drivers/pwm/pwm-twl-led.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for TWL4030/6030 Pulse Width Modulator used as LED driver
   4  *
   5  * Copyright (C) 2012 Texas Instruments
   6  * Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
   7  *
   8  * This driver is a complete rewrite of the former pwm-twl6030.c authorded by:
   9  * Hemanth V <hemanthv@ti.com>
  10  *
  11  * Reference manual for the twl6030 is available at:
  12  * https://www.ti.com/lit/ds/symlink/twl6030.pdf
  13  *
  14  * Limitations:
  15  * - The twl6030 hardware only supports two period lengths (128 clock ticks and
  16  *   64 clock ticks), the driver only uses 128 ticks
  17  * - The hardware doesn't support ON = 0, so the active part of a period doesn't
  18  *   start at its beginning.
  19  * - The hardware could support inverted polarity (with a similar limitation as
  20  *   for normal: the last clock tick is always inactive).
  21  * - The hardware emits a constant low output when disabled.
  22  * - A request for .duty_cycle = 0 results in an output wave with one active
  23  *   clock tick per period. This should better use the disabled state.
  24  * - The driver only implements setting the relative duty cycle.
  25  * - The driver doesn't implement .get_state().
  26  */
  27
  28 #include <linux/module.h>
  29 #include <linux/of.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/pwm.h>
  32 #include <linux/mfd/twl.h>
  33 #include <linux/slab.h>
  34
  35 /*
  36  * This driver handles the PWM driven LED terminals of TWL4030 and TWL6030.
  37  * To generate the signal on TWL4030:
  38  *  - LEDA uses PWMA
  39  *  - LEDB uses PWMB
  40  * TWL6030 has one LED pin with dedicated LEDPWM
  41  */
  42
  43 #define TWL4030_LED_MAX         0x7f
  44 #define TWL6030_LED_MAX         0xff
  45
  46 /* Registers, bits and macro for TWL4030 */
  47 #define TWL4030_LEDEN_REG       0x00
  48 #define TWL4030_PWMA_REG        0x01
  49
  50 #define TWL4030_LEDXON          (1 << 0)
  51 #define TWL4030_LEDXPWM         (1 << 4)
  52 #define TWL4030_LED_PINS        (TWL4030_LEDXON | TWL4030_LEDXPWM)
  53 #define TWL4030_LED_TOGGLE(led, x)      ((x) << (led))
  54
  55 /* Register, bits and macro for TWL6030 */
  56 #define TWL6030_LED_PWM_CTRL1   0xf4
  57 #define TWL6030_LED_PWM_CTRL2   0xf5
  58
  59 #define TWL6040_LED_MODE_HW     0x00
  60 #define TWL6040_LED_MODE_ON     0x01
  61 #define TWL6040_LED_MODE_OFF    0x02
  62 #define TWL6040_LED_MODE_MASK   0x03
  63
  64 struct twl_pwmled_chip {
  65         struct pwm_chip chip;
  66         struct mutex mutex;
  67 };
  68
  69 static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
  70 {
  71         return container_of(chip, struct twl_pwmled_chip, chip);
  72 }
  73
  74 static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
  75                               int duty_ns, int period_ns)
  76 {
  77         int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
  78         u8 pwm_config[2] = { 1, 0 };
  79         int base, ret;
  80
  81         /*
  82          * To configure the duty period:
  83          * On-cycle is set to 1 (the minimum allowed value)
  84          * The off time of 0 is not configurable, so the mapping is:
  85          * 0 -> off cycle = 2,
  86          * 1 -> off cycle = 2,
  87          * 2 -> off cycle = 3,
  88          * 126 - > off cycle 127,
  89          * 127 - > off cycle 1
  90          * When on cycle == off cycle the PWM will be always on
  91          */
  92         if (duty_cycle == 1)
  93                 duty_cycle = 2;
  94         else if (duty_cycle > TWL4030_LED_MAX)
  95                 duty_cycle = 1;
  96
  97         base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
  98
  99         pwm_config[1] = duty_cycle;
 100
 101         ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
 102         if (ret < 0)
 103                 dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
 104
 105         return ret;
 106 }
 107
 108 static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 109 {
 110         struct twl_pwmled_chip *twl = to_twl(chip);
 111         int ret;
 112         u8 val;
 113
 114         mutex_lock(&twl->mutex);
 115         ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
 116         if (ret < 0) {
 117                 dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
 118                 goto out;
 119         }
 120
 121         val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
 122
 123         ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
 124         if (ret < 0)
 125                 dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
 126
 127 out:
 128         mutex_unlock(&twl->mutex);
 129         return ret;
 130 }
 131
 132 static void twl4030_pwmled_disable(struct pwm_chip *chip,
 133                                    struct pwm_device *pwm)
 134 {
 135         struct twl_pwmled_chip *twl = to_twl(chip);
 136         int ret;
 137         u8 val;
 138
 139         mutex_lock(&twl->mutex);
 140         ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
 141         if (ret < 0) {
 142                 dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
 143                 goto out;
 144         }
 145
 146         val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
 147
 148         ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
 149         if (ret < 0)
 150                 dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
 151
 152 out:
 153         mutex_unlock(&twl->mutex);
 154 }
 155
 156 static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 157                                 const struct pwm_state *state)
 158 {
 159         int ret;
 160
 161         if (state->polarity != PWM_POLARITY_NORMAL)
 162                 return -EINVAL;
 163
 164         if (!state->enabled) {
 165                 if (pwm->state.enabled)
 166                         twl4030_pwmled_disable(chip, pwm);
 167
 168                 return 0;
 169         }
 170
 171         /*
 172          * We cannot skip calling ->config even if state->period ==
 173          * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
 174          * because we might have exited early in the last call to
 175          * pwm_apply_state because of !state->enabled and so the two values in
 176          * pwm->state might not be configured in hardware.
 177          */
 178         ret = twl4030_pwmled_config(pwm->chip, pwm,
 179                                     state->duty_cycle, state->period);
 180         if (ret)
 181                 return ret;
 182
 183         if (!pwm->state.enabled)
 184                 ret = twl4030_pwmled_enable(chip, pwm);
 185
 186         return ret;
 187 }
 188
 189
 190 static const struct pwm_ops twl4030_pwmled_ops = {
 191         .apply = twl4030_pwmled_apply,
 192         .owner = THIS_MODULE,
 193 };
 194
 195 static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
 196                               int duty_ns, int period_ns)
 197 {
 198         int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
 199         u8 on_time;
 200         int ret;
 201
 202         on_time = duty_cycle & 0xff;
 203
 204         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
 205                                TWL6030_LED_PWM_CTRL1);
 206         if (ret < 0)
 207                 dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
 208
 209         return ret;
 210 }
 211
 212 static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 213 {
 214         struct twl_pwmled_chip *twl = to_twl(chip);
 215         int ret;
 216         u8 val;
 217
 218         mutex_lock(&twl->mutex);
 219         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 220         if (ret < 0) {
 221                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 222                         pwm->label);
 223                 goto out;
 224         }
 225
 226         val &= ~TWL6040_LED_MODE_MASK;
 227         val |= TWL6040_LED_MODE_ON;
 228
 229         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 230         if (ret < 0)
 231                 dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
 232
 233 out:
 234         mutex_unlock(&twl->mutex);
 235         return ret;
 236 }
 237
 238 static void twl6030_pwmled_disable(struct pwm_chip *chip,
 239                                    struct pwm_device *pwm)
 240 {
 241         struct twl_pwmled_chip *twl = to_twl(chip);
 242         int ret;
 243         u8 val;
 244
 245         mutex_lock(&twl->mutex);
 246         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 247         if (ret < 0) {
 248                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 249                         pwm->label);
 250                 goto out;
 251         }
 252
 253         val &= ~TWL6040_LED_MODE_MASK;
 254         val |= TWL6040_LED_MODE_OFF;
 255
 256         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 257         if (ret < 0)
 258                 dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
 259
 260 out:
 261         mutex_unlock(&twl->mutex);
 262 }
 263
 264 static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 265                                 const struct pwm_state *state)
 266 {
 267         int err;
 268
 269         if (state->polarity != pwm->state.polarity)
 270                 return -EINVAL;
 271
 272         if (!state->enabled) {
 273                 if (pwm->state.enabled)
 274                         twl6030_pwmled_disable(chip, pwm);
 275
 276                 return 0;
 277         }
 278
 279         err = twl6030_pwmled_config(pwm->chip, pwm,
 280                                     state->duty_cycle, state->period);
 281         if (err)
 282                 return err;
 283
 284         if (!pwm->state.enabled)
 285                 err = twl6030_pwmled_enable(chip, pwm);
 286
 287         return err;
 288 }
 289
 290 static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
 291 {
 292         struct twl_pwmled_chip *twl = to_twl(chip);
 293         int ret;
 294         u8 val;
 295
 296         mutex_lock(&twl->mutex);
 297         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 298         if (ret < 0) {
 299                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 300                         pwm->label);
 301                 goto out;
 302         }
 303
 304         val &= ~TWL6040_LED_MODE_MASK;
 305         val |= TWL6040_LED_MODE_OFF;
 306
 307         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 308         if (ret < 0)
 309                 dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
 310
 311 out:
 312         mutex_unlock(&twl->mutex);
 313         return ret;
 314 }
 315
 316 static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
 317 {
 318         struct twl_pwmled_chip *twl = to_twl(chip);
 319         int ret;
 320         u8 val;
 321
 322         mutex_lock(&twl->mutex);
 323         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 324         if (ret < 0) {
 325                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 326                         pwm->label);
 327                 goto out;
 328         }
 329
 330         val &= ~TWL6040_LED_MODE_MASK;
 331         val |= TWL6040_LED_MODE_HW;
 332
 333         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 334         if (ret < 0)
 335                 dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
 336
 337 out:
 338         mutex_unlock(&twl->mutex);
 339 }
 340
 341 static const struct pwm_ops twl6030_pwmled_ops = {
 342         .apply = twl6030_pwmled_apply,
 343         .request = twl6030_pwmled_request,
 344         .free = twl6030_pwmled_free,
 345         .owner = THIS_MODULE,
 346 };
 347
 348 static int twl_pwmled_probe(struct platform_device *pdev)
 349 {
 350         struct twl_pwmled_chip *twl;
 351
 352         twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
 353         if (!twl)
 354                 return -ENOMEM;
 355
 356         if (twl_class_is_4030()) {
 357                 twl->chip.ops = &twl4030_pwmled_ops;
 358                 twl->chip.npwm = 2;
 359         } else {
 360                 twl->chip.ops = &twl6030_pwmled_ops;
 361                 twl->chip.npwm = 1;
 362         }
 363
 364         twl->chip.dev = &pdev->dev;
 365
 366         mutex_init(&twl->mutex);
 367
 368         return devm_pwmchip_add(&pdev->dev, &twl->chip);
 369 }
 370
 371 #ifdef CONFIG_OF
 372 static const struct of_device_id twl_pwmled_of_match[] = {
 373         { .compatible = "ti,twl4030-pwmled" },
 374         { .compatible = "ti,twl6030-pwmled" },
 375         { },
 376 };
 377 MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
 378 #endif
 379
 380 static struct platform_driver twl_pwmled_driver = {
 381         .driver = {
 382                 .name = "twl-pwmled",
 383                 .of_match_table = of_match_ptr(twl_pwmled_of_match),
 384         },
 385         .probe = twl_pwmled_probe,
 386 };
 387 module_platform_driver(twl_pwmled_driver);
 388
 389 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 390 MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
 391 MODULE_ALIAS("platform:twl-pwmled");
 392 MODULE_LICENSE("GPL");