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_resume_and_get(chip->dev);
 132         if (ret < 0)
 133                 return ret;
 134
 135         val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 136         val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
 137         val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
 138                 PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
 139         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 140
 141         val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
 142               (timebase << PWM_CH_CFG_TMBASE_SHIFT);
 143         img_pwm_writel(pwm_chip, PWM_CH_CFG(pwm->hwpwm), val);
 144
 145         pm_runtime_mark_last_busy(chip->dev);
 146         pm_runtime_put_autosuspend(chip->dev);
 147
 148         return 0;
 149 }
 150
 151 static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 152 {
 153         u32 val;
 154         struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
 155         int ret;
 156
 157         ret = pm_runtime_resume_and_get(chip->dev);
 158         if (ret < 0)
 159                 return ret;
 160
 161         val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 162         val |= BIT(pwm->hwpwm);
 163         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 164
 165         regmap_update_bits(pwm_chip->periph_regs, PERIP_PWM_PDM_CONTROL,
 166                            PERIP_PWM_PDM_CONTROL_CH_MASK <<
 167                            PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm), 0);
 168
 169         return 0;
 170 }
 171
 172 static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 173 {
 174         u32 val;
 175         struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
 176
 177         val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 178         val &= ~BIT(pwm->hwpwm);
 179         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
 180
 181         pm_runtime_mark_last_busy(chip->dev);
 182         pm_runtime_put_autosuspend(chip->dev);
 183 }
 184
 185 static int img_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 186                          const struct pwm_state *state)
 187 {
 188         int err;
 189
 190         if (state->polarity != PWM_POLARITY_NORMAL)
 191                 return -EINVAL;
 192
 193         if (!state->enabled) {
 194                 if (pwm->state.enabled)
 195                         img_pwm_disable(chip, pwm);
 196
 197                 return 0;
 198         }
 199
 200         err = img_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
 201         if (err)
 202                 return err;
 203
 204         if (!pwm->state.enabled)
 205                 err = img_pwm_enable(chip, pwm);
 206
 207         return err;
 208 }
 209
 210 static const struct pwm_ops img_pwm_ops = {
 211         .apply = img_pwm_apply,
 212         .owner = THIS_MODULE,
 213 };
 214
 215 static const struct img_pwm_soc_data pistachio_pwm = {
 216         .max_timebase = 255,
 217 };
 218
 219 static const struct of_device_id img_pwm_of_match[] = {
 220         {
 221                 .compatible = "img,pistachio-pwm",
 222                 .data = &pistachio_pwm,
 223         },
 224         { }
 225 };
 226 MODULE_DEVICE_TABLE(of, img_pwm_of_match);
 227
 228 static int img_pwm_runtime_suspend(struct device *dev)
 229 {
 230         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 231
 232         clk_disable_unprepare(pwm_chip->pwm_clk);
 233         clk_disable_unprepare(pwm_chip->sys_clk);
 234
 235         return 0;
 236 }
 237
 238 static int img_pwm_runtime_resume(struct device *dev)
 239 {
 240         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 241         int ret;
 242
 243         ret = clk_prepare_enable(pwm_chip->sys_clk);
 244         if (ret < 0) {
 245                 dev_err(dev, "could not prepare or enable sys clock\n");
 246                 return ret;
 247         }
 248
 249         ret = clk_prepare_enable(pwm_chip->pwm_clk);
 250         if (ret < 0) {
 251                 dev_err(dev, "could not prepare or enable pwm clock\n");
 252                 clk_disable_unprepare(pwm_chip->sys_clk);
 253                 return ret;
 254         }
 255
 256         return 0;
 257 }
 258
 259 static int img_pwm_probe(struct platform_device *pdev)
 260 {
 261         int ret;
 262         u64 val;
 263         unsigned long clk_rate;
 264         struct img_pwm_chip *pwm;
 265         const struct of_device_id *of_dev_id;
 266
 267         pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
 268         if (!pwm)
 269                 return -ENOMEM;
 270
 271         pwm->dev = &pdev->dev;
 272
 273         pwm->base = devm_platform_ioremap_resource(pdev, 0);
 274         if (IS_ERR(pwm->base))
 275                 return PTR_ERR(pwm->base);
 276
 277         of_dev_id = of_match_device(img_pwm_of_match, &pdev->dev);
 278         if (!of_dev_id)
 279                 return -ENODEV;
 280         pwm->data = of_dev_id->data;
 281
 282         pwm->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
 283                                                            "img,cr-periph");
 284         if (IS_ERR(pwm->periph_regs))
 285                 return PTR_ERR(pwm->periph_regs);
 286
 287         pwm->sys_clk = devm_clk_get(&pdev->dev, "sys");
 288         if (IS_ERR(pwm->sys_clk)) {
 289                 dev_err(&pdev->dev, "failed to get system clock\n");
 290                 return PTR_ERR(pwm->sys_clk);
 291         }
 292
 293         pwm->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
 294         if (IS_ERR(pwm->pwm_clk)) {
 295                 dev_err(&pdev->dev, "failed to get pwm clock\n");
 296                 return PTR_ERR(pwm->pwm_clk);
 297         }
 298
 299         platform_set_drvdata(pdev, pwm);
 300
 301         pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
 302         pm_runtime_use_autosuspend(&pdev->dev);
 303         pm_runtime_enable(&pdev->dev);
 304         if (!pm_runtime_enabled(&pdev->dev)) {
 305                 ret = img_pwm_runtime_resume(&pdev->dev);
 306                 if (ret)
 307                         goto err_pm_disable;
 308         }
 309
 310         clk_rate = clk_get_rate(pwm->pwm_clk);
 311         if (!clk_rate) {
 312                 dev_err(&pdev->dev, "pwm clock has no frequency\n");
 313                 ret = -EINVAL;
 314                 goto err_suspend;
 315         }
 316
 317         /* The maximum input clock divider is 512 */
 318         val = (u64)NSEC_PER_SEC * 512 * pwm->data->max_timebase;
 319         do_div(val, clk_rate);
 320         pwm->max_period_ns = val;
 321
 322         val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS;
 323         do_div(val, clk_rate);
 324         pwm->min_period_ns = val;
 325
 326         pwm->chip.dev = &pdev->dev;
 327         pwm->chip.ops = &img_pwm_ops;
 328         pwm->chip.npwm = IMG_PWM_NPWM;
 329
 330         ret = pwmchip_add(&pwm->chip);
 331         if (ret < 0) {
 332                 dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
 333                 goto err_suspend;
 334         }
 335
 336         return 0;
 337
 338 err_suspend:
 339         if (!pm_runtime_enabled(&pdev->dev))
 340                 img_pwm_runtime_suspend(&pdev->dev);
 341 err_pm_disable:
 342         pm_runtime_disable(&pdev->dev);
 343         pm_runtime_dont_use_autosuspend(&pdev->dev);
 344         return ret;
 345 }
 346
 347 static int img_pwm_remove(struct platform_device *pdev)
 348 {
 349         struct img_pwm_chip *pwm_chip = platform_get_drvdata(pdev);
 350
 351         pm_runtime_disable(&pdev->dev);
 352         if (!pm_runtime_status_suspended(&pdev->dev))
 353                 img_pwm_runtime_suspend(&pdev->dev);
 354
 355         pwmchip_remove(&pwm_chip->chip);
 356
 357         return 0;
 358 }
 359
 360 #ifdef CONFIG_PM_SLEEP
 361 static int img_pwm_suspend(struct device *dev)
 362 {
 363         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 364         int i, ret;
 365
 366         if (pm_runtime_status_suspended(dev)) {
 367                 ret = img_pwm_runtime_resume(dev);
 368                 if (ret)
 369                         return ret;
 370         }
 371
 372         for (i = 0; i < pwm_chip->chip.npwm; i++)
 373                 pwm_chip->suspend_ch_cfg[i] = img_pwm_readl(pwm_chip,
 374                                                             PWM_CH_CFG(i));
 375
 376         pwm_chip->suspend_ctrl_cfg = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 377
 378         img_pwm_runtime_suspend(dev);
 379
 380         return 0;
 381 }
 382
 383 static int img_pwm_resume(struct device *dev)
 384 {
 385         struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev);
 386         int ret;
 387         int i;
 388
 389         ret = img_pwm_runtime_resume(dev);
 390         if (ret)
 391                 return ret;
 392
 393         for (i = 0; i < pwm_chip->chip.npwm; i++)
 394                 img_pwm_writel(pwm_chip, PWM_CH_CFG(i),
 395                                pwm_chip->suspend_ch_cfg[i]);
 396
 397         img_pwm_writel(pwm_chip, PWM_CTRL_CFG, pwm_chip->suspend_ctrl_cfg);
 398
 399         for (i = 0; i < pwm_chip->chip.npwm; i++)
 400                 if (pwm_chip->suspend_ctrl_cfg & BIT(i))
 401                         regmap_update_bits(pwm_chip->periph_regs,
 402                                            PERIP_PWM_PDM_CONTROL,
 403                                            PERIP_PWM_PDM_CONTROL_CH_MASK <<
 404                                            PERIP_PWM_PDM_CONTROL_CH_SHIFT(i),
 405                                            0);
 406
 407         if (pm_runtime_status_suspended(dev))
 408                 img_pwm_runtime_suspend(dev);
 409
 410         return 0;
 411 }
 412 #endif /* CONFIG_PM */
 413
 414 static const struct dev_pm_ops img_pwm_pm_ops = {
 415         SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend,
 416                            img_pwm_runtime_resume,
 417                            NULL)
 418         SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume)
 419 };
 420
 421 static struct platform_driver img_pwm_driver = {
 422         .driver = {
 423                 .name = "img-pwm",
 424                 .pm = &img_pwm_pm_ops,
 425                 .of_match_table = img_pwm_of_match,
 426         },
 427         .probe = img_pwm_probe,
 428         .remove = img_pwm_remove,
 429 };
 430 module_platform_driver(img_pwm_driver);
 431
 432 MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>");
 433 MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
 434 MODULE_LICENSE("GPL v2");