drivers/pwm/pwm-rockchip.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * PWM driver for Rockchip SoCs
   4  *
   5  * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
   6  * Copyright (C) 2014 ROCKCHIP, Inc.
   7  */
   8
   9 #include <linux/clk.h>
  10 #include <linux/io.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/of_device.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/pwm.h>
  16 #include <linux/time.h>
  17
  18 #define PWM_CTRL_TIMER_EN       (1 << 0)
  19 #define PWM_CTRL_OUTPUT_EN      (1 << 3)
  20
  21 #define PWM_ENABLE              (1 << 0)
  22 #define PWM_CONTINUOUS          (1 << 1)
  23 #define PWM_DUTY_POSITIVE       (1 << 3)
  24 #define PWM_DUTY_NEGATIVE       (0 << 3)
  25 #define PWM_INACTIVE_NEGATIVE   (0 << 4)
  26 #define PWM_INACTIVE_POSITIVE   (1 << 4)
  27 #define PWM_POLARITY_MASK       (PWM_DUTY_POSITIVE | PWM_INACTIVE_POSITIVE)
  28 #define PWM_OUTPUT_LEFT         (0 << 5)
  29 #define PWM_LOCK_EN             (1 << 6)
  30 #define PWM_LP_DISABLE          (0 << 8)
  31
  32 struct rockchip_pwm_chip {
  33         struct pwm_chip chip;
  34         struct clk *clk;
  35         struct clk *pclk;
  36         const struct rockchip_pwm_data *data;
  37         void __iomem *base;
  38 };
  39
  40 struct rockchip_pwm_regs {
  41         unsigned long duty;
  42         unsigned long period;
  43         unsigned long cntr;
  44         unsigned long ctrl;
  45 };
  46
  47 struct rockchip_pwm_data {
  48         struct rockchip_pwm_regs regs;
  49         unsigned int prescaler;
  50         bool supports_polarity;
  51         bool supports_lock;
  52         u32 enable_conf;
  53 };
  54
  55 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
  56 {
  57         return container_of(c, struct rockchip_pwm_chip, chip);
  58 }
  59
  60 static void rockchip_pwm_get_state(struct pwm_chip *chip,
  61                                    struct pwm_device *pwm,
  62                                    struct pwm_state *state)
  63 {
  64         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
  65         u32 enable_conf = pc->data->enable_conf;
  66         unsigned long clk_rate;
  67         u64 tmp;
  68         u32 val;
  69         int ret;
  70
  71         ret = clk_enable(pc->pclk);
  72         if (ret)
  73                 return;
  74
  75         clk_rate = clk_get_rate(pc->clk);
  76
  77         tmp = readl_relaxed(pc->base + pc->data->regs.period);
  78         tmp *= pc->data->prescaler * NSEC_PER_SEC;
  79         state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
  80
  81         tmp = readl_relaxed(pc->base + pc->data->regs.duty);
  82         tmp *= pc->data->prescaler * NSEC_PER_SEC;
  83         state->duty_cycle =  DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
  84
  85         val = readl_relaxed(pc->base + pc->data->regs.ctrl);
  86         state->enabled = (val & enable_conf) == enable_conf;
  87
  88         if (pc->data->supports_polarity && !(val & PWM_DUTY_POSITIVE))
  89                 state->polarity = PWM_POLARITY_INVERSED;
  90         else
  91                 state->polarity = PWM_POLARITY_NORMAL;
  92
  93         clk_disable(pc->pclk);
  94 }
  95
  96 static void rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  97                                const struct pwm_state *state)
  98 {
  99         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 100         unsigned long period, duty;
 101         u64 clk_rate, div;
 102         u32 ctrl;
 103
 104         clk_rate = clk_get_rate(pc->clk);
 105
 106         /*
 107          * Since period and duty cycle registers have a width of 32
 108          * bits, every possible input period can be obtained using the
 109          * default prescaler value for all practical clock rate values.
 110          */
 111         div = clk_rate * state->period;
 112         period = DIV_ROUND_CLOSEST_ULL(div,
 113                                        pc->data->prescaler * NSEC_PER_SEC);
 114
 115         div = clk_rate * state->duty_cycle;
 116         duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
 117
 118         /*
 119          * Lock the period and duty of previous configuration, then
 120          * change the duty and period, that would not be effective.
 121          */
 122         ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
 123         if (pc->data->supports_lock) {
 124                 ctrl |= PWM_LOCK_EN;
 125                 writel_relaxed(ctrl, pc->base + pc->data->regs.ctrl);
 126         }
 127
 128         writel(period, pc->base + pc->data->regs.period);
 129         writel(duty, pc->base + pc->data->regs.duty);
 130
 131         if (pc->data->supports_polarity) {
 132                 ctrl &= ~PWM_POLARITY_MASK;
 133                 if (state->polarity == PWM_POLARITY_INVERSED)
 134                         ctrl |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
 135                 else
 136                         ctrl |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
 137         }
 138
 139         /*
 140          * Unlock and set polarity at the same time,
 141          * the configuration of duty, period and polarity
 142          * would be effective together at next period.
 143          */
 144         if (pc->data->supports_lock)
 145                 ctrl &= ~PWM_LOCK_EN;
 146
 147         writel(ctrl, pc->base + pc->data->regs.ctrl);
 148 }
 149
 150 static int rockchip_pwm_enable(struct pwm_chip *chip,
 151                                struct pwm_device *pwm,
 152                                bool enable)
 153 {
 154         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 155         u32 enable_conf = pc->data->enable_conf;
 156         int ret;
 157         u32 val;
 158
 159         if (enable) {
 160                 ret = clk_enable(pc->clk);
 161                 if (ret)
 162                         return ret;
 163         }
 164
 165         val = readl_relaxed(pc->base + pc->data->regs.ctrl);
 166
 167         if (enable)
 168                 val |= enable_conf;
 169         else
 170                 val &= ~enable_conf;
 171
 172         writel_relaxed(val, pc->base + pc->data->regs.ctrl);
 173
 174         if (!enable)
 175                 clk_disable(pc->clk);
 176
 177         return 0;
 178 }
 179
 180 static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 181                               const struct pwm_state *state)
 182 {
 183         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 184         struct pwm_state curstate;
 185         bool enabled;
 186         int ret = 0;
 187
 188         ret = clk_enable(pc->pclk);
 189         if (ret)
 190                 return ret;
 191
 192         pwm_get_state(pwm, &curstate);
 193         enabled = curstate.enabled;
 194
 195         if (state->polarity != curstate.polarity && enabled &&
 196             !pc->data->supports_lock) {
 197                 ret = rockchip_pwm_enable(chip, pwm, false);
 198                 if (ret)
 199                         goto out;
 200                 enabled = false;
 201         }
 202
 203         rockchip_pwm_config(chip, pwm, state);
 204         if (state->enabled != enabled) {
 205                 ret = rockchip_pwm_enable(chip, pwm, state->enabled);
 206                 if (ret)
 207                         goto out;
 208         }
 209
 210 out:
 211         clk_disable(pc->pclk);
 212
 213         return ret;
 214 }
 215
 216 static const struct pwm_ops rockchip_pwm_ops = {
 217         .get_state = rockchip_pwm_get_state,
 218         .apply = rockchip_pwm_apply,
 219         .owner = THIS_MODULE,
 220 };
 221
 222 static const struct rockchip_pwm_data pwm_data_v1 = {
 223         .regs = {
 224                 .duty = 0x04,
 225                 .period = 0x08,
 226                 .cntr = 0x00,
 227                 .ctrl = 0x0c,
 228         },
 229         .prescaler = 2,
 230         .supports_polarity = false,
 231         .supports_lock = false,
 232         .enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN,
 233 };
 234
 235 static const struct rockchip_pwm_data pwm_data_v2 = {
 236         .regs = {
 237                 .duty = 0x08,
 238                 .period = 0x04,
 239                 .cntr = 0x00,
 240                 .ctrl = 0x0c,
 241         },
 242         .prescaler = 1,
 243         .supports_polarity = true,
 244         .supports_lock = false,
 245         .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 246                        PWM_CONTINUOUS,
 247 };
 248
 249 static const struct rockchip_pwm_data pwm_data_vop = {
 250         .regs = {
 251                 .duty = 0x08,
 252                 .period = 0x04,
 253                 .cntr = 0x0c,
 254                 .ctrl = 0x00,
 255         },
 256         .prescaler = 1,
 257         .supports_polarity = true,
 258         .supports_lock = false,
 259         .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 260                        PWM_CONTINUOUS,
 261 };
 262
 263 static const struct rockchip_pwm_data pwm_data_v3 = {
 264         .regs = {
 265                 .duty = 0x08,
 266                 .period = 0x04,
 267                 .cntr = 0x00,
 268                 .ctrl = 0x0c,
 269         },
 270         .prescaler = 1,
 271         .supports_polarity = true,
 272         .supports_lock = true,
 273         .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 274                        PWM_CONTINUOUS,
 275 };
 276
 277 static const struct of_device_id rockchip_pwm_dt_ids[] = {
 278         { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
 279         { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
 280         { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
 281         { .compatible = "rockchip,rk3328-pwm", .data = &pwm_data_v3},
 282         { /* sentinel */ }
 283 };
 284 MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
 285
 286 static int rockchip_pwm_probe(struct platform_device *pdev)
 287 {
 288         const struct of_device_id *id;
 289         struct rockchip_pwm_chip *pc;
 290         struct resource *r;
 291         u32 enable_conf, ctrl;
 292         int ret, count;
 293
 294         id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
 295         if (!id)
 296                 return -EINVAL;
 297
 298         pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 299         if (!pc)
 300                 return -ENOMEM;
 301
 302         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 303         pc->base = devm_ioremap_resource(&pdev->dev, r);
 304         if (IS_ERR(pc->base))
 305                 return PTR_ERR(pc->base);
 306
 307         pc->clk = devm_clk_get(&pdev->dev, "pwm");
 308         if (IS_ERR(pc->clk)) {
 309                 pc->clk = devm_clk_get(&pdev->dev, NULL);
 310                 if (IS_ERR(pc->clk))
 311                         return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk),
 312                                              "Can't get bus clk\n");
 313         }
 314
 315         count = of_count_phandle_with_args(pdev->dev.of_node,
 316                                            "clocks", "#clock-cells");
 317         if (count == 2)
 318                 pc->pclk = devm_clk_get(&pdev->dev, "pclk");
 319         else
 320                 pc->pclk = pc->clk;
 321
 322         if (IS_ERR(pc->pclk)) {
 323                 ret = PTR_ERR(pc->pclk);
 324                 if (ret != -EPROBE_DEFER)
 325                         dev_err(&pdev->dev, "Can't get APB clk: %d\n", ret);
 326                 return ret;
 327         }
 328
 329         ret = clk_prepare_enable(pc->clk);
 330         if (ret) {
 331                 dev_err(&pdev->dev, "Can't prepare enable bus clk: %d\n", ret);
 332                 return ret;
 333         }
 334
 335         ret = clk_prepare(pc->pclk);
 336         if (ret) {
 337                 dev_err(&pdev->dev, "Can't prepare APB clk: %d\n", ret);
 338                 goto err_clk;
 339         }
 340
 341         platform_set_drvdata(pdev, pc);
 342
 343         pc->data = id->data;
 344         pc->chip.dev = &pdev->dev;
 345         pc->chip.ops = &rockchip_pwm_ops;
 346         pc->chip.base = -1;
 347         pc->chip.npwm = 1;
 348
 349         if (pc->data->supports_polarity) {
 350                 pc->chip.of_xlate = of_pwm_xlate_with_flags;
 351                 pc->chip.of_pwm_n_cells = 3;
 352         }
 353
 354         ret = pwmchip_add(&pc->chip);
 355         if (ret < 0) {
 356                 clk_unprepare(pc->clk);
 357                 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 358                 goto err_pclk;
 359         }
 360
 361         /* Keep the PWM clk enabled if the PWM appears to be up and running. */
 362         enable_conf = pc->data->enable_conf;
 363         ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
 364         if ((ctrl & enable_conf) != enable_conf)
 365                 clk_disable(pc->clk);
 366
 367         return 0;
 368
 369 err_pclk:
 370         clk_unprepare(pc->pclk);
 371 err_clk:
 372         clk_disable_unprepare(pc->clk);
 373
 374         return ret;
 375 }
 376
 377 static int rockchip_pwm_remove(struct platform_device *pdev)
 378 {
 379         struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
 380
 381         /*
 382          * Disable the PWM clk before unpreparing it if the PWM device is still
 383          * running. This should only happen when the last PWM user left it
 384          * enabled, or when nobody requested a PWM that was previously enabled
 385          * by the bootloader.
 386          *
 387          * FIXME: Maybe the core should disable all PWM devices in
 388          * pwmchip_remove(). In this case we'd only have to call
 389          * clk_unprepare() after pwmchip_remove().
 390          *
 391          */
 392         if (pwm_is_enabled(pc->chip.pwms))
 393                 clk_disable(pc->clk);
 394
 395         clk_unprepare(pc->pclk);
 396         clk_unprepare(pc->clk);
 397
 398         return pwmchip_remove(&pc->chip);
 399 }
 400
 401 static struct platform_driver rockchip_pwm_driver = {
 402         .driver = {
 403                 .name = "rockchip-pwm",
 404                 .of_match_table = rockchip_pwm_dt_ids,
 405         },
 406         .probe = rockchip_pwm_probe,
 407         .remove = rockchip_pwm_remove,
 408 };
 409 module_platform_driver(rockchip_pwm_driver);
 410
 411 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
 412 MODULE_DESCRIPTION("Rockchip SoC PWM driver");
 413 MODULE_LICENSE("GPL v2");