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 mutex mutex;
  66 };
  67
  68 static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
  69 {
  70         return pwmchip_get_drvdata(chip);
  71 }
  72
  73 static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
  74                               int duty_ns, int period_ns)
  75 {
  76         int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
  77         u8 pwm_config[2] = { 1, 0 };
  78         int base, ret;
  79
  80         /*
  81          * To configure the duty period:
  82          * On-cycle is set to 1 (the minimum allowed value)
  83          * The off time of 0 is not configurable, so the mapping is:
  84          * 0 -> off cycle = 2,
  85          * 1 -> off cycle = 2,
  86          * 2 -> off cycle = 3,
  87          * 126 - > off cycle 127,
  88          * 127 - > off cycle 1
  89          * When on cycle == off cycle the PWM will be always on
  90          */
  91         if (duty_cycle == 1)
  92                 duty_cycle = 2;
  93         else if (duty_cycle > TWL4030_LED_MAX)
  94                 duty_cycle = 1;
  95
  96         base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
  97
  98         pwm_config[1] = duty_cycle;
  99
 100         ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
 101         if (ret < 0)
 102                 dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
 103
 104         return ret;
 105 }
 106
 107 static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 108 {
 109         struct twl_pwmled_chip *twl = to_twl(chip);
 110         int ret;
 111         u8 val;
 112
 113         mutex_lock(&twl->mutex);
 114         ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
 115         if (ret < 0) {
 116                 dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
 117                 goto out;
 118         }
 119
 120         val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
 121
 122         ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
 123         if (ret < 0)
 124                 dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
 125
 126 out:
 127         mutex_unlock(&twl->mutex);
 128         return ret;
 129 }
 130
 131 static void twl4030_pwmled_disable(struct pwm_chip *chip,
 132                                    struct pwm_device *pwm)
 133 {
 134         struct twl_pwmled_chip *twl = to_twl(chip);
 135         int ret;
 136         u8 val;
 137
 138         mutex_lock(&twl->mutex);
 139         ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
 140         if (ret < 0) {
 141                 dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
 142                 goto out;
 143         }
 144
 145         val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
 146
 147         ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
 148         if (ret < 0)
 149                 dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
 150
 151 out:
 152         mutex_unlock(&twl->mutex);
 153 }
 154
 155 static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 156                                 const struct pwm_state *state)
 157 {
 158         int ret;
 159
 160         if (state->polarity != PWM_POLARITY_NORMAL)
 161                 return -EINVAL;
 162
 163         if (!state->enabled) {
 164                 if (pwm->state.enabled)
 165                         twl4030_pwmled_disable(chip, pwm);
 166
 167                 return 0;
 168         }
 169
 170         /*
 171          * We cannot skip calling ->config even if state->period ==
 172          * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
 173          * because we might have exited early in the last call to
 174          * pwm_apply_might_sleep because of !state->enabled and so the two values in
 175          * pwm->state might not be configured in hardware.
 176          */
 177         ret = twl4030_pwmled_config(chip, pwm,
 178                                     state->duty_cycle, state->period);
 179         if (ret)
 180                 return ret;
 181
 182         if (!pwm->state.enabled)
 183                 ret = twl4030_pwmled_enable(chip, pwm);
 184
 185         return ret;
 186 }
 187
 188
 189 static const struct pwm_ops twl4030_pwmled_ops = {
 190         .apply = twl4030_pwmled_apply,
 191 };
 192
 193 static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
 194                               int duty_ns, int period_ns)
 195 {
 196         int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
 197         u8 on_time;
 198         int ret;
 199
 200         on_time = duty_cycle & 0xff;
 201
 202         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
 203                                TWL6030_LED_PWM_CTRL1);
 204         if (ret < 0)
 205                 dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
 206
 207         return ret;
 208 }
 209
 210 static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 211 {
 212         struct twl_pwmled_chip *twl = to_twl(chip);
 213         int ret;
 214         u8 val;
 215
 216         mutex_lock(&twl->mutex);
 217         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 218         if (ret < 0) {
 219                 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
 220                         pwm->label);
 221                 goto out;
 222         }
 223
 224         val &= ~TWL6040_LED_MODE_MASK;
 225         val |= TWL6040_LED_MODE_ON;
 226
 227         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 228         if (ret < 0)
 229                 dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
 230
 231 out:
 232         mutex_unlock(&twl->mutex);
 233         return ret;
 234 }
 235
 236 static void twl6030_pwmled_disable(struct pwm_chip *chip,
 237                                    struct pwm_device *pwm)
 238 {
 239         struct twl_pwmled_chip *twl = to_twl(chip);
 240         int ret;
 241         u8 val;
 242
 243         mutex_lock(&twl->mutex);
 244         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 245         if (ret < 0) {
 246                 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
 247                         pwm->label);
 248                 goto out;
 249         }
 250
 251         val &= ~TWL6040_LED_MODE_MASK;
 252         val |= TWL6040_LED_MODE_OFF;
 253
 254         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 255         if (ret < 0)
 256                 dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
 257
 258 out:
 259         mutex_unlock(&twl->mutex);
 260 }
 261
 262 static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 263                                 const struct pwm_state *state)
 264 {
 265         int err;
 266
 267         if (state->polarity != pwm->state.polarity)
 268                 return -EINVAL;
 269
 270         if (!state->enabled) {
 271                 if (pwm->state.enabled)
 272                         twl6030_pwmled_disable(chip, pwm);
 273
 274                 return 0;
 275         }
 276
 277         err = twl6030_pwmled_config(chip, pwm,
 278                                     state->duty_cycle, state->period);
 279         if (err)
 280                 return err;
 281
 282         if (!pwm->state.enabled)
 283                 err = twl6030_pwmled_enable(chip, pwm);
 284
 285         return err;
 286 }
 287
 288 static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
 289 {
 290         struct twl_pwmled_chip *twl = to_twl(chip);
 291         int ret;
 292         u8 val;
 293
 294         mutex_lock(&twl->mutex);
 295         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 296         if (ret < 0) {
 297                 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
 298                         pwm->label);
 299                 goto out;
 300         }
 301
 302         val &= ~TWL6040_LED_MODE_MASK;
 303         val |= TWL6040_LED_MODE_OFF;
 304
 305         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 306         if (ret < 0)
 307                 dev_err(pwmchip_parent(chip), "%s: Failed to request PWM\n", pwm->label);
 308
 309 out:
 310         mutex_unlock(&twl->mutex);
 311         return ret;
 312 }
 313
 314 static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
 315 {
 316         struct twl_pwmled_chip *twl = to_twl(chip);
 317         int ret;
 318         u8 val;
 319
 320         mutex_lock(&twl->mutex);
 321         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 322         if (ret < 0) {
 323                 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
 324                         pwm->label);
 325                 goto out;
 326         }
 327
 328         val &= ~TWL6040_LED_MODE_MASK;
 329         val |= TWL6040_LED_MODE_HW;
 330
 331         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 332         if (ret < 0)
 333                 dev_err(pwmchip_parent(chip), "%s: Failed to free PWM\n", pwm->label);
 334
 335 out:
 336         mutex_unlock(&twl->mutex);
 337 }
 338
 339 static const struct pwm_ops twl6030_pwmled_ops = {
 340         .apply = twl6030_pwmled_apply,
 341         .request = twl6030_pwmled_request,
 342         .free = twl6030_pwmled_free,
 343 };
 344
 345 static int twl_pwmled_probe(struct platform_device *pdev)
 346 {
 347         struct pwm_chip *chip;
 348         struct twl_pwmled_chip *twl;
 349         unsigned int npwm;
 350         const struct pwm_ops *ops;
 351
 352         if (twl_class_is_4030()) {
 353                 ops = &twl4030_pwmled_ops;
 354                 npwm = 2;
 355         } else {
 356                 ops = &twl6030_pwmled_ops;
 357                 npwm = 1;
 358         }
 359
 360         chip = devm_pwmchip_alloc(&pdev->dev, npwm, sizeof(*twl));
 361         if (IS_ERR(chip))
 362                 return PTR_ERR(chip);
 363         twl = to_twl(chip);
 364
 365         chip->ops = ops;
 366
 367         mutex_init(&twl->mutex);
 368
 369         return devm_pwmchip_add(&pdev->dev, chip);
 370 }
 371
 372 #ifdef CONFIG_OF
 373 static const struct of_device_id twl_pwmled_of_match[] = {
 374         { .compatible = "ti,twl4030-pwmled" },
 375         { .compatible = "ti,twl6030-pwmled" },
 376         { },
 377 };
 378 MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
 379 #endif
 380
 381 static struct platform_driver twl_pwmled_driver = {
 382         .driver = {
 383                 .name = "twl-pwmled",
 384                 .of_match_table = of_match_ptr(twl_pwmled_of_match),
 385         },
 386         .probe = twl_pwmled_probe,
 387 };
 388 module_platform_driver(twl_pwmled_driver);
 389
 390 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 391 MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
 392 MODULE_ALIAS("platform:twl-pwmled");
 393 MODULE_LICENSE("GPL");