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"); 393