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"); 391