int             min_period_ns;
  70         const struct img_pwm_soc_data   *data;
  71         u32             suspend_ctrl_cfg;
  72         u32             suspend_ch_cfg[IMG_PWM_NPWM];
  73 };
  74
  75 static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
  76 {
  77         return container_of(chip, struct img_pwm_chip, chip);
  78 }
  79
  80 static inline void img_pwm_writel(struct img_pwm_chip *chip,
  81                                   u32 reg, u32 val)
  82 {
  83         writel(val, chip->base + reg);
  84 }
  85
  86 static inline u32 img_pwm_readl(struct img_pwm_chip *chip,
  87                                          u32 reg)
  88 {
  89         return readl(chip->base + reg);
  90 }
  91
  92 static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  93                           int duty_ns, int period_ns)
  94 {
  95         u32 val, div, duty, timebase;
  96         unsigned long mul, output_clk_hz, input_clk_hz;
  97         struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
  98         unsigned int max_timebase = pwm_chip->data->max_timebase;
  99         int ret;
 100
 101         if (period_ns < pwm_chip->min_period_ns ||
 102             period_ns > pwm_chip->max_period_ns) {
 103                 dev_err(chip->dev, "configured period not in range\n");
 104                 return -ERANGE;
 105         }
 106
 107         input_clk_hz = clk_get_rate(pwm_chip->pwm_clk);
 108         output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns);
 109
 110         mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz);
 111         if (mul <= max_timebase) {
 112                 div = PWM_CTRL_CFG_NO_SUB_DIV;
 113                 timebase = DIV_ROUND_UP(mul, 1);
 114         } else if (mul <= max_timebase * 8) {
 115                 div = PWM_CTRL_CFG_SUB_DIV0;
 116                 timebase = DIV_ROUND_UP(mul, 8);
 117         } else if (mul <= max_timebase * 64) {
 118                 div = PWM_CTRL_CFG_SUB_DIV1;
 119                 timebase = DIV_ROUND_UP(mul, 64);
 120         } else if (mul <= max_timebase * 512) {
 121                 div = PWM_CTRL_CFG_SUB_DIV0_DIV1;
 122                 timebase = DIV_ROUND_UP(mul, 512);
 123         } else {
 124                 dev_err(chip->dev,
 125                         "failed to configure timebase steps/divider value\n");
 126                 return -EINVAL;
 127         }
 128
 129         duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
 130
 131         ret = pm_runtime_get_sync(chip->dev);
 132         if (ret < 0) {
 133                 pm_runtime_put_autosuspend(chip->dev);
 134                 return ret;
 135         }
 136
 137         val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 138         val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
 139         val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
 140                 PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
 141         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 142
 143         val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
 144               (timebase << PWM_CH_CFG_TMBASE_SHIFT);
 145         img_pwm_writel(pwm_chip, PWM_CH_CFG(pwm->hwpwm), val);
 146
 147         pm_runtime_mark_last_busy(chip->dev);
 148         pm_runtime_put_autosuspend(chip->dev);
 149
 150         return 0;
 151 }
 152
 153 static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 154 {
 155         u32 val;
 156         struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
 157         int ret;
 158
 159         ret = pm_runtime_resume_and_get(chip->dev);
 160         if (ret < 0)
 161                 return ret;
 162
 163         val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 164         val |= BIT(pwm->hwpwm);
 165         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 166
 167         regmap_update_bits(pwm_chip->periph_regs, PERIP_PWM_PDM_CONTROL,
 168                            PERIP_PWM_PDM_CONTROL_CH_MASK <<
 169                            PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm), 0);
 170
 171         return 0;
 172 }
 173
 174 static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 175 {
 176         u32 val;
 177         struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
 178
 179         val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 180         val &= ~BIT(pwm->hwpwm);
 181         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 182
 183         pm_runtime_mark_last_busy(chip->dev);
 184         pm_runtime_put_autosuspend(chip->dev);
 185 }
 186
 187 static const struct pwm_ops img_pwm_ops = {
 188         .config = img_pwm_config,
 189         .enable = img_pwm_enable,
 190         .disable = img_pwm_disable,
 191         .owner = THIS_MODULE,
 192 };
 193
 194 static const struct img_pwm_soc_data pistachio_pwm = {
 195         .max_timebase = 255,
 196 };
 197
 198 static const struct of_device_id img_pwm_of_match[] = {
 199         {
 200                 .compatible = "img,pistachio-pwm",
 201                 .data = &pistachio_pwm,
 202         },
 203         { }
 204 };
 205 MODULE_DEVICE_TABLE(of, img_pwm_of_match);
 206
 207 static int img_pwm_runtime_suspend(struct device *dev)
 208 {
 209         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 210
 211         clk_disable_unprepare(pwm_chip->pwm_clk);
 212         clk_disable_unprepare(pwm_chip->sys_clk);
 213
 214         return 0;
 215 }
 216
 217 static int img_pwm_runtime_resume(struct device *dev)
 218 {
 219         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 220         int ret;
 221
 222         ret = clk_prepare_enable(pwm_chip->sys_clk);
 223         if (ret < 0) {
 224                 dev_err(dev, "could not prepare or enable sys clock\n");
 225                 return ret;
 226         }
 227
 228         ret = clk_prepare_enable(pwm_chip->pwm_clk);
 229         if (ret < 0) {
 230                 dev_err(dev, "could not prepare or enable pwm clock\n");
 231                 clk_disable_unprepare(pwm_chip->sys_clk);
 232                 return ret;
 233         }
 234
 235         return 0;
 236 }
 237
 238 static int img_pwm_probe(struct platform_device *pdev)
 239 {
 240         int ret;
 241         u64 val;
 242         unsigned long clk_rate;
 243         struct img_pwm_chip *pwm;
 244         const struct of_device_id *of_dev_id;
 245
 246         pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
 247         if (!pwm)
 248                 return -ENOMEM;
 249
 250         pwm->dev = &pdev->dev;
 251
 252         pwm->base = devm_platform_ioremap_resource(pdev, 0);
 253         if (IS_ERR(pwm->base))
 254                 return PTR_ERR(pwm->base);
 255
 256         of_dev_id = of_match_device(img_pwm_of_match, &pdev->dev);
 257         if (!of_dev_id)
 258                 return -ENODEV;
 259         pwm->data = of_dev_id->data;
 260
 261         pwm->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
 262                                                            "img,cr-periph");
 263         if (IS_ERR(pwm->periph_regs))
 264                 return PTR_ERR(pwm->periph_regs);
 265
 266         pwm->sys_clk = devm_clk_get(&pdev->dev, "sys");
 267         if (IS_ERR(pwm->sys_clk)) {
 268                 dev_err(&pdev->dev, "failed to get system clock\n");
 269                 return PTR_ERR(pwm->sys_clk);
 270         }
 271
 272         pwm->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
 273         if (IS_ERR(pwm->pwm_clk)) {
 274                 dev_err(&pdev->dev, "failed to get pwm clock\n");
 275                 return PTR_ERR(pwm->pwm_clk);
 276         }
 277
 278         platform_set_drvdata(pdev, pwm);
 279
 280         pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
 281         pm_runtime_use_autosuspend(&pdev->dev);
 282         pm_runtime_enable(&pdev->dev);
 283         if (!pm_runtime_enabled(&pdev->dev)) {
 284                 ret = img_pwm_runtime_resume(&pdev->dev);
 285                 if (ret)
 286                         goto err_pm_disable;
 287         }
 288
 289         clk_rate = clk_get_rate(pwm->pwm_clk);
 290         if (!clk_rate) {
 291                 dev_err(&pdev->dev, "pwm clock has no frequency\n");
 292                 ret = -EINVAL;
 293                 goto err_suspend;
 294         }
 295
 296         /* The maximum input clock divider is 512 */
 297         val = (u64)NSEC_PER_SEC * 512 * pwm->data->max_timebase;
 298         do_div(val, clk_rate);
 299         pwm->max_period_ns = val;
 300
 301         val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS;
 302         do_div(val, clk_rate);
 303         pwm->min_period_ns = val;
 304
 305         pwm->chip.dev = &pdev->dev;
 306         pwm->chip.ops = &img_pwm_ops;
 307         pwm->chip.npwm = IMG_PWM_NPWM;
 308
 309         ret = pwmchip_add(&pwm->chip);
 310         if (ret < 0) {
 311                 dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
 312                 goto err_suspend;
 313         }
 314
 315         return 0;
 316
 317 err_suspend:
 318         if (!pm_runtime_enabled(&pdev->dev))
 319                 img_pwm_runtime_suspend(&pdev->dev);
 320 err_pm_disable:
 321         pm_runtime_disable(&pdev->dev);
 322         pm_runtime_dont_use_autosuspend(&pdev->dev);
 323         return ret;
 324 }
 325
 326 static int img_pwm_remove(struct platform_device *pdev)
 327 {
 328         struct img_pwm_chip *pwm_chip = platform_get_drvdata(pdev);
 329         u32 val;
 330         unsigned int i;
 331         int ret;
 332
 333         ret = pm_runtime_get_sync(&pdev->dev);
 334         if (ret < 0) {
 335                 pm_runtime_put(&pdev->dev);
 336                 return ret;
 337         }
 338
 339         for (i = 0; i < pwm_chip->chip.npwm; i++) {
 340                 val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 341                 val &= ~BIT(i);
 342                 img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 343         }
 344
 345         pm_runtime_put(&pdev->dev);
 346         pm_runtime_disable(&pdev->dev);
 347         if (!pm_runtime_status_suspended(&pdev->dev))
 348                 img_pwm_runtime_suspend(&pdev->dev);
 349
 350         return pwmchip_remove(&pwm_chip->chip);
 351 }
 352
 353 #ifdef CONFIG_PM_SLEEP
 354 static int img_pwm_suspend(struct device *dev)
 355 {
 356         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 357         int i, ret;
 358
 359         if (pm_runtime_status_suspended(dev)) {
 360                 ret = img_pwm_runtime_resume(dev);
 361                 if (ret)
 362                         return ret;
 363         }
 364
 365         for (i = 0; i < pwm_chip->chip.npwm; i++)
 366                 pwm_chip->suspend_ch_cfg[i] = img_pwm_readl(pwm_chip,
 367                                                             PWM_CH_CFG(i));
 368
 369         pwm_chip->suspend_ctrl_cfg = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 370
 371         img_pwm_runtime_suspend(dev);
 372
 373         return 0;
 374 }
 375
 376 static int img_pwm_resume(struct device *dev)
 377 {
 378         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 379         int ret;
 380         int i;
 381
 382         ret = img_pwm_runtime_resume(dev);
 383         if (ret)
 384                 return ret;
 385
 386         for (i = 0; i < pwm_chip->chip.npwm; i++)
 387                 img_pwm_writel(pwm_chip, PWM_CH_CFG(i),
 388                                pwm_chip->suspend_ch_cfg[i]);
 389
 390         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, pwm_chip->suspend_ctrl_cfg);
 391
 392         for (i = 0; i < pwm_chip->chip.npwm; i++)
 393                 if (pwm_chip->suspend_ctrl_cfg & BIT(i))
 394                         regmap_update_bits(pwm_chip->periph_regs,
 395                                            PERIP_PWM_PDM_CONTROL,
 396                                            PERIP_PWM_PDM_CONTROL_CH_MASK <<
 397                                            PERIP_PWM_PDM_CONTROL_CH_SHIFT(i),
 398                                            0);
 399
 400         if (pm_runtime_status_suspended(dev))
 401                 img_pwm_runtime_suspend(dev);
 402
 403         return 0;
 404 }
 405 #endif /* CONFIG_PM */
 406
 407 static const struct dev_pm_ops img_pwm_pm_ops = {
 408         SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend,
 409                            img_pwm_runtime_resume,
 410                            NULL)
 411         SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume)
 412 };
 413
 414 static struct platform_driver img_pwm_driver = {
 415         .driver = {
 416                 .name = "img-pwm",
 417                 .pm = &img_pwm_pm_ops,
 418                 .of_match_table = img_pwm_of_match,
 419         },
 420         .probe = img_pwm_probe,
 421         .remove = img_pwm_remove,
 422 };
 423 module_platform_driver(img_pwm_driver);
 424
 425 MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>");
 426 MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
 427 MODULE_LICENSE("GPL v2");