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 };
 193
 194 static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
 195                               int duty_ns, int period_ns)
 196 {
 197         int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
 198         u8 on_time;
 199         int ret;
 200
 201         on_time = duty_cycle & 0xff;
 202
 203         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
 204                                TWL6030_LED_PWM_CTRL1);
 205         if (ret < 0)
 206                 dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
 207
 208         return ret;
 209 }
 210
 211 static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 212 {
 213         struct twl_pwmled_chip *twl = to_twl(chip);
 214         int ret;
 215         u8 val;
 216
 217         mutex_lock(&twl->mutex);
 218         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 219         if (ret < 0) {
 220                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 221                         pwm->label);
 222                 goto out;
 223         }
 224
 225         val &= ~TWL6040_LED_MODE_MASK;
 226         val |= TWL6040_LED_MODE_ON;
 227
 228         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 229         if (ret < 0)
 230                 dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
 231
 232 out:
 233         mutex_unlock(&twl->mutex);
 234         return ret;
 235 }
 236
 237 static void twl6030_pwmled_disable(struct pwm_chip *chip,
 238                                    struct pwm_device *pwm)
 239 {
 240         struct twl_pwmled_chip *twl = to_twl(chip);
 241         int ret;
 242         u8 val;
 243
 244         mutex_lock(&twl->mutex);
 245         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 246         if (ret < 0) {
 247                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 248                         pwm->label);
 249                 goto out;
 250         }
 251
 252         val &= ~TWL6040_LED_MODE_MASK;
 253         val |= TWL6040_LED_MODE_OFF;
 254
 255         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 256         if (ret < 0)
 257                 dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
 258
 259 out:
 260         mutex_unlock(&twl->mutex);
 261 }
 262
 263 static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 264                                 const struct pwm_state *state)
 265 {
 266         int err;
 267
 268         if (state->polarity != pwm->state.polarity)
 269                 return -EINVAL;
 270
 271         if (!state->enabled) {
 272                 if (pwm->state.enabled)
 273                         twl6030_pwmled_disable(chip, pwm);
 274
 275                 return 0;
 276         }
 277
 278         err = twl6030_pwmled_config(pwm->chip, pwm,
 279                                     state->duty_cycle, state->period);
 280         if (err)
 281                 return err;
 282
 283         if (!pwm->state.enabled)
 284                 err = twl6030_pwmled_enable(chip, pwm);
 285
 286         return err;
 287 }
 288
 289 static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
 290 {
 291         struct twl_pwmled_chip *twl = to_twl(chip);
 292         int ret;
 293         u8 val;
 294
 295         mutex_lock(&twl->mutex);
 296         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 297         if (ret < 0) {
 298                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 299                         pwm->label);
 300                 goto out;
 301         }
 302
 303         val &= ~TWL6040_LED_MODE_MASK;
 304         val |= TWL6040_LED_MODE_OFF;
 305
 306         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 307         if (ret < 0)
 308                 dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
 309
 310 out:
 311         mutex_unlock(&twl->mutex);
 312         return ret;
 313 }
 314
 315 static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
 316 {
 317         struct twl_pwmled_chip *twl = to_twl(chip);
 318         int ret;
 319         u8 val;
 320
 321         mutex_lock(&twl->mutex);
 322         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 323         if (ret < 0) {
 324                 dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 325                         pwm->label);
 326                 goto out;
 327         }
 328
 329         val &= ~TWL6040_LED_MODE_MASK;
 330         val |= TWL6040_LED_MODE_HW;
 331
 332         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 333         if (ret < 0)
 334                 dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
 335
 336 out:
 337         mutex_unlock(&twl->mutex);
 338 }
 339
 340 static const struct pwm_ops twl6030_pwmled_ops = {
 341         .apply = twl6030_pwmled_apply,
 342         .request = twl6030_pwmled_request,
 343         .free = twl6030_pwmled_free,
 344 };
 345
 346 static int twl_pwmled_probe(struct platform_device *pdev)
 347 {
 348         struct twl_pwmled_chip *twl;
 349
 350         twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
 351         if (!twl)
 352                 return -ENOMEM;
 353
 354         if (twl_class_is_4030()) {
 355                 twl->chip.ops = &twl4030_pwmled_ops;
 356                 twl->chip.npwm = 2;
 357         } else {
 358                 twl->chip.ops = &twl6030_pwmled_ops;
 359                 twl->chip.npwm = 1;
 360         }
 361
 362         twl->chip.dev = &pdev->dev;
 363
 364         mutex_init(&twl->mutex);
 365
 366         return devm_pwmchip_add(&pdev->dev, &twl->chip);
 367 }
 368
 369 #ifdef CONFIG_OF
 370 static const struct of_device_id twl_pwmled_of_match[] = {
 371         { .compatible = "ti,twl4030-pwmled" },
 372         { .compatible = "ti,twl6030-pwmled" },
 373         { },
 374 };
 375 MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
 376 #endif
 377
 378 static struct platform_driver twl_pwmled_driver = {
 379         .driver = {
 380                 .name = "twl-pwmled",
 381                 .of_match_table = of_match_ptr(twl_pwmled_of_match),
 382         },
 383         .probe = twl_pwmled_probe,
 384 };
 385 module_platform_driver(twl_pwmled_driver);
 386
 387 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 388 MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
 389 MODULE_ALIAS("platform:twl-pwmled");
 390 MODULE_LICENSE("GPL");