drivers/pwm/pwm-img.c

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