linux/drivers/pwm/pwm-twl-led.c
<<
>>
Prefs
   1/*
   2 * Driver for TWL4030/6030 Pulse Width Modulator used as LED driver
   3 *
   4 * Copyright (C) 2012 Texas Instruments
   5 * Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
   6 *
   7 * This driver is a complete rewrite of the former pwm-twl6030.c authorded by:
   8 * Hemanth V <hemanthv@ti.com>
   9 *
  10 * This program is free software; you can redistribute it and/or modify it
  11 * under the terms of the GNU General Public License version 2 as published by
  12 * the Free Software Foundation.
  13 *
  14 * This program is distributed in the hope that it will be useful, but WITHOUT
  15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  17 * more details.
  18 *
  19 * You should have received a copy of the GNU General Public License along with
  20 * this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23#include <linux/module.h>
  24#include <linux/of.h>
  25#include <linux/platform_device.h>
  26#include <linux/pwm.h>
  27#include <linux/i2c/twl.h>
  28#include <linux/slab.h>
  29
  30/*
  31 * This driver handles the PWM driven LED terminals of TWL4030 and TWL6030.
  32 * To generate the signal on TWL4030:
  33 *  - LEDA uses PWMA
  34 *  - LEDB uses PWMB
  35 * TWL6030 has one LED pin with dedicated LEDPWM
  36 */
  37
  38#define TWL4030_LED_MAX         0x7f
  39#define TWL6030_LED_MAX         0xff
  40
  41/* Registers, bits and macro for TWL4030 */
  42#define TWL4030_LEDEN_REG       0x00
  43#define TWL4030_PWMA_REG        0x01
  44
  45#define TWL4030_LEDXON          (1 << 0)
  46#define TWL4030_LEDXPWM         (1 << 4)
  47#define TWL4030_LED_PINS        (TWL4030_LEDXON | TWL4030_LEDXPWM)
  48#define TWL4030_LED_TOGGLE(led, x)      ((x) << (led))
  49
  50/* Register, bits and macro for TWL6030 */
  51#define TWL6030_LED_PWM_CTRL1   0xf4
  52#define TWL6030_LED_PWM_CTRL2   0xf5
  53
  54#define TWL6040_LED_MODE_HW     0x00
  55#define TWL6040_LED_MODE_ON     0x01
  56#define TWL6040_LED_MODE_OFF    0x02
  57#define TWL6040_LED_MODE_MASK   0x03
  58
  59struct twl_pwmled_chip {
  60        struct pwm_chip chip;
  61        struct mutex mutex;
  62};
  63
  64static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
  65{
  66        return container_of(chip, struct twl_pwmled_chip, chip);
  67}
  68
  69static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
  70                              int duty_ns, int period_ns)
  71{
  72        int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
  73        u8 pwm_config[2] = { 1, 0 };
  74        int base, ret;
  75
  76        /*
  77         * To configure the duty period:
  78         * On-cycle is set to 1 (the minimum allowed value)
  79         * The off time of 0 is not configurable, so the mapping is:
  80         * 0 -> off cycle = 2,
  81         * 1 -> off cycle = 2,
  82         * 2 -> off cycle = 3,
  83         * 126 - > off cycle 127,
  84         * 127 - > off cycle 1
  85         * When on cycle == off cycle the PWM will be always on
  86         */
  87        if (duty_cycle == 1)
  88                duty_cycle = 2;
  89        else if (duty_cycle > TWL4030_LED_MAX)
  90                duty_cycle = 1;
  91
  92        base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
  93
  94        pwm_config[1] = duty_cycle;
  95
  96        ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
  97        if (ret < 0)
  98                dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
  99
 100        return ret;
 101}
 102
 103static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 104{
 105        struct twl_pwmled_chip *twl = to_twl(chip);
 106        int ret;
 107        u8 val;
 108
 109        mutex_lock(&twl->mutex);
 110        ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
 111        if (ret < 0) {
 112                dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
 113                goto out;
 114        }
 115
 116        val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
 117
 118        ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
 119        if (ret < 0)
 120                dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
 121
 122out:
 123        mutex_unlock(&twl->mutex);
 124        return ret;
 125}
 126
 127static void twl4030_pwmled_disable(struct pwm_chip *chip,
 128                                   struct pwm_device *pwm)
 129{
 130        struct twl_pwmled_chip *twl = to_twl(chip);
 131        int ret;
 132        u8 val;
 133
 134        mutex_lock(&twl->mutex);
 135        ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
 136        if (ret < 0) {
 137                dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
 138                goto out;
 139        }
 140
 141        val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
 142
 143        ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
 144        if (ret < 0)
 145                dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
 146
 147out:
 148        mutex_unlock(&twl->mutex);
 149}
 150
 151static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
 152                              int duty_ns, int period_ns)
 153{
 154        int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
 155        u8 on_time;
 156        int ret;
 157
 158        on_time = duty_cycle & 0xff;
 159
 160        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
 161                               TWL6030_LED_PWM_CTRL1);
 162        if (ret < 0)
 163                dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
 164
 165        return ret;
 166}
 167
 168static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 169{
 170        struct twl_pwmled_chip *twl = to_twl(chip);
 171        int ret;
 172        u8 val;
 173
 174        mutex_lock(&twl->mutex);
 175        ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 176        if (ret < 0) {
 177                dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 178                        pwm->label);
 179                goto out;
 180        }
 181
 182        val &= ~TWL6040_LED_MODE_MASK;
 183        val |= TWL6040_LED_MODE_ON;
 184
 185        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 186        if (ret < 0)
 187                dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
 188
 189out:
 190        mutex_unlock(&twl->mutex);
 191        return ret;
 192}
 193
 194static void twl6030_pwmled_disable(struct pwm_chip *chip,
 195                                   struct pwm_device *pwm)
 196{
 197        struct twl_pwmled_chip *twl = to_twl(chip);
 198        int ret;
 199        u8 val;
 200
 201        mutex_lock(&twl->mutex);
 202        ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 203        if (ret < 0) {
 204                dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 205                        pwm->label);
 206                goto out;
 207        }
 208
 209        val &= ~TWL6040_LED_MODE_MASK;
 210        val |= TWL6040_LED_MODE_OFF;
 211
 212        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 213        if (ret < 0)
 214                dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
 215
 216out:
 217        mutex_unlock(&twl->mutex);
 218}
 219
 220static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
 221{
 222        struct twl_pwmled_chip *twl = to_twl(chip);
 223        int ret;
 224        u8 val;
 225
 226        mutex_lock(&twl->mutex);
 227        ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 228        if (ret < 0) {
 229                dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 230                        pwm->label);
 231                goto out;
 232        }
 233
 234        val &= ~TWL6040_LED_MODE_MASK;
 235        val |= TWL6040_LED_MODE_OFF;
 236
 237        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 238        if (ret < 0)
 239                dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
 240
 241out:
 242        mutex_unlock(&twl->mutex);
 243        return ret;
 244}
 245
 246static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
 247{
 248        struct twl_pwmled_chip *twl = to_twl(chip);
 249        int ret;
 250        u8 val;
 251
 252        mutex_lock(&twl->mutex);
 253        ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
 254        if (ret < 0) {
 255                dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
 256                        pwm->label);
 257                goto out;
 258        }
 259
 260        val &= ~TWL6040_LED_MODE_MASK;
 261        val |= TWL6040_LED_MODE_HW;
 262
 263        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
 264        if (ret < 0)
 265                dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
 266
 267out:
 268        mutex_unlock(&twl->mutex);
 269}
 270
 271static const struct pwm_ops twl4030_pwmled_ops = {
 272        .enable = twl4030_pwmled_enable,
 273        .disable = twl4030_pwmled_disable,
 274        .config = twl4030_pwmled_config,
 275        .owner = THIS_MODULE,
 276};
 277
 278static const struct pwm_ops twl6030_pwmled_ops = {
 279        .enable = twl6030_pwmled_enable,
 280        .disable = twl6030_pwmled_disable,
 281        .config = twl6030_pwmled_config,
 282        .request = twl6030_pwmled_request,
 283        .free = twl6030_pwmled_free,
 284        .owner = THIS_MODULE,
 285};
 286
 287static int twl_pwmled_probe(struct platform_device *pdev)
 288{
 289        struct twl_pwmled_chip *twl;
 290        int ret;
 291
 292        twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
 293        if (!twl)
 294                return -ENOMEM;
 295
 296        if (twl_class_is_4030()) {
 297                twl->chip.ops = &twl4030_pwmled_ops;
 298                twl->chip.npwm = 2;
 299        } else {
 300                twl->chip.ops = &twl6030_pwmled_ops;
 301                twl->chip.npwm = 1;
 302        }
 303
 304        twl->chip.dev = &pdev->dev;
 305        twl->chip.base = -1;
 306        twl->chip.can_sleep = true;
 307
 308        mutex_init(&twl->mutex);
 309
 310        ret = pwmchip_add(&twl->chip);
 311        if (ret < 0)
 312                return ret;
 313
 314        platform_set_drvdata(pdev, twl);
 315
 316        return 0;
 317}
 318
 319static int twl_pwmled_remove(struct platform_device *pdev)
 320{
 321        struct twl_pwmled_chip *twl = platform_get_drvdata(pdev);
 322
 323        return pwmchip_remove(&twl->chip);
 324}
 325
 326#ifdef CONFIG_OF
 327static const struct of_device_id twl_pwmled_of_match[] = {
 328        { .compatible = "ti,twl4030-pwmled" },
 329        { .compatible = "ti,twl6030-pwmled" },
 330        { },
 331};
 332MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
 333#endif
 334
 335static struct platform_driver twl_pwmled_driver = {
 336        .driver = {
 337                .name = "twl-pwmled",
 338                .of_match_table = of_match_ptr(twl_pwmled_of_match),
 339        },
 340        .probe = twl_pwmled_probe,
 341        .remove = twl_pwmled_remove,
 342};
 343module_platform_driver(twl_pwmled_driver);
 344
 345MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 346MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
 347MODULE_ALIAS("platform:twl-pwmled");
 348MODULE_LICENSE("GPL");
 349